1,459 research outputs found
The Effect of Micro-oxygenation on the Phenolic Composition, Quality and Aerobic Wine-Spoilage Microorganisms of Different South African Red Wines
The effect of micro-oxygenation treatments on the composition of different South African red wines was evaluated. In some wines, micro-oxygenation led to an increase in colour density, with a corresponding change in colour, due to the formation of polymeric pigments. This increase also led to the red colour becoming more resistant to the bleaching effect of SO2. Micro-oxygenation also seemed to be more effective in increasing the colour densities of younger red wines than the older ones, although total red pigments were found to be highest in an older red wine that had received micro-oxygenation. Differences in the gelatine index were also observed over time. The micro-oxygenated and barrel-matured wines also had lower concentrations of catechin and the procyanidin B1, and showed a corresponding increase in polymeric pigment and polymeric phenols. Micro-oxygenation led to higher acetic acid bacteria counts, although no increase in volatile acidity was observed in these wines. A tasting panel preferredyounger red wines that had undergone micro-oxygenation. In an older red wine prolonged micro-oxygenation led to the wine becoming over-aged, with an increase in the barnyard/medicinal character, which corresponded with an increase in Brettanomyces counts. Micro-oxygenation can be used to increase the quality of young red wines, but further research is needed in this area
Response of Grape and Wine Phenolic Composition in Vitis vinifera L. cv. Merlot to Variation in Grapevine Water Status
Grape and wine phenolic composition was monitored over two consecutive seasons in Vitis vinifera cv. Merlotfollowing application of irrigation treatments that produced seasonal average stem water potentials rangingbetween -0.7 MPa and -1.4 MPa. Fresh weight of berries was significantly reduced in response to water deficit,primarily due to decreases in pericarp weight. Increases in the concentration of grape anthocyanins andflavonols in response to water deficit were found when expressed per unit grape berry fresh weight. Skin-derivedtannin concentration in grape berries was not affected by the irrigation treatments. The concentration of grapederivedphenolics was monitored during five days of fermentation in a small-lot winemaking experiment. Duringfermentation, the concentration of anthocyanins and flavonols in wine were highest in the non-irrigated and lowfrequency-irrigated treatments, which was reflected in changes in the wine colour of ferments. Finished winesfrom non-irrigated and low frequency irrigated grapevines showed increases in bisulphite-resistant pigmentswhen compared with those irrigated at a high frequency, but differences in phenolic composition were minor.Increases in bisulphite-resistant pigments were associated with increases in vitisin A and polymeric pigmentin the first and second seasons of the study respectively. Ageing of wines for an 18-month period increasedbisulphite-resistant pigments, and treatment differences in wine colour density were enhanced, such thatincreases in both parameters were associated with the non-irrigated and low-frequency-irrigated treatments
The Effect of Landscape History on the Urban Environment: Past Landscapes, Present Patterns
Peer reviewe
SWIRP (Submm-Wave and Long Wave InfraRed Polarimeter); Development and Characterization of a Sub-Mm Polarimeter for Ice Cloud Investigations
A major source of uncertainty in climate models is the presence, shape and distribution of ice particles in the uppermost layers of the clouds. The effects of this component are poorly constrained, turning ice particles into an almost-free variable in many climate models.NASA-GSFC is developing a new instrument aimed at measuring the size and shape of ice particles. The instrument consists of two sub-mm polarimeters (at 220 and 670 GHz) coupled with a long-wave infrared polarimeter at 10 micron. Each polarimeter has identical V-pol and H-pol channels; the axes of polarization are defined geometrically by the orientation of the waveguide elements, and the purity has been measured in the lab. The instrument is configured as a conical scanner, suitable for deployment as a payload on a small satellite or on a high-altitude sub-orbital platform. From a 400 km orbit, the instrument has a 3dB spatial resolution of 20 (10) km at 220 (670) GHz and a swath of 600 km over 180 degrees of view.The BAPTA (Bearing And Power Transfer Assembly) carries heritage from the SSMIS design, now in its 22nd year of on-orbit operation, but with a much reduced SWaP (Size Weight and Power) footprint, suitable for a small satellite.The main components of the instrument have been fabricated and are undergoing final testing prior to their integration as a single unit. The sub-mm channels have dedicated secondary reflectors which illuminate a shared primary reflector. The receiving units are placed behind the focal point of the optical arrangement, so that all beams equally illuminate the primary reflector and are almost co-located on the ground (within a single 220 GHz footprint). Primary and secondary beam patterns have been measured and verified to match the as-designed expectations. A Zytex (TM) window is deployed to protect the secondary reflectors and the feed horns from debris and other contaminants, and to reduce the heat load from the active (hot) IR calibration unit. The insertion loss of Zytex has been measured and is accounted in the calibration equation of the sub-mm channels.The radiometric performance of the sub-mm receivers has been characterized in the lab and under operational conditions of temperature and pressure.This paper discusses the design constraints on the sub-mm components, details of the scientific goals and their flowdown, and describes the characterization of the polarimeters. Options to optimize the layout and distribution of the masses within the assembly, with the goal of making the instrument even more compact and fully-compatible with cubesat-class satellites will be presented
A 10-year analysis of organ donor referrals to a South African tertiary public sector hospital
Background. South Africa (SA) has one of the lowest deceased organ donor rates in the world (1.4 donors per million population), with thousands of patients awaiting solid-organ transplantation. In order to improve access to transplantation we have to clearly define the reasons for the low deceased donation rate, specific to the population we serve.Objectives. Review of actual donor statistics highlights our successes, yet is not able to contextualise the factors responsible for the unsuccessful conversion of referred organ donors to actual organ donors. In an attempt to identify key factors preventing referred donors from becoming actual donors, we analysed the donor referral patterns at our institution over a 10-year period.Methods. This was a retrospective descriptive study of consecutive deceased donor referrals at Groote Schuur Hospital, Cape Town, SA (from January 2007 to December 2016), utilising a regional donor referral registry. Qualitative and quantitative data were collected and presented as descriptive statistics and temporal trends.Results. Over the 10-year study period, 861 possible organ donors were referred, with a steady increase in the number of referrals over time. Of the referrals, 514 (59.7%) were eligible for donation of at least one solid organ. Of the 508 families that were approached for consent to donation, 342 declined consent for a variety of reasons, resulting in a consent rate of 32.7%. Ultimately, at least one solid organ was obtained from 159 of the 166 consented donors. Despite the increasing number of possible and eligible donors, a statistically significant decline in consent rate was observed over time (ptrend=0.023). Furthermore, increasing trends in medical (as opposed to trauma) (ptrend<0.001) and extended criteria (as opposed to standard criteria) donor referrals (ptrend<0.001) were observed over the 10-year study period.Conclusions. Donor referral patterns have changed over time, with a notable increase in medical and extended criteria donors. Despite the increase in possible and eligible donors, the consent rate has declined. Further qualitative and quantitative research studies are required to understand and address this trend.
Genetic Analysis of the Henry Mountains Bison Herd
Wild American plains bison (Bison bison) populations virtually disappeared in the late 1800s, with some remnant animals retained in what would become Yellowstone National Park and on private ranches. Some of these private bison were intentionally crossbred with cattle for commercial purposes. This forced hybridization resulted in both mitochondrial and nuclear introgression of cattle genes into some of the extant bison genome. As the private populations grew, excess animals, along with their history of cattle genetics, provided founders for newly established public bison populations. Of the US public bison herds, only those in Yellowstone and Wind Cave National Parks (YNP and WCNP) appear to be free of detectable levels of cattle introgression. However, a small free-ranging population (~350 animals) exists on public land, along with domestic cattle, in the Henry Mountains (HM) of southern Utah. This isolated bison herd originated from a founder group translocated from YNP in the 1940s. Using genetic samples from 129 individuals, we examined the genetic status of the HM population and found no evidence of mitochondrial or nuclear introgression of cattle genes. This new information confirms it is highly unlikely for free-living bison to crossbreed with cattle, and this disease-free HM bison herd is valuable for the long-term conservation of the species. This bison herd is a subpopulation of the YNP/WCNP/HM metapopulation, within which it can contribute significantly to national efforts to restore the American plains bison to more of its native range
A phylogenetically distinct lineage of Pyrenopeziza brassicae associated with chlorotic leaf spot of Brassicaceae in North America
Light leaf spot, caused by the ascomycete Pyrenopeziza brassicae Sutton & Rawlinson, is an established disease of Brassicaceae in the United Kingdom (UK), continental Europe, and Oceania (OC, including New Zealand and Australia). The disease was reported in North America (NA) for the first time in 2014 on Brassica spp. in the Willamette Valley of western Oregon, followed by detection in Brassica juncea cover crops and on B. rapa weeds in northwestern Washington in 2016. Preliminary DNA sequence data and field observations suggest that isolates of the pathogen present in NA might be distinct from those in the UK, continental Europe, and OC. Comparisons of isolates from these regions genetically (multilocus sequence analysis, MAT gene sequences, and rep-PCR DNA fingerprinting), pathogenically (B. rapa inoculation studies), biologically (sexual compatibility), and morphologically (colony and conidial morphology) demonstrated two genetically distinct evolutionary lineages. Lineage 1 comprised isolates from the UK, continental Europe, and OC, and included the P. brassicae type specimen. Lineage 2 contained the NA isolates associated with recent disease outbreaks in the Pacific Northwest region of the USA. Symptoms caused by isolates of the two lineages on B. rapa and B. juncea differed, so ‘chlorotic leaf spot’ is proposed for the disease caused by lineage 2 isolates of P. brassicae. Isolates of the two lineages differed in genetic diversity as well as sensitivity to the fungicides carbendazim and prothioconazole
Winter Feeding of Elk in the Greater Yellowstone Ecosystem and its Effects on Disease Dynamics
Providing food to wildlife during periods when natural food is limited results in aggregations that may facilitate disease transmission. This is exemplified in western Wyoming where institutional feeding over the past century has aimed to mitigate wildlife–livestock conflict and minimize winter mortality of elk (Cervus canadensis). Here we review research across 23 winter feedgrounds where the most studied disease is brucellosis, caused by the bacterium Brucella abortus. Traditional veterinary practices (vaccination, test-and-slaughter) have thus far been unable to control this disease in elk, which can spill over to cattle. Current disease-reduction efforts are being guided by ecological research on elk movement and density, reproduction, stress, co-infections and scavengers. Given the right tools, feedgrounds could provide opportunities for adaptive management of brucellosis through regular animal testing and population-level manipulations. Our analyses of several such manipulations highlight the value of a research–management partnership guided by hypothesis testing, despite the constraints of the sociopolitical environment. However, brucellosis is now spreading in unfed elk herds, while other diseases (e.g. chronic wasting disease) are of increasing concern at feedgrounds. Therefore experimental closures of feedgrounds, reduced feeding and lower elk populations merit consideration
- …