2016: A new dawn for adult education

No abstract available

Internal solitary waves in the ocean: Analysis using the periodic, inverse scattering transform

The periodic, inverse scattering transform (PIST) is a powerful analytical tool in the theory of integrable, nonlinear evolution equations. Osborne pioneered the use of the PIST in the analysis of data form inherently nonlinear physical processes. In particular, Osborne's so-called nonlinear Fourier analysis has been successfully used in the study of waves whose dynamics are (to a good approximation) governed by the Korteweg--de Vries equation. In this paper, the mathematical details and a new application of the PIST are discussed. The numerical aspects of and difficulties in obtaining the nonlinear Fourier (i.e., PIST) spectrum of a physical data set are also addressed. In particular, an improved bracketing of the "spectral eigenvalues" (i.e., the +/-1 crossings of the Floquet discriminant) and a new root-finding algorithm for computing the latter are proposed. Finally, it is shown how the PIST can be used to gain insightful information about the phenomenon of soliton-induced acoustic resonances, by computing the nonlinear Fourier spectrum of a data set from a simulation of internal solitary wave generation and propagation in the Yellow Sea.Comment: 10 pages, 4 figures (6 images); v2: corrected a few minor mistakes and typos, version accepted for publication in Math. Comput. Simu

Directive Versus Supportive Approaches Used by Midwives When Providing Care During the Second Stage of Labor

Introduction: Although the risks associated with using sustained and forceful maternal bearing‐down efforts during the second stage of labor have been well documented, most women who give birth in the United States bear down in response to direction from care providers about when and how to push rather than in response to their own physiologic urges. The purpose of this study was to describe the practices used by certified nurse‐midwives/certified midwives (CNMs/CMs) in response to maternal bearing‐down efforts when caring for women in second‐stage labor and to identify factors associated with the use of supportive approaches to second‐stage labor care. Methods: A national survey of 705 CNMs/CMs was conducted using mailed questionnaires. The instrument was an 84‐item, fixed‐choice questionnaire using Likert type scales that had been validated. A 72.6% response rate was achieved, and 375 of the respondents cared for women during the second stage of labor. Results: Most CNMs/CMs (82.4%) often or almost always supported women without epidural anesthesia to initiate bearing‐down efforts only when the woman felt an urge to do so. When caring for women without an epidural, most of the respondents (67%) reported that they often or almost always supported a woman\u27s spontaneous bearing‐down efforts without providing direction. Most participants reported using more directive practices when caring for women with epidural anesthesia. Whether caring for women with or without an epidural, most respondents (77.1% and 79.6%, respectively) often or almost always provided more direction as the fetal head emerged and the final stretching of the perineum was taking place. A change in fetal heart tones that led the midwife to believe the birth needed to occur quickly was the circumstance that had the greatest degree of influence on the participant\u27s (90.6%) decision to provide more direction during bearing‐down efforts. Many participants indicated that they also were influenced to provide more direction when women in labor asked for more direction (73.3%) or appeared to be fatigued (74.6%). Discussion: The majority of CNMs/CMs use supportive approaches to bearing‐down efforts during second‐stage labor care and most used directive approaches as an intervention aimed at avoiding potential problems

Editorial

No abstract available

Acetaldehyde metabolism by wine lactic acid bacteria and its oenological implications : a thesis presented in fulfillment of the requirements for the degree of Master of Science in Microbiology at Massey University

Acetaldehyde is one of the most important sensory carbonyl compounds formed during vinification. Excess acetaldehyde can adversely affect the flavour of wine and acetaldehyde plays a role in the colour development of red wines. Excess acetaldehyde is usually masked by the addition of sulphur dioxide (SO2) to the wine (SO2 is also used as an antimicrobial and antioxidant agent in wine and acetaldehyde bound SO2 is less effective in these roles). To date there has been no definitive study of the impact of wine LAB on free and bound acetaldehyde. Therefore, this study investigated the metabolism of free and bound acetaldehyde and its oenological implications. A survey of 11 commercial malolactic starter cultures (mostly Oenococcus oeni strains) showed that 9 out of 11 were able to metabolise acetaldehyde (in a resting state) with the corresponding formation of ethanol and acetic acid as products. SO2 bound acetaldehyde was also metabolised by the two strains tested (Lactobacillus buchneri CUC-3 and Oenococcus oeni MCW). This is the first evidence that LAB can indeed catabolise SO2 bound acetaldehyde, therefore releasing free SO2. During growth Oenococcus oeni EQ54 and Oenococcus oeni VFO were able to metabolise free acetaldehyde in wine at pH 3.3 and pH 3.6. In wine containing SO2 bound acetaldehyde, Oenococcus oeni EQ54 and Oenococcus oeni VFO were able to metabolise SO2 bound acetaldehyde at pH 3.6 after a period of sluggish growth. At pH 3.3 there was no metabolism of SO2 bound acetaldehyde by Oenococcus oeni EQ54 and Oenococcus oeni VFO during the incubation period. Results from growth experiments showed that in broth there was inhibition of growth at 300 mg/L concentration of acetaldehyde for all strains. In wine, no significant inhibition or stimulation of the cultures examined was found at any acetaldehyde concentrations up to 300 mg/L. In a simultaneous resting cell incubation of Saccharomyces bayanus Première Cuvée and Oenococcus oeni Lol11, acetaldehyde produced by the yeast was metabolised by the wine LAB. The metabolism of acetaldehyde by wine LAB is expected to influence wine flavour as small amounts of ethanol and acetic acid are produced and acetaldehyde is removed. This removal of acetaldehyde by wine LAB suggests that less SO2 will need to be added to the wine to mask excess acetaldehyde when malolactic fermentation is performed. Inhibition of wine LAB growth in broth by high levels of acetaldehyde suggests a role for acetaldehyde in stuck or sluggish MLF. Sluggish growth in wine containing SO2 bound acetaldehyde also suggests a possible role of SO2 bound acetaldehyde in stuck and sluggish MLF. This is due to the release of free SO2 through the metabolism of the acetaldehyde moiety of SO2 bound acetaldehyde

Editorial

No abstract available

Estimation of Stochastic Attribute-Value Grammars using an Informative Sample

We argue that some of the computational complexity associated with estimation of stochastic attribute-value grammars can be reduced by training upon an informative subset of the full training set. Results using the parsed Wall Street Journal corpus show that in some circumstances, it is possible to obtain better estimation results using an informative sample than when training upon all the available material. Further experimentation demonstrates that with unlexicalised models, a Gaussian Prior can reduce overfitting. However, when models are lexicalised and contain overlapping features, overfitting does not seem to be a problem, and a Gaussian Prior makes minimal difference to performance. Our approach is applicable for situations when there are an infeasibly large number of parses in the training set, or else for when recovery of these parses from a packed representation is itself computationally expensive.Comment: 6 pages, 2 figures. Coling 2000, Saarbr\"{u}cken, Germany. pp 586--59

Editorial

No abstract available