1,721,144 research outputs found
Seismic and Newtonian Noise in the GW Detectors
No full textGravitational wave detectors aim to measure relative length variations of the order of ΔL/L≃10−21, or less. Thus, any mechanism that is able to reproduce such a tiny variation can, in principle, threaten the sensitivity of these instruments, representing a source of noise. There are many examples of such noise, and seismic and Newtonian noise are among these and will be the subject of this review. Seismic noise is generated by the incessant ground vibration that characterizes Earth. Newtonian noise is instead produced by the tiny fluctuations of the Earth’s gravitational field. These fluctuations are generated by variations of air and soil density near the detector test masses. Soil density variations are produced by the same seismic waves comprising seismic noise. Thus, it makes sense to address these two sources of noise in the same review. An overview of seismic and Newtonian noise is presented, together with a review of the strategies adopted to mitigate them
Monthly mowing frequency does not affect soil CO2 emissions of fertilized Bromus erectus-dominated grasslands
Get PDFSecondary origin grasslands are widespread habitats that provide a wide array of ecosystem services. Their conservation relies on management practices that can, in turn, alter their soil carbon cycle to result in higher soil respiration rates. In the perspective of social and climate change scenarios, there is the need to seek the best management practices for conservation of secondary origin grasslands, climate mitigation and economic sustainability for farmers. The aim of this study was to investigate whether increasing the customary practice of mowing twice a year to monthly mowing through the growing season (when herbage production was feasible; i.e., >0.5 t/ha dry matter) generates changes to the drivers and rates of soil respiration of fertilized Bromus erectus-dominated grasslands. Soil CO2 efflux, temperature and moisture were recorded over 3 years (2016-2018) under these "customary" and "monthly" mowing frequencies (twice per year; 4-6 times per year, respectively). Soil CO2 efflux, temperature and moisture were not affected by the higher mowing frequency over the study period. Independent of mowing frequency, soil water content was the main driver of soil CO2 emissions during the growing season (April to October, inclusive), whereas soil temperature was the main driver during the nongrowing season (November to March, inclusive). Therefore, increasing the customary mowing of twice a year to the monthly mowing frequency through the growing season does not impact upon soil respiration of B. erectus-dominated grasslands, at least over a 3-year period
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Adequacy of stocking rates applied on protected pastures of Monti Sibillini (Central Apennines)
No full textThe management of permanent pastures aims at achieving a balance between stocking rate and
their carrying capacity to prevent undesired vegetation dynamics and to maximize the provision of ecosystem
services. Among all methods, pastoral value (PV) is considered a valuable option that provides preliminary
evaluation of pastures productive potential exploiting data already available (i.e., phytosociological surveys
and maps). The current paper aims to compare the actual stocking rate and the potential carrying capacity
calculated by applying the PV method in several Natura 2000 sites (1000-2448 m a.s.l.) of Monti Sibillini
(Marche region, Italy). Available vegetation data and maps were used to calculate PV of the pastures located
in the grazing areas used by the monitored livestock farms. Geographic Information System (GIS)
technologies were used to measure the grasslands surface and the site characteristics of the grazing areas
to be used in the integrated measurements. PV of the grasslands varying between 1.7 and 28.2 was
assessed and used to calculate carrying capacity ranging from 0.06 to 1.62 LU ha-1 per 120 grazing days.
Actual Stocking Rate in the range of the study areas demonstrated to be in general adequate to the carrying
capacity allowed by vegetation types and site characteristics of the grazing areas
Effect of wood gasification biochar on soil physicochemical properties and enzyme activities, and on crop yield in a wheat-production system with sub-alkaline soil
Get PDFBiochar may have beneficial effects on soil depending on its properties and pedoclimatic conditions. Highly sloping soils are prone to erosion and organic matter depletion, and biochar can be useful to restore soil fertility and quality, and crop yields. To test the effect of wood gasification biochar (WGB), we conducted a field experiment applying 0 and 60 Mg ha 1 of WGB only (no fertilizer) to a sub-alkaline and fine-textured soil under Mediterranean climate conditions. The effect of WGB on the soil physicochemical properties and on 12 enzyme activities involved in the C, N, P, and S cycles was monitored during a wheat-growing season along with its effect on grain yield. The results show that WGB was rather recalcitrant, and the application of a high dose of it had no effect on most of the soil physicochemical properties, enzyme activities and wheat grain yield. Since enzyme activities involved in the C cycle were similar in WGB-treated and not-treated soils, WGB failed to stimulate organic matter mineralization during the monitored period, with no contribution to N and P supply. Since WGB can contribute to soil C stock with no detrimental effects on wheat yield, wood gasification can allow recycling waste woody materials of urban origin to produce energy and return biochar back to agricultural soils. We suggest that future studies on WGB focus on the effect of its aging in soil on soil physicochemical and biochemical properties, and on crop performances
Implementazione delle Misure Agro-ambientali a scala territoriale: la necessità del coinvolgimento degli Stakeholder locali
No full textSoil refinement accelerates in-field degradation rates of soil-biodegradable mulch films
Get PDFSoil-biodegradable mulch films are a promising solution to replace conventional polyethylene-based mulch films, the use of which has led to negative environmental impacts. Soil-biodegradable mulch films are specifically designed to be incorporated into the soil at the end of the cropping cycle and are expected to be biodegraded by soil microorganisms. The biodegradability of such products must be tested under laboratory-controlled conditions following international standards, although these can fail to represent real environmental conditions where mulch films are used. The objective of this study was to evaluate the effects of soil refinement on the degradation rates of three different commercial soil-biodegradable mulch films after their incorporation into the soil. The hypotheses were that: i) soil refinement (i.e., ploughing followed by grubbing) creates more favourable conditions for film biodegradation compared to ploughing alone; and ii) different mulch films show different degradation rates. An open-field, completely randomised design was applied to test the effects of soil refinement by ploughing to 0.35 m depth without and with subsequent grubbing to 0.15 m depth twice. Three commercially available soil-biodegradable mulch films were sampled in 2020 (i.e., two Mater-bi-based, one Ecovio-based) at the end of courgette growing season (similar to 3 months) when films were still lying above ground and were later buried at 0.2 m depth inside mesh bags. Biodegradation rates of the sampled films were assessed with the indirect indicators of film weight loss and surface area loss at similar to 2-month intervals over 314 days. The results showed that soil refinement significantly accelerated the degradation of the three tested mulch films by 14% and 17% according to the loss of weight and surface area indicators, respectively. One Mater-bi-based film showed higher degradation rates compared to the other two films. Future studies are needed to quantify the time needed for these different mulch films to be completely biodegraded. Such studies should follow standards for laboratory incubation and/or in-field quantification of residual polymers in the soil over time
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