59 research outputs found
An interdisciplinary vision of "Cova Beneito"
Aquest freball ofereix una visió interdisciplimiria i global dels nivells del paleolític mijà i superior de la cova Beneito (Muro del Comtat, Alacant).
L'estudi sedimentològic, palinològic i faunístic de la seua dilatada estratigrafia aporta dades imprescindibles per al reconeixement de l'lnterestadial II-III, per a la consolidació de la climatoestratigrafia del Pleistocé Superior i, a més, una comprensió millor de la relació home-medi.
El desenvolupamenr cultural ofereix altenatives interessants per a la seqüència mediterrànea i aporta la novetat de I'Aurinyacià evolucionat final a l'ambit valencià. S'hi dedica una apartat a l'estudi d'una tomba ritual secundària solutriogravetiana.The present work attempts to offer an interdisciplinary and global vision on the levels of the Middle and Upper Paleolithic period in "Cova Beneito" (Muro-Alicante-Spain).
The sedimentological, palynological and faunistic study of its vast stratigraphy bring forward essential facts for the identification of the midlast glacial stage and for strengthening of the climatostratigraphy of the Upper Pleistocene, as well as for a better reconstruction of the retationship between man and environment.
The cultural development supplies interesting alternatives to the Mediterranean sequence, and brings out the novelty of the Evolued Aurignacian in the Valencian area. There is a special section on the study of a secondary Solutrean-Gravettian ritual burial.El presente trabajo ofrece una visión interdisciplinar y global de los niveles del Paleolítico Medio y Superior de Cova Beneito (Muro- Alicante).
El estudio sedimentológico, palinológico y faunístico de su dilatada estratigrafía aportan datos imprescindibles para el reconocimiento del Interestadial II-III y el afianzamiento de la climatoestratigrafía del Pleistoceno Superior, así como para una mejor comprensidn de la relación hombre-medio.
El desarrollo cultural ofrece alternativas interesantes a tu secuencia mediterránea, aportando la novedad del Auriñaciense evolucionado final al ámbito valenciano. Se dedica un apartado al estudio de un enterramiento ritual secundario Solútreogravetiense
Climate change and future pollen allergy in Europe
Background: Globally pollen allergy is a major public health problem, but a fundamental unknown is the likely impact of climate change. To our knowledge, this is the first study to quantify the consequences of climate change upon pollen allergy in humans. Objectives: To produce quantitative estimates of the potential impact of climate change upon pollen allergy in humans, focusing upon common ragweed (Ambrosia artemisiifolia) in Europe. Methods: A process-based model estimated the change in ragweed’s range under climate change. A second model simulated current and future ragweed pollen levels. These were translated into health burdens using a dose-response curve generated from a systematic review and current and future population data. Models considered two different suites of regional climate/pollen models, two greenhouse gas emissions scenarios (RCP4.5 and 8.5), and three different plant invasion scenarios. Results: Our primary estimates indicate that sensitization to ragweed will more than double in Europe, from 33 to 77 million people, by 2041-2060. According to our projections, while sensitization will increase in countries with an existing ragweed problem (e.g. Hungary, the Balkans), the greatest proportional increases will occur where sensitization is uncommon (e.g. Germany, Poland, France). Higher pollen concentrations and a longer pollen season may also increase the severity of symptoms. Our model projections are driven predominantly by changes in climate (66%), but also are influenced by current trends in the spread of this invasive plant species. Assumptions about the rate at which ragweed spreads throughout Europe have a large influence upon the results. Conclusions: Our quantitative estimates indicate that ragweed pollen allergy will become a common health problem across Europe, expanding into areas where it is currently uncommon. Control of ragweed spread may be an important adaptation strategy in response to climate change
La fauna del pleistoceno inferior de la sierra de Quibas (Abanilla, Murcia)
El yacimiento kárstico cuaternario de la Sierra de Quibas (Abanilla, Murcia) ha proporcionado
una amplia lista faunística constituida por 53 especies repartidas entre gasterópodos,
miriápodos, anfibios, reptiles, aves y mamíferos. En el conjunto de los gasterópodos
destaca Palaeoglandina, un género que se extingue en el resto de Europa durante el Plioceno
y que se mantiene como relicto en el Pleistoceno de la Península Ibérica. Dos de las
especies de aves determinadas, Gypaetus barbatus y Gerontieus eremita, y una de las serpientes,
Elaphe cf. E. sealaris, apenas se hallan representadas en el registro fósil. Hay además
varias especies de aves cuya aparición en Quibas supone la primera cita en el Pleistoceno
inferior de la Península Ibérica. Entre los mamíferos posee una especial relevancia la
presencia del cercopitécido Macaca sylvanus. La asociación de los taxones Arvieola deuealíon,
Castillomys rivas rivas, Elíomys intermedius, Equus altidens y Capra sp. aff. C.
alba permite la correlación con Plines 1, Orce 3 y Venta Micena, entre otros. El yacimiento
de Quibas puede situarse, por tanto, antes del final del Pleistoceno inferior, con una antigüedad
entre 1.3 y 1 Ma. Por lo que se refiere a las condiciones paleoclimáticas, podemos
inferir a partir de la asociación faunística un régimen xerófilo, muy semejante al actual en
el área geográfica, aunque quizás con valores de humedad y temperatura algo superiores.
El entorno de la cavidad kárstica estaba formado por roquedo calcáreo con áreas abiertas
de matorral, pero en las proximidades se desarrollaron humedales y zonas arboladas, como
así lo atestigua la presencia de aves y micromamíferos típicos de estos hábitats.The Quaternary karstic site of Sierra de Quibas (Abanilla, Murcia, Spain) has provided
a wide faunallist with 53 species distributed among gastropods, myriapods, amphibians,
reptiles, birds and mammals. Especially interesting among the gastropods is
Palaeoglandina that became extinct in Europe during the Pliocene. It remains as a relict
genus in the Pleistocene of the Iberian Peninsula. Two of the birds, Gypaetus barbatus
and Geronticus eremita, and a snake, Elaphe cf. E. sealaris, are scarcely represented in the fossil record. For several birds, it is the first record in the Lower Pleistocene of the
Iberian Peninsula. Among the mammals, the presence of the Cercopithecine Macaca sylvanus
is especially relevant. The assemblage of the taxa Arvicola deucalion, Castillomys
rivas rivas, Eliomys intermedius, Equus altidens and Capra sp. aff. C. alba allows the
correlation with Plines 1, Orce 3 and Venta Micena, among other sites. Therefore Quibas
can be clated before the end of Lower Pleistocene, between 1.3 and 1 Ma. A dry paleoclimatic
regime, very similar to the current climate in the geographical area, though perhaps
slightly wetter and warmer, can be inferred from the faunal assemblage. The environment
of the karstic cavity was a rocky place with open brushwood areas, but in the
proximities there were wetlands and woodlands, as can be inferred from the presence of
birds and micromammals characteristic of these [email protected] [email protected]
Arbuscular mycorrhizal colonisation of roots of grass species differing in invasiveness
Recent research indicates that the soil microbial community, particularly arbuscular mycorrhizal
fungi (AMF), can influence plant invasion in several ways. We tested if 1) invasive species are
colonised by AMF to a lower degree than resident native species, and 2) AMF colonisation of native
plants is lower in a community inhabited by an invasive species than in an uninvaded resident
community. The two tests were run in semiarid temperate grasslands on grass (Poaceae) species,
and the frequency and intensity of mycorrhizal colonisation, and the proportion of arbuscules and
vesicles in plant roots have been measured. In the first test, grasses representing three classes of
invasiveness were included: invasive species, resident species becoming abundant upon
disturbance, and non-invasive native species. Each class contained one C3 and one C4 species. The
AMF colonisation of the invasive Calamagrostis epigejos and Cynodon dactylon was consistently
lower than that of the non-invasive native Chrysopogon gryllus and Bromus inermis, and contained
fewer arbuscules than the post-disturbance dominant resident grasses Bothriochloa ischaemum and
Brachypodium pinnatum. The C3 and C4 grasses behaved alike despite their displaced phenologies
in these habitats. The second test compared AMF colonisation for sand grassland dominant grasses
Festuca vaginata and Stipa borysthenica in stands invaded by either C. epigejos or C. dactylon, and
in the uninvaded natural community. Resident grasses showed lower degree of AMF colonisation in the invaded stand compared to the uninvaded natural community with F. vaginata responding so to
both invaders, while S. borysthenica responding to C. dactylon only. These results indicate that
invasive grasses supposedly less reliant on AMF symbionts have the capacity of altering the soil
mycorrhizal community in such a way that resident native species can establish a considerably
reduced extent of the beneficial AMF associations, hence their growth, reproduction and ultimately
abundance may decline. Accumulating evidence suggests that such indirect influences of invasive
alien plants on resident native species mediated by AMF or other members of the soil biota is probably more the rule than the exception
Nuclear and Chloroplast Microsatellites Show Multiple Introductions in the Worldwide Invasion History of Common Ragweed, Ambrosia artemisiifolia
BACKGROUND: Ambrosia artemisiifolia is a North American native that has become one of the most problematic invasive plants in Europe and Asia. We studied its worldwide population genetic structure, using both nuclear and chloroplast microsatellite markers and an unprecedented large population sampling. Our goals were (i) to identify the sources of the invasive populations; (ii) to assess whether all invasive populations were founded by multiple introductions, as previously found in France; (iii) to examine how the introductions have affected the amount and structure of genetic variation in Europe; (iv) to document how the colonization of Europe proceeded; (v) to check whether populations exhibit significant heterozygote deficiencies, as previously observed. PRINCIPAL FINDINGS: We found evidence for multiple introductions of A. artemisiifolia, within regions but also within populations in most parts of its invasive range, leading to high levels of diversity. In Europe, introductions probably stem from two different regions of the native area: populations established in Central Europe appear to have originated from eastern North America, and Eastern European populations from more western North America. This may result from differential commercial exchanges between these geographic regions. Our results indicate that the expansion in Europe mostly occurred through long-distance dispersal, explaining the absence of isolation by distance and the weak influence of geography on the genetic structure in this area in contrast to the native range. Last, we detected significant heterozygote deficiencies in most populations. This may be explained by partial selfing, biparental inbreeding and/or a Wahlund effect and further investigation is warranted. CONCLUSIONS: This insight into the sources and pathways of common ragweed expansion may help to better understand its invasion success and provides baseline data for future studies on the evolutionary processes involved during range expansion in novel environments
Sea level and climate changes during OIS 5e in the Western Mediterranean
Palaeontological, geomorphological and sedimentological data supported by isotopic dating on Oxygen
Isotopic Stage (OIS) 5e deposits from the Spanish Mediterranean coast, are interpreted with the aim of
reconstructing climatic instability in the Northern Hemisphere. Data point to marked climatic instability
during the Last Interglacial (OIS 5e), with a change in meteorological conditions and, consequently, in the
sedimentary environment. The oolitic facies generated during the first part of OIS 5e (ca. 135 kyr) shift into
reddish conglomeratic facies during the second part (ca. 117 kyr). Sea surface Temperature (SST) and salinity
are interpreted mainly on the basis of warm Senegalese fauna, which show chronological and spatial
differential distribution throughout the Western Mediterranean. Present hydrological and meteorological
conditions are used also as modern analogues to reconstruct climatic variability throughout the Last
Interglacial, and this variability is interpreted within the wider framework of the North Atlantic record. All
the available data indicate an increase in storminess induced by an increase in the influence of northwesterlies,
a slight drop of SST in the northern Western Mediterranean, and an important change in
meteorological conditions at the end of OIS 5e (117 kyr). These changes correlate well with the decrease in
summer insolation and with the climatic instability recorded in North Atlantic high latitudes
Estimation of pollen and seed production of common ragweed in France
Common ragweed (Ambrosia artemisiifolia L.) is an invasive weed of fi eld crops and human-disturbed habitats in Europe. As well as in its natural range (North America), common ragweed is a threat to human health due to its abundant allergenic pollen release. Most studies have been focused on airborne pollen monitoring, but to date, no data have been available on precise individual plant pollen and seed production related to plant traits growing in natural environment and on their corresponding source of variation. The aim of this study was to evaluate pollen and seed production of common ragweed plants in several populations in France. Seasonal pollen production per plant ranged from 100 million to 3 billion and seed production from 346 to 6,114, depending on plant size and habitat. Common ragweed plants developing in fi eld crops produced more pollens and seeds than those growing in other habitats. Pollen and seed production was closely related to plant volume and biomass, thus providing a means of estimating potential pollen and seed production in given target areas. Such biological data could be integrated into population management strategies or into airborne pollen modelling
Gated Local Adaptive Binarization using Supervised Learning
Image thresholding is one of the most popular problems in image processing. However, changes in lightning and contrast in an image can cause trouble for the existing algorithms that use a global threshold for all the image. A solution for this problem is the adaptive thresholding, in which an image can have different thresholds for different parts of the image. Yet, the problem of choosing the most suitable threshold for each region of the image is still open. In this paper we present the Gated Local Adaptive Binarization algorithm, in which we choose the most appropriate threshold for each region of the image using a logistic regression. Our results show that this algorithm can effectively learn the most appropriate threshold in each situation, and beats other adaptive binarization solutions for a standard dataset in the literature
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