Cyclic expression of the voltage-gated potassium channel Kν10.1 promotes disassembly of the primary cilium

The primary cilium, critical for morphogenic and growth factor signaling, is assembled upon cell cycle exit, but the links between ciliogenesis and cell cycle progression are unclear. KV10.1 is a voltage‐gated potassium channel frequently overexpressed in tumors. We have previously reported that expression of KV10.1 is temporally restricted to a time period immediately prior to mitosis in healthy cells. Here, we provide microscopical and biochemical evidence that KV10.1 localizes to the centrosome and the primary cilium and promotes ciliary disassembly. Interference with KV10.1 ciliary localization abolishes not only the effects on ciliary disassembly, but also KV10.1‐induced tumor progression in vivo. Conversely, upon knockdown of KV10.1, ciliary disassembly is impaired, proliferation is delayed, and proliferating cells show prominent primary cilia. Thus, modulation of ciliogenesis by KV10.1 can explain the influence of KV10.1 expression on the proliferation of normal cells and is likely to be a major mechanism underlying its tumorigenic effects.EMBO Reports (2016) 17: 708–72

Convergencia y matices de la neutralidad en la red en América del Sur

The Internet has become the ultimate platform for convergence, closely associated with network, technology, and media, due to its open and nondiscriminatory architecture. Convergence in telecommunications is propelled by ideas, ideologies, and policies progressively and cyclically, bringing further technological advancement, market, business, and policy changes. As a response to convergence, net neutrality seeks to regulate the relationship between Internet service providers and users to avoid discriminatory practices and ensure the openness of the Internet as a platform for innovation, economic development, and access to information for all. The objective of this work is to analyze the development of convergence in the telecommunications sector and the progress of net neutrality policies in South America, with five specific cases using a qualitative empirical approach. Within the findings, we identify different approaches for legislating net neutrality, controversies concerning the levels of commitment to the principles, ambiguity for effective enforcement of the rules, and commercial arrangements that in practice violate net neutrality.El Internet se ha convertido en la plataforma definitiva para la convergencia, estrechamente asociada con las redes, la tecnología y los medios, debido a su arquitectura abierta y no discriminatoria. La convergencia en las telecomunicaciones es impulsada por ideas, ideologías y políticas de manera progresiva y cíclica, lo que genera más avances tecnológicos, cambios en el mercado, los negocios y las políticas. Como respuesta a la convergencia, la neutralidad en la red busca regular la relación entre los proveedores de servicios de Internet y los usuarios para evitar prácticas discriminatorias y asegurar un Internet abierto como plataforma de innovación, desarrollo económico y acceso a la información para todos. El objetivo de este trabajo es analizar el desarrollo de la convergencia en el sector de las telecomunicaciones y el avance de las políticas de neutralidad en la red en América del Sur, con cinco casos específicos utilizando un enfoque empírico cualitativo. Dentro de los hallazgos, se identifican diferentes enfoques para legislar la neutralidad en la red, controversias sobre los niveles de compromiso con los principios, ambigüedad para la aplicación efectiva de las reglas y acuerdos comerciales que en la práctica violan la neutralidad de la red

Climate change communication in Colombia

This is the author accepted manuscript. The final version is available from Oxford University Press via the DOI in this record.Peru is one of the most biodiverse countries on the planet. More than 65% of the country is covered by the Amazon rainforest, and the Andes region is home to more than 70% of the world’s tropical glaciers. This abundance of natural resources also makes the country highly vulnerable to the effects of climate change. The Peruvian government therefore requires the development and implementation of action plans to adapt to the present and future impacts of climate change. At the same time, it requires the development of sound communication strategies that include collaboration with stakeholders such as the media and nongovernmental organizations. Media coverage of climate change can have important implications for policy decision making. This is especially salient in a context of low information availability where media reports play an important role in filling knowledge gaps that in turn can affect the way policies are developed. Climate change, as an environmental and social issue in Peru, is not highly politicized, as it is in countries such as the United States and Australia. There is no major debate about the reality of climate change, the scientific evidence, or the need for political action and technological and policy innovations. This approach is also reflected in the media’s coverage of the issue. Peru’s media tend to focus on climate change mostly during key policy events. Among these major events was the capital city of Lima’s hosting in 2010 of the V meeting of Latin American, Caribbean, and European Union countries, where the main topics of discussion were climate change and poverty. In addition, Lima hosted the COP20, which preceded the Paris meeting in 2015 that led to a major global agreement. The media’s coverage of these events was intense. These were the exceptions: A good proportion of Peru’s newspaper coverage comes from international news wire agencies. Coverage from those sources focuses mostly on mitigation actions, instead of adaptation, which is more relevant to vulnerable countries such as Peru. This coverage is in line with the government’s view of mitigation as a business opportunity. There is, however, a lack of studies that explore, first, the factors that affect this coverage, and, second, the way other mediums such as television or radio cover the issue. Strategic communication by governmental organizations, as well as accurate and fact-based media reporting about climate change, is necessary to better communicate the urgency and magnitude of the problem to the general public, grassroots organizations, industry, and international agencies, among others

Potassium channels in cell cycle and cell proliferation

Normal cell-cycle progression is a crucial task for every multicellular organism, as it determines body size and shape, tissue renewal and senescence, and is also crucial for reproduction. On the other hand, dysregulation of the cell-cycle progression leading to uncontrolled cell proliferation is the hallmark of cancer. Therefore, it is not surprising that it is a tightly regulated process, with multifaceted and very complex control mechanisms. It is now well established that one of those mechanisms relies on ion channels, and in many cases specifically on potassium channels. Here, we summarize the possible mechanisms underlying the importance of potassium channels in cell-cycle control and briefly review some of the identified channels that illustrate the multiple ways in which this group of proteins can influence cell proliferation and modulate cell-cycle progression

New Insights From Pre-Columbian Land Use and Fire Management in Amazonian Dark Earth Forests

This is the final version of the article. Available from Frontiers Media via the DOI in this record.Anthropogenic climate change driven by increased carbon emissions is leading to more severe fire seasons and increasing the frequency of mega-fires in the Amazon. This has the potential to convert Amazon forests from net carbon sinks to net carbon sources. Although modern human influence over the Earth is substantial, debate remains over when humans began to dominate Earth's natural systems. To date, little is known about the history of human land use in key regions like the Amazon. Here, we examine the history of human occupation from a ~8,500 year-old sediment core record from Lake Caranã (LC) in the eastern Amazon. The onset of pre-Columbian activity at LC (~4,500 cal yr B.P.) is associated with the beginning of fire management and crop cultivation, later followed by the formation of Amazonian Dark Earth soils (ADEs) ~2,000 cal yr B.P. Selective forest enrichment of edible plants and low-severity fire activity altered the composition and structure of forests growing on ADEs (ADE forests) making them more drought susceptible and fire-prone. Following European colonization (1661 A.D.), the Amazon rubber boom (mid-1800s to 1920 A.D.) is associated with record-low fire activity despite drier regional climate, indicating fire exclusion. The formation of FLONA Reserve in 1974 A.D. is accompanied by the relocation of traditional populations and a fire suppression policy. Despite suppression efforts, biomass burning and fire severity in the past decade is higher than any other period in the record. This is attributed to combined climate and human factors which create optimal conditions for mega-fires in ADE forests and threatens to transform the Amazon from a net carbon sink to a net carbon source. To help mitigate the occurrence of mega-fires, a fire management policy reducing fire-use and careful fire management for farming may help to reduce fuel loads and the occurrence of mega-fires in fire-prone ADE forests. As both natural and anthropogenic pressures are projected to increase in the Amazon, this study provides valuable insights into the legacy of past human land use on modern ADE forest composition, structure, and flammability that can inform ecological benchmarks and future management efforts in the eastern Amazon.Funding for this research was supported by the PAST (Pre-Columbian Amazon-Scale Transformations) European Research Council Consolidator Grant to JI (ERC_Cog 616179). Research was conducted under permit 01506.004836/2014-69 from the Instituto do Patrimônio Histórico e Artístico Nacional (IPHAN) and ICMBio permit 106/14-FNT. We thank all residents of Maguarí and Jamaraquá community for their hospitality and help

Effect of Lubricant-Refrigerant Mixture Properties on Compressor Efficiencies

Lubricants are utilized on compressors to lower friction thus increasing efficiency while decreasing wear and increase longevity. While pure lubricant properties are commonly cited in literature due to more readily available property data, far more meaningful results are obtained when lubricant-refrigerant mixture properties are utilized. The most critical of these properties are the vapor-liquid equilibrium data, which relates temperatures, pressures, and concentrations, to other intensive properties such as density and viscosity. To determine the impact of fundamental refrigerant-lubricant mixture properties on compressor performance, a series of lubricants having known mixture properties where utilized in a semi-hermetic transcritical carbon dioxide compressor. This compressor was installed in a calorimeter which allowed compressor electrical power consumption to be accurately measured. Likewise, refrigerant temperatures, pressures, and mass flows were measured. As this calorimeter utilized the full refrigeration cycle with both a gas-cooler and evaporator, it was possible to accurately determine the oil circulation ratio (OCR) via the sample based method given by ASHRAE Standard 41.4. The compressor was operated at a series of suction and discharge pressures and temperatures which were near the edge of the operating envelop. Combining the property information with experimental data from the calorimeter experiments allow for analysis of the impact of refrigerant-lubricant mixture properties on compressor efficiencies. Due to the relatively small changes in performance, it was necessary to properly account for the presence of lubricant in the definitions of isentropic and volumetric efficiencies. After accounting for these properties, multivariate least square curve fitting was utilized to understand the relative impact of mixture properties and OCR on compressor efficiency. The analysis is furthered to show the impact of compressor efficiency on system performance for the purpose of pointing towards selecting lubricants to minimize energy consumption

Effects of Refrigerant-Lubricant Combinations on the Energy Efficiency of a Convertible Split-System Residential Air-Conditioner

Polyol ester (POE) lubricants of different viscosity ISO grades (32-80) and possessing distinctly different compatibilities (miscible vs. immiscible) were tested with R-410A, R-32, and L-41b. For each refrigerant-lubricant pair tested, the cooling coefficient of performance (COP), heating performance factor (HPF), and oil circulation ratio (OCR) were determined while operating at AHRI Standard 210/240 conditions A, B, C, H1 & H2. The results were correlated to the properties of the working fluids. Due to its higher density, yet comparable specific heat, R-32 showed increased cooling capacity compared to R-410A. However, the COPs of these refrigerants were similar because the capacity increase was offset by increased compressor power consumption. L-41b required the least compressor power, but also had the lowest cooling capacity and COP of the three refrigerants. Lubricant choice had minimal impact on cooling capacity. However, immiscible lubricants lowered cooling capacity by about 4% for R-32, condition B. A larger effect was observed in the compressor, where lubricants specifically designed for R-32 lowered discharge temperatures by 6 °C and reduced power consumption by up to 10%. For R-32-lubricant pairs tested under AHRI cooling condition B, the highest and lowest COPs measured were 4.19 (optimized ISO 68 POE) and 3.72 (commercial ISO 32 POE) ? a 12% improvement by replacing the standard R-410A lubricant

Refrigerant and Lubricant Mass Distribution in a Convertible Split System Residential Air-Conditioner

Lubricants are utilized in air-conditioning systems for the purpose of decreasing friction and wear within the compressor. While ideally the lubricant remains in the compressor, some lubricant is entrained and transported by the refrigerant to the other system components. During operational transients, the lubricant is redistributed throughout the various system components. The equilibrium distribution of lubricant depends among other things on fluid properties, phase change processes, flow rates, geometries, and operating conditions. Experiments were conducted in a commercially available, split-system, residential, air-conditioning system with a nominal 3-ton capacity that could be operated both as an air-conditioner and a heat-pump. While the system was designed to operate with R410A, most of the testing was conducted with pure R32, which is a leading candidate for R410A replacement pending regulatory discontinuation of its other constituent: R125. The lubricants used in this study were traditional and advanced polyol ester lubricants. Advanced polyol ester lubricants promise to improve lubricity and wear protection compared to current lubricants. The lubricants had nominal viscosities ranging from 32 to 80 cSt. To inventory the distribution of refrigerant and lubricant, the system was modified by the installation of ball valves which could be utilized to separate the system into its constituents: compressor, condenser, liquid line, evaporator, suction line, and accumulator. The system was brought to equilibrium at conditions A, B, C, H1, and H2 which are defined in AHRI Standard 210/240. After maintaining equilibrium, simultaneously the compressor being shut off and the ball valves were closed which isolated refrigerant and lubricant within each component. The components were subsequently removed and weighed in a manner which allowed the mass of refrigerant and lubricant in each component to be determined. Analysis of the results focuses on the change in mass distribution due to refrigerant-lubricant mixture properties and due to changes in operating conditions. The implications of the net migration of lubricant from the compressor to the remainder of the system will also be discussed

Modern pollen-vegetation relationships along a steep temperature gradient in the Tropical Andes of Ecuador

This is the author accepted manuscript. The final version is available from Cambridge University Press via the DOI in this record.The characterization of modern pollen rain assemblages along environmental gradients is an essential prerequisite for reliable interpretations of fossil pollen records. In this study, we identify pollen-vegetation relationships using modern pollen rain assemblages in moss polsters (n = 13) and lake sediment surface samples (n = 11) along a steep temperature gradient of 7°C (3100–4200 m above sea level) on the western Andean Cordillera, Ecuador. The pollen rain is correlated to vascular plant abundance data recorded in vegetation relevées (n = 13). Results show that pollen spectra from both moss polsters and sediment surface samples reflect changes in species composition along the temperature gradient, despite overrepresentation of upper montane forest taxa in the latter. Estimated pollen transport distance for a lake (Laguna Llaviucu) situated in a steep upper montane forest valley is 1–2 km, while a lake (Laguna Pallcacocha) in the páramo captures pollen input from a distance of up to 10–40 km. Weinmannia spp., Podocarpus spp., and Hedyosmum sp. are indicators of local upper montane forest vegetation, while Phlegmariurus spp. and Plantago spp. are indicators for local páramo vegetation.Earth and Life Science council (ALW) of the Netherlands Organisation of Scientific Researc

The timing and ecological consequences of Pleistocene megafaunal decline in the eastern Andes of Colombia (article)

This is the final version. Available on open access from Cambridge University Press via the DOI in this recordData availability: The data supporting this publication are openly available from the NERC Data repository or can be accessed by contacting the corresponding author(s).Examining the ecological consequences of the late Quaternary megafaunal extinctions within biodiversity hotspots is crucial for our understanding of the potential consequences of contemporary extinctions. We present the first multi-species record of spores of coprophilous fungi (SCF) from Monquentiva and the high-Andean forests of Colombia to reconstruct Late Pleistocene and Holocene megafaunal abundance. Fossilised pollen and charcoal are used to examine the consequences of megafaunal declines on the surrounding vegetation and fire activity. Our SCF record indicates the presence of Pleistocene megafauna at least since 30,290 BP, with two waves of megafaunal decline at ca. 22,900 BP and 10,990 BP. At Monquentiva, megafaunal decline in the Early Holocene resulted in transitional non-analogue vegetation, loss of some herbivore-dispersed plant taxa, an encroachment of palatable and woody flora, and a rise in fire activity. Differences with other published South-American records suggest that ecological consequences of megafaunal declines were habitat-specific. Overall, we show that ecosystems in the eastern Colombian Cordillera were highly sensitive to the decline of megafaunal populations. Under the current biodiversity crisis, management and conservation efforts must account for the effects of local herbivore declines on plant dispersal, on fire activity, and the potential loss of ecosystem services.Natural Environment Research Council (NERC)Arts and Humanities Research Council (AHRC