777 research outputs found
Intramode and Fermi relaxation in CO2, their influence on multiple-pass, short-pulse energy extraction
Analytical, experimental and numerical results concerning the influence of intramode and Fermi relaxation on multiple-pass, nanosecond-pulse energy extraction are presented. Multiple-pass energy extraction experiments show satisfactory agreement with the analytical and numerical calculations which predict a significant increase in extracted energy. In three passes, an amount of 9.7 J/l was extracted at an efficiency of 4.3%, These values are taken with respect to the volume of the beam inside the amplifier. In a single pass only 3.5 J/l was extracted
Triggering synchronized oscillations through arbitrarily weak diversity in close-to-threshold excitable media
It is shown that arbitrarily weak (frozen) heterogeneity can induce global
synchronized oscillations in excitable media close to threshold. The work is
carried out on networks of coupled van der Pol-FitzHugh-Nagumo oscillators. The
result is shown to be robust against the presence of internal dynamical noise.Comment: 4 pages (RevTeX 3 style), 5 EPS figures, submitted to Phys. Rev. E
(16 aug 2001
Nonlinear Differential Equations Satisfied by Certain Classical Modular Forms
A unified treatment is given of low-weight modular forms on \Gamma_0(N),
N=2,3,4, that have Eisenstein series representations. For each N, certain
weight-1 forms are shown to satisfy a coupled system of nonlinear differential
equations, which yields a single nonlinear third-order equation, called a
generalized Chazy equation. As byproducts, a table of divisor function and
theta identities is generated by means of q-expansions, and a transformation
law under \Gamma_0(4) for the second complete elliptic integral is derived.
More generally, it is shown how Picard-Fuchs equations of triangle subgroups of
PSL(2,R) which are hypergeometric equations, yield systems of nonlinear
equations for weight-1 forms, and generalized Chazy equations. Each triangle
group commensurable with \Gamma(1) is treated.Comment: 40 pages, final version, accepted by Manuscripta Mathematic
Emergent global oscillations in heterogeneous excitable media: The example of pancreatic beta cells
Using the standard van der Pol-FitzHugh-Nagumo excitable medium model I
demonstrate a novel generic mechanism, diversity, that provokes the emergence
of global oscillations from individually quiescent elements in heterogeneous
excitable media. This mechanism may be operating in the mammalian pancreas,
where excitable beta cells, quiescent when isolated, are found to oscillate
when coupled despite the absence of a pacemaker region.Comment: See home page http://lec.ugr.es/~julya
Intramode and Fermi relaxation in CO2, their influence on multiple-pass, short-pulse energy extraction
Parathyroidectomy versus cinacalcet for tertiary hyperparathyroidism; a retrospective analysis
Introduction Tertiary hyperparathyroidism (tHPT), i.e., persistent HPT after kidney transplantation, affects 17–50% of transplant
recipients. Treatment of tHPT is mandatory since persistently elevated PTH concentrations after KTx increase the risk of renal
allograft dysfunction and osteoporosis. The introduction of cinacalcet in 2004 seemed to offer a medical treatment alternative to
parathyroidectomy (PTx). However, the optimal management of tHPT remains unclear.
Methods A retrospective analysis was performed on patients receiving a kidney transplantation (KT) in two academic centers in
the Netherlands. Thirty patients undergoing PTx within 3 years of transplantation and 64 patients treated with cinacalcet 1 year
after transplantation for tHPT were included. Primary outcomes were serum calcium and PTH concentrations 1 year after KT and
after PTx.
Results Serum calcium normalized in both the cinacalcet and the PTx patients. PTH concentrations remained above the upper
limit of normal (median 22.0 pmol/L) 1 year after KT, but returned to within the normal range in the PTx group (median
3.7 pmol/L). Side effects of cinacalcet were difficult to assess; minor complications occurred in three patients. Re-exploration
due to persistent tHPT was performed in three (10%) patients.
Conclusion In patients with tHPT, cinacalcet normalizes serum calcium, but does not lead to a normalization of serum PTH
concentrations. In contrast, PTx leads to a normalization of both serum calcium and PTH concentrations. These findings suggest
that PTx is the treatment of choice for tHPT
The effects of cobalt protoporphyrin IX and tricarbonyldichlororuthenium (II) dimer treatments and its interaction with nitric oxide in the locus coeruleus of mice with peripheral inflammation
Funding: This work was supported by Ministerio de Economía y Competitividad, Instituto de Salud Carlos III, Madrid, Spain and FondoEuropeo de Desarrollo Regional (FEDER), Unión Europea [Grants: PS0900968 and PI1400927], and CAPES/PROEX, CNPq,Brasil [401472/2014-0].Heme oxygenase 1 (HO-1) and carbon monoxide were shown to normalize oxidative stress and inflammatory reactions induced by neuropathic pain in the central nervous system, but their effects in the locus coeruleus (LC) of animals with peripheral inflammation and their interaction with nitric oxide are unknown. In wild-type (WT) and knockout mice for neuronal (NOS1-KO) or inducible (NOS2-KO) nitric oxide synthases with inflammatory pain induced by complete Freund's adjuvant (CFA), we assessed: 1) antinociceptive actions of cobalt protoporphyrin IX (CoPP), an HO-1 inducer; 2) effects of CoPP and tricarbonyldichlororuthenium(II)dimer (CORM-2), a carbon monoxide-liberating compound, on the expression of HO-1, NOS1, NOS2, CD11b/c, GFAP,and mitogen-activated protein kinases (MAPK)in the LC. CoPP reduced inflammatory pain in different time-dependent manners in WT and KO mice. Peripheral inflammation activated astroglia in the LC of all genotypes and increased the levels of NOS1 and phosphorylated extracellular signal-regulated kinase 1/2 (p-ERK 1/2) in WT mice. CoPP and CORM-2 enhanced HO-1 and inhibited astroglial activationin all genotypes. Both treatments blocked NOS1 overexpression,and CoPP normalized ERK 1/2 activation. This study reveals an interaction between HO-1 and NOS1/NOS2 during peripheral inflammation andshows that CoPP and CORM-2 improved HO-1 expression and modulated the inflammatory and/or plasticity changes caused by peripheral inflammation in the LC
Postoperative Ultrasound in Kidney Transplant Recipients: Association Between Intrarenal Resistance Index and Cardiovascular Events
Background. Doppler ultrasound, including intrarenal resistance index (RI) measurement, is a widely used modality to
assess kidney transplantation (KTx) vascularization. The aim of this study is to gain insight in the associations between early
postoperative RI measurements and cardiovascular events (CVEs), all-cause mortality, and death-censored graft survival.
Methods. From 2015 to 2017, a prospective cohort study was
Life span and reproductive cost explain interspecific variation in the optimal onset of reproduction.
Fitness can be profoundly influenced by the age at first reproduction (AFR), but to date the AFR-fitness relationship only has been investigated intraspecifically. Here, we investigated the relationship between AFR and average lifetime reproductive success (LRS) across 34 bird species. We assessed differences in the deviation of the Optimal AFR (i.e., the species-specific AFR associated with the highest LRS) from the age at sexual maturity, considering potential effects of life history as well as social and ecological factors. Most individuals adopted the species-specific Optimal AFR and both the mean and Optimal AFR of species correlated positively with life span. Interspecific deviations of the Optimal AFR were associated with indices reflecting a change in LRS or survival as a function of AFR: a delayed AFR was beneficial in species where early AFR was associated with a decrease in subsequent survival or reproductive output. Overall, our results suggest that a delayed onset of reproduction beyond maturity is an optimal strategy explained by a long life span and costs of early reproduction. By providing the first empirical confirmations of key predictions of life-history theory across species, this study contributes to a better understanding of life-history evolution
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