37,416 research outputs found
Nonparaxial accelerating Bessel-like beams
No full textA new class of nonparaxial accelerating optical waves is introduced. These are beams with a Bessel-like profile that are capable of shifting laterally along fairly arbitrary trajectories as the wave propagates in free space. The concept expands on our previous proposal of paraxial accelerating Bessel-like beams to include beams with subwavelength lobes and/or large trajectory angles. Such waves are produced when the phase at the input plane is engineered so that the interfering ray cones are made to focus along the prespecified path. When the angle of these cones is fixed, the beams possess a diffraction-free Bessel profile on planes that stay normal to their trajectory, which can be considered as a generalized definition of diffractionless propagation in the nonparaxial regime. The analytical procedure leading to these results is based on a ray optics interpretation of Rayleigh-Sommerfeld diffraction and is presented in detail. The evolution of the proposed waves is demonstrated through a series of numerical examples and a variety of trajectories
Proteomic analysis of outer membranes and vesicles from wild-type serogroup B Neisseria meningitidis and a lipopolysaccharide deficient mutant
No full textCurrent experimental vaccines against serogroup B Neisseria meningitidis are based on meningococcal outer membrane (OM) proteins present in vesicles depleted of toxic lipopolysaccharide by detergent extraction (OMV). Knowledge of the composition of OM and OMV is essential for developing new meningococcal vaccines based on defined antigens. In the current study, SDS-PAGE and nanocapillary liquid chromatography- tandem mass spectrometry was used to investigate the proteome of OM and OMV from meningococcal strain MC58, and OM from a lipopolysaccharide-deficient mutant. Analysis of OM revealed a much more complex composition than has previously been reported, with a total of 236 proteins being identified, of which only 6.4% were predicted to be outer membrane-located. The most abundant proteins included not only the well-established major OM proteins (PorA, PorB, Opc, Rmp, Opa) but also other proteins such as pilus-associated protein Q (PilQ) and a putative macrophage infectivity protein (MIP). All of these proteins were also present in OMV obtained by extraction of the OM with deoxycholate. Some additional proteins had markedly increased abundance in OM from the lipopolysaccharide-deficient mutant, including enzymes that contribute to the TCA cycle. In all the preparations, the proteins not predicted to have an OM location were predominantly periplasmic, cytoplasmic or of unknown location with relatively few cytoplasmic membrane proteins detected. However, several proteins that have previously been identified as potential vaccine candidates were not detected in either OM preparation or in OMV. These results have important implications for the development and use of vaccines based on outer membrane proteins
Calorimetry of photon gases in nonlinear multimode optical fibers
No full textRecent studies have shown that light propagating in a nonlinear, highly multimode system can thermalize in a manner totally analogous to that encountered in traditional statistical mechanics. At thermal equilibrium, the system’s entropy is at a maximum, in full accord with the second law of thermodynamics. In such arrangements, the entropy is extremized once the statistical power allocation among modes associated with this photon gas attains a Rayleigh-Jeans distribution that is fully characterized by an optical temperature
T
and a chemical potential
μ
. However, it has been theoretically argued that the variables
T
and
μ
represent actual thermodynamic forces that control the exchange of the respective conjugate quantities between two subsystems. In this work, we report, for the first time, optical calorimetric measurements in nonlinear multimode fibers, which unambiguously demonstrate that both the temperature
T
and the chemical potential
μ
dictate the flow of their associated extensive quantities, i.e., the energy and the optical power. Specifically, we study the process of light thermalization associated with two orthogonally polarized laser beams. Our observations are enabled by recently developed techniques that allow one to judiciously multiplex/demultiplex the optical power within various mode groups. Our results indicate that because of photon-photon collisions, “heat” only flows from a hot to a cold photon gas subsystem—thus providing an unequivocal demonstration of the second law in such all-optical thermodynamic arrangements. In addition to being fundamental, our findings provide a new approach to manipulate laser beams using thermodynamic principles
A retrospective long-term study on age at menarche and menstrual characteristics in 85 young women with Transfusion-Dependent β-Thalassemia (TDT)
No full textBackground: Menarche is an important milestone in a feminine reproductive life, and regular menstrual cycles reflect normal functioning of the hypothalamic-pituitary-ovarian axis, a vital sign of women's general health. Aim of the study: We explored the age at menarche and the following menstrual cycles characteristics among 85 unmarried Transfusion-Dependent β-Thalassemia (TDT) women, born between 1965 and 1995, concerning iron chelation therapy (ICT) with desferrioxamine (DFO) and nutritional status, assessed by body mass index (BMI). Results: 53 adolescents who had begun ICT before the age of 10 years experienced menarche at 13,7 ± 1,6 years (mean ± DS), whereas 32 who began treatment after ten years experienced menarche significantly later (15.5 ± 1.9 yrs; p: 0.001). At the age of menarche: BMI-Z score (n= 67, - 0,09 ±1) was inversely correlated with both age at starting ICT (r = - 0,39; p = 0001) and age at menarche (- 0,45, p = 0,0001). Serum ferritin levels (SF) were significantly correlated with the age at starting chelation therapy (n = 79; r = 0,34; p = 0,022). In 56 TDT adolescents who developed secondary amenorrhea (SA), the SF levels were significantly higher (4,098 ± 1,907 ng/mL) compared to 23 TDT adolescents with regular menstrual cycles (2,913±782 ng/mL; p = 0,005). Nutritional status of "thinness" at menarche was associated with a lower prevalence of subsequent regular menstrual cycles and a higher prevalence of early SA. Conclusion: An early ICT in TDT patients was associated with a normal "tempo" of pubertal onset and a higher frequency of subsequent regular menstrual cycles. In TDT patients, who developed SA, a diagnosis of acquired central hypogonadism was made, mainly due to the chronic exposure to iron overload, however other potential causes linked to nutritional status, deficient levels of circulating nutrients, and the chronic disease itself cannot be fully excluded
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A scale to measure consumer’s engagement with social media brand-related content
No full textThe purpose of this study is to fill the gap in the literature concerning to the measurement of consumer’s engagement with social media brand-related content (hereafter, CESBC). We introduce empirical evidence for the development and measurement of CESBC scale. The scale is based on the consumer's online brand-related framework and comprises three dimensions: consumption, contribution, and creation. We used qualitative techniques to prepare an initial list of items and tested and validated the CESBC scale with confirmatory factor analysis (CFA). Results (n = 2252) confirmed the three-factor structure of the CESBC and indicated its good psychometric properties
1ST MEASUREMENT OF GAMMA(D(S)(+)-]MU+NU)/GAMMA(D(S)(+)-]PHI-PI+)
No full textComplete Author List:
ACOSTA D, ATHANAS M, MASEK G, PAAR H, BEAN A, GRONBERG J, KUTSCHKE R, MENARY S, MORRISON RJ, NAKANISHI S, NELSON HN, NELSON TK, RICHMAN JD, RYD A, TAJIMA H, SCHMIDT D, SPERKA D, WITHERELL MS, PROCARIO M, YANG S, BALEST R, CHO K, DAOUDI M, FORD WT, JOHNSON DR, LINGEL K, LOHNER M, RANKIN P, SMITH JG, ALEXANDER JP, BEBEK C, BERKELMAN K, BESSON D, BROWDER TE, CASSEL DG, CHO HA, COFFMAN DM, DRELL PS, EHRLICH R, GALIK RS, GARCIASCIVERES M, GEISER B, GITTELMAN B, GRAY SW, HARTILL DL, HELTSLEY BK, JONES CD, JONES SL, KANDASWAMY J, KATAYAMA N, KIM PC, KREINICK DL, LUDWIG GS, MASUI J, MEVISSEN J, MISTRY NB, NG CR, NORDBERG E, OGG M, PATTERSON JR, PETERSON D, RILEY D, SALMAN S, SAPPER M, WORDEN H, WURTHWEIN F, AVERY P, FREYBERGER A, RODRIGUEZ J, STEPHENS R, YELTON J, CINABRO D, HENDERSON S, KINOSHITA K, LIU T, SAULNIER M, SHEN F, WILSON R, YAMAMOTO H, ONG B, SELEN M, SADOFF AJ, AMMAR R, BALL S, BARINGER P, COPPAGE D, COPTY N, DAVIS R, HANCOCK N, KELLY M, KWAK N, LAM H, KUBOTA Y, LATTERY M, NELSON JK, PATTON S, PERTICONE D, POLING R, SAVINOV V, SCHRENK S, WANG R, ALAM MS, KIM IJ, NEMATI B, ONEILL JJ, SEVERINI H, SUN CR, ZOELLER MM, CRAWFORD G, DAUBENMIER CM, FULTON R, FUJINO D, GAN KK, HONSCHEID K, KAGAN H, KASS R, LEE J, MALCHOW R, MORROW F, SKOVPEN Y, SUNG M, WHITE C, WHITMORE J, WILSON P, BUTLER F, FU X, KALBFLEISCH G, LAMBRECHT M, ROSS WR, SKUBIC P, SNOW J, WANG PL, WOOD M, BORTOLETTO D, BROWN DN, FAST J, MCILWAIN RL, MIAO T, MILLER DH, MODESITT M, SCHAFFNER SF, SHIBATA EI, SHIPSEY IPJ, WANG PN, BATTLE M, ERNST J, KROHA H, ROBERTS S, SPARKS K, THORNDIKE EH, WANG CH, DOMINICK J, SANGHERA S, SHELKOV V, SKWARNICKI T, STROYNOWSKI R, VOLOBOUEV I, ZADOROZHNY P, ARTUSO M, HE D, GOLDBERG M, HORWITZ N, KENNETT R, MONETI GC, MUHEIM F, MUKHIN Y, PLAYFER S, ROZEN Y, STONE S, THULASIDAS M, VASSEUR G, ZHU G, BARTELT J, CSORNA SE, EGYED Z, JAIN V, SHELDON P, AKERIB DS, BARISH B, CHADHA M, CHAN S, COWEN DF, EIGEN G, MILLER JS, OGRADY C, URHEIM J, WEINSTEIN A
"Closing the R&D Gap, Evaluating the Sources of R&D Spending"
No full textBoth spending and tax policies have been implemented in the United States with the goal of stimulating private sector research and development (R&D). Karier questions whether current R&D policy, especially the research and experimentation tax credit, can contribute to closing the gap between nondefense expenditures on R&D in the United States and such expenditures in other countries, such as Japan and Germany. He also explores possible changes to our current R&D policy to make it more effective.
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Identifying idiolect in forensic authorship attribution: an n-gram textbite approach
No full textForensic authorship attribution is concerned with identifying authors of disputed or anonymous documents, which are potentially evidential in legal cases, through the analysis of linguistic clues left behind by writers. The forensic linguist “approaches this problem of questioned authorship from the theoretical position that every native speaker has their own distinct and individual version of the language [. . . ], their own idiolect” (Coulthard, 2004: 31). However, given the diXculty in empirically substantiating a theory of idiolect, there is growing concern in the Veld that it remains too abstract to be of practical use (Kredens, 2002; Grant, 2010; Turell, 2010). Stylistic, corpus, and computational approaches to text, however, are able to identify repeated collocational patterns, or n-grams, two to six word chunks of language, similar to the popular notion of soundbites: small segments of no more than a few seconds of speech that journalists are able to recognise as having news value and which characterise the important moments of talk. The soundbite oUers an intriguing parallel for authorship attribution studies, with the following question arising: looking at any set of texts by any author, is it possible to identify ‘n-gram textbites’, small textual segments that characterise that author’s writing, providing DNA-like chunks of identifying material
Gaps in intervals of N-expansions
No full textFor N ∈ N≥2 and α ∈ R such that 0 < α ≤ N − 1, the continued fraction map Tα: [α, α+1] → [α, α+1) is defined as Tα (x):= N/x−d(x), where d: [α, α+1] → N is defined by d(x):= ⌊N/x − α⌋. A maximal open interval (a, b) ⊂ Iα is called a gap of Iα if for almost every x ∈ Iα there is an n0 (x) ∈ N such that xn /∈ (a, b) for all n ≥ n0 . In this paper, all conditions are given in which Iα is gapless. For α =√N − 1 it is shown that the number of gaps is a finite, monotonically non-decreasing and unbounded function of N.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Applied Probabilit
Challenge in R&D Management : Tata Steel A Case Study
No full textThe purpose of R&D management is to promote innovation as
well as wealth creation. The paper traces the history of R&D managementhow it has changed from the first generation when only innovation was the main objective to the fifth generation where IT plays an important role. It is now necessary to understand the needs of market for conducting worthwhile research. The author shares his experience of R&D management at Tata Steel. The experience shows that by adopting judicious R&D strategy it is possible to face the challenges of reconciling innovation with wealth
creation is possible by a judicious R&D strategy
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