439 research outputs found
DPD Linearization Complexity Reduction of Remote Radio Heads in C-RAN with Radio over Fiber Fronthaul
Radio-over-Fiber (RoF) is a suitable technology for efficiently developing the cloud-RAN concept in Fifth Generation (5G) deployments based on Long Term Evolution Advanced LTE-A. Distortion coming out from the radiofrequency (RF) power amplifier should be taken into account in order to achieve the desired performance at the base station. In this paper, a complexity reduction technique based on a variable degree polynomial predistorter is proposed. The obtained results show that it is possible to achieve a reduction of operations with a penalty of 1.6 dB in ACLR and negligible impact on the EVM
Effect of invader removal: pollinators stay but some native plants miss their new friend
Removal of invasive species often benefits
biological diversity allowing ecosystems’ recovery.
However, it is important to assess the functional roles
that invaders may have established in their new areas
to avoid unexpected results from species elimination.
Invasive animal-pollinated plants may affect the
plant–pollination interactions by changing pollinator
availability and/or behaviour in the community. Thus,
removal of an invasive plant may have important
effects on pollinator community that may then be
reflected positive or negatively on the reproductive
success of native plants. The objective of this study
was to assess the effect of removing Oxalis pescaprae,
an invasive weed widely spread in the
Mediterranean basin, on plant–pollinator interactions
and on the reproductive success of co-flowering native
plants. For this, a disturbed area in central Portugal,
where this species is highly abundant, was selected.
Visitation rates, natural pollen loads, pollen tube
growth and natural fruit set of native plants were
compared in the presence of O. pes-caprae and after
manual removal of their flowers. Our results showed a
highly resilient pollination network but also revealed
some facilitative effects of O. pes-caprae on the
reproductive success of co-flowering native plants.
Reproductive success of the native plants seems to
depend not only on the number and diversity of floral
visitors, but also on their efficiency as pollinators. The
information provided on the effects of invasive species
on the sexual reproductive success of natives is
essential for adequate management of invaded areas.This work is financed by FEDER funds through the
COMPETE Program and by Portuguese Foundation for Science
and Technology (FCT) funds in the ambit of the project PTDC/
BIA-BIC/110824/2009, by CRUP Acc¸o˜es Integradas Luso-
Espanholas 2010 with the project E10/10, by MCI-Programa de
Internacionalizacio´n de la I ? D (PT2009-0068) and by the
Spanish DGICYT (CGL2009-10466), FEDER funds from the
European Union, and the Xunta de Galicia (INCITE09-
3103009PR). FCT also supported the work of S. Castro (FCT/
BPD/41200/2007) and J. Costa (CB/C05/2009/209; PTDC/
BIA-BIC/110824/2009). The work of V. Ferrero was supported
by the Fundacio´n Ramo´n Areces
Parásitos de peces nativos de la cuenca del Río Laja (Chile Central) y alcances sobre sus ciclos de vida
The parasites from three species of native freshwater fishes, Trichomycterusareolatus, Diplomystes nahuelbutaensis and Percilia irwini, common from Central Chile were studied. These parasites are interesting because they could infect farmed salmon. Fishes were caught from an Andean watershed (37º20S; 72º56W) and examined in laboratory for parasites. A camera placed on a stereomicroscope and microscope were used for the photographs and observations. The specimens were later fixed in formalin at 5% or ethanol at 70%. The prevalence and intensity of seven parasites taxa were recorded: Mixobolus sp., Henneguyasp., Ancrynocephalidae (Monogenea), Zoogonidae (Digenea), Steganodermata sp (Zoogonidae), Nematoda and Pomphorhynchus sp. (Acanthocephala). P. irwini harbours the most diverse and rich parasite assemblage with 4 species, followed by T. areolatus with 3 taxa. D. nahuelbutaensis have only one parasite species but with high prevalence levels (89%). The life cycle of these parasites, the possible new host-parasite association and its consequences are discussed.Considerando que en Chile los estudios parasitológicos en peces de agua dulce son escasos, es relevante reconocer las especies de parásitos presentes en las poblaciones de peces nativos como reservorios o potenciales infecciones para especies de importancia comercial. Esto permite indagar sobre los posibles hospedadores que participan de los ciclos de vida de los parásitos encontrados y elaborar estrategias de mitigación para las parasitosis potencialmente importantes, con una adecuada anticipación. En este contexto se estudió la parasitofauna de tres especies de peces de agua dulce nativos, Trichomycterus areolatus, Diplomystes nahuelbutaensis y Percilia irwini en una cuenca andina de Chile Central. Los peces fueron capturados en la parte media de la cuenca del río Laja (37º20’S; 72º56’O) y examinados en laboratorio. En la muestra total de peces examinados se registró la presencia de Mixobolus sp, Henneguya sp, Ancyrocephalidae (Monogenea), Zoogonidae (Digenea), Steganodermata sp (Zoogonidae), Nematoda y Pomphorhynchus sp (Acantocephala). P. irwini presentó la mayor riqueza específica de parásitos con 4 de los taxa encontrados, al que le sigue T. areolatus con 3 taxa. D. nahuelbutaensis con un solo taxón parasitario presenta altos valores de prevalencia con un 89% de los individuos parasitados. Se discute el ciclo de vida general para los taxa parásitos encontrados y su eventual relación con peces de importancia económica.
 
Brief Intervention in Type 1 diabetes – Education for Self-efficacy (BITES): Protocol for a randomised control trial to assess biophysical and psychological effectiveness
An update of the Worldwide Integrated Assessment (WIA) on systemic insecticides. Part 2: impacts on organisms and ecosystems
New information on the lethal and sublethal effects of neonicotinoids and fipronil on organisms is presented in this review, complementing the previous WIA in 2015. The high toxicity of these systemic insecticides to invertebrates has been confirmed and expanded to include more species and compounds. Most of the recent research has focused on bees and the sublethal and ecological impacts these insecticides have on pollinators. Toxic effects on other invertebrate taxa also covered predatory and parasitoid natural enemies and aquatic arthropods. Little, while not much new information has been gathered on soil organisms. The impact on marine coastal ecosystems is still largely uncharted. The chronic lethality of neonicotinoids to insects and crustaceans, and the strengthened evidence that these chemicals also impair the immune system and reproduction, highlights the dangers of this particular insecticidal classneonicotinoids and fipronil. , withContinued large scale – mostly prophylactic – use of these persistent organochlorine pesticides has the potential to greatly decreasecompletely eliminate populations of arthropods in both terrestrial and aquatic environments. Sublethal effects on fish, reptiles, frogs, birds and mammals are also reported, showing a better understanding of the mechanisms of toxicity of these insecticides in vertebrates, and their deleterious impacts on growth, reproduction and neurobehaviour of most of the species tested. This review concludes with a summary of impacts on the ecosystem services and functioning, particularly on pollination, soil biota and aquatic invertebrate communities, thus reinforcing the previous WIA conclusions (van der Sluijs et al. 2015)
In vivo cell tracking with 52Mn PET: Targetry, Separation, and Applications
Introduction
52Mn (t½ =5.59 d, β+ = 29.6%, Eβmax = 0.58 MeV) has great potential as a long lived PET isotope for use in cell tracking studies, observation of immunologic response to disease states, or as an alternative to manganese-based MRI contrast agents. Its favorable max positron energy leads to superb imaging resolution, comparable to that of 18F.[1]
Manganese is naturally taken up by cells via a multitude of pathways including the divalent metal transporter (DMT1), ZIP8, transferrin receptors (TfR), store-operated Ca2+ channels (SOC-Ca2+), and ionotropic glutamate receptor Ca2+ channels (GluR).[2] These natural transport mechanisms make 52Mn an attractive isotope for applications necessitating non-perturbative cell uptake. In particular, cell tracking is critical to the development and translation of stem cell therapies in regenerative medicine. Alternative-ly, 52Mn could be used in immunotherapy techniques such as adoptive cellular therapy (ACT) to evaluate the ability of external immune cells to reach their intended target.
Material and Methods
52Mn was produced by natCr(p,x)52Mn using 16 MeV protons. The average thick target production yield was 0.23 mCi/µA-h with less than 0.25% co-production of 54Mn. Small amounts of 51Cr were observed in the target, but were absent from the radiochemically separated product.
Target construction consisted of a water jet cooled chromium disc (3/4” diameter, 0.4” thick). Targets were purchased from Kamis Inc, and are 99.95% pure. Targets withstood beam currents of 30 µA with no visible aberration.
Chromium targets were etched by concentrated HCl following bombardment. Mn2+ ions were extracted from 9M HCl to 0.8M trioctylamine in cyclohexane leaving the bulk chromium in the aqueous phase. After isolating the organic phase, 0.001M NH4OH was used to back-extract the Mn2+ ions to aqueous phase. This purification cycle was conducted a total of three times for each 52Mn production.
Results and Conclusion
For a starting bulk chromium mass of 456 ± 1 mg, a post-separation chromium mass of 5.35 ± 0.04 ng was measured by microwave plasma atomic emission spectrometry (MP-AES). This mass reduction corresponds to an average separation factor of 440 for a single purification cycle. Each purification cycle had a 52Mn recovery efficiency of 73 ± 7 % (n = 6), resulting in an overall separation efficiency of approximately 35 %. These efficiencies and separation factors agree reasonably well with the work conducted by Lahiri et. al.[3] Prior to use, the product was passed through a C-18 Sep-Pak to remove any residual organic phase.
After four target irradiations and etchings, some pitting became noticeable on the target face. These have not yet compromised the o-ring seal with the target deplater, but it is possible that target replacement after every 6–9 52Mn productions will be necessary moving forward.
Following the successful separation of 52Mn from chromium, in vitro experiments were conducted to demonstrate the uptake of 52Mn by human stem cells and mouse tumor cells. A linear uptake response was observed as a function of the amount of activity exposed to the cells for both cell models. These experiments have shown great promise for 52Mn as a long-lived PET isotope in cell tracking studies. Details will be presented
Donovanosis en mujeres indígenas
La donovanosis es una rara infección causada por la bacteriaCalymmatobacteriumgranulomatisque produce importantes lesiones ulcero-granulomatosas, preferentemente en la zonaanogenital.Considerada como enfermedad de trasmisión sexual, no es ésta la única vía detrasmisión, siendo también importantes las condiciones higiénicas, socioeconómicas y ambientalesen su etiopatogenia.Afecta áreas tropicales de varios continentes, incluido el americano, donde hayseries descriptas en varios países. En el Paraguay ha sido poco reportada, por lo que esta serie decuatro pacientes mujeres, jóvenes, indígenas de varias parcialidades, con lesiones exuberantes enzona anogenital, de larga evolución, tres de ellas embarazadas y dos con extensión a órganosinternos, es importante. El objetivo de este trabajo es llamar la atención sobre un problema de granmorbilidad y que exige mejorar la cobertura de salud y condiciones de vida de estas comunidadesindígenas
A Network Perspective for Community Assembly
Species interactions are responsible for many key mechanisms that govern the dynamics of ecological communities. Variation in the way interactions are organized among species results in different network structures, which translates into a community's ability to resist collapse and change. To better understand the factors involved in dictating ongoing dynamics in a community at a given time, we must unravel how interactions affect the assembly process. Here, we build a novel, integrative conceptual model for understanding how ecological communities assemble that combines ecological networks and island biogeography theory, as well as the principles of niche theory. Through our conceptual model, we show how the rate of species turnover and gene flow within communities will influence the structure of ecological networks. We conduct a preliminary test of our predictions using plant-herbivore networks from differently-aged sites in the Hawaiian archipelago. Our approach will allow future modeling and empirical studies to develop a better understanding of the role of the assembly process in shaping patterns of biodiversity
Aplicación del bioensayo EROD-H4IIE para la determinación de dioxinas en carnes de pollos broiler: un estudio de equivalencia con la cromatografía de gases de alta resolución acoplada a espectrometría de masas de alta resolución
The EROD bioassay with H4IIE cell line was applied in this study to determine the equivalence of the results for chicken meat between the EROD-H4IIE Bioassay in pg TCDD-EQ/g of tissue, and the results of the gas chromatography coupled to high resolution spectrometry (HRGC/HRMS) in pg WHO-TEQ/g of fat of TEQs. 41 compound samples of chicken drumsticks were used. The samples were obtained in slaughtering plants of 4 different production facilities of Chile, during the sacrifice of animals (38 and 43 days old) between 2004 and 2007. Each sample was analysed with both analytical techniques. A regression model for the equivalence of both techniques was determined from the results. The model obtained was: HRGC/ HRMS = 0.481 + 0.051[EROD-H4IIE]2, R2 = 0.885, therefore for a value in EROD-H4IIE of 2.2 pg TCDD-EQ/g of tissue it is estimated that it will correspond to 0.73 pg WHO-TEQ/g of fat in HRGC/HRMS. Also, for the same value of EROD-H4IIE with a 95% confidence, an estimate as an upper limit equal to 0.83 pg WHO-TEQ/g of fat in HRGC/HRMS will be obtained. An upper limit equal to 0.88 pg WHO-TEQ/g of fat in HRGC/HRMS is estimated by taking the same value of EROD-H4IIE with 99% confidence. It is concluded that de EROD-H4IIE bioassay can be applied as a screening method in animal production systems and specifically in broiler chicken production.
En el presente estudio se aplicó el bioensayo EROD con línea celular H4IIE para determinar la equivalencia de resultados para carnes de pollo, entre el bioensayo EROD-H4IIE en pg TCDD-EQ/g de tejido y los resultados de la cromatografía de gases de alta resolución acoplada a espectrometría de alta resolución (HRGC/HRMS) en pg WHO-TEQ/g de grasa. Para lo anterior se utilizaron 41 muestras compuestas de trutros de pollo. Éstas fueron obtenidas en la planta faenadora de 4 planteles diferentes de Chile, durante el beneficio de animales (38 y 43 días de edad) entre los años 2004 y 2007. Cada muestra fue analizada mediante ambas técnicas analíticas. Con los resultados se determinó un modelo de regresión para la equivalencia de ambas técnicas. De esta forma el modelo obtenido fue: HRGC/HRMS = 0,481 + 0,051[EROD-H4IIE]2, R2 = 0,885, en que para un valor en EROD-H4IIE de 2,2 pg TCDD-EQ/g de tejido se estima que corresponderá a 0,73 pg WHO-TEQ/g de grasa en HRGC/HRMS. Además, para el mismo valor de EROD-H4IIE con un 95% de confianza, se obtendrá una estimación como límite superior que equivaldrá a 0,83 pg WHO-TEQ/g de grasa en HRGC/HRMS. Al tomar el mismo valor de EROD-H4IIE con un 99% de confianza, se estima un límite superior que equivaldrá a 0,88 pg WHO-TEQ/g de grasa en HRGC/HRMS. De esta manera se concluye que el bioensayo EROD-H4IIE puede ser aplicado como método de cribado en sistemas de producción animal y específicamente en producción de pollos broiler.
 
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