Flavonol haze in white wines

The formation of a yellow haze in commercial white wines, and of yellow sediments from both juices and wines, was due to precipitation of quercetin. The vine leaves were found to be the major source of soluble quercetin glycosides, leading to excessive levels of free quercetin after hydrolysis during juice or wine storage. Flavonols were analysed by reversed-phase HPLC. Widespread use of machine harvesting, with higher leaf contamination of the grape crush, is considered to be the primary cause of this new form of wine instability. An enzymatic procedure for detecting susceptibility to such deposition in juices and wines is described

Evolution of red wines II. An assessment of the role of acetaldehyde

Factors influencing formation and utilisation of acetaldehyde during red vinification have been examined, with emphasis on its production during primary fermentation and depletfon during early maturation.Acetaldehyde concentrations in new wines were controlled at predictably low levels by addition of SO2 at 30- 50 mg/l before fermentation. There was no appreciable effect from yeast strain, pH or temperature on acetaldehyde production. Significant decrease in acetaldehyde, a-ketoglutaric acid and pyruvic acid, with release of free SO2, occurred during malolactic fermentation. The rate of acetaldehyde consumption in sterile-filtered wine was increased at higher te·mperature and decreased by the presence of free SO2 at high levels. Progressive change in pigment composition of new wines was not influenced by variation in bound acetaldehyde within the range 2-103 mg/l.Acetaldehyde concentration also decreased in a majority of red wines during conservation in commercial cellars. Increases were attributed to abnormal conditions of wine exposure to air. lt was concluded that acetaldehyde formation in wine is probably a surface phenomenon, involving autoxidation of ethanol at the wine interface with atmospheric oxygen. Increase in acetaldehyde during vinification was considered to be adverse in relation to sensory properties and stability of red wine

IN-SYNC. VII. Evidence for a decreasing spectroscopic binary fraction from 1 to 100 Myr within the IN-SYNC sample

We study the occurrence of spectroscopic binaries in young star-forming regions using the INfrared Spectroscopy of Young Nebulous Clusters(IN-SYNC) survey, carried out in SDSS-III with the APOGEE spectrograph. Multi-epoch observations of thousands of low-mass stars in Orion A, NGC 2264, NGC 1333, IC 348, and the Pleiades have been carried out, yielding H-band spectra with a nominal resolution of R=22,500 for sources with H $\le$ 12 mag. Radial velocity precisions of $\sim$0.3 $km\:s^{-1}$ were achieved, which we use to identify radial velocity variations indicative of undetected companions. We use Monte Carlo simulations to assess the types of spectroscopic binaries to which we are sensitive, finding sensitivity to binaries with orbital periods $< 10^{4}$ d, for stars with $2500 {\rm K} \le T_\mathrm{eff} \le 6000 {\rm K}$ and $\it{v} \sin \it{i}$ $\le$ 100 $km\:s^{-1}$. Using Bayesian inference, we find evidence for a decline in the spectroscopic binary fraction, by a factor of 3-4 from the age of our pre-main-sequence sample to the Pleiades age . The significance of this decline is weakened if spot-induced radial-velocity jitter is strong in the sample, and is only marginally significant when comparing any one of the pre-main-sequence clusters against the Pleiades. However, the same decline in both sense and magnitude is found for each of the five pre-main-sequence clusters, and the decline reaches statistical significance of greater than 95% confidence when considering the pre-main-sequence clusters jointly. Our results suggest that dynamical processes disrupt the widest spectroscopic binaries ($P_{\rm orb} \approx 10^3 - 10^4$ d) as clusters age, indicating that this occurs early in the stars' evolution, while they still reside within their nascent clusters.Comment: 21 pages, 9 Figure

“…not some young tourist”: The male overseas-acquired HIV social research study

As with the trend in the rest of Australia, the majority of HIV diagnoses in Western Australia (WA) over the past 20 years have been amongst men who have sex with men in Australia. However, a differing trend seen more recently in WA has been the number of HIV diagnoses among heterosexual and homosexual men who acquired HIV while overseas compared to other states. The number of Western Australians acquiring HIV overseas has increased from 41 people in 2002-2004 to 91 people in 2005-2007. The upward trend of overseas acquired notifications continued in 2008-2009 (Combs and Giele 2009; DoH (WA) 2009). While the epidemiological data clearly showed an increase in overseas acquired HIV, there was little information on why the increase was occurring. The Male Overseas Acquired HIV Social Research Study investigated the social, cultural, behavioural and cognitive factors which may have contributed to the overseas-acquisition of HIV by male WA residents. The study used a qualitative approach to collecting and analysing data from in depth interviews with men who had acquired HIV while travelling or working overseas. The study was a joint project of the WA Centre for Health Promotion Research, National Centre in HIV Social Research, National Centre in HIV Epidemiology and Clinical Research and the Australian Research Centre in Sex, Health and Society and funded by the Western Australian Department of Health, Sexual Health and Blood Borne Virus Program. Men were recruited through the WA AIDS Council, Royal Perth Hospital, Fremantle Hospital, Northern Territory AIDS and Hepatitis Council and Clinic 34, Darwin. Fourteen men participated in the study during 2008 and 2009

“…not some young tourist”: The male overseas-acquired HIV social research study

As with the trend in the rest of Australia, the majority of HIV diagnoses in Western Australia (WA) over the past 20 years have been amongst men who have sex with men in Australia. However, a differing trend seen more recently in WA has been the number of HIV diagnoses among heterosexual and homosexual men who acquired HIV while overseas compared to other states. The number of Western Australians acquiring HIV overseas has increased from 41 people in 2002-2004 to 91 people in 2005-2007. The upward trend of overseas acquired notifications continued in 2008-2009 (Combs and Giele 2009; DoH (WA) 2009). While the epidemiological data clearly showed an increase in overseas acquired HIV, there was little information on why the increase was occurring. The Male Overseas Acquired HIV Social Research Study investigated the social, cultural, behavioural and cognitive factors which may have contributed to the overseas-acquisition of HIV by male WA residents. The study used a qualitative approach to collecting and analysing data from in depth interviews with men who had acquired HIV while travelling or working overseas. The study was a joint project of the WA Centre for Health Promotion Research, National Centre in HIV Social Research, National Centre in HIV Epidemiology and Clinical Research and the Australian Research Centre in Sex, Health and Society and funded by the Western Australian Department of Health, Sexual Health and Blood Borne Virus Program. Men were recruited through the WA AIDS Council, Royal Perth Hospital, Fremantle Hospital, Northern Territory AIDS and Hepatitis Council and Clinic 34, Darwin. Fourteen men participated in the study during 2008 and 2009