1,231 research outputs found
Is the incidence of dementia declining?
No full textAction on preventative health could lower the risk of dementia for future generations, argues this report.
Executive summary
The world-wide projections of the prevalence of dementia in the coming decades have been a source of great concern to health systems and societies around the world. The World Alzheimer Report 2010 estimated that there were 36 million people with dementia in 2010, with an expected doubling every 20 years to nearly 115 million in 2050. These sobering figures are based on assumptions that the age-adjusted prevalence of dementia would remain constant and the population would continue to age at the current rate.
The assumption that the incidence of dementia will remain stable is now being put into question. There is emerging evidence to suggest that the incidence of dementia in older individuals may be declining. It appears that this change may be recent and has possibly occurred only in the last one to two decades. It may also be restricted so far to high income countries, although data from low and middle income countries are lacking.
The reasons for this change are not understood, but education, more stimulating environments and better control of vascular risk factors may have contributed. The data are still preliminary and more studies are needed to establish the extent of this change and understand its causes. It should be noted that the decline is not large enough to offset the increase in prevalence of dementia due to the ageing of the population and therefore investment and efforts to develop better treatments and care for people with dementia need to continue.
The fact that dementia rates are malleable is an encouraging finding but the reduction cannot be taken for granted as gains in population health can easily be lost if societies do not remain vigilant and continually proactive. These preliminary findings provide a strong argument for large scale Government investment in dementia-prevention strategies, which should start from early life
Generalized Burgers equations and Euler–Painlevé transcendents. III
No full textIt was proposed earlier [P. L. Sachdev, K. R. C. Nair, and V. G. Tikekar, J. Math. Phys. 27, 1506 (1986); P. L. Sachdev and K. R. C. Nair, ibid. 28, 977 (1987)] that the Euler–Painlevé equations y(d2y/dη2)+a(dy/dη)2+f(η)y(dy/dη)+g(η)y2+b(dy/dη)+c=0 represent generalized Burgers equations (GBE's) in the same way as Painlevé equations represent the Korteweg–de Vries type of equations. The earlier studies were carried out in the context of GBE's with damping and those with spherical and cylindrical symmetry. In the present paper, GBE's with variable coefficients of viscosity and those with inhomogeneous terms are considered for their possible connection to Euler–Painleve equations. It is found that the Euler–Painlevé equation, which represents the GBE ut+uβux=(δ/2)g(t)uxx, g(t)=(1+t)n, β>0, has solutions, which either decay or oscillate at η=±∞, only when -1<n<1. The solutions are shocklike when η=1. On the other hand, they oscillate over the whole real line when n=-1. Furthermore, the solutions monotonically decay both at η=+∞ and η=-∞, that is, they have a single hump form if β≥βn=(1-n)/(1+n). For β<βn, the solutions have an oscillatory behavior either at η=+∞ or at η=-∞, or at η=+∞ and η=-∞. For β=βn, there exists a single parameter family of exact single hump solutions, similar to those found for the nonplanar Burgers equations in Paper II. Thus the parametric value β=βn seems to bifurcate the families of solutions, which remain bounded at η=±∞. Other GBE's considered here are also found to be reducible to Euler–Painlevé equations.The scope of these equations is broadened by relating them to a large number of nonlinear DE's selected from the compendia of Kamke [Differential Gleichungen : Lô sungsmethoden und Lô sungen (Akademische Verlagsgesellschaft, Leipzig, 1943)] and Murphy [Ordinary Differential Equations and their Solutions (Van Nostrand, Princeton, NJ, 1960)]. These latter equations arise from a wide range of physical applications and are of some historical interest as well. They are all special cases of a slightly generalized form of the Euler–painleve equation
Generalized Burgers equations and Euler–Painlevé transcendents. II
No full textIt was proposed earlier [P. L. Sachdev, K. R. C. Nair, and V. G. Tikekar, J. Math. Phys. 27, 1506 (1986)] that the Euler–Painlevé equation yy"+ay'2+f(x)yy'+g(x) y2+by'+c=0 represents the generalized Burgers equations (GBE's) in the same manner as Painlevé equations do the KdV type. The GBE was treated with a damping term in some detail. In this paper another GBE ut+uaux+Ju/2t =(gd/2)uxx (the nonplanar Burgers equation) is considered. It is found that its self-similar form is again governed by the Euler–Painlevé equation. The ranges of the parameter a for which solutions of the connection problem to the self-similar equation exist are obtained numerically and confirmed via some integral relations derived from the ODE's. Special exact analytic solutions for the nonplanar Burgers equation are also obtained. These generalize the well-known single hump solutions for the Burgers equation to other geometries J=1,2; the nonlinear convection term, however, is not quadratic in these cases. This study fortifies the conjecture regarding the importance of the Euler–Painlevé equation with respect to GBE's
Generalized Burgers equations and Euler–Painlevé transcendents. III
No full textIt was proposed earlier [P. L. Sachdev, K. R. C. Nair, and V. G. Tikekar, J. Math. Phys. 27, 1506 (1986); P. L. Sachdev and K. R. C. Nair, ibid. 28, 977 (1987)] that the Euler–Painlevé equations y(d2y/dη2)+a(dy/dη)2 +f(η)y(dy/dη)+g(η)y2+b(dy/dη) +c=0 represent generalized Burgers equations (GBE’s) in the same way as Painlevé equations represent the Korteweg–de Vries type of equations. The earlier studies were carried out in the context of GBE’s with damping and those with spherical and cylindrical symmetry. In the present paper, GBE’s with variable coefficients of viscosity and those with inhomogeneous terms are considered for their possible connection to Euler–Painlevé equations. It is found that the Euler–Painlevé equation, which represents the GBE ut+uβux=(δ/2)g(t)uxx, g(t)=(1+t)n, β>0, has solutions, which either decay or oscillate at η=±∞, only when −1<n<1. The solutions are shocklike when n=1. On the other hand, they oscillate over the whole real line when n=−1. Furthermore, the solutions monotonically decay both at η=+∞ and η=−∞, that is, they have a single hump form if β≥βn=(1−n)/(1+n). For β<βn, the solutions have an oscillatory behavior either at η=+∞ or at η=−∞, or at η=+∞ and η=−∞. For β=βn, there exists a single parameter family of exact single hump solutions, similar to those found for the nonplanar Burgers equations in Paper II. Thus the parametric value β=βn seems to bifurcate the families of solutions, which remain bounded at η=±∞. Other GBE’s considered here are also found to be reducible to Euler–Painlevé equations
Ultrapotent and broad neutralization of SARS-CoV-2 variants by modular, tetravalent, bi-paratopic antibodies
No full textNeutralizing antibodies (nAbs) that target the SARS-CoV-2 spike protein have received emergency use approval for treatment of COVID-19. However, with the emergence of variants of concern, there is a need for new treatment options. We report a format that enables modular assembly of bi-paratopic tetravalent nAbs with antigen-binding sites from two distinct nAbs. The tetravalent nAb purifies in high yield and exhibits biophysical characteristics that are comparable to those of clinically used therapeutic antibodies. The tetravalent nAb binds to the spike protein trimer at least 100-fold more tightly than bivalent IgGs (apparent K(D) < 1 pM) and neutralizes a broad array of SARS-CoV-2 pseudoviruses, chimeric viruses, and authentic viral variants with high potency. Together, these results establish the tetravalent diabody-Fc-Fab as a robust, modular platform for rapid production of drug-grade nAbs with potencies and breadth of coverage that greatly exceed those of conventional bivalent IgGs
Generalized Burgers equations and Euler-Painleve transcendents. II
No full textIt was proposed earlier [P. L. Sachdev, K. R. C. Nair, and V. G. Tikekar, J. Math. Phys. 27, 1506 (1986)] that the Euler Painlevé equation yy[script `]+ay[script ']2+ f(x)yy[script ']+g(x) y2+by[script ']+c=0 represents the generalized Burgers equations (GBE's) in the same manner as Painlevé equations do the KdV type. The GBE was treated with a damping term in some detail. In this paper another GBE ut+uaux+Ju/2t =(gd/2)uxx (the nonplanar Burgers equation) is considered. It is found that its self-similar form is again governed by the Euler Painlevé equation. The ranges of the parameter alpha for which solutions of the connection problem to the self-similar equation exist are obtained numerically and confirmed via some integral relations derived from the ODE's. Special exact analytic solutions for the nonplanar Burgers equation are also obtained. These generalize the well-known single hump solutions for the Burgers equation to other geometries J=1,2; the nonlinear convection term, however, is not quadratic in these cases. This study fortifies the conjecture regarding the importance of the Euler Painlevé equation with respect to GBE's. Journal of Mathematical Physics is copyrighted by The American Institute of Physics
A principal components approach to parent-to-newborn body composition associations in South India
No full textBackground: size at birth is influenced by environmental factors, like maternal nutrition and parity, and by genes. Birth weight is a composite measure, encompassing bone, fat and lean mass. These may have different determinants. The main purpose of this paper was to use anthropometry and principal components analysis (PCA) to describe maternal and newborn body composition, and associations between them, in an Indian population. We also compared maternal and paternal measurements (body mass index (BMI) and height) as predictors of newborn body composition.Methods: weight, height, head and mid-arm circumferences, skinfold thicknesses and external pelvic diameters were measured at 30 ± 2 weeks gestation in 571 pregnant women attending the antenatal clinic of the Holdsworth Memorial Hospital, Mysore, India. Paternal height and weight were also measured. At birth, detailed neonatal anthropometry was performed. Unrotated and varimax rotated PCA was applied to the maternal and neonatal measurements.Results: rotated PCA reduced maternal measurements to 4 independent components (fat, pelvis, height and muscle) and neonatal measurements to 3 components (trunk+head, fat, and leg length). An SD increase in maternal fat was associated with a 0.16 SD increase (?) in neonatal fat (p < 0.001, adjusted for gestation, maternal parity, newborn sex and socio-economic status). Maternal pelvis, height and (for male babies) muscle predicted neonatal trunk+head (? = 0. 09 SD; p = 0.017, ? = 0.12 SD; p = 0.006 and ? = 0.27 SD; p < 0.001). In the mother-baby and father-baby comparison, maternal BMI predicted neonatal fat (? = 0.20 SD; p < 0.001) and neonatal trunk+head (? = 0.15 SD; p = 0.001). Both maternal (? = 0.12 SD; p = 0.002) and paternal height (? = 0.09 SD; p = 0.030) predicted neonatal trunk+head but the associations became weak and statistically non-significant in multivariate analysis. Only paternal height predicted neonatal leg length (? = 0.15 SD; p = 0.003).Conclusion: principal components analysis is a useful method to describe neonatal body composition and its determinants. Newborn adiposity is related to maternal nutritional status and parity, while newborn length is genetically determined. Further research is needed to understand mechanisms linking maternal pelvic size to fetal growth and the determinants and implications of the components (trunk v leg length) of fetal skeletal growt
CO2-dependent opening of an inwardly rectifying K+ channel
No full textCO2 chemosensing is a vital function for the
maintenance of life that helps to control acid–base balance.
Most studies have reported that CO2 is measured via its
proxy, pH. Here we report an inwardly rectifying channel,
in outside-out excised patches from HeLa cells that was
sensitive to modest changes in PCO2 under conditions of
constant extracellular pH. As PCO2 increased, the open
probability of the channel increased. The single-channel
currents had a conductance of 6.7 pS and a reversal
potential of –70 mV, which lay between the K+ and Cl–
equilibrium potentials. This reversal potential was shifted
by +61 mV following a tenfold increase in extracellular
[K+] but was insensitive to variations of extracellular [Cl–].
The single-channel conductance increased with extracellular
[K+]. We propose that this channel is a member of the
Kir family. In addition to this K+ channel, we found that
many of the excised patches also contained a conductance
carried via a Cl–-selective channel. This CO2-sensitive Kir
channel may hyperpolarize excitable cells and provides a
potential mechanism for CO2-dependent inhibition during
hypercapnia
Evolution and decay of spherical and cylindrical N waves
No full textThe Burgers equation, in spherical and cylindrical symmetries, is studied numerically using pseudospectral and implicit finite difference methods, starting from discontinuous initial (N wave) conditions. The study spans long and varied regimes–embryonic shock, Taylor shock, thick evolutionary shock, and (linear) old age. The initial steep-shock regime is covered by the more accurate pseudospectral approach, while the later smooth regime is conveniently handled by the (relatively inexpensive) implicit scheme. We also give some analytic results for both spherically and cylindrically symmetric cases. The analytic forms of the Reynolds number are found. These give results in close agreement with those found from the numerical solutions. The terminal (old age) solutions are also completely determined. Our analysis supplements that of Crighton & Scott (1979) who used a matched asymptotic approach. They found analytic solutions in the embryonic-shock and the Taylor-shock regions for all geometries, and in the evolutionary-shock region, leading to old age, for the spherically symmetric case. The numerical solution of Sachdev & Seebass (1973) is updated in a comprehensive manner; in particular, the embryonic-shock regime and the old-age solution missed by their study are given in detail. We also study numerically the non-planar equation in the form for which the viscous term has a variable coefficient. It is shown that the numerical methods used in the present study are sufficiently versatile to tackle initial-value problems for generalized Burgers equations
Measurement of neutrino-induced neutral-current coherent production in the NOvA near detector
No full text© 2020 authors. Open access. Published by the American Physical Society under the terms of the "https://creativecommons.org/licenses/by/4.0/"Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI. Funded by SCOAP3..
WSU authors: Meyer, Holger; Muether, Mathew; Solomey, Nickolas. The complete list includes: Acero, M.A.; Adamson, P.; Aliaga, L.; Alion, T.; Allakhverdian, V.; Anfimov, N.; Antoshkin, A.; Arrieta-Diaz, E.; Aurisano, A.; Back, A.; Backhouse, C.; Baird, M.; Balashov, N.; Baldi, P.; Bambah, B.A.; Basher, S.; Bays, K.; Behera, B.; Bending, S.; Bernstein, R.; Bhatnagar, V.; Bhuyan, B.; Bian, J.; Blair, J.; Booth, A.C.; Bolshakova, A.; Bour, P.; Bromberg, C.; Buchanan, N.; Butkevich, A.; Campbell, M.; Carroll, T.J.; Catano-Mur, E.; Childress, S.; Choudhary, B.C.; Chowdhury, B.; Coan, T.E.; Colo, M.; Corwin, L.; Cremonesi, L.; Cronin-Hennessy, D.; Davies, G.S.; Derwent, P.F.; Ding, P.; Djurcic, Z.; Doyle, D.; Dukes, E.C.; Dung, P.; Duyang, H.; Edayath, S.; Ehrlich, R.; Feldman, G.J.; Flanagan, W.; Frank, M.J.; Gallagher, H.R.; Gandrajula, R.; Gao, F.; Germani, S.; Giri, A.; Gomes, R.A.; Goodman, M.C.; Grichine, V.; Groh, M.; Group, R.; Guo, B.; Habig, A.; Hakl, F.; Hartnell, J.; Hatcher, R.; Hatzikoutelis, A.; Heller, K.; Himmel, A.; Holin, A.; Howard, B.; Huang, J.; Hylen, J.; Jediny, F.; Johnson, C.; Judah, M.; Kakorin, I.; Kalra, D.; Kaplan, D.M.; Keloth, R.; Klimov, O.; Koerner, L.W.; Kolupaeva, L.; Kotelnikov, S.; Kreymer, A.; Kullenberg, C.; Kumar, A.; Kuruppu, C.D.; Kus, V.; Lackey, T.; Lang, K.; Lin, S.; Lokajicek, M.; Lozier, J.; Luchuk, S.; Maan, K.; Magill, S.; Mann, W.A.; Marshak, M.L.; Matveev, V.; Méndez, D.P.; Messier, M.D.; Meyer, H.; Miao, T.; Miller, W.H.; Mishra, S.R.; Mislivec, A.; Mohanta, R.; Moren, A.; Mualem, L.; Muether, M.; Mulder, K.; Mufson, S.; Murphy, R.; Musser, J.; Naples, D.; Nayak, N.; Nelson, J.K.; Nichol, R.; Niner, E.; Norman, A.; Nosek, T.; Oksuzian, Y.; Olshevskiy, A.; Olson, T.; Paley, J.; Patterson, R.B.; Pawloski, G.; Pershey, D.; Petrova, O.; Petti, R.; Plunkett, R.K.; Potukuchi, B.; Principato, C.; Psihas, F.; Raj, V.; Radovic, A.; Rameika, R.A.; Rebel, B.; Rojas, P.; Ryabov, V.; Sachdev, K.; Samoylov, O.; Sanchez, M.C.; Seong, I.S.; Shanahan, P.; Sheshukov, A.; Singh, P.; Singh, V.; Smith, E.; Smolik, J.; Snopok, P.; Solomey, N.; Song, E.; Sousa, A.; Soustruznik, K.; Strait, M.; Suter, L.; Talaga, R.L.; Tas, P.; Thayyullathil, R.B.; Thomas, J.; Tiras, E.; Torbunov, D.; Tripathi, J.; Tsaris, A.; Torun, Y.; Urheim, J.; Vahle, P.; Vasel, J.; Vinton, L.; Vokac, P.; Vrba, T.; Wang, B.; Warburton, T.K.; Wetstein, M.; While, M.; Whittington, D.; Wojcicki, S.G.; Wolcott, J.; Yadav, N.; Yallappa Dombara, A.; Yang, S.; Yonehara, K.; Yu, S.; Zalesak, J.; Zamorano, B.; Zwaska, R.l; NOvA Collaboration.The cross section of neutrino-induced neutral-current coherent production on a carbon-dominated target is measured in the NOvA near detector. This measurement uses a narrow-band neutrino beam with an average neutrino energy of 2.7\,GeV, which is of interest to ongoing and future long-baseline neutrino oscillation experiments. The measured flux-averaged cross section is
, consistent with model prediction. This result is the most precise measurement of neutral-current coherent production in the few-GeV neutrino energy region.Document was prepared by the NOvA Collaboration using the resources of the Fermi National Accelerator Laboratory (Fermilab), a U.S. Department of Energy, Office of Science, HEP user facility. Fermilab is managed by Fermi Research Alliance, LLC (FRA), acting under Contract No. DE-AC02-07CH11359. This work was supported by the U.S. Department of Energy; the U.S. National Science Foundation; the Department of Science and Technology, India; the European Research Council; the MSMT CR, GA UK, Czech Republic; the RAS, RFBR, RMES, RSF, and BASIS Foundation, Russia; CNPq and FAPEG, Brazil; STFC and the Royal Society, United Kingdom; and the state and University of Minnesota
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