Drawing Planar Graphs with Few Geometric Primitives

We define the \emph{visual complexity} of a plane graph drawing to be the number of basic geometric objects needed to represent all its edges. In particular, one object may represent multiple edges (e.g., one needs only one line segment to draw a path with an arbitrary number of edges). Let $n$ denote the number of vertices of a graph. We show that trees can be drawn with $3n/4$ straight-line segments on a polynomial grid, and with $n/2$ straight-line segments on a quasi-polynomial grid. Further, we present an algorithm for drawing planar 3-trees with $(8n-17)/3$ segments on an $O(n)\times O(n^2)$ grid. This algorithm can also be used with a small modification to draw maximal outerplanar graphs with $3n/2$ edges on an $O(n)\times O(n^2)$ grid. We also study the problem of drawing maximal planar graphs with circular arcs and provide an algorithm to draw such graphs using only $(5n - 11)/3$ arcs. This is significantly smaller than the lower bound of $2n$ for line segments for a nontrivial graph class.Comment: Appeared at Proc. 43rd International Workshop on Graph-Theoretic Concepts in Computer Science (WG 2017

Lombardi Drawings of Graphs

We introduce the notion of Lombardi graph drawings, named after the American abstract artist Mark Lombardi. In these drawings, edges are represented as circular arcs rather than as line segments or polylines, and the vertices have perfect angular resolution: the edges are equally spaced around each vertex. We describe algorithms for finding Lombardi drawings of regular graphs, graphs of bounded degeneracy, and certain families of planar graphs.Comment: Expanded version of paper appearing in the 18th International Symposium on Graph Drawing (GD 2010). 13 pages, 7 figure

Sexual orientation and symptoms of common mental disorder or low wellbeing: combined meta-analysis of 12 UK population health surveys

Background Previous studies have indicated increased risk of mental disorder symptoms, suicide and substance misuse in lesbian, gay and bisexual (LGB) adults, compared to heterosexual adults. Our aims were to determine an estimate of the association between sexual orientation identity and poor mental health and wellbeing among adults from 12 population surveys in the UK, and to consider whether effects differed for specific subgroups of the population. Methods Individual data were pooled from the British Cohort Study 2012, Health Survey for England 2011, 2012 and 2013, Scottish Health Survey 2008 to 2013, Longitudinal Study of Young People in England 2009/10 and Understanding Society 2011/12. Individual participant meta-analysis was used to pool estimates from each study, allowing for between-study variation. Results Of 94,818 participants, 1.1 % identified as lesbian/gay, 0.9 % as bisexual, 0.8 % as ‘other’ and 97.2 % as heterosexual. Adjusting for a range of covariates, adults who identified as lesbian/gay had higher prevalence of common mental disorder when compared to heterosexuals, but the association was different in different age groups: apparent for those under 35 (OR = 1.78, 95 % CI 1.40, 2.26), weaker at age 35–54.9 (OR = 1.42, 95 % CI 1.10, 1.84), but strongest at age 55+ (OR = 2.06, 95 % CI 1.29, 3.31). These effects were stronger for bisexual adults, similar for those identifying as ‘other’, and similar for 'low wellbeing'. Conclusions In the UK, LGB adults have higher prevalence of poor mental health and low wellbeing when compared to heterosexuals, particularly younger and older LGB adults. Sexual orientation identity should be measured routinely in all health studies and in administrative data in the UK in order to influence national and local policy development and service delivery. These results reiterate the need for local government, NHS providers and public health policy makers to consider how to address inequalities in mental health among these minority groups

Effect of sirolimus on malignancy and survival after kidney transplantation: systematic review and meta-analysis of individual patient data

Objective To examine risk of malignancy and death in patients with kidney transplant who receive the immunosuppressive drug sirolimus.Design Systematic review and meta-analysis of individual patient data.Data sources Medline, Embase, and the Cochrane Central Register of Controlled Trials from inception to March 2013.Eligibility Randomized controlled trials comparing immunosuppressive regimens with and without sirolimus in recipients of kidney or combined pancreatic and renal transplant for which the author was willing to provide individual patient level data. Two reviewers independently screened titles/abstracts and full text reports of potentially eligible trials to identify studies for inclusion. All eligible trials reported data on malignancy or survival.Results the search yielded 2365 unique citations. Patient level data were available from 5876 patients from 21 randomized trials. Sirolimus was associated with a 40% reduction in the risk of malignancy (adjusted hazard ratio 0.60, 95% confidence interval 0.39 to 0.93) and a 56% reduction in the risk of non-melanoma skin cancer (0.44, 0.30 to 0.63) compared with controls. the most pronounced effect was seen in patients who converted to sirolimus from an established immunosuppressive regimen, resulting in a reduction in risk of malignancy (0.34, 0.28 to 0.41), non-melanoma skin cancer (0.32, 0.24 to 0.42), and other cancers (0.52, 0.38 to 0.69). Sirolimus was associated with an increased risk of death (1.43, 1.21 to 1.71) compared with controls.Conclusions Sirolimus was associated with a reduction in the risk of malignancy and non-melanoma skin cancer in transplant recipients. the benefit was most pronounced in patients who converted from an established immunosuppressive regimen to sirolimus. Given the risk of mortality, however, the use of this drug does not seem warranted for most patients with kidney transplant. Further research is needed to determine if different populations, such as those at high risk of cancer, might benefit from sirolimus.PfizerOttawa Hosp, Res Inst, Ottawa, ON K1H 7W9, CanadaUniv Ottawa, Ottawa, ON, CanadaCairo Univ, Cairo Kidney Ctr, Cairo, EgyptLimites Med Res, Vacallo, SwitzerlandUniv Manitoba, Dept Pediat & Childs Hlth, Winnipeg, MB, CanadaLund Univ, Dept Nephrol & Transplantat, Malmo, SwedenUniversidade Federal de São Paulo, Hosp Rim & Hipertensao, São Paulo, BrazilAddenbrookes Hosp, Dept Renal Med, Cambridge, EnglandNorthwestern Univ, Feinberg Sch Med, Chicago, IL 60611 USAMaastricht Univ, Med Ctr, Maastricht, NetherlandsSt Louis Hosp, Dept Nephrol, Paris, FranceHosp JW Goethe, Div Nephrol, Frankfurt, GermanyUniv Munich, Dept Surg, Munich, GermanyGoethe Univ Frankfurt, JW Goethe Clin, Clin Dermatol Venerol & Allergol, Frankfurt, GermanyInst Klin Expt Med, Dept Nephrol, Prague, Czech RepublicUniv Cambridge, Addenbrookes Hosp, Dept Surg, NIHR Cambridge Biomed Res Ctr, Cambridge CB2 2QQ, EnglandUniversidade Federal de São Paulo, Hosp Rim & Hipertensao, São Paulo, BrazilWeb of Scienc

Efecto promotor del agregado de rodio a catalizadores de Co/ZnAl2O4 para la combustión catalítica de hidrocarburos

Una serie de catalizadores de cobalto soportados sobre aluminato de zinc (Cox-ZnAl) modificados con Rh, fue preparada, caracterizada mediante diversas técnicas (BET, XRD, TPR, DRS, FTIR y XPS) y aplicados en las reacciones de oxidación catalítica de propano y naftaleno

Hacia la valorización de neumáticos fuera de uso mediante pirólisis catalítica: efecto del catalizador sobre la distribución de productos

La disposición de los neumáticos fuera de uso (NFU) se ha convertido en una gran preocupación a nivel mundial, debido a que se requieren grandes extensiones para su almacenamiento y estos lugares se convierten en focos de incendios o de propagación de enfermedades

Síntesis de catalizadores metálicos a partir de la perovskita tipo LaNi0.38B(Fe,Ti,Al)0.62O3-δ: influencia del sitio B en la exsolución del Ni y su comportamiento durante la reacción de reformado de etanol con vapor para la producción de hidrógeno

 En el presente estudio se sintetizaron catalizadores metálicos de Ni a partir de las perovskitas tipo LaNi0.38B0.62O3-δ (donde B= Ti, Al, Fe) mediante el método de exsolución, a dos temperaturas diferentes, 500 y 750°C, con el fin de evaluar tanto la influencia de la naturaleza química del sitio B, como la temperatura de reducción en la tendencia de exsolución de Ni0 y su actividad catalítica en la reacción de reformado de etanol con vapor. La caracterización por Difracción de Rayos X (DRX), demostró la formación de las perovskitas dopadas y confirmaron la exsolución de Ni después de la reducción. Estos resultados sugieren que la difusión del Ni se vio favorecida por la presencia de cationes reducibles en el sitio B, los cuales podrían promover la formación de vacancias de oxígeno. Entre los catalizadores evaluados, se observó que los catalizadores reducidos de LaNi0.38Ti0.62O3-δ y LaNi0.38Al0.62O3-δ reducido a 750°C exhibieron los mayores rendimientos a H2

Pirólisis de biomasa residual procedente de restos de poda urbana y valorización catalítica del biolíquido

En este trabajo se estudia la pirólisis de restos de Platanus × hispánica proveniente de poda urbana de la ciudad de Junín. Se utilizaron muestras de biomasa sin tratar y con diferentes pre-tratamientos básicos (KOH al 2%, 5%, 10% y 20% p/p). Se determinó la composición de las muestras en cuanto a contenido de humedad, cenizas y carbohidratos estructurales y se estudiaron por análisis termogravimétrico (TGA). En el caso de la muestra sin tratamiento previo, el rendimiento a biolíquido (BL) fue de 34.43% mientras que, de las muestras pre-tratadas con base, el rendimiento máximo a BL fue de 29,33% con KOH al 5% y presentan compuestos de bajo peso molecular, principalmente especies de uno, dos y tres carbonos como metanol, etilenglicol, además de ácido acético y compuestos de tipo fenólicos. El BL obtenido se valorizó mediante una reacción de esterificación con etilenglicol, usando un líquido iónico como catalizador, obteniéndose un extracto orgánico con 63% de monoacetato de etilenglicol y 37% de diacetato de etilenglicol

Mitigación de acidez de bio-oils debida a la presencia de ácidos orgánicos volátiles mediante catalizadores heterogéneos

Los bio-oils son potenciales combustibles y materias primas para obtener catalíticamente hidrocarburos. Para poder coprocesar un bio-oil en la refinería es necesario eliminar la alta acidez. Los ácidos orgánicos volátiles como el ácido acético (se encuentra en mayor concentración) y fórmico son los responsables de la acidez.&nbsp

Efficient Enumeration of Bipartite Subgraphs in Graphs

Subgraph enumeration problems ask to output all subgraphs of an input graph that belongs to the specified graph class or satisfy the given constraint. These problems have been widely studied in theoretical computer science. As far, many efficient enumeration algorithms for the fundamental substructures such as spanning trees, cycles, and paths, have been developed. This paper addresses the enumeration problem of bipartite subgraphs. Even though bipartite graphs are quite fundamental and have numerous applications in both theory and application, its enumeration algorithms have not been intensively studied, to the best of our knowledge. We propose the first non-trivial algorithms for enumerating all bipartite subgraphs in a given graph. As the main results, we develop two efficient algorithms: the one enumerates all bipartite induced subgraphs of a graph with degeneracy $k$ in $O(k)$ time per solution. The other enumerates all bipartite subgraphs in $O(1)$ time per solution