The Bonenblust-Hille inequality for homogeneous polynomials is hypercontractive

The Bohnenblust-Hille inequality says that the $\ell^{\frac{2m}{m+1}}$ -norm of the coefficients of an $m$-homogeneous polynomial $P$ on $\Bbb{C}^n$ is bounded by $\| P \|_\infty$ times a constant independent of $n$, where $\|\cdot \|_\infty$ denotes the supremum norm on the polydisc $\mathbb{D}^n$. The main result of this paper is that this inequality is hypercontractive, i.e., the constant can be taken to be $C^m$ for some $C>1$. Combining this improved version of the Bohnenblust-Hille inequality with other results, we obtain the following: The Bohr radius for the polydisc $\mathbb{D}^n$ behaves asymptotically as $\sqrt{(\log n)/n}$ modulo a factor bounded away from 0 and infinity, and the Sidon constant for the set of frequencies $\bigl\{ \log n: n \text{a positive integer} \le N\bigr\}$ is $\sqrt{N}\exp\{(-1/\sqrt{2}+o(1))\sqrt{\log N\log\log N}\}$.

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Älykkään vaihtuvan ohjausjärjestelmän pilotointi, esiselvitys : Valtatie 4 Koskela, Helsinki - Järvenpää

Valtatie 4 Helsingin Koskelan ja Järvenpään eritasoliittymien välillä on erittäin vilkkaasti liikennöity väylä, joka ruuhkautuu sekä aamun että iltapäivän ruuhkatunteina ja jonka turvallisuustilanne on heikko. Ongelmien ratkaisemiseksi on aiemmissa suunnitteluvaiheissa esitetty nykyaikaisen vaihtuvan ohjausjärjestelmän toteuttamista valtatielle 4 Järvenpäähän saakka sekä valtatielle 7 välille vt 4–Kehä III. Tämän esiselvityksen tavoitteena oli laatia alustava suunnitelma laadukkaan ja monipuolisen liikennetieto-ohjauksen mahdollistavasta ohjausjärjestelmästä, jossa on huomioitu uusien seurantateknologioiden luomat mahdollisuudet. Laadittu suunnitelma sisältää tavanomaisiin liikenteen vaihtuviin ohjausjärjestelmiin nähden uusina elementteinä aiempaa monipuolisemman ja tarkemman liikenteen seurantajärjestelmän sekä aiempaa proaktiivisemman ja hienojakoisemman liikenteen ohjausjärjestelmän ja –politiikan. Lisäksi järjestelmän operointi tieliikennekeskuksessa poikkeaa totutusta, koska ohjauksen automaatiotaso on korkeampi. Uutta on myös järjestelmän integraatio tieliikenteen ohjauksen integroidun käyttöliittymän ympäristöön (TLOIK) sekä muista piloteista, kuten kooperatiivisista järjestelmistä, saatavat herätteet. Suunnitellun vaihtuvan ohjausjärjestelmän voidaan kansainvälisten kokemusten valossa arvioida ehkäisevän henkilövahinkoihin johtavia onnettomuuksia Suomen olosuhteissa noin 10 % ja pienentävän ruuhka-aikojen viivytyksiä vähintään 20 %. Pääkaupunkiseudun säteittäisväylien vaihtuvan ohjauksen hyöty-kustannussuhteeksi on aiemmin laskettu 3,3–6,3, eli investointi on erittäin kannattava. Hanke kannattaa toteuttaa kaksivaiheisena pilottina, jonka tavoitteena on selvittää toimivimmat teknologiat ja ohjauspolitiikat laajempaa hyödyntämistä varten. Valtakunnallisesta ulottuvuudesta johtuen hanketta kannattaa viedä eteenpäin Liikenneviraston ja Uudenmaan ELY-keskuksen yhteishankkeena. Järjestelmästä saatavia kokemuksia voidaan hyödyntää sekä muiden pääkaupunkiseudun pääväylien liikenteen hallintajärjestelmien uusimisen/toteutuksen yhteydessä että muiden kaupunkiseutujen vastaavien järjestelmien toteutuksessa. Pilottihankkeen ensimmäisen osan, seurantapilotin alustava kustannusarvio on 320 000 euroa ja toisen, varsinaisen ohjauspilotin kustannusarvio 6,0 miljoonaa euroa sisältäen koko ohjausjärjestelmän toteutuksen.

Pseudo-almost periodic solutions for abstract partial functional differential equations

In this work we study the existence and uniqueness of pseudo-almost periodic solutions for a first-order abstract functional differential equation with a linear part dominated by a Hille-Yosida type operator with a non-dense domain. (C) 2009 Published by Elsevier Ltd

Estimation of the pore size of the large-conductance mechanosensitive ion channel of Escherichia coli

The open channel diameter of Escherichia coli recombinant large-conductance mechanosensitive ion channels (MscL) was estimated using the model of Hille (Hille, B. 1968. Pharmacological modifications of the sodium channels of frog nerve. J. Gen. Physiol. 51:199-219)that relates the pore size to conductance. Based on the MscL conductance of 3.8 nS, and assumed pore lengths, a channel diameter of 34 to 46 Angstrom was calculated. To estimate the pore size experimentally, the effect of large organic ions on the conductance of MscL was examined. Poly-L-lysines (PLLs) with a diameter of 37 Angstrom or larger significantly reduced channel conductance, whereas spermine (similar to 15 Angstrom), PLL19 (similar to 25 Angstrom) and 1,1'-bis-(3-(1'-methyl-(4,4'-bipyridinium)-1-yl)-propyl)-4,4'-bipyridinium (similar to 30 Angstrom) had no effect. The smaller organic ions putrescine, cadaverine, spermine, and succinate all permeated the channel. We conclude that the open pore diameter of the MscL is similar to 40 Angstrom, indicating that the MscL has one of the largest channel pores yet described. This channel diameter is consistent with the proposed homohexameric model of the MscL.

Efeitos do Emprego público na produção privada

Recentemente tem existido a preocupação em diminuir o emprego público e aumentar a eficiência das administrações públicas, como forma de promover o crescimento económico. No presente artigo analisa-se a relação entre o emprego público e produção do sector privado, para um conjunto de 191 países da OCDE no período de 1960-2008. Seguindo a especificação de Koskela e Virén (2000) os resultados sugerem que aquela relação não é linear, mas depende da dimensão do sector público. Da mesma forma, nas economias onde o sector público apresenta uma dimensão inferior à crítica (maximizadora da produção privada) o aumento do emprego público estimula o crescimento da produção privada. Pelo contrário, quando a dimensão do sector público é excessiva, o aumento do emprego neste sector tem um impacto negativo no output privado.

Efeitos do emprego público na produção privada

Recentemente tem existido a preocupação em diminuir o emprego público e aumentar a eficiência das administrações públicas, como forma de promover o crescimento económico. No presente artigo analisa-se a relação entre o emprego público e produção do sector privado, para um conjunto de 19[1] países da OCDE no período de 1960-2008. Seguindo a especificação de Koskela e Virén (2000) os resultados sugerem que aquela relação não é linear, mas depende da dimensão do sector público. Da mesma forma, nas economias onde o sector público apresenta uma dimensão inferior à crítica (maximizadora da produção privada) o aumento do emprego público estimula o crescimento da produção privada. Pelo contrário, quando a dimensão do sector público é excessiva, o aumento do emprego neste sector tem um impacto negativo no output privado.

Gehring-Hayman theorem for conformal deformations

We study conformal deformations of a uniform space that satisfies the Ahlfors Q-regularity condition on balls of Whitney type. We verify the Gehring–Hayman Theorem by using a Whitney Covering of the space.

Circulating estrogens and progesterone during primiparous pregnancies and risk of maternal breast cancer.

Pregnancy reduces maternal risk of breast cancer in the long term, but the biological determinants of the protection are unknown. Animal experiments suggest that estrogens and progesterone could be involved, but direct human evidence is scant. A case-control study (536 cases and 1,049 controls) was nested within the Finnish Maternity Cohort. Eligible were primiparous women who delivered at term a singleton offspring before age 40. For each case, two individually matched controls by age (±6 months) and date of sampling (±3 months) were selected. Estradiol, estrone and progesterone in first-trimester serum were measured by high-performance liquid chromatography tandem mass spectrometry and sex-hormone binding globulin (SHBG) by immunoassay. Odds ratios (OR) and 95% confidence intervals (CI) were estimated through conditional logistic regression. In the whole study population there was no association of breast cancer with any of the studied hormones. In analyses stratified by age at diagnosis, however, estradiol concentrations were positively associated with risk of breast cancer before age 40 (upper quartile OR, 1.81; CI, 1.08-3.06), but inversely associated with risk in women who were diagnosed ≥age 40 (upper quartile OR, 0.64; CI, 0.40-1.04), p(interaction) 0.004. Risk estimates for estrone mirrored those for estradiol but were less pronounced. Progesterone was not associated with risk of subsequent breast cancer. Our results provide initial evidence that concentrations of estrogens during the early parts of a primiparous pregnancy are associated with maternal risk of breast cancer and suggest that the effect may differ for tumors diagnosed before and after age 40.