5,428 research outputs found
Temperature effects on the universal equation of state of solids
Recently it has been argued based on theoretical calculations and experimental data that there is a universal form for the equation of state of solids. This observation was restricted to the range of temperatures and pressures such that there are no phase transitions. The use of this universal relation to estimate pressure-volume relations (i.e., isotherms) required three input parameters at each fixed temperature. It is shown that for many solids the input data needed to predict high temperature thermodynamical properties can be dramatically reduced. In particular, only four numbers are needed: (1) the zero pressure (P=0) isothermal bulk modulus; (2)it P=0 pressure derivative; (3) the P=0 volume; and (4) the P=0 thermal expansion; all evaluated at a single (reference) temperature. Explicit predictions are made for the high temperature isotherms, the thermal expansion as a function of temperature, and the temperature variation of the isothermal bulk modulus and its pressure derivative. These predictions are tested using experimental data for three representative solids: gold, sodium chloride, and xenon. Good agreement between theory and experiment is found
Universality in the compressive behavior of solids
It was discovered that the isothermal equation of state for solids in compression is a simple, universal form. This single form accurately describes the pressure and bulk modulus as a function of volume for tonic, metallic, covalent, and rare gas solids
A multivariate framework to explore firms' internationalization patterns: the role of individual heterogeneity
In this paper, we explore the internationalization pattern of firms and its relationship with firms\u2019 heterogeneity. Besides the more traditional exports and Foreign Direct Investments (FDI), we consider various forms of non-equity internationalization. The use of a Multivariate Probit Model allows us to assess the associations among the choices driving the firms\u2019 internationalization strategy as a whole and, at the same time, to avoid a priori assumptions on the internationalization patterns. From the empirical evidence, two main results emerge. At first, we observe that Italian firms jointly adopt various internalization forms, others than exports and FDI, conditionally to characteristics of the firms. The hypothesis reported in literature of a complementary or subsidiary relationship between exports and FDI is then confirmed also for non-equity internationalization forms. Secondly, we find that the heterogeneity of firms, measured by a large range of variables, has an important role in defining the choice of firms on the patterns of internalization. Thus in this context, we endorse the emerging opinion asserting that various dimensions other than productivity are relevant
Molecular and phenotypic features of <i>Pseudomonas syringae</i> pv. <i>actinidiae</i> isolated during recent epidemics of bacterial canker on yellow kiwifruit (<i>Actinidia chinensis</i>) in central Italy
Pseudomonas syringae pv. actinidiae (Psa) was identified as the causal agent of severe epidemics of bacterial canker on Actinidia chinensis (yellow kiwifruit) in central Italy occurring during 2008–9. A total of 101 strains were obtained from infected leaves, twigs, branches and trunks of cvs Hort16A, Jin Tao and CK3. Outbreaks were also found on A. deliciosa cv. Hayward. A representative set of 21 strains were compared with other Psa strains isolated from previous outbreaks in Japan and Italy as well as with P. s. pv. syringae strains obtained from A. chinensis and with strains of genomospecies 8. Repetitive‐sequence PCR (rep‐PCR) typing using BOX and ERIC primer sets revealed that all Psa strains obtained during 2008–9 showed the same fingerprinting profile. This profile, however, was different from those of strains previously isolated in Japan and Italy. Multilocus sequence typing (MLST) of gapA, gltA, gyrB and rpoD revealed a higher genetic variability among the strains than rep‐PCR, with some of them showing the same sequence pattern although isolated from different areas, cultivars and years. None of the recently obtained strains possessed genes coding for phaseolotoxin or coronatine, and all had an effector protein, namely hopA1, differentiating them from the strains causing past outbreaks in Japan and Italy. All isolates were inhibited in vitro by copper‐based compounds, antibiotics, geraniol, citronellol and by a chitin‐based organic compound. The recent epidemics found in central Italy on yellow kiwifruit appear to have been caused by a different Psa population than those previously recorded in Japan, South Korea and Italy
The effect of residential urban greenness on allergic respiratory diseases in youth: A narrative review
Background: Environmental exposures across the life course may be a contributor to the increased worldwide prevalence of respiratory and allergic diseases occurring in the last decades. Asthma and rhinoconjunctivitis especially contribute to the global burden of disease. Greenness has been suggested to have beneficial effects in terms of reduction of occurrence of allergic respiratory diseases. However, the available evidence of a relationship between urban greenness and childhood health outcomes is not yet conclusive. The current review aimed at investigating the current state of evidence, exploring the relationship between children's exposure to residential urban greenness and development of allergic respiratory diseases, jointly considering health outcomes and study design. Methods: The search strategy was designed to identify studies linking urban greenness exposure to asthma, rhinoconjunctivitis, and lung function in children and adolescents. This was a narrative review of literature following PRISMA guidelines performed using electronic search in databases of PubMed and Embase (Ovid) from the date of inception to December 2018. Results: Our search strategy identified 2315 articles; after exclusion of duplicates (n = 701), 1614 articles were screened. Following review of titles and abstracts, 162 articles were identified as potentially eligible. Of these, 148 were excluded following full-text evaluation, and 14 were included in this review. Different methods for assessing greenness exposure were found; the most used was Normalized Difference Vegetation Index. Asthma, wheezing, bronchitis, rhinoconjunctivitis, allergic symptoms, lung function, and allergic sensitization were the outcomes assessed in the identified studies; among them, asthma was the one most frequently investigated. Conclusions: The present review showed inconsistencies in the results mainly due to differences in study design, population, exposure assessment, geographic region, and ascertainment of outcome. Overall, there is a suggestion of an association between urban greenness in early life and the occurrence of allergic respiratory diseases during childhood, although the evidence is still inconsistent. It is therefore hard to draw a conclusive interpretation, so that the understanding of the impact of greenness on allergic respiratory diseases in children and adolescents remains difficult
Fundamental Limits of Low-Density Spreading NOMA with Fading
Spectral efficiency of low-density spreading non-orthogonal multiple access
channels in the presence of fading is derived for linear detection with
independent decoding as well as optimum decoding. The large system limit, where
both the number of users and number of signal dimensions grow with fixed ratio,
called load, is considered. In the case of optimum decoding, it is found that
low-density spreading underperforms dense spreading for all loads. Conversely,
linear detection is characterized by different behaviors in the underloaded vs.
overloaded regimes. In particular, it is shown that spectral efficiency changes
smoothly as load increases. However, in the overloaded regime, the spectral
efficiency of low- density spreading is higher than that of dense spreading
Public policies and food security and family farming networks: contributions to the construction of effectiveness indicators.
This work presents a methodology for investigating the performance of public politics regarding food security networks formed in Brazilian municipalities aimed at increasing income and employment in familiar farming. These programs need to further develop the methodologies used for studying their efficiency so that they can reach a new stage in the improvement and use of management tools thereby achieving beteer results of social inclusion and/or food security. This paper constitutes a first effort to bring together indicators for the evaluation of the efficiency of public politicies
Analyses of odours from concentrated animal feeding operations: a review
Concentrated Animal Feeding Operations (CAFOs) are widely present all over the world due to the high population demand for food and products of animal origin. However, they have generated several environmental concerns, including odour nuisance, which affects people health and quality of life. Odours from livestock are a very complex mixtures of molecules and their analytical investigation is highly demanding. Many works have been published regarding the study of odours from CAFOs, using different techniques and technologies to face the issue. Thus, the aim of this review paper is to summarize all the ways to study odours from CAFOs, starting from the sampling methods and then treating in general the principles of Dynamic Olfactometry, Gas Chromatography coupled with Mass Spectrometry and Electronic Noses. Finally, a deep literature summary of Gas Chromatography coupled with Mass Spectrometry and Electronic Noses applied to odours coming from poultry, dairy and swine feeding operations is reported. This work aims to make some order in this field and it wants to help future researchers to deal with this environmental problem, constituting a state-of-the-art in this field
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