2,420 research outputs found
Do Birds of a Feather Flock Together? Immigration Flows and Cultural Clustering in Host Countries
This paper presents a simple theoretical framework in which immigrants have a relative incentive to cluster in host countries where cultural characteristics and imperfect information sustain the segmentation of the labor market and a higher wage in foreign communities. The hypothesis is tested on a panel of immigration flows to OECD countries. The pull effect of cultural communities is supported and it is found that the minimum size of a given cultural community is around 5% of the foreign population. It is also found that the pull effect weakens as the community grows as predicted by the theoretical framework.International migrations; relative incomes; cultural clustering
Numerical study of a rotating fluid in a spheroidal container.
The motion of an incompressible, viscous rotating fluid contained in a spheroidal conainer is studied by a direct numerical simulation in a oblate speroidal system. An appropriate formalism is first derived which allows us to expand any scalar field in spherical harmonics and to decompose any vector field into its sphero-poloidal and sphero-toroidal scalar parts
PDO as a mechanism for reterritorialisation and agri-food governance: a comparative analysis of cheese products in the UK and Switzerland
The protection of geographical indications (European regl. 1151/2012) is arguably the most significant initiative, certainly within Europe, that promotes foods with territorial associations and reorganises agri-food chain governance through a strategy of reterritorialisation. Research on PDOs and PGIs suggests that they generate significant economic value at an EU-level, especially in certain countries. They can also help to deliver territorial rural development policy and develop new food markets. In this paper we examine the way the PDO scheme has been developed and applied in one commodity sector (cheese) in two countries (Switzerland and the UK), where the uptake of PDOs is variable. We adopt a food chain approach and examine specific cheese product case studies (at micro and meso levels) in both countries to better understand how the PDO scheme (as a territorialisation and respacing strategy) is implemented. L’Etivaz and Le Gruyère are examined in Switzerland. Single Gloucester and West Country cheddar are examined in the UK. The PDO scheme is an important governance strategy and regulatory system, but despite strict guidelines regarding implementation and geographical infrastructure there are notable differences between the UK and Switzerland in terms of how the label is used to organise and respatalise food chains: it is framed as a strategy to protect the rural economy in Switzerland but is promoted more as a mechanism to communicate and reconnect with consumers in the UK
Una historiografía en medio del vado
Hace exactamente un año, Otto-Gerhard Oexle nos introducía en las “tendencias recientes de la historia medieval en Alemania”, mostrándonos con fineza en qué medida los medievalistas alemanes de hoy buscan, más o menos explícitamente, reconciliarse con el gran vuelco sociológico alemán de comienzos de siglo ?especialmente aquel de Georg Simmel y de Max Weber? contrarrestado, como es sabido, por la “catastrofe “ del nazismo y sus consecuencias sobre la historiografía durante ese período y, probablemente también fuera de ella. En Francia, la fecundidad del pensamiento de un Marc Bloch o de un Maurice Halbwachs, por el contrario, pudo inscribirse en la continuidad de la ruptura epistemológica iniciada a comienzos del siglo XX por Emile Durkheim. No nos detendremos en esto para avocarnos a la situación francesa de épocas más recientes. En este sentido, comenzamos por una doble constatación..
Wilson's disease in southern Brazil: a 40-year follow-up study
BACKGROUND: Long-term data on the clinical follow-up and the treatment effectiveness of Wilson's disease are limited because of the low disease frequency. This study evaluated a retrospective cohort of Wilson's disease patients from southern Brazil during a 40-year follow-up period. METHODS: Thirty-six Wilson's disease patients, diagnosed from 1971 to 2010, were retrospectively evaluated according to their clinical presentation, epidemiological and social features, response to therapy and outcome. RESULTS: Examining the patients' continental origins showed that 74.5% had a European ancestor. The mean age at the initial symptom presentation was 23.3 ± 9.3 years, with a delay of 27.5 ± 41.9 months until definitive diagnosis. At presentation, hepatic symptoms were predominant (38.9%), followed by mixed symptoms (hepatic and neuropsychiatric) (30.6%) and neuropsychiatric symptoms (25%). Kayser-Fleischer rings were identified in 55.6% of patients, with a higher frequency among those patients with neuropsychiatric symptoms (77.8%). Eighteen patients developed neuropsychiatric features, most commonly cerebellar syndrome. Neuroradiological imaging abnormalities were observed in 72.2% of these patients. Chronic liver disease was detected in 68% of the patients with hepatic symptoms. 94.2% of all the patients were treated with D-penicillamine for a mean time of 129.9 ± 108.3 months. Other treatments included zinc salts, combined therapy and liver transplantation. After initiating therapy, 78.8% of the patients had a stable or improved outcome, and the overall survival rate was 90.1%. CONCLUSION: This study is the first retrospective description of a population of Wilson's disease patients of mainly European continental origin who live in southern Brazil. Wilson's disease is treatable if correctly diagnosed, and an adequate quality of life can be achieved, resulting in a long overall survival
Comparing the Sustainability of Local and Global Food Chains: A Case Study of Cheese Products in Switzerland and the UK
Local food has recently gained popularity under the assumption that it is more sustainable than food from distant locations. However, evidence is still lacking to fully support this assumption. The goal of this study is to compare local and global food chains in five dimensions of sustainability (environmental, economic, social, ethical and health), covering all stages of the chain. In particular, four cheese supply chains are compared in detail: a local (L’Etivaz) and global (Le Gruyère) case in Switzerland and a local (Single Gloucester) and global (Cheddar) case in the UK. A multi-dimensional perspective is adopted to compare their sustainability performance. Eight attributes of performance (affordability, creation and distribution of added value, information and communication, consumer behaviour, resource use, biodiversity, nutrition and animal welfare) are used to frame the comparative analysis. The results suggest that local cheese performs better in the field of added value creation and distribution, animal welfare and biodiversity. Global chains, by contrast, perform better in terms of affordability and efficiency and some environmental indicators. This analysis needed to be expressed in qualitative terms rather than quantified indicators and it has been especially useful to identify the critical issues and trade-offs that hinder sustainability at different scales. Cheese supply chains in Switzerland and the UK also often present hybrid arrangements in term of local and global scales. Comparison is therefore most meaningful when presented on a local (farmhouse)/global (creamery) continuum
Witnessing effective entanglement over a 2km fiber channel
We present a fiber-based continuous-variable quantum key distribution system.
In the scheme, a quantum signal of two non-orthogonal weak optical coherent
states is sent through a fiber-based quantum channel. The receiver
simultaneously measures conjugate quadratures of the light using two homodyne
detectors. From the measured Q-function of the transmitted signal, we estimate
the attenuation and the excess noise caused by the channel. The estimated
excess noise originating from the channel and the channel attenuation including
the quantum efficiency of the detection setup is investigated with respect to
the detection of effective entanglement. The local oscillator is considered in
the verification. We witness effective entanglement with a channel length of up
to 2km.Comment: 11 pages, 5 figure
Two interacting Hopf algebras of trees
Hopf algebra structures on rooted trees are by now a well-studied object,
especially in the context of combinatorics. In this work we consider a Hopf
algebra H by introducing a coproduct on a (commutative) algebra of rooted
forests, considering each tree of the forest (which must contain at least one
edge) as a Feynman-like graph without loops. The primitive part of the graded
dual is endowed with a pre-Lie product defined in terms of insertion of a tree
inside another. We establish a surprising link between the Hopf algebra H
obtained this way and the well-known Connes-Kreimer Hopf algebra of rooted
trees by means of a natural H-bicomodule structure on the latter. This enables
us to recover recent results in the field of numerical methods for differential
equations due to Chartier, Hairer and Vilmart as well as Murua.Comment: Error in antipode formula (section 7) corrected. Erratum submitte
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