1,217 research outputs found
Renorming spaces with greedy bases
We study the problem of improving the greedy constant or the democracy
constant of a basis of a Banach space by renorming. We prove that every Banach
space with a greedy basis can be renormed, for a given \vare>0, so that the
basis becomes (1+\vare)-democratic, and hence (2+\vare)-greedy, with
respect to the new norm. If in addition the basis is bidemocratic, then there
is a renorming so that in the new norm the basis is (1+\vare)-greedy. We also
prove that in the latter result the additional assumption of the basis being
bidemocratic can be removed for a large class of bases. Applications include
the Haar systems in , , and in dyadic Hardy space ,
as well as the unit vector basis of Tsirelson space
Notes on the Forests of Southern Iowa
In the southernmost tier of counties in Iowa, particularly in Jefferson, Van Buren, Wapello, Davis, Monroe, Appanoose, Lucas and Wayne counties there exist rather extensive natural forests of oak and other hardwood species. These counties lie within an area of considerable loessal soils. This part of the state has been designated in agricultural parlance as the southern Iowa pasture section. The relief of the land in these parts consists of a rather distinct upland plain lying generally about 1000 feet above sea-level. Dissection of this plain by drainage has resulted in numerous fingering and tortuous headwaters creating slopes or terraces, and flat to narrow ridges and bottoms of variable widths and patterns. The plain is composed of a number of soil types in; the Clinton silt loam, the Lindley silt loam, the Edina, the Marion and Grundy silt loams, etc. The Clinton silt loam is one of the most prevalent upland loess soils; it has a light gray yellow and buff color and a loose texture. It over-lies much of the loose and erosive Lindley drift soil which comprises a goodly proportion of the slope land. Some upland sections contain small quantities of the whitish Edina and powdery Marion soils. In the bottoms we find generally deep accumulations of the dark and fertile Wabash silt loam
Mucociliary clearance in COPD can be increased by both a D2/β2 and a standard β2 agonists
SummaryIn addition to breathlessness and cough, excessive mucus production is one of the main symptoms of chronic obstructive pulmonary disease (COPD). Excess mucus coupled with deteriorating mucociliary clearance is associated with a decline in lung function and an increased risk of death from pulmonary infection. The effect of ViozanTM (Sibenadet HCI, AR-C68397AA), a novel dual D2 dopamine receptor, β2-adrenoceptor agonist, on mucociliary clearance was investigated together with that of a β2-adrenoceptor agonist, salbutamol. Using a double blind, parallel group study design, 15 patients with COPD, all habitual smokers, were randomised to receive nebulised sidenadet (3mg tid; n=7) or salbutamol (5mg tid; n=8) for 10 days. Lung mucociliary clearance rates were measured, by a standard radioaerosol technique, before and after the treatment period, as were 24-h sputum volumes. Both sibenadet and salbutamol therapies resulted in significant (P<0.02) enhancement of lung mucociliary clearance. The 24-h sputum volume was significantly reduced following sibenadet therapy (P<0.03) whereas salbutamol therapy had no effect. Our results, in addition to illustrating the effects of a standard β2 agonist on mucociliary clearance, strongly suggest the potential dual benefit of dual-agonist compounds in lessening sputum production whilst simultaneously enhancing mucociliary clearance. For reasons unconnected with the present study, development work on this specific formulation is no longer proceeding
A polynomial bound for untangling geometric planar graphs
To untangle a geometric graph means to move some of the vertices so that the
resulting geometric graph has no crossings. Pach and Tardos [Discrete Comput.
Geom., 2002] asked if every n-vertex geometric planar graph can be untangled
while keeping at least n^\epsilon vertices fixed. We answer this question in
the affirmative with \epsilon=1/4. The previous best known bound was
\Omega((\log n / \log\log n)^{1/2}). We also consider untangling geometric
trees. It is known that every n-vertex geometric tree can be untangled while
keeping at least (n/3)^{1/2} vertices fixed, while the best upper bound was
O(n\log n)^{2/3}. We answer a question of Spillner and Wolff [arXiv:0709.0170
2007] by closing this gap for untangling trees. In particular, we show that for
infinitely many values of n, there is an n-vertex geometric tree that cannot be
untangled while keeping more than 3(n^{1/2}-1) vertices fixed. Moreover, we
improve the lower bound to (n/2)^{1/2}.Comment: 14 pages, 7 figure
Complete genome sequence of the Medicago microsymbiont Ensifer (Sinorhizobium) medicae strain WSM419
Ensifer (Sinorhizobium) medicae is an effective nitrogen fixing microsymbiont of a diverse range of annual Medicago (medic) species. Strain WSM419 is an aerobic, motile, non-spore forming, Gram-negative rod isolated from a M. murex root nodule collected in Sardinia, Italy in 1981. WSM419 was manufactured commercially in Australia as an inoculant for annual medics during 1985 to 1993 due to its nitrogen fixation, saprophytic competence and acid tolerance properties. Here we describe the basic features of this organism, together with the complete genome sequence, and annotation. This is the first report of a complete genome se-quence for a microsymbiont of the group of annual medic species adapted to acid soils. We reveal that its genome size is 6,817,576 bp encoding 6,518 protein-coding genes and 81 RNA only encoding genes. The genome contains a chromosome of size 3,781,904 bp and 3 plasmids of size 1,570,951 bp, 1,245,408 bp and 219,313 bp. The smallest plasmid is a fea-ture unique to this medic microsymbiont
Blurred Boundaries: Gender and Work-Family Interference in Cross-National Context
Although well theorized at the individual level, previous research has neglected the role of national context in shaping overall levels of nonwork-work and work-nonwork interference. This study fills this gap by examining how a national context of gender empowerment affects the likelihood of experiencing nonwork-work and work-nonwork interference at the individual and national levels. Controlling for individual-level differences in the distribution of job demands and resources, results from our multilevel models indicate that women's empowerment has significant net gender and parenthood effects on nonwork-work interference. By contrast, gender empowerment equally structures work-nonwork interference for these groups. Our results highlight the need to investigate interference bidirectionally and in a multilevel context. © The Author(s) 2013
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