Geometric optimal control of the contrast imaging problem in Nuclear Magnetic Resonance

The objective of this article is to introduce the tools to analyze the contrast imaging problem in Nuclear Magnetic Resonance. Optimal trajectories can be selected among extremal solutions of the Pontryagin Maximum Principle applied to this Mayer type optimal problem. Such trajectories are associated to the question of extremizing the transfer time. Hence the optimal problem is reduced to the analysis of the Hamiltonian dynamics related to singular extremals and their optimality status. This is illustrated by using the examples of cerebrospinal fluid / water and grey / white matter of cerebrum.Comment: 30 pages, 13 figur

Cotilos impactados vs. roscados no cementados: estudio radiológico post-operatorio comparativo

Se han valorado radiografías AP de pelvis obtenidas tras colocación de 102 pró- tesis no cementadas en 97 pacientes: 51 eran del tipo cótilo roscado (CR), y 51 del tipo cótilo impactado (CI). Se ha medido el ángulo de inclinación, la posición del cotilo, el grado de centraje, el grado de protrusión/extrusión, y la superficie de contacto entre cótilo y la cavidad acetabular. Globahnente los CR quedan implantados más verticalmente que los CI (p=0,006), así como más lateralizados (p=0,02). El porcentaje de cótilos bien centrados en relación al acetábulo es mayor entre los CI que entre los CR (p=0,002). Un 19% de los CR quedaron parcialmente extraídos, no llegando a contactar con el fondo de la cavidad acetabular, mientras que en ningún caso de los CI se apreció este problema. En conclusión, a pesar de la teórica ventaja de poseer una estabilidad inicial mayor, la orientación de los CR no resulta tan óptima como la obtenida con los CI, lo que asegura una estabilidad mejor a largo plazo y una menor usura del polietileno.—Post-operative anteroposterior radiographs of the pelvis in 102 patients receiving a cementless total hip arthroplasty were analyzed. In a group, a screwed spherical socket (SCR) was applied, while in other a press-fit impacted socket (IMP) was used. The following parameters were studied: inclination angle, location and centering of the acetabular component, degree of protrusion-extrusion, and porcentage of contact surface between the socket and the acetabulum. SCR sockets appeared to be placed more vertically (p=0.006), and laterally (p=0.02) than IMP prostheses. The percent of properly centered sockets was higher among IMP than among SCR implants (p=0.002). SCR prostheses were found to be partly extruded in 19% of cases while none of the IMP prostheses had this problem. In conclussion, despite the theoretical advantage of the SCR implants having a better initial fixation than the IMP implants, the latter tend to be implanted in a more optimal position, thus ensuring a better longterm stability and therefore less wear problems can be expected

"Ethnic disparities in the prevalence of Molar-Incisor-Hypomineralisation (MIH) and caries among 6-12-year-old children in Catalonia, Spain"

AIM: To study the prevalence of MIH and caries in 6- and 12-year-old schoolchildren and their association with ethnic disparities and other relevant factors. BACKGROUND: In recent years, there has been uneven improvement in school children's oral health, highlighting inequalities in access to dental care and health outcomes, particularly among ethnic minorities. The most prevalent oral disease in childhood, caries, is preventable, as its risk factors are well known. However, MIH, a common condition affecting the enamel of permanent incisors and/or molars, has no established aetiology or preventive measures. METHODS: A cross-sectional study among schoolchildren was conducted in 725 children from Masnou (Barcelona, 2013) and in 577 children from Sant Andreu de Llavaneres (Barcelona, 2018-2020). Data collection was carried out by means of clinical examination and a selfreferenced questionnaire. Oral health outcomes included: presence of dental caries, presence of MIH, hypomineralised second primary molars (HSPM). All variables were analysed according to ethnic disparities and other variables such as socioeconomics, diet, hygiene habits, plaque and access to dental services. We performed multivariate Poisson regression models with robust variance to examine ethnic disparities in MIH and caries. CONCLUSION: This cross-sectional study based in Catalonia, Spain showed that there are ethnic disparities in caries as observed with other child's diseases; however, they do not seem to follow the same pattern for MIH. More studies are needed (i) to explore how MIH behaves among populations in terms of inequality; (ii) to study the aetiological factors of MIH; and (iii) to identify potential factors associated with MIH and caries that have not been studied and that may contribute to the observed ethnic disparities.</p

Acidification and solar drying of manure-based digestate to produce improved fertilizing products

The increase in energy and fertilizer consumption makes it necessary to develop sustainable alternatives for agriculture. Anaerobic digestion and digestates appeared to be suitable options. However, untreated digestates still have high water content and can increase greenhouse gas emissions during storage and land application. In this study, manure-derived digestate and solid fraction of digestate after separation were treated with a novel solar drying technology to reduce their water content, combined with acidification to reduce the gaseous emissions. The acidified digestate and acidified solid fraction of digestate recovered more nitrogen and ammonia nitrogen than their respective non-acidified products (1.5–1.3 times for TN; 14 times for TAN). Ammonia and methane emissions were reduced up to 94% and 72% respectively, compared to the non-acidified ones, while N2O increased more than 3 times. Dried digestate and dried acidified digestate can be labeled as NPK organic fertilizer regarding the European regulation, and the dried solid fraction and the improved dried acidified solid fraction can be labeled as N or P organic fertilizer. Moreover, plant tests showed that N concentrations in fresh lettuce leaves were within the EU limit with all products in all the cases. However, zinc concentration appeared to be a limitation in some of the products as their concentration exceeded the European legal limits.This work was funded by the European Union under the Circular Agronomics project (H2020 research and innovation project Nº.773649) and Nutry2Cycle project (H2020 research and innovation project Nº.773682). IRTA thanks the support of the CERCA Program and the Consolidated Research Group TERRA (ref.2017SGR1292), both from the Generalitat de Catalunya. L. Morey thanks the financial support of AGAUR, of the Generalitat de Catalunya (grant reference number 2019FI_B00694). We would like to thank the help of Celia Segura Godoy and Pau Berenguer i Planas during the sampling campaigns.Peer ReviewedPostprint (published version

Acidification and solar drying of manure-based digestate to produce improved fertilizing products

The increase in energy and fertilizer consumption makes it necessary to develop sustainable alternatives for agriculture. Anaerobic digestion and digestates appeared to be suitable options. However, untreated digestates still have high water content and can increase greenhouse gas emissions during storage and land application. In this study, manure-derived digestate and solid fraction of digestate after separation were treated with a novel solar drying technology to reduce their water content, combined with acidification to reduce the gaseous emissions. The acidified digestate and acidified solid fraction of digestate recovered more nitrogen and ammonia nitrogen than their respective non-acidified products (1.5–1.3 times for TN; 14 times for TAN). Ammonia and methane emissions were reduced up to 94% and 72% respectively, compared to the non-acidified ones, while N2O increased more than 3 times. Dried digestate and dried acidified digestate can be labeled as NPK organic fertilizer regarding the European regulation, and the dried solid fraction and the improved dried acidified solid fraction can be labeled as N or P organic fertilizer. Moreover, plant tests showed that N concentrations in fresh lettuce leaves were within the EU limit with all products in all the cases. However, zinc concentration appeared to be a limitation in some of the products as their concentration exceeded the European legal limitsinfo:eu-repo/semantics/publishedVersio

Hospital emergency department utilisation rates among the immigrant population in Barcelona, Spain

<p>Abstract</p> <p>Background</p> <p>The recent increase in the number of immigrants of Barcelona represents a challenge for the public healthcare system, the emergency department being the most used healthcare service by this group. However, utilisation rates in our environment have not yet been studied. We aimed to compare emergency department utilisation rates between Spanish-born and foreign-born residents in a public hospital of Barcelona.</p> <p>Methods</p> <p>The <it>s</it>tudy population included all adults residing in the area of study and visiting the emergency department of Hospital del Mar in 2004. The emergency care episodes were selected from the Emergency Department register, and the population figures from the Statistics Department of Barcelona. Emergency care episodes were classified into five large clinical categories. Adjusted rate ratios (RR) of utilisation among foreign-born vs. Spanish-born residents were assessed through negative binomial regression.</p> <p>Results</p> <p>The overall utilisation rate was 382 emergency contacts per 1,000 persons-years. The RR for foreign-born versus Spanish-born residents was 0.62 (95% CI: 0.52; 0.74%). The RR was also significantly below one in surgery (0.51, 95% CI: 0.42; 0.63), traumatology (0.47, 95% CI: 0.38; 0.59), medicine (0.48, 95% CI: 0.38; 0.59) and psychiatry (0.42, 95% CI: 0.18; 0.97). No differences were found in utilisation of gynaecology and minor emergency services.</p> <p>Conclusion</p> <p>The overall lower utilisation rates obtained for foreign-born residents is consistent with previous studies and is probably due to the "healthy immigrant effect". Thus, the population increase due to immigration does not translate directly into a corresponding increase in the number of emergency contacts. The lack of differences in minor and gynaecological emergency care supports the hypothesis that immigrants overcome certain barriers by using the emergency department to access to health services. The issue of healthcare barriers should therefore be addressed, especially among immigrants.</p

Communicative competence and institutional affiliation: interactional processes of identity construction by immigrant students in Catalonia

The growing presence of children of immigrant families in the public school system in the bilingual region of Catalonia provides us with an opportunity to study how young multilingual and multicultural speakers construct their social competencies and their identity within the specific context of a gate-keeping social institution such as the school. The study reported in this paper approaches language learning as a process of socialisation that involves not only learning how to make sense of linguistic signs but also learning how to enact different social roles in particular institutions. The analysis focuses on the interactional profiles of two immigrant students in two types of communicative activities that are representative of the school context: responding to questions from an adult and cooperating with a peer in the resolution of a learning task. By shifting the focus of analysis from a decontextualised notion of communicative competence to the notion of 'institutionally affiliated communicative competence' and concentrating on issues such as the (1) the relationship between knowledge and participation, (2) language choice inside and outside school and (3) definitions of correctness in language use, the study reveals how the two students construct a highly 'affiliated' identit

Impact of immigration on the cost of emergency visits in Barcelona (Spain)

BACKGROUND: The impact of immigration on health services utilisation has been analysed by several studies performed in countries with lower levels of immigration than Spain. These studies indicate that health services utilisation is lower among the immigrant population than among the host population and that immigrants tend to use hospital emergency services at the expense of primary care. We aimed to quantify the relative over-utilisation of emergency services in the immigrant population. METHODS: Emergency visits to Hospital del Mar in Barcelona in 2002 and 2003 were analysed. The country of origin, gender, age, discharge-related circumstances (hospital admission, discharge to home, or death), medical specialty, and variable cost related to medical care were registered. Immigrants were grouped into those from high-income countries (IHIC) and those from low-income countries (ILIC) and the average direct cost was compared by country of origin. A multivariate linear mixed model of direct costs was adjusted by country of origin (classified in five groups) and by the individual variables of age, gender, hospital admission, and death as a cause of discharge. Medical specialty was considered as a random effect. RESULTS: With the exception of gynaecological emergency visits, costs resulting from emergency visits by both groups of immigrants were lower than those due to visits by the Spanish-born population. This effect was especially marked for emergency visits by adults. CONCLUSION: Immigrants tend to use the emergency department in preference to other health services. No differences were found between IHIC and ILIC, suggesting that this result was due to the ease of access to emergency services and to lack of knowledge about the country's health system rather than to poor health status resulting from immigrants' socioeconomic position. The use of costs as a variable of complexity represents an opportunistic use of a highly exhaustive registry, which is becoming ever more frequent in hospitals and which overcomes the lack of clinical information related to outpatient activity