Parameterized Complexity of Biclique Contraction and Balanced Biclique Contraction

In this work, we initiate the complexity study of Biclique Contraction and Balanced Biclique Contraction. In these problems, given as input a graph G and an integer k, the objective is to determine whether one can contract at most k edges in G to obtain a biclique and a balanced biclique, respectively. We first prove that these problems are NP-complete even when the input graph is bipartite. Next, we study the parameterized complexity of these problems and show that they admit single exponential-time FPT algorithms when parameterized by the number k of edge contractions. Then, we show that Balanced Biclique Contraction admits a quadratic vertex kernel while Biclique Contraction does not admit any polynomial compression (or kernel) under standard complexity-theoretic assumptions

Coexisting aegirine and magnesioriebeckite from Bababudan Hills, Mysore State

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Flares on AM Canum Venaticorum

AM CVn, an interacting binary system consisting of two helium white dwarfs, has been classified as a nova-like object. Normally it exhibits only small amplitude modulations of 0.05 mag with a 1051 s periodicity. The authors report what is believed to be for the first time, two unusually intense optical flares in AM CVn during 1985-87. The characteristics of the two flares in white light observed on 1985 February 24 and 1986 February 7 with Δm=0.34 and Δm=1.07 respectively are described. The authors estimate the maximum amount of energy released from these flares as 2.7×1036 erg and suggest in the light of current models possible sites of origin of the flaring activity

Pricing reverse mortgages in Spain

[EN] In Spain, as in other European countries, the continuous ageing of the population creates a need for long-term care services and their financing. However, in Spain the development of this kind of services is still embryonic. The aim of this article is to obtain a calculation method for reverse mortgages in Spain based on the fit and projection of dynamic tables for Spanish mortality, using the Lee and Carter model. Mortality and life expectancy for the next 20 years are predicted using the fitted model, and confidence intervals are obtained from the prediction errors of parameters for the mortality index of the model. The last part of the article illustrates an application of the results to calculate the reverse mortgage model promoted by the Spanish Instituto de Crédito Oficial (Spanish State Financial Agency), for which the authors have developed a computer application.The authors are indebted to Jose Garrido, whose suggestions improved the original manuscript, and to the anonymous referee for his/her valuable comments. This work was partially supported by grants from the MEyC (Ministerio de Educacio´n y Ciencia, Spain), projects MTM2010- 14961 and MTM2008-05152.Debón Aucejo, AM.; Montes, F.; Sala, R. (2013). Pricing reverse mortgages in Spain. European Actuarial Journal. 3:23-43. https://doi.org/10.1007/s13385-013-0071-yS23433Blay-Berrueta D (2007) Sistemas de cofinaciaciación de la dependencia: seguro privado frente a hipoteca inversa. Cuadernos de la Fundación, Fundación Mapfre Estudios, Madrid.Booth H (2006) Demographic forecasting: 1980 to 2005 in review. Int J Forecast 22(3):547–582Booth H, Hyndman R, Tickle L, de Jong P (2006) Lee–Carter mortality forecasting: a multi-country comparison of variants and extensions. Demogr Res 15(9):289–310Booth H, Maindonald J, Smith L (2002) Applying Lee–Carter under conditions of variable mortality decline. Popul Stud 56(3):325–336Booth H, Tickle L (2003) The future aged: new projections of Australia’s ederly population. Popul Stud 22(4):38–44Brouhns N, Denuit M, Keilegom IV (2005) Bootstrapping Poisson log-bilinear model for mortality forecasting. Scand Actuar J 2005(3):212–224Brouhns N, Denuit M, Vermunt J (2002) A Poisson log-bilinear regression approach to the construction of projected lifetables. Insur Math Econ 31(3):373–393Carter L, Lee R (1992) Modeling and forecasting US sex differentials in mortality. Int J Forecast 8(3):393–411Carter L, Prkawetz A (2001) Examining structural shifs in mortality using the Lee–Carter method. Mpidr wp 2001–2007, Center for Demography and Ecology Information, University of Wisconsin-Madison.Chinloy P, Megbolugbe I (1994) Reverse mortgages: contracting and crossover. J Am Real Estate Urban Econ Assoc 22(2):367–386Coale A, Guo G (1989) Revisited regional model life tables at very low levels of mortality. Popul Index 55:613–643Coale A, Kisker E (1990) Defects in data old age mortality in the United States: New procedures for calculating approximately accurate mortality schedules and lifes tables at the highest ages. Asian Pac Popul Forum 4:1–31Cossette H, Delwarde A, Denuit M, Guillot F, Étienne M (2007) Pension plan valuation and mortality projection: a case study with mortality data. N Am Actuar J 11(2):1–34.Costa-Font J (2009) Ageing in place? exploring elderly people’s housing preferences in Spain. Urban Stud 46(2):295–316Costa-Font J (2013) Housing-related well-being in older people: the impact of environmental and financial influences. Urban Stud 50(4):657–673Currie I, Kirkby J, Durban M, Eilers P (2004) Smooth Lee–Carter models and beyond. In: Workshop on Lee–Carter Methods, http://www.ma.hw.ac.uk/~iain/workshop/workshop.html . Accessed 4 Mar 2005Czado C, Delwarde A, Denuit M (2005) Bayesian Poisson log-bilinear mortality projections. Insur Math Econ 36(3):260–284D’Amato V, Haberman S, Piscopo G, Russolillo M (2012) Modelling dependent data for longevity projections. Insur Math Econ 51(3):694–701Davidoff T (2012) Can ‘high costs’ justify weak demand for the home equity conversion mortgage? Technical report, available at SSRNDavidoff T, Welke G (2007) Selection and moral hazard in the reverse mortgage market. Technical report, Haas School of Business, UC BerkeleyDebón A, Montes F, Mateu J, Porcu E, Bevilacqua M (2008) Modelling residuals dependence in dymanic life tables. Comput Stat Data Anal 52(3):3128–3147Debón A, Montes F, Puig F (2008) Modelling and forecasting mortality in Spain. Eur J Oper Res 189(3):624–637Debón A, Montes F, Sala R (2009) Tablas de mortalidad dinámicas. Una aplicación a la hipoteca inversa en España. Fundación ICO. Publicaciones de la Universitat de Valéncia, ValenciaDebón A, Montes F, Martínez-Ruiz F (2011) Statistical methods to compare mortality for a group with non-divergent populations: an application to Spanish regions. Eur Actuar J 1:291–308Delwarde A, Denuit M, Eilers P (2007) Smoothing the Lee–Carter and poisson log-bilinear models for mortality forecasting: a penalized log-likelihood approach. Stat Modell 7(1):29–48Denuit M (2007) Distribution of the random future life expectancies in log-bilinear mortality projections models. Lifetime Data Anal 13(3):381–397Denuit M, Goderniaux A (2004) Closing and projecting lifetables using log-linear models. Mitteilungen. der Schweizerischen Aktuarvereingung 1:29–49Felipe A, Guillén M, Pérez-Marín A (2002) Recent mortality trends in the Spanish population. Br Actuar J 8(4):757–786.Forfar D, McCutcheon J, Wilkie A (1988) On graduation by mathematical formula. J Inst Actuar 115(459):1–149Guillen M, Vidiella-i-Anguera A (2005) Forecasting Spanish natural life expectancy. Risk Anal 25(5):1161–1170Heligman L, Pollard J (1980) The age pattern of mortality. J Inst Actuar 107:49–80Herranz-Gonzalez R (2006) Hipoteca inversa y figuras afines. Informes Portal Mayores 49, IMSERSO, Madrid, http://www.imsersomayores.csic.es/documentos/documentos/herranz-hipoteca-01.pdfHoriuchi S, Wilmoth J (1998) Decelaration in the age pattern of mortality at older ages. Demography 35:391–412Hyndman RJ (2008) Forecast: forecasting functions for time series. R package version 1.11Koissi M, Shapiro A, Hgns G (2006) Evaluating and extending the Lee–Carter model for mortality forecasting confidence interval. Insur Math Econ 38(1):1–20Kutty N (1998) The scope for poverty alleviation among elderly home-owners in the United States through reverse mortgages. Urban Stud 35(1):113–129Lee R (2000) The Lee–Carter method for forecasting mortality, with various extensions and applications. N Am Actuar J 4(1):80–91Lee R, Carter L (1992) Modelling and forecasting US mortality. J Am Stat Assoc 87(419):659–671Lee R, Nault F (1993) Modeling and forecasting provincial mortality in Canada. Montreal world congress of the International Union for Scientific Study of PopulationLee R, Rofman R (1994) Modelación y Proyección de la mortalidad en Chile. Notas Poblacin 22(59):182–213Li N, Lee R (2005) Coherent mortality forecast for a group of populations: an extension of the Lee–Carter method. Demography 42(3):575–593Li S-H, Hardy M, Tan K (2009) Uncertainty in mortality forecasting: an extensin to the classical Lee–Carter approach. Astin Bull 31:137–164Lindbergson M (2001) Mortality among the elderly in Sweden. Scan Actuar J 1:79–94Liu X, Braun WJ (2010) Investigating mortality uncertainty using the block bootstrap. J Probab Stat 2010:385–399McNown R, Rogers A (1989) Forecasting mortality: a parametrized time series aproach. Demography 26(4):645–660McNown R, Rogers A (1992) Forecasting cause-specific mortality using time series methods. Int J Forecast 8(3):413–432Miceli T, Sirmans C (1994) Reverse mortgages and borrower maintenance risk. J Am Real Estate Urban Econ Assoc 22(2):433–450Pedroza C (2006) A bayesian forecasting model: predicting US male mortality. Biostatistics 7(4):530–550Renshaw A, Haberman S (2003) Lee–Carter mortality forecasting: a parallel generalized linear modelling aproach for England and Wales mortality projections. J R Stat Soc C 52(1):119–137Renshaw A, Haberman S (2003) Lee–Carter mortality forecasting with age specific enhancement. Insur Math Econ 33(2):255–272Renshaw A, Haberman S (2003) On the forecasting of mortality reduction factors. Insur Math Econ 32(3):379–401Renshaw A, Haberman S (2006) A cohort-based extension to the Lee–Carter model for mortality reduction factors. Insur Math Econ 38(3):556–570Renshaw A, Haberman S (2008) On simulation-based approaches to risk measurement in mortality with specific reference to poisson Lee–Carter modelling. Insur Math Econ 42(2):797–816Shiller R, Weiss A (2000) Moral hazard in home equity conversion. Real Estate Econ 28(1):1–31Skarr D (2008) Financial planner’s guide to the FHA insured home equity conversion mortgage. J Financ Plan 21(5):68–75Sánchez-Álvarez I, Lpez-Ares S, Quiroga-García R (2007) Diseño de hipotecas inversas en el mercado español. Proyecto 205/05 3, Instituto de Mayores y Servicios SocialesTaffin C (2006) La hipoteca inversa o vitalicia. Informes externos, Asociación Hipotecaria EspañolaThatcher A, Kannisto V, Andreev K (2002) The survivor ratio method for estimating numbers at high ages. Demogr Res 6(1):1–18Thatcher A, Kannisto V, Vaupel J (1998) The force of mortality at ages 80 to 120. Odense University Press, OdenseTuljapurkar S, Li N, Boe C (2000) A universal pattern of mortality decline in the G7 countries. Nature 405(6788):789–792Wang L, Valdez E, Piggott J (2008) Securization of longevity risk in reverse mortgages. N Am Actuar J 12(4):345–370Wilmoth J (1993) Computational methods for fitting and extrapolating the Lee–Carter model of mortality change. Technical report, Departament of Demography, University of California, BerkeleyWilmoth J (1996) Health and mortality among elderly populations, chapter mortality projections for Japan: a comparison of four methods. Oxford University Press, Oxford, pp 266–28

3D Real-Time Echocardiography Combined with Mini Pressure Wire Generate Reliable Pressure-Volume Loops in Small Hearts

BACKGROUND: Pressure-volume loops (PVL) provide vital information regarding ventricular performance and pathophysiology in cardiac disease. Unfortunately, acquisition of PVL by conductance technology is not feasible in neonates and small children due to the available human catheter size and resulting invasiveness. The aim of the study was to validate the accuracy of PVL in small hearts using volume data obtained by real-time three-dimensional echocardiography (3DE) and simultaneously acquired pressure data. METHODS: In 17 piglets (weight range: 3.6–8.0 kg) left ventricular PVL were generated by 3DE and simultaneous recordings of ventricular pressure using a mini pressure wire (PVL3D). PVL3D were compared to conductance catheter measurements (PVLCond) under various hemodynamic conditions (baseline, alpha-adrenergic stimulation with phenylephrine, beta-adrenoreceptor-blockage using esmolol). In order to validate the accuracy of 3D volumetric data, cardiac magnetic resonance imaging (CMR) was performed in another 8 piglets. RESULTS: Correlation between CMR- and 3DE-derived volumes was good (enddiastolic volume: mean bias -0.03ml ±1.34ml). Computation of PVL3D in small hearts was feasible and comparable to results obtained by conductance technology. Bland-Altman analysis showed a low bias between PVL3D and PVLCond. Systolic and diastolic parameters were closely associated (Intraclass-Correlation Coefficient for: systolic myocardial elastance 0.95, arterial elastance 0.93, diastolic relaxation constant tau 0.90, indexed end-diastolic volume 0.98). Hemodynamic changes under different conditions were well detected by both methods (ICC 0.82 to 0.98). Inter- and intra-observer coefficients of variation were below 5% for all parameters. CONCLUSIONS: PVL3D generated from 3DE combined with mini pressure wire represent a novel, feasible and reliable method to assess different hemodynamic conditions of cardiac function in hearts comparable to neonate and infant size. This methodology may be integrated into clinical practice and cardiac catheterization programs and has the capability to contribute to clinical decision making even in small hearts

Transcultural Diabetes Nutrition Therapy Algorithm: The Asian Indian Application

India and other countries in Asia are experiencing rapidly escalating epidemics of type 2 diabetes (T2D) and cardiovascular disease. The dramatic rise in the prevalence of these illnesses has been attributed to rapid changes in demographic, socioeconomic, and nutritional factors. The rapid transition in dietary patterns in India—coupled with a sedentary lifestyle and specific socioeconomic pressures—has led to an increase in obesity and other diet-related noncommunicable diseases. Studies have shown that nutritional interventions significantly enhance metabolic control and weight loss. Current clinical practice guidelines (CPGs) are not portable to diverse cultures, constraining the applicability of this type of practical educational instrument. Therefore, a transcultural Diabetes Nutrition Algorithm (tDNA) was developed and then customized per regional variations in India. The resultant India-specific tDNA reflects differences in epidemiologic, physiologic, and nutritional aspects of disease, anthropometric cutoff points, and lifestyle interventions unique to this region of the world. Specific features of this transculturalization process for India include characteristics of a transitional economy with a persistently high poverty rate in a majority of people; higher percentage of body fat and lower muscle mass for a given body mass index; higher rate of sedentary lifestyle; elements of the thrifty phenotype; impact of festivals and holidays on adherence with clinic appointments; and the role of a systems or holistic approach to the problem that must involve politics, policy, and government. This Asian Indian tDNA promises to help guide physicians in the management of prediabetes and T2D in India in a more structured, systematic, and effective way compared with previous methods and currently available CPGs

Stock markets and effective exchange rates in European countries: threshold cointegration findings

© 2015, Eurasia Business and Economics Society. The nexus between stock markets and exchange rates is examined in the case of eight European countries. The sample consists of four economies with national currencies and four that have adopted the euro. Thus, if differences between the two groups in the relationship governing the two markets exist, they will be unveiled. To this effect, a threshold cointegration methodology is adopted that allows for more reliable inferences to be drawn for both the short and long run nexus between the two markets. Monthly data is used covering the period 01/2000–12/2014. The findings reported herein offer support in favor of the portfolio approach thesis over the recent economic crisis period, but this finding is not the case for the entire sample. Bidirectional causality is found for Norway and the UK, pointing to a currency effect on stock markets. In view of the findings reported herein, policies aiming at reducing uncertainty in the stock markets can exert beneficial effects on currency markets