650 research outputs found
Delineation of site‐specific management zones using estimation of distribution algorithms
In this paper, we present a novel methodology to solve the problem of delineating homogeneous site-specific management zones (SSMZ) in agricultural fields. This problem consists of dividing the field into small regions for which a specific rate of inputs is required. The objec- tive is to minimize the number of management zones, which must be homogeneous according to a specific soil property: physical or chem- ical. Furthermore, as opposed to oval zones, SSMZ with rectangular shapes are preferable since they are more practical for agricultural technologies. The methodology we propose is based on evolutionary computation, specifically on a class of the estimation of distribution algorithms (EDAs). One of the strongest contributions of this study is the representation used to model the management zones, which gener- ates zones with orthogonal shapes, e.g., L or T shapes, and minimizes the number of zones required to delineate the field. The experimental results show that our method is efficient to solve real-field and ran- domly generated instances. The average improvement of our method consists in reducing the number of management zones in the agricul- tural fields concerning other operations research methods presented in the literature. The improvement depends on the size of the field and the level of homogeneity established for the resulting management zones.IT1244-19
TIN2016-78365-R
PID2019-104966GB-I0
Influence of telomerase activity and initial distribution on human follicular aging: Moving from a discrete to a continuum model
Producción CientíficaA discrete model is proposed for the temporal evolution of a population of cells sorted according to their telomeric length. This model assumes that, during cell division, the distribution of the genetic material to daughter cells is asymmetric, i.e. chromosomes of one daughter cell have the same telomere length as the mother, while in the other daughter cell telomeres are shorter. Telomerase activity and cell death are also taken into account. The continuous model is derived from the discrete model by introducing the generational age as a continuous variable in , being the Hayflick limit, i.e. the number of times that a cell can divide before reaching the senescent state. A partial differential equation with boundary conditions is obtained. The solution to this equation depends on the initial telomere length distribution. The initial and boundary value problem is solved exactly when the initial distribution is of exponential type. For other types of initial distributions, a numerical solution is proposed. The model is applied to the human follicular growth from preantral to preovulatory follicle as a case study and the aging rate is studied as a function of telomerase activity, the initial distribution and the Hayflick limit. Young, middle and old cell-aged initial normal distributions are considered. In all cases, when telomerase activity decreases, the population ages and the smaller the value, the higher the aging rate becomes. However, the influence of these two parameters is different depending on the initial distribution. In conclusion, the worst-case scenario corresponds to an aged initial telomere distribution.Ministerio de Ciencia e Innovación (PGC2018-101443-B-I00)CDTI and FEDER (IDI-20190160 and IDI-20181240)Instituto de Salud Carlos III (Spanish Government) (PI20/00252)FINOX through FORWARD 2018-6 to E.V. and J.A.G.V. and by IVIRMA (2004-FIVI-041-MV; 1711-FIVI-111-MV; 1707-FIVI-084-MV; 1711-FIVI-112-MV; 2207-MAD-093-MV)
Foraging habitat selection by gull–billed tern (Gelochelidon nilotica) in Central Spain (Castilla–La Mancha)
Foraging habitat selection by gull–billed tern (Gelochelidon nilotica) in Central Spain (Castilla–La Mancha). The
gull–billed tern breeds in temporary lakes in Castilla–La Mancha in Central Spain but depends on surrounding
land habitats to feed its chicks. It is therefore vital to know the type of environments it selects to capture prey
to feed nestlings. The aim of this study was to evaluate the use of habitats for hunting by adult gull–billed tern.
Of 66 lakes monitored between 1996 and 2016, we found the gull–billed tern used 12 for breeding. Each lake
was used during this period for 1–14 breeding seasons. We selected circular areas around the three wetlands
where the species bred in 2013 and 2014. Within these circles, we sampled a total of 60 random points and
recorded 125 gull–billed tern contacts (including between 1 and 39 birds). We estimated the same environmental
variables at contact and random points, including land use and the distance to the nearest wetland, the nearest
colony and to several types of anthropic uses (paved roads, houses, and cities). To evaluate habitat selection
we calculated the Manly selection index for soil use variables, and fitted linear mixed models to evaluate differences
in the distance variables. Land uses selected for foraging by the gull–billed tern were mainly cereal
crops, whereas vineyards were avoided. The birds foraged on average up to 2 km from the colonies and tended
to avoid proximity of towns and paved roads, suggesting that the species is sensitive to human disturbance.
Vineyards are the main land use in this region and the intensity is increasing. Our results suggest vineyards
should be limited in areas around these wetlands so that gull–billed terns may forage in their preferred sites
The reproductive microbiome – clinical practice recommendations for fertility specialists
The interest in and understanding of the human microbiome has grown remarkably over recent years. Advances in molecular techniques have allowed researchers to identify and study the microbiota and also use this information to develop therapeutic solutions for a spectrum of conditions. Alongside the growing interest in the microbiome, societal changes have resulted in many couples looking to start families later in life, therefore increasing the demand for as
Trends and outcome of neoadjuvant treatment for rectal cancer: A retrospective analysis and critical assessment of a 10-year prospective national registry on behalf of the Spanish Rectal Cancer Project
Introduction: Preoperative treatment and adequate surgery increase local control in rectal cancer. However, modalities and indications for neoadjuvant treatment may be controversial. Aim of this study was to assess the trends of preoperative treatment and outcomes in patients with rectal cancer included in the Rectal Cancer Registry of the Spanish Associations of Surgeons.
Method: This is a STROBE-compliant retrospective analysis of a prospective database. All patients operated on with curative intention included in the Rectal Cancer Registry were included. Analyses were performed to compare the use of neoadjuvant/adjuvant treatment in three timeframes: I)2006–2009; II)2010–2013; III)2014–2017. Survival analyses were run for 3-year survival in timeframes I-II.
Results: Out of 14, 391 patients, 8871 (61.6%) received neoadjuvant treatment. Long-course chemo/radiotherapy was the most used approach (79.9%), followed by short-course radiotherapy ± chemotherapy (7.6%). The use of neoadjuvant treatment for cancer of the upper third (15-11 cm) increased over time (31.5%vs 34.5%vs 38.6%, p = 0.0018). The complete regression rate slightly increased over time (15.6% vs 16% vs 18.5%; p = 0.0093); the proportion of patients with involved circumferential resection margins (CRM) went down from 8.2% to 7.3%and 5.5% (p = 0.0004). Neoadjuvant treatment significantly decreased positive CRM in lower third tumors (OR 0.71, 0.59–0.87, Cochrane-Mantel-Haenszel P = 0.0008). Most ypN0 patients also received adjuvant therapy. In MR-defined stage III patients, preoperative treatment was associated with significantly longer local-recurrence-free survival (p < 0.0001), and cancer-specific survival (p < 0.0001). The survival benefit was smaller in upper third cancers.
Conclusion: There was an increasing trend and a potential overuse of neoadjuvant treatment in cancer of the upper rectum. Most ypN0 patients received postoperative treatment. Involvement of CRM in lower third tumors was reduced after neoadjuvant treatment. Stage III and MRcN + benefited the most
Consenso sobre las actuaciones a seguir durante la edad fértil, el embarazo, el posparto y la lactancia en pacientes con psoriasis
Objetivo
Desarrollar recomendaciones basadas en la mejor evidencia y experiencia sobre el manejo de pacientes con psoriasis durante la edad fértil, el embarazo, el posparto y la lactancia.
Métodos
Se siguió la metodología de grupos nominales y Delphi. Se seleccionó un grupo director de expertos (12 dermatólogos —de los cuales 2 fueron los coordinadores—, 1 reumatólogo, 2 ginecólogos). Se realizó una revisión sistemática de la literatura sobre fertilidad, embarazo, posparto y lactancia en pacientes con psoriasis. Con esta información los coordinadores generaron una serie de recomendaciones preliminares. Todo ello se presentó y discutió con el resto de expertos en una reunión de grupo nominal donde se definió el alcance, los usuarios, los apartados del documento, y donde se generaron las recomendaciones definitivas. El grado de acuerdo con las recomendaciones se votó siguiendo la metodología Delphi, que se extendió a 51 dermatólogos más, según una escala de 1 (total desacuerdo) a 10 (total acuerdo), definiéndose el acuerdo como una puntuación = 7 por al menos el 70% de los participantes. El nivel de evidencia y el grado de recomendación se clasificaron según el modelo del Center for Evidence Based Medicine de Oxford. El documento completo final fue aprobado por el panel de expertos.
Resultados
Se generaron 23 recomendaciones sobre el periodo pre-concepcional (fertilidad y anticoncepción), el embarazo (planificación, manejo farmacológico y seguimiento) y la lactancia (manejo y seguimiento). Todas las recomendaciones menos una alcanzaron el nivel de acuerdo definido.
Conclusiones
En los pacientes con psoriasis en edad fértil estas recomendaciones pueden mejorar el manejo, los resultados y el pronóstico.
Objective
To develop evidence- and experience-based recommendations for the management of psoriasis during preconception, pregnancy, postpartum, and breastfeeding.
Methods
The nominal group technique and the Delphi method were used. Fifteen experts (12 dermatologists, 2 of whom were appointed coordinators; 1 rheumatologist; and 2 gynecologists) were selected to form an expert panel. Following a systematic review of the literature on fertility, pregnancy, postpartum, and breastfeeding in women with psoriasis, the coordinators drew up a series of preliminary recommendations for discussion by the panel at a nominal group meeting. The experts defined the scope, sections, and intended users of the statement and prepared a final list of recommendations. Consensus was obtained using a Delphi process in which an additional 51 dermatologists rated their level of agreement with each recommendation on a scale of 1 (total disagreement) to 10 (total agreement). Consensus was defined by a score of 7 or higher assigned by at least 70% of participants. Level of evidence and strength of recommendation were reported using the Oxford Center for Evidence-Based Medicine categories. The final statement was approved by the expert panel.
Results
The resulting consensus statement includes 23 recommendations on preconception (fertility and contraception), pregnancy (planning, pharmacological management, and follow-up), and breastfeeding (management and follow-up). Consensus was achieved for all recommendations generated except one.
Conclusions
These recommendations for the better management of psoriasis in women of childbearing age could improve outcomes and prognosis
Overview of recent TJ-II stellarator results
The main results obtained in the TJ-II stellarator in the last two years are reported. The most important topics investigated have been modelling and validation of impurity transport, validation of gyrokinetic simulations, turbulence characterisation, effect of magnetic configuration on transport, fuelling with pellet injection, fast particles and liquid metal plasma facing components. As regards impurity transport research, a number of working lines exploring several recently discovered effects have been developed: the effect of tangential drifts on stellarator neoclassical transport, the impurity flux driven by electric fields tangent to magnetic surfaces and attempts of experimental validation with Doppler reflectometry of the variation of the radial electric field on the flux surface. Concerning gyrokinetic simulations, two validation activities have been performed, the comparison with measurements of zonal flow relaxation in pellet-induced fast transients and the comparison with experimental poloidal variation of fluctuations amplitude. The impact of radial electric fields on turbulence spreading in the edge and scrape-off layer has been also experimentally characterized using a 2D Langmuir probe array. Another remarkable piece of work has been the investigation of the radial propagation of small temperature perturbations using transfer entropy. Research on the physics and modelling of plasma core fuelling with pellet and tracer-encapsulated solid-pellet injection has produced also relevant results. Neutral beam injection driven Alfvénic activity and its possible control by electron cyclotron current drive has been examined as well in TJ-II. Finally, recent results on alternative plasma facing components based on liquid metals are also presented. ISSN:0029-5515 ISSN:1741-432
Association of a single nucleotide polymorphism combination pattern of the Klotho gene with non-cardiovascular death in patients with chronic kidney disease
Chronic kidney disease (CKD) is associated with an elevated risk of all-cause mortality, with cardiovascular death being extensively investigated. However, non-cardiovascular mortality represents the biggest percentage, showing an evident increase in recent years. Klotho is a gene highly expressed in the kidney, with a clear influence on lifespan. Low levels of Klotho have been linked to CKD progression and adverse outcomes. Single nucleotide polymorphisms (SNPs) of the Klotho gene have been associated with several diseases, but studies investigating the association of Klotho SNPs with noncardiovascular death in CKD populations are lacking. The main aim of this study was to assess whether 11 Klotho SNPs were associated with non-cardiovascular death in a subpopulation of the National Observatory of Atherosclerosis in Nephrology (NEFRONA) study (n ¼ 2185 CKD patients). After 48 months of follow-up, 62 cardiovascular deaths and 108 non-cardiovascular deaths were recorded. We identified a high non-cardiovascular death risk combination of SNPs corresponding to individuals carrying the most frequent allele (G) at rs562020, the rare allele (C) at rs2283368 and homozygotes for the rare allele (G) at rs2320762 (rs562020 GG/AG þ rs2283368 CC/CT þ rs2320762 GG). Among the patients with the three SNPs genotyped (n ¼ 1016), 75 (7.4%) showed this combination. Furthermore, 95 (9.3%) patients showed a low-risk combination carrying all the opposite genotypes (rs562020 AA þ rs2283368 TT þ rs2320762 GT/TT). All the other combinations [n ¼ 846 (83.3%)] were considered as normal risk. Using competing risk regression analysis, we confirmed that the proposed combinations are independently associated with a higher fhazard ratio [HR] 3.28 [confidence interval (CI) 1.51-7.12]g and lower [HR 6 × 10- (95% CI 3.3 × 10--1.1 × 10-)] risk of suffering a non-cardiovascular death in the CKD population of the NEFRONA cohort compared with patients with the normal-risk combination. Determination of three SNPs of the Klotho gene could help in the prediction of non-cardiovascular death in CKD
Association of candidate gene polymorphisms with chronic kidney disease : Results of a case-control analysis in the NEFRONA cohort
Chronic kidney disease (CKD) is a major risk factor for end-stage renal disease, cardiovascular disease and premature death. Despite classical clinical risk factors for CKD and some genetic risk factors have been identified, the residual risk observed in prediction models is still high. Therefore, new risk factors need to be identified in order to better predict the risk of CKD in the population. Here, we analyzed the genetic association of 79 SNPs of proteins associated with mineral metabolism disturbances with CKD in a cohort that includes 2,445 CKD cases and 559 controls. Genotyping was performed with matrix assisted laser desorption ionization-time of flight mass spectrometry. We used logistic regression models considering different genetic inheritance models to assess the association of the SNPs with the prevalence of CKD, adjusting for known risk factors. Eight SNPs (rs1126616, rs35068180, rs2238135, rs1800247, rs385564, rs4236, rs2248359, and rs1564858) were associated with CKD even after adjusting by sex, age and race. A model containing five of these SNPs (rs1126616, rs35068180, rs1800247, rs4236, and rs2248359), diabetes and hypertension showed better performance than models considering only clinical risk factors, significantly increasing the area under the curve of the model without polymorphisms. Furthermore, one of the SNPs (the rs2248359) showed an interaction with hypertension, being the risk genotype affecting only hypertensive patients. We conclude that 5 SNPs related to proteins implicated in mineral metabolism disturbances (Osteopontin, osteocalcin, matrix gla protein, matrix metalloprotease 3 and 24 hydroxylase) are associated to an increased risk of suffering CKD
Consenso Mexicano de Hepatitis Alcohólica
La hepatitis alcohólica es una condición frecuente en la población mexicana, se
caracteriza por insuficiencia hepática aguda sobre crónica, importante reacción inflamatoria
sistémica y fallo multiorgánico, que en la variante grave de la enfermedad implica una elevada
mortalidad. Por lo anterior, la Asociación Mexicana de Gastroenterología y la Asociación Mexicana
de Hepatología conjuntaron un equipo multidisciplinario de profesionales de la salud para
elaborar el primer consenso mexicano de hepatitis alcohólica. El consenso fue elaborado con la
metodología Delphi, emitiendo 37 recomendaciones. La enfermedad hepática relacionada con
el consumo de alcohol comprende un amplio espectro, que incluye esteatosis, esteatohepatitis,
fibrosis en diferentes grados, cirrosis y sus complicaciones. La hepatitis alcohólica grave se
define por una función modificada de Maddrey
≥
32 o por un puntaje de MELD (Model for End-
Stage Liver Disease) igual o mayor a 21. Actualmente no existe un biomarcador específico para el diagnóstico. La presencia de leucocitosis con neutrofilia, hiperbilirrubinemia (> 3 mg/dL),AST > 50 U/L ( 1.5-2 pueden orientar al diagnóstico. La piedraangular del tratamiento es la abstiencia junto con el soporte nutricional. Los esteroides estanindicados en la forma grave, en donde han resultado efectivos para reducir la mortalidad a28 días. El trasplante hepático es en la actualidad la única opción con que se cuenta parasalvar la vida de pacientes que no responden a los esteroides. Ciertos fármacos, como la N-acetilcisteína, el factor estimulante de colonias de granulocitos y la metadoxina, pueden seruna terapia adyuvante que puede mejorar la supervivencia de los pacientes
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