bluuebunny/crossref_metadata_2025_split huggingface dataset:
A survey of useful salt additives in matrix‐assisted laser desorption/ionization mass spectrometry and tandem mass spectrometry of lipids: introducing nitrates for improved analysis
Authors: Griffiths Rian L. , Bunch Josephine 
Published: May 2012

RATIONALEMatrix‐assisted laser desorption/ionization (MALDI) is a powerful technique for the direct analysis of lipids in complex mixtures and thin tissue sections, making it an extremely attractive method for profiling lipids in health and disease. Lipids are readily detected as [M+H]+, [M+Na]+ and [M+K]+ ions in positive ion MALDI mass spectrometry (MS) experiments. This not only decreases sensitivity, but can also lead to overlapping m/z values of the various adducts of different lipids. Additives can be used to promote formation of a particular adduct, improving sensitivity, reducing spectral complexity and enhancing structural characterization in collision‐induced dissociation (CID) experiments.METHODSLi+, Na+, K+, Cs+ and NH4+ cations were considered as a range of salt types (acetates, chlorides and nitrates) incorporated into DHB matrix solutions at concentrations between 5 and 80 mM. The study was extended to evaluate the effect of these additives on CID experiments of a lipid standard, after optimization of collision energy parameters. Experiments were performed on a hybrid quadrupole time‐of‐flight (QqTOF) instrument.RESULTSThe systematic evaluation of new and existing additives in MALDI‐MS and MS/MS of lipids demonstrated the importance of additive cation and anion choice and concentration for tailoring spectral results.CONCLUSIONSThe recommended choice of additive depends on the desired outcomes of the experiment to be performed (MS or MS/MS). Nitrates are found to be particularly useful additives for lipid analysis. Copyright © 2012 John Wiley & Sons, Ltd.
Can amino acid carbon isotope ratios distinguish primary producers in a mangrove ecosystem?
Authors: Larsen Thomas , Wooller Matthew J. , Fogel Marilyn L. , O'Brien Diane M. 
Published: May 2012

RATIONALEThe relative contribution of carbon from terrestrial vs. marine primary producers to mangrove‐based food webs can be challenging to resolve with bulk carbon isotope ratios (δ13C). In this study we explore whether patterns of δ13C values among amino acids (AAs) can provide an additional tool for resolving terrestrial and marine origins of carbon.METHODSAmino acid carbon isotope ratios (δ13CAA) were measured for several terrestrial and marine primary producers in a mangrove ecosystem at Spanish Lookout Caye (SLC), Belize, using gas chromatography‐combustion‐isotope ratio mass spectrometry. The δ13C values of essential amino acids (δ13CEAA) were measured to determine whether they could be used to differentiate terrestrial and marine producers using linear discriminant analysis.RESULTSMarine and terrestrial producers had distinct patterns of δ13CEAA values in addition to their differences in bulk δ13C values. Microbial mat samples and consumers (Crassostrea rhizophorae, Aratus pisonii, Littoraria sp., Lutjanus griseus) were most similar to marine producers. Patterns of δ13CEAA values for terrestrial producers were very similar to those described for other terrestrial plants.CONCLUSIONSThe findings suggest that δ13CEAA values may provide another tool for estimating the contribution of terrestrial and marine sources to detrital foodwebs. Preliminary analyses of consumers indicate significant use of aquatic resources, consistent with other studies of mangrove foodwebs. Copyright © 2012 John Wiley & Sons, Ltd.
Sphingosine kinase 1 in viral infections
Authors: Carr Jillian M. , Mahalingam Suresh , Bonder Claudine S. , Pitson Stuart M. 
Published: May 2012

SUMMARYSphingosine kinase 1 (SphK1) is an enzyme that phosphorylates the lipid sphingosine to generate sphingosine‐1‐phosphate (S1P). S1P can act intracellularly as a signaling molecule and extracellularly as a receptor ligand. The SphK1/S1P axis has well‐described roles in cell signaling, the cell death/survival decision, the production of a pro‐inflammatory response, immunomodulation, and control of vascular integrity. Agents targeting the SphK1/S1P axis are being actively developed as therapeutics for cancer and immunological and inflammatory disorders. Control of cell death/survival and pro‐inflammatory immune responses is central to the pathology of infectious disease, and we can capitalize on the knowledge provided by investigations of SphK1/S1P in cancer and immunology to assess its application to selected human infections. We have herein reviewed the growing literature relating viral infections to changes in SphK1 and S1P. SphK1 activity is reportedly increased following human cytomegalovirus and respiratory syncytial virus infections, and elevated SphK1 enhances influenza virus infection. In contrast, SphK1 activity is reduced in bovine viral diarrhea virus and dengue virus infections. Sphingosine analogs that modulate S1P receptors have proven useful in animal models in alleviating influenza virus infection but have shown no benefit in simian human immunodeficiency virus and lymphocytic choriomeningitis virus infections. We have rationalized a role for SphK1/S1P in dengue virus, chikungunya virus, and Ross River virus infections, on the basis of the biology and the pathology of these diseases. The increasing number of effective SphK1 and S1P modulating agents currently in development makes it timely to investigate these roles with the potential for developing modulators of SphK1 and S1P for novel anti‐viral therapies. Copyright © 2012 John Wiley & Sons, Ltd.
Rumor spreading on random regular graphs and expanders
Authors: Fountoulakis Nikolaos , Panagiotou Konstantinos 
Published: May 2012

AbstractBroadcasting algorithms are important building blocks of distributed systems. In this work we investigate the typical performance of the classical and well‐studied push model. Assume that initially one node in a given network holds some piece of information. In each round, every one of the informed nodes chooses independently a neighbor uniformly at random and transmits the message to it. In this paper we consider random networks where each vertex has degree d ≥ 3, i.e., the underlying graph is drawn uniformly at random from the set of all d ‐regular graphs with n vertices. We show that with probability 1 ‐ o(1) the push model broadcasts the message to all nodes within (1 + o(1))Cd lnn rounds, where

Particularly, we can characterize precisely the effect of the node degree to the typical broadcast time of the push model. Moreover, we consider pseudo‐random regular networks, where we assume that the degree of each node is very large. There we show that the broadcast time is (1 + o(1))Clnn with probability 1 ‐ o(1), where
\documentclass{article}\usepackage{mathrsfs, amsmath, amssymb}\pagestyle{empty}\begin{document}\begin{align*}C = \lim_{d\to\infty}C_d = \frac{1}{\ln2} + 1\end{align*} \end{document}. © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 2013
The property of having a k ‐regular subgraph has a sharp threshold
Authors: Letzter Shoham 
Published: May 2012

AbstractIn this paper it is proved that in the random graph model G(n,p), the property of containing a k ‐regular subgraph, has a sharp threshold for k ≥ 3. It is also shown how to use similar methods to prove, quite easily, the (known fact of) sharpness of having a non empty k ‐core for k ≥ 3. © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 42, 509–519, 2013
Longest cycles in sparse random digraphs
Authors: Krivelevich Michael , Lubetzky Eyal , Sudakov Benny 
Published: May 2012

AbstractLong paths and cycles in sparse random graphs and digraphs were studied intensively in the 1980's. It was finally shown by Frieze in 1986 that the random graph
\documentclass{article}\usepackage{mathrsfs, amsmath, amssymb}\pagestyle{empty}\begin{document}${\mathcal{G}}(n,p)$\end{document}
with p = c/n has a cycle on at all but at most (1 + ε)ce−cn vertices with high probability, where ε = ε (c) → 0 as c → ∞. This estimate on the number of uncovered vertices is essentially tight due to vertices of degree 1. However, for the random digraph \documentclass{article}\usepackage{mathrsfs, amsmath, amssymb}\pagestyle{empty}\begin{document}${\mathcal{D}}(n,p)$\end{document}
no tight result was known and the best estimate was a factor of c/2 away from the corresponding lower bound. In this work we close this gap and show that the random digraph \documentclass{article}\usepackage{mathrsfs, amsmath, amssymb}\pagestyle{empty}\begin{document}${\mathcal{D}}(n,p)$\end{document}
with p = c/n has a cycle containing all but (2 + ε)e−cn vertices w.h.p., where ε = ε (c) → 0 as c → ∞. This is essentially tight since w.h.p. such a random digraph contains (2e−c − o(1))n vertices with zero in‐degree or out‐degree. © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 2013
Weighted enumeration of spanning subgraphs in locally tree‐like graphs
Authors: Salez Justin 
Published: May 2012

AbstractUsing the theory of negative association for measures and the notion of unimodularity for random weak limits of sparse graphs, we establish the validity of the cavity method for counting spanning subgraphs subject to local constraints in asymptotically tree‐like graphs. Specifically, the normalized logarithm of the associated partition function (free energy) is shown to converge along any sequence of graphs whose random weak limit is a tree, and the limit is directly expressed in terms of the unique solution to a limiting cavity equation. On a Galton–Watson tree, the latter simplifies into a recursive distributional equation which can be solved explicitly. As an illustration, we provide a new asymptotic formula for the maximum size of a b‐matching in the Erdős–Rényi random graph with fixed average degree and diverging size, for any
\documentclass{article}\usepackage{mathrsfs, amsmath, amssymb}\pagestyle{empty}\begin{document}$b\in\mathbb{N}$\end{document}. To the best of our knowledge, this is the first time that correlation inequalities and unimodularity are combined together to yield a general proof of uniqueness of Gibbs measures on infinite trees. We believe that a similar argument is applicable to other Gibbs measures than those over spanning subgraphs considered here. © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 2013
The Bohman‐Frieze process near criticality
Authors: Kang Mihyun , Perkins Will , Spencer Joel 
Published: May 2012

AbstractThe Erdős‐Rényi process begins with an empty graph on n vertices, with edges added randomly one at a time to the graph. A classical result of Erdős and Rényi states that the Erdős‐Rényi process undergoes a phase transition, which takes place when the number of edges reaches n/2 (we say at time 1) and a giant component emerges. Since this seminal work of Erdős and Rényi, various random graph models have been introduced and studied. In this paper we study the Bohman‐Frieze process, a simple modification of the Erdős‐Rényi process.The Bohman‐Frieze process also begins with an empty graph onnvertices. At each step two random edges are presented, and if the first edge would join two isolated vertices, it is added to a graph; otherwise the second edge is added. We present several new results on the phase transition of the Bohman‐Frieze process. We show that it has a qualitatively similar phase transition to the Erdős‐Rényi process in terms of the size and structure of the components near the critical point. We prove that all components at timetc− ϵ (that is, when the number of edges are (tc− ϵ)n/2) are trees or unicyclic components and that the largest component is of size Ω(ϵ‐2logn). Further, attc+ ϵ, all components apart from the giant component are trees or unicyclic and the size of the second‐largest component is Θ(ϵ‐2logn). Each of these results corresponds to an analogous well‐known result for the Erdős‐Rényi process. Our proof techniques include combinatorial arguments, the differential equation method for random processes, and the singularity analysis of the moment generating function for the susceptibility, which satisfies a quasi‐linear partial differential equation. © 2012 Wiley Periodicals, Inc. Random Struct. Alg., 2013
Employment, job quality and social implications of the global crisis
Authors: Curci Federico , Rani Uma , Sekerler Richiardi Pelin 
Published: May 2012

AbstractSluggish recovery of employment after the crisis and worsening job quality. Poverty and inequality on the rise in advanced economies. The sluggish recovery of employment from the crisis is worsened by continuing economic slowdown. Progress in reducing poverty was hampered in many developing countries and the upwards trend in poverty was clear‐cut in the developed world.
Fiscal consolidation and employment growth
Authors: Escudero Verónica , Mourelo Elva López 
Published: May 2012

AbstractThis chapter assesses the magnitude and nature of the fiscal consolidation challenge. Indeed, while fiscal unbalances need to be addressed in the near term, countries are facing the challenge of doing so without damaging further recovery prospects and in turn public finances. In this regard, the chapter examines the evolution of fiscal balances and the recent build‐up of public debt. In addition, it provides an analysis of the sustainability of public debt, putting emphasis on the medium‐term effects. Moreover, the chapter looks at the recent austerity measures governments are taking with a view to consolidating public finances, so as to illustrate the manner in which governments intend to raise revenue and how they attempt to reduce expenditures during 2012. Finally, the chapter assesses the important employment and social implications of poorly designed fiscal cuts to shed light on how fiscal and employment goals can be achieved together.
Investing in a sustainable recovery
Authors: Corley Marva , Samaan Daniel 
Published: May 2012

AbstractThe chapter analyses global investment trends before and after the economic crisis of 2008 ‐ 2010 and investigates the relationship between employment and real investment. A focus is laid upon the impact of uncertainty on investment activity and employment outcomes. The chapter finds that investors’ perception of uncertainty has been increasing over the last decades and so has the volatility of real investment for many advanced countries. Using a vector autoregression, the impact of increasing uncertainty on investment and employment is quantified and shows that significant gains in terms of investment and employment could be achieved if economic uncertainty could be reduced. In response to the uncertain environment many firms have been significantly increasing their cash holdings and continue to hold back large investments.
Full Report ‐ World of Work Report 2012: Better jobs for a better economy
Authors:   International Labour Organization
Published: May 2012

AbstractThis publication provides a comprehensive analysis of recent labour market and social trends, assesses risks of social unrest and presents employment projections for the next five years. The report emphasises that while employment has begun to recover slowly, job quality is deteriorating and there is a growing sense of unfairness. Moreover, given the pressure on governments to rein in expenditure, policy efforts have focused on structural reforms to boost employment creation. However, if policy instruments are not carefully designed, they could exacerbate the employment situation and aggravate further equity concerns, with potentially long‐lasting adverse consequences for both the economy and society.This report calls for a carefully designed policy approach that takes into consideration the urgent need to create quality jobs while at the same time laying the ground for a more productive, fairer economy and labour market.
Large eddy simulations of turbulent Couette–Poiseuille and Couette flows inside a square duct
Authors: Hsu Hsin-Wei , Hsu Jian-Bin , Lo Wei , Lin Chao-An 
Published: May 2012

AbstractTurbulent Couette–Poiseuille and Couette flows at different mean strain rates (velocity ratio of Couette wall to bulk flow, $r= 0. 6$–$3. 15$), in a square duct at a bulk Reynolds number $\approx $10 000 are investigated by large eddy simulation. The numerical framework consists of a finite-volume method with a staggered-grid arrangement of dependent variables. Spatial derivatives are approximated using second-order centred differencing, and a fractional-step method is used for temporal integration. Simulations are conducted with $160\ensuremath{\times} 160\ensuremath{\times} 256$ grids. Secondary flow near the Couette wall shows a gradual change of vortex size and position as the moving wall velocity increased, where the two clockwise rotating vortices gradually merge in tandem with speed of the moving wall and form a large clockwise vortex. A linear relation is observed to exist between the angle of the two vortices and the parameter $r$, and the angle saturates beyond $r\ensuremath{\sim} 2. 06$. Also, at $0. 6\lt r\lt 1. 6$, together with a small counter-clockwise corner vortex, this vortex pattern is similar to that observed in the corner region of the duct flow with a free surface. The change of the vortex patterns also influences the dominant transport terms in the streamwise vorticity transport equation. Near the moving wall due to the reduction of the streamwise velocity fluctuation at the moving wall, turbulence structure gradually moves towards a rod-like axisymmetric turbulence, and as $r$ increases beyond $1. 2$, turbulence reverts to the disc-like structure.
Three-dimensional effects in hovering flapping flight
Authors: Jardin T. , Farcy A. , David L. 
Published: May 2012

AbstractThis paper aims at understanding the influence of three-dimensional effects in hovering flapping flight. Numerical simulations at a Reynolds number of 1000 are performed to compare two types of flapping kinematics whose plunging phase is characterized by either a rectilinear translation or a revolving motion. In this way, we are able to isolate the three-dimensional effects induced by the free end condition from that induced by the spanwise incident velocity gradient (and the associated implicit Coriolis and centrifugal effects). In the rectilinear translation case, the analysis of the wake and of the aerodynamic loads reveals that the wingspan can be compartmented into three distinct regions whether it is predominantly subjected to an unstable two-dimensional flow, a stable three-dimensional flow or both two-dimensional and three-dimensional effects. It is found that this partitioning exhibits common features for three different aspect ratios of the wing. In conjunction with the previous results of Ringuette, Milano & Gharib (J. Fluid Mech., vol. 581, 2007, pp. 453–468), this suggests that the influence of the tip vortex over the wingspan is driven by a characteristic length scale. In addition, this length scale matches the position of the connecting point between leading and tip vortices observed in the revolving case, providing insight into the connecting process. In both translating and revolving cases, leading edge vortex attachment and strong spanwise velocities are found to be strongly correlated phenomena. Spanwise velocities (that mostly confine at the periphery of the vortices), together with downward velocities, do not only affect the leading edge vortex but also act as an inhibitor for the trailing edge vortex growth. As a consequence, cross-wake interactions between leading and trailing edge vortices are locally limited, hence contributing to flow stabilization.
Reactive-infiltration instabilities in rocks. Fracture dissolution
Authors: Szymczak Piotr , Ladd Anthony J. C. 
Published: May 2012

AbstractA reactive fluid dissolving the surface of a uniform fracture will trigger an instability in the dissolution front, leading to spontaneous formation of pronounced well-spaced channels in the surrounding rock matrix. Although the underlying mechanism is similar to the wormhole instability in porous rocks there are significant differences in the physics, due to the absence of a steadily propagating reaction front. In previous work we have described the geophysical implications of this instability in regard to the formation of long conduits in soluble rocks. Here we describe a more general linear stability analysis, including axial diffusion, transport-limited dissolution, nonlinear kinetics, and a finite-length system.
SHARP ESTIMATES FOR FUNCTIONS OF BOUNDED LOWER OSCILLATION
Authors: OSȨKOWSKI ADAM 
Published: May 2012

AbstractLet f:ℝ→ℝ be a locally integrable function of bounded lower oscillation. The paper contains the proofs of sharp strong-type, weak-type and exponential estimates for the mean oscillation of f. In particular, this yields the precise value of the norm of the embedding BLO⊂BMOp, 1≤p<∞. Higher-dimensional analogues for anisotropic BLO spaces are also established.
ON THE GROUND STATE OF SPIN-1 BOSE–EINSTEIN CONDENSATES WITH AN EXTERNAL IOFFE–PITCHARD MAGNETIC FIELD
Authors: LUO WEI , LÜ ZHONGXUE , LIU ZUHAN 
Published: May 2012

AbstractIn this paper, we prove the existence of the ground state for the spinor Bose–Einstein condensates with an external Ioffe–Pitchard magnetic field in the one-dimensional case. We also characterise the ground states of spin-1 Bose–Einstein condensates with an external Ioffe–Pitchard magnetic field; that is, for ferromagnetic systems, we show that, under some condition, searching for the ground state of ferromagnetic spin-1 Bose–Einstein condensates with an external Ioffe–Pitchard magnetic field can be reduced to a ‘one-component’ minimisation problem.
Metabolic programming of sirtuin 1 (SIRT1) expression by moderate energy restriction during gestation in rats may be related to obesity susceptibility in later life
Authors: Palou Mariona , Priego Teresa , Sánchez Juana , Palou Andreu , Picó Catalina 
Published: May 2012

In rats, 20 % gestational energy restriction programmes offspring for higher food intake, which in adulthood results in higher body weight in males but not in females. Here, we aimed to assess whether the effects of moderate energy restriction during gestation and the sex-related outcomes on adult body weight may be related to the metabolic programming of sirtuin expression in different tissues. For this purpose, 25-d-old offspring of control and 20 % energy-restricted (ER) rats (from days 1–12 of pregnancy) were studied. Body weight and the weight of white adipose tissue (WAT) depots and liver were recorded and mRNA expression of sirtuin 1 (SIRT1) and selected genes in the WAT, liver, muscle and hypothalamus were analysed. No differences were found in body weight or the weight of WAT and liver between the control and ER animals. A similar pattern ofSIRT1mRNA expression was found in the WAT, liver and skeletal muscle of ER animals, but in a sex-dependent manner: ER males showed lowerSIRT1mRNA levels than the controls, while no differences were found in females. A sex-different pattern was also observed in the hypothalamus. ER males, but not females, also showed lower mRNA levels of adipose TAG lipase (ATGL) and uncoupling protein 2 in WAT and of sterol response element binding protein 1c and stearoyl-CoA desaturase-1 in the liver. Both sexes of ER animals showed lower mRNA levels of 5′ adenosine monophosphate-activated protein kinase andATGLin the liver. In conclusion, moderate maternal energy restriction during gestation programmes a particular, sex-dependent gene expression profile ofSIRT1in different peripheral tissues, which may be related to obesity predisposition in adulthood; thereforeSIRT1expression emerges as a potential early biomarker of obesity susceptibility.