6,516 research outputs found
Trends in High Nature Value farmland studies: A systematic review
Background. Since the High Nature Value (HNV) concept was defined in the early 1990s, several studies on HNV farmland has been increasing over the past 30 years in Europe, highlighting the interest by scientific community of HNV farming systems supporting biodiversity conservation. The aim of this study was to evaluate the trends and main gaps on HNV farmland peer-reviewed publications in order to contribute to the effectiveness of future research in this field. Methods. Searches were conducted using the databases Web of SciencesTM and Scopus in order to identify only peer-reviewed articles on HNV farmland, published prior to July 2017. The inclusion and exclusion criteria were developed a priori. Data as year, country, type of document, subject area, taxa studied and biodiversity metrics assessed were extracted and explored in order to analyse the spatial and temporal distribution of the concept, including the main topics addressed in HNV farmland literature. Results. After screening 308 original articles, 90 were selected for this review. HNV farmland studies involved several disciplines, mainly biodiversity and conservation and environmental sciences and ecology. Most peer-reviewed articles focused on HNV farming were conducted in Spain, Italy, Ireland and Portugal. The main studied taxa were plants and birds. Taxonomic diversity was the biodiversity metric more often used to assess the biodiversity status on HNV farmland areas. A positive correlation was found between HNV farmland area and HNV farmland studies conducted in respective countries. Discussion. The HNV farmland research subject is a relative novel approach, and this systematic review provides a comprehensive overview about the main topics in the HNV farmland peer-reviewed literature contributing to highlight the main gaps and provide some considerations in order to assist the performance of HNV farming systems and conservation policies, addressed to sustain high levels of biodiversity
Metriorhynchidae (Crocodylomorpha: Thalattosuchia) del jurásico superior–cretácico inferior de la Cuenca Neuquina (Argentina), con comentarios sobre los moldes naturales del encéfalo
Los Metriorhynchidae fueron los únicos Crocodylomorpha con un estilo de vida marino pelágico. Relacionado con este estilo de vida, su peculiar plan corporal permite diferenciarlos claramente de los demás Crocodylomorpha. El registro fósil de los metriorrínquidos titonienses–berriasienses de la Formación Vaca Muerta (Cuenca Neuquina, Argentina) es excepcional, tanto en términos cuantitativos como cualitativos. Su diversidad taxonómica está compuesta por cuatro taxones: Cricosaurus araucanensis, Cricosaurus lithographicus, Dakosaurus andiniensis y Purranisaurus potens. Este registro fósil también se caracteriza por la preservación tridimensional de los materiales y por la preservación de numerosos moldes naturales de las cavidades del cráneo. En este trabajo se presenta una descripción de los moldes naturales del encéfalo de Cricosaurus araucanensis junto con una síntesis de los avances en el conocimiento realizados, en los últimos años, sobre estos cuatro taxones argentinos. La calidad de la información que aporta los moldes naturales, sumado a la cantidad de moldes recuperados, hacen del registro patagónico una pieza clave para la exploración y reconstrucción de la anatomía blanda de estos crocodilomorfos, y para la comprensión de los cambios fisiológicos que acompañaron los cambios estructurales del esqueleto. La comprensión de estos cambios permitirá delimitar las innovaciones evolutivas claves que le permitieron a los metriorrínquidos la conquista, sin paralelo entre los arcosaurios, del medio pelágico.Metriorhynchidae was the only Crocodylomorpha with a pelagic marine lifestyle. Related to this lifestyle, its peculiar body plan al- lows clearly differentiate them from others Crocodylomorpha. The fossil record of metriorhynchids from Tithonian–Berriasian levels of the Vaca Muerta Formation (Neuquén Basin, Argentina) is outstanding, in terms of quantitative and qualitative record. Its taxonomical diversity is composed by four taxa: Cricosaurus araucanensis, Cricosaurus lithographicus, Dakosaurus andiniensis, and Purranisaurus potens. This fossil record is also characterized by the tridimensional preservation of the materials and by the preservation of numerous natural endocasts of the skull cavities. Here, I made a description of the natural endocasts of the brain of Cricosaurus araucanensis together with a synthesis of the advances in the knowledge of these four taxa that were performed during the last years. The information that provides the endocasts, to- gether with the quantity of endocasts, make of the Patagonian fossil record of metriorhynchids a key to the exploration and reconstruction of soft anatomy of these crocodylomorphs, and for the understanding of the physiological changes that accompanied the structural changes of the skeleton. Understanding these changes will allow defining the key innovations that allowed to the metriorhynchids conquer the pelagic environment, unparalleled among archosaurs.Fil: Herrera, Laura Yanina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
Effects of increasing cow urine deposition area on soil mineral nitrogen movement and pasture growth on a recent soil in the Manawatu region, New Zealand : a thesis presented in partial fulfilment of the requirements for the degree of Master of Environmental Management at Massey University, Manawatū, Palmerston North, New Zealand
The cow urine patch is a major source of nitrate (NO3¯) leaching from grazed dairy pasture
farms. Increasing the urine deposition area is a direct way of reducing the potential risk of
this cause N leaching losses. Research is required to quantity the effectiveness of this
mitigation across a range of different soil and climatic conditions. The objective of this
study was to determine the effect of increasing the cow urine deposition area on NO3¯
leaching risk and short-term pasture accumulation on Recent soil in the Manawatu Region,
New Zealand. A field trial was conducted, which consisted of three treatments evaluated
on pasture plots: Urine (1 m2), Urine (0.2 m2) and No-urine. The two urine treatments
received the same volume of 2.1 L urine/patch. Urine treatments were applied on the 6th of
March 2017, and soil inorganic N was measured on three occasions; 15, 36 and 53 days
after urine application (DAUA). At the third soil sampling time, which was 24 days after
the drainage season was estimated to have commenced, the net inorganic N (inorganic N in
the urine treatment minus the value for the No-urine treatment) in the 45-120 cm soil depth
was 1.08 g net inorganic N/patch for the Urine (1 m2) treatment compared to 2.97 g net
inorganic N/patch for the Urine (0.2 m2) treatment. Therefore, the Urine (1 m2) treatment
resulted in a 63.6% reduction in the quantity of net inorganic N that was highly susceptible
to leaching, compared to the more typical urine patch area of 0.2 m2. At a paddock scale,
when net inorganic N from the urine treatments is multiplied by an estimate of the quantity
of urine patches per hectare in a single grazing, this equates to a reduction of 2.53 kg N/ha
from a single autumn grazing. It is expected that increasing urine deposition area at
multiple grazings would result in greater reductions in the annual NO3¯ leaching risk.
Over the two pasture harvests conducted in the trial, the pasture DM accumulation for the
No-urine treatment produced an average of 3220 kg DM/ha. The two urine patch
treatments achieved a similar level of pasture DM accumulation to that of the No-urine
treatment. The lack of a pasture growth response from the added urine could have been
influenced by the high clover content (35.9%) of the pasture, and in addition, there may
have been adequate background soil mineral N levels, which together could have
contributed to N not being growth limiting during the trial.
This research has demonstrated that increasing cow urine deposition area in autumn has
potential to be an effective mitigation for decreasing N leaching losses from grazed dairy
pastures. Further research is required to investigate the effects of increasing cow urine
deposition area at multiple grazings, in order to determine the effect of this mitigation
option on annual NO3¯ leaching and pasture production
Influence of Water Temperature on the MXR Activity and P-glycoprotein Expression in the Freshwater Snail, Physa acuta (Draparnaud, 1805)
P-glycoprotein (P-gp) mediated multixenobioticresistance (MXR) is a mechanism analogous to multidrug resistance, which has been extensivelycharacterized in mammalian tumours. The expression and function of the MXR mechanism hasbeen demonstrated in numerous aquatic organisms and has been proposed as a biomarker forpollution assessment. A close relationship between thermal stress and MXR response has beenreported in some aquatic organisms. Seasonal studies in freshwater organisms are scarce andconducted mainly in zebra mussel (Dreissena polymorpha), whose presence has not been reportedin South America. The general purpose of the present study was to evaluate seasonal variation of abiomarker, the MXR mechanism, in the worldwide distributed freshwater snail P. acuta. Weanalyzed the in situ influence of temperature on the biomarker response over an 18-month fieldstudy. MXR defence system was evaluated by a combination of functional assays (RB accumulation)and molecular approaches to analyse P-gp expression. The results demonstrated a linear correlationbetween MXR response, at activity and expression level, and water temperature at sample site, in P.acuta snails. The characterization of the MXR system in worldwide distributed species, includingthe study of their seasonal fluctuations, could contribute to the increasing interest to incorporate thisbiomarker to provide an integrated assessment of mussel health status. This work supports thepossible use of P. acuta snails with this purpose and also highlights that the occurrence of variationsin MXR response related to water temperature has to be taken into account in the interpretation ofin situ monitoring studiesFil: Horak, Cristina Natalia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia ; ArgentinaFil: Assef, Yanina Andrea. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Centro de Investigación Esquel de Montaña y Estepa Patagóica. Universidad Nacional de la Patagonia ; Argentin
Feature Selection for Functional Data
In this paper we address the problem of feature selection when the data is
functional, we study several statistical procedures including classification,
regression and principal components. One advantage of the blinding procedure is
that it is very flexible since the features are defined by a set of functions,
relevant to the problem being studied, proposed by the user. Our method is
consistent under a set of quite general assumptions, and produces good results
with the real data examples that we analyze.Comment: 22 pages, 4 figure
Lignocellulosic Recycled Materials to Design Molded Products: Optimization of Physical and Mechanical Properties
The object is to contribute to the reduction of environmental pollution, by reusing a fraction of urban solid waste, forestry and agroindustrial waste: newspaper (ONP), office paper (OWP), corrugated cardboard (OCC), pine sawdust, eucalyptus sawdust and sugar cane bagasse as raw material to design biocontainers suitable for growing plants, by applying pulp molding technology. The purpose is to evaluate the effects of the combination of these lignocellulosic materials on the physical-mechanical properties and optimize responses in order to select an ideal mixture on basis the product?s necessities. An experimental design of type mixture of extreme vertices was followed, considering secondary fibers as base material, in a 0-100% proportion, and pine sawdust, eucalyptus sawdust and bagasse fibers as reinforcement, in a 0-40% proportion. An experimental matrix by each reinforcing material was proposed. Properties were evaluated: density, tensile, bursting, tearing, compression, stiffness, wet tensile, permeability and water retention, testing handsheets weighing 150 g/m2. Responses were optimized using a statistical program. It was found that OWP pulps increase strength properties; OCC pulps increases tear and wet tensile; ONP pulps increase stiffness and reinforcement materials increase permeability. Factors that allow reaching the objectives are a mixture of pulp OWP/OCC in a 50/50 proportion.Fil: Aguerre, Yanina Susel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Instituto de Materiales de Misiones; ArgentinaFil: Gavazzo, Graciela Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Instituto de Materiales de Misiones; Argentin
The AWGN Red Alert Problem
Consider the following unequal error protection scenario. One special
message, dubbed the "red alert" message, is required to have an extremely small
probability of missed detection. The remainder of the messages must keep their
average probability of error and probability of false alarm below a certain
threshold. The goal then is to design a codebook that maximizes the error
exponent of the red alert message while ensuring that the average probability
of error and probability of false alarm go to zero as the blocklength goes to
infinity. This red alert exponent has previously been characterized for
discrete memoryless channels. This paper completely characterizes the optimal
red alert exponent for additive white Gaussian noise channels with block power
constraints.Comment: 13 pages, 10 figures, To appear in IEEE Transactions on Information
Theor
Critical current and topology of the supercooled vortex state in NbSe2
We study the behavior of the critical current, Ic(H,T), of pure and Fe doped
NbSe2 crystals in the denominated disordered vortex region, limited by the
critical field Hc2(T) and the field Hp(T) at which the peak effect in Ic(H,T)
is detected. The critical current follows an individual pinning response as
demonstrated by its field independent universal function of the superfluid
density. Transport measurements combined with Bitter decorations show no
evidence of the existence of an amorphous phase in the high temperature region.Comment: 7 pages, figures included. Submitted to Phys. Rev.
Low-noise high-voltage DC power supply for nanopositioning applications
Nanopositioning techniques currently applied to characterize physical
properties of materials interesting for applications at the microscopic scale
rely on high-voltage electronic control circuits that should have the lowest
possible noise level. Here we introduce a simple, flexible, and custom-built
power supply circuit that can provide +375\,V with a noise level below 10\,ppm.
The flexibility of the circuit comes from its topology based on discrete MOSFET
components that can be suitable replaced in order to change the polarity as
well as the output voltage and current.Comment: 3 pages, 2 figure
Hierarchical bioglass scaffolds: Introducing the "milky way" for templated bioceramics
Free standing hierarchical bioglass scaffolds were prepared by the ISISA (ice-segregation-induced self-assembly) method. Commercial low-cost precursors such as Ludox® HS-40 and cow milk were employed as the source of SiO2 and biominerals (Ca(ii), P(v), Na(i) and K(i)), respectively. Then, in a single macroscopic piece, three levels of porosity coexist due to the simultaneous templating effect of ice (macropores), milk (50-200 nm mesopores) and the voids left between preformed Ludox® nano building blocks (2-5 nm mesopores). These low cost and green biological nanotemplates, coupled with the ISISA texturing method, allows the preparation of free standing bioglass monoliths, with hierarchical porosity. The effect of the main preparative variables on the final texture is explored; in vitro biomineralization revealed a well-distributed hydroxyapatite-like nanoparticulated layer within 24 h of exposure to a simulated body fluid.Fil: Onna, Diego Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Minaberry, Yanina Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Jobbagy, Matias. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; Argentin
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