2,899 research outputs found
Effects of Land Management Strategies on the Dispersal Pattern of a Beneficial Arthropod
Several arthropods are known to be highly beneficial to agricultural production. Consequently it is of great relevance to study the importance of land management and land composition for the conservation of beneficial aphid-predator arthropod species in agricultural areas. Therefore our study focusing on the beneficial arthropod Bembidion lampros had two main purposes: I) identifying the physical barriers to the speciesâ dispersal in the agricultural landscape, and II) assessing the effect of different land management strategies (i.e. use of pesticides and intensiveness) on the dispersal patterns. The study was conducted using genetic analysis (microsatellite markers) applied to samples from two agricultural areas (in Denmark) with different agricultural intensity. Land management effects on dispersal patterns were investigated with particular focus on: physical barriers, use of pesticide and intensity of cultivation. The results showed that Bembidion lampros disperse preferably through hedges rather than fields, which act as physical barriers to gene flow. Moreover the results support the hypothesis that organic fields act as reservoirs for the re-colonization of conventional fields, but only when cultivation intensity is low. These results show the importance of non-cultivated areas and of low intensity organic managed areas within the agricultural landscape as corridors for dispersal (also for a species typically found within fields). Hence, the hypothesis that pesticide use cannot be used as the sole predictor of agricultureâs effect on wild species is supported as land structure and agricultural intensity can be just as important
Footprints of a possible Ceres asteroid paleo-family
Ceres is the largest and most massive body in the asteroid main belt.
Observational data from the Dawn spacecraft reveal the presence of at least two
impact craters about 280~km in diameter on the Ceres surface, that could have
expelled a significant number of fragments. Yet, standard techniques for
identifying dynamical asteroid families have not detected any Ceres family. In
this work, we argue that linear secular resonances with Ceres deplete the
population of objects near Ceres. Also, because of the high escape velocity
from Ceres, family members are expected to be very dispersed, with a
considerable fraction of km-sized fragments that should be able to reach the
pristine region of the main belt, the area between the 5J:-2A and 7J:-3A
mean-motion resonances, where the observed number of asteroids is low. Rather
than looking for possible Ceres family members near Ceres, here we propose to
search in the pristine region. We identified 156 asteroids whose taxonomy,
colors, albedo could be compatible with being fragments from Ceres. Remarkably,
most of these objects have inclinations near that of Ceres itself.Comment: 12 pages, 6 figures, 1 table. Accepted for publication in MNRA
Genetic parameters for milk mineral content and acidity predicted by mid-infrared spectroscopy in HolsteinâFriesian cows
peer-reviewedThis article was first published in animal, Volume 9, Issue 05, May 2015, pp 775-780 © The Animal Consortium 2015The aim of the present study was to estimate genetic parameters for calcium (Ca), phosphorus (P) and titratable acidity (TA) in bovine milk predicted by mid-IR spectroscopy (MIRS). Data consisted of 2458 Italian HolsteinâFriesian cows sampled once in 220 farms. Information per sample on protein and fat percentage, pH and somatic cell count, as well as test-day milk yield, was also available. (Co)variance components were estimated using univariate and bivariate animal linear mixed models. Fixed effects considered in the analyses were herd of sampling, parity, lactation stage and a two-way interaction between parity and lactation stage; an additive genetic and residual term were included in the models as random effects. Estimates of heritability for Ca, P and TA were 0.10, 0.12 and 0.26, respectively. Positive moderate to strong phenotypic correlations (0.33 to 0.82) existed between Ca, P and TA, whereas phenotypic weak to moderate correlations (0.00 to 0.45) existed between these traits with both milk quality and yield. Moderate to strong genetic correlations (0.28 to 0.92) existed between Ca, P and TA, and between these predicted traits with both fat and protein percentage (0.35 to 0.91). The existence of heritable genetic variation for Ca, P and TA, coupled with the potential to predict these components for routine cow milk testing, imply that genetic gain in these traits is indeed possible
Hydrogeomorphic processes and torrent control works on a large alluvial fan in the eastern Italian Alps
Abstract. Alluvial fans are often present at the outlet of small drainage basins in alpine valleys; their formation is due to sediment transport associated with flash floods and debris flows. Alluvial fans are preferred sites for human settlements and are frequently crossed by transport routes. In order to reduce the risk for economic activities located on or near the fan and prevent loss of lives due to floods and debris flows, torrent control works have been extensively carried out on many alpine alluvial fans. Hazard management on alluvial fans in alpine regions is dependent upon reliable procedures to evaluate variations in the frequency and severity of hydrogeomorphic processes and the long-term performance of the torrent training works. An integrated approach to the analysis of hydrogeomorphic processes and their interactions with torrent control works has been applied to a large alluvial fan in the southern Carnic Alps (northeastern Italy). Study methods encompass field observations, interpretation of aerial photographs, analysis of historical documents, and numerical modelling of debris flows. The overall performance of control works implemented in the early decades of 20th century was satisfactory, and a reduction of hazardous events was recognised from features observed in the field and in aerial photographs, as well as from the analysis of historical records. The 2-D simulation of debris flows confirms these findings, indicating that debris flow deposition would not affect urban areas or main roads, even in the case of a high-magnitude event. Present issues in the management of the studied alluvial fan are representative of situations frequently found in the European Alps and deal with the need for maintenance of the control structures and the pressures for land use changes aimed at the economic exploitation of the fan surface
Statistical Seismic Analysis by b-Value and Occurrence Time of the Latest Earthquakes in Italy
The study reported in this paper concerns the temporal variation in the b-value of the GutenbergâRichter frequencyâmagnitude law, applied to the earthquakes that struck Italy from 2009 to 2016 in the geographical areas of LâAquila, the Emilia Region, and AmatriceâNorcia. Generally, the b-value varies from one region to another dependent on earthquake incidences. Higher values of this parameter are correlated to the occurrence of low-magnitude events spread over a wide geographical area. Conversely, a lower b-value may lead to the prediction of a major earthquake localized along a fault. In addition, it is observed that each seismic event has a different âoccurrence timeâ, which is a key point in the statistical study of earthquakes. In particular, its results are absolutely different for each specific event, and may vary from years to months or even just a few hours. Hence, both short- and long-term precursor phenomena have to be examined. Accordingly, the b-value analysis has to be performed by choosing the best time windows to study the foreshock and aftershock activities
Energy Transition at Home: A Survey on the Data and Practices That Lead to a Change in Household Energy Behavior
Since energy transition depends significantly on reducing the built environmentâs energy needs, many regulations and incentives have been implemented globally over the last three decades. Despite some positive results, many scholars suggest that householdsâ behavioral change could greatly accelerate progress. Peopleâs levels of awareness and willingness to change, as well as the provision of feedback technologies, are important factors affecting the process. In spite of the extent of this body of literature, household consumption keeps rising. Our thesis is that the subject has been investigated without considering some important correlations among factors. Therefore, this study developed a survey to investigate actual consumersâ perspectives on the topic by combining peopleâs awareness of energy use, interaction with metering devices, and user motivation into a coherent framework. A testing session involving 500 people was held as a validation phase for a future large-scale launch of the questionnaire. The test yielded some early outcomes on how people become more interested in changing as they gain more knowledge and are offered suggestions. However, despite their supposedly advanced knowledge as educators and students, the sampleâs level of awareness was low, suggesting that a more user-centered approach is needed for wide-scale progress
Reservas de amido em sarmentos de videira 'Isabel precoce' submetida a diferentes Ă©pocas de poda e duas safras no ciclo.
Na regiĂŁo sul do Brasil, onde o clima Ă© temperado, tradicionalmente colhe-se apenas uma safra/ciclo por ano. Alguns locais, como na DepressĂŁo Central do RS estĂŁo adotando manejo de dupla poda a fim de obter duas safras e oferecendo uma maior viabilidade financeira para o produtor que alĂ©m de obter uma segunda safra, poderĂĄ ofertar em um perĂodo de baixa oferta de uva no mercado, recebendo mais pela produção. O objetivo deste trabalho foi avaliar as reservas de amido em sarmentos que se desenvolveram a partir de distintas datas de poda e em videiras com ou sem a prĂĄtica de dupla colheita. O vinhedo de Isabel Precoce onde foi realizado o experimento estĂĄ localizado no municĂpio de Eldorado do Sul-RS. A quantificação do amido foi por processo enzimĂĄtico com posterior leitura em espectrofotĂŽmetro. Concluiu-se que a precocidade na poda de inverno auxilia no acĂșmulo de reservas de amido em sarmentos da videira por aumentar o ciclo vegetativo fotossinteticamente ativo das plantas e a dupla poda/colheita reduz os conteĂșdos de amido presentes no sarmento, principalmente no segundo perĂodo de crescimento, podendo debilitar a planta caso esta prĂĄtica seja associada a podas tardias e realizada em anos sucessivos
Nurturing International Business research through Global Value Chains literature: A review and discussion of future research opportunities
This article offers a comprehensive and systematic review of the literature on Global Value Chains (GVCs). The GVC framework has received growing attention in the last decade, providing theoretical concepts and analytical tools to understand and assess patterns of value creation in view of the new international division of labour. In this area, a broad overlap of research interest exists with the international business (IB) literature. Yet, few interactions between the two fields of study have been recorded so far. Performing a quantitative content analysis on all academic publications on GVCs in the period 1994â2018, this paper describes the evolution of GVC studies, emphasizing points of contact and potential synergies with the IB literature. It also identifies research opportunities along the four key dimensions of the GVC framework: geographical and industrial scope, governance, upgrading, and institutional context
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