Apple superficial scald preventi1on by vapour treatments

Superficial scald is a postharvest physiological disorder of apples characterized by browning of apple skin during prolonged storage. It has been hypothesized that conjugated triene hydroperoxides (CTH) attack cell membranes causing membrane perturbation and the manifestation of the disorder. The purpose of this study was to compare the common synthetic antioxidant diphenylamine (DPA) treatment with postharvest vapour treatments for superficial scald prevention. Apples cv. ‚Granny Smith™ were treated with ethanol, methanol and »apple aroma« vapours. The influence of these treatments on scald susceptibility and sensorial quality of apples was examined. The ethanol treatments were effective in superficial scald prevention but they caused a high incidence of internal browning after two months of storage. The 10 day treatments at 20 °C developed very pronounced internal browning after storage. The aroma treatment was the least effective in apple scald prevention but no internal disorders appeared after storage. Apples treated with methanol at 20 °C retain a great deal of their initial green colour. Vapour treatments demonstrated to be potential methods for scald prevention. Additional research is needed to minimise the internal disorders of treated fruit

Seasonal dynamics of three lepidopteran stored grain pests in Slovenia

In the period 2004-2006 seasonal dynamics of Mediterranean flour moth (Ephestia kuehniella), Indianmeal moth (Plodia interpunctella) and Angoumois grain moth (Sitotroga cerealella) was studied in the mills and grain warehouses in central Slovenia. For this purpose pheromone traps were used from April until December, and the males of all three lepidopteran pests were counted in two week intervals. The three insect pests under investigation developed two peaks in capture per year that might represent two distinct generations per year. In the maize open air storage Ephestia kuehniella was the most numerous, while Plodia interpunctella was more frequent in the closed storage in mills and warehouses, Sitotroga cerealella was slightly less common in these latter closed warehouses. Keywords: Monitoring, Lepidoptera, Stored grain pest, Pheromones, Sloveni

Changes during storing and astringency removal of persimmon fruit Diospyros kaki L.

Physiological changes during ripening, storing and astringency removal of persimmon fruits were traced. The fruits were stored under normal (NA), controlled (CA) and vacuum atmospheres (VA). The fruits were stored for 100 days and analysed for firmness, acetaldehyde and ethanol content and soluble tannins, both before and after storing. The same analyses were done during the deastringency treatment carried out with a high CO2 concentration (99.99%) for 20 h at 20 °C. The persimmon fruits stored under NA, CA, VA or treated with high CO2 for 20 h accumulated acetaldehyde and ethanol in the fruit tissue. CA conditions caused the highest acetaldehyde accumulation; vacuum conditions the lowest. Ethanol content increased 20 fold during storage; the highest accumulation was observed in vacuum stored fruit followed by CA (3% CO2Ś2% O2 and 0.5% CO2Ś2% O2) conditions. Astringency removal treatment caused an immediate increase of acetaldehyde and ethanol, nearly to the same extent as in conventionally ripened or stored fruit. The amount of soluble tannins, the main cause of an astringent taste, decreased during storage, and it did much faster during deastringency removal at the same level. The sensory evaluation test revealed that fruit treated with high CO2 was preferred to conventionally ripened fruit

Spectroscopy and 3D imaging of the Crab nebula

Spectroscopy of the Crab nebula along different slit directions reveals the 3 dimensional structure of the optical nebula. On the basis of the linear radial expansion result first discovered by Trimble (1968), we make a 3D model of the optical emission. Results from a limited number of slit directions suggest that optical lines originate from a complicated array of wisps that are located in a rather thin shell, pierced by a jet. The jet is certainly not prominent in optical emission lines, but the direction of the piercing is consistent with the direction of the X-ray and radio jet. The shell's effective radius is ~ 79 seconds of arc, its thickness about a third of the radius and it is moving out with an average velocity 1160 km/s.Comment: 21 pages, 14 figures, submitted to ApJ, 3D movie of the Crab nebula available at http://www.fiz.uni-lj.si/~vidrih

Effect of spraying speed on head coverage of winter wheat with fungicide, occurrence of Fusarium head blight and deoxynivalenol, yield and grain quality

The effect of spraying speed (5, 8.5 or 12 km/h) on deposition quality of fungicide on a winter wheat head, yield, grain quality, occurrence of Fusarium head blight (FHB) and deoxynivalenol (DON) content in grains was investigated in 2011 and 2012. Asymmetric double flat fan air-injector nozzles were used in the trial at a spraying pressure of 5.0 bars. A prothiconazole + tebuconazole fungicide mixture was used for spraying. An increase of spraying speed significantly lowered coverage values at the front and rear parts of a wheat head. At all three spraying speeds, the rear part of a wheat head reached a better coverage value. The effect of spraying speed was significant in 2011, when the 5 km/h spraying speed generated a significantly higher grain yield and a significantly higher thousand-grain weight in comparison with the other treatments. In both trial years, the lowest grain yield occurred on the unsprayed control. In 2011 and 2012, the latter also reached the lowest hectolitre weight and thousand-grain weight. In both trial years, the unsprayed control had a significantly higher DONcontent than the other treatments. In 2012, the DONcontent on the unsprayed control exceeded the allowed maximum level. The spraying speed did not affect the DON content in the grains. The effect of spraying speed was also noted in the FHB incidence. A significantly lower FHB incidence occurred at the 5 and 8.5 km/h spraying speeds

The Origin of the Bifurcation in the Sagittarius Stream

The latest Sloan Digital Sky Survey data reveal a prominent bifurcation in the distribution of debris of the Sagittarius dwarf spheroidal (Sgr) beginning at a right ascension of roughly 190 degrees. Two branches of the stream (A and B) persist at roughly the same heliocentric distance over at least 50 degrees of arc. There is also evidence for a more distant structure (C) well behind the A branch. This paper provides the first explanation for the bifurcation. It is caused by the projection of the young leading (A) and old trailing (B) tidal arms of the Sgr, whilst the old leading arm (C) lies well behind A. This explanation is only possible if the halo is close to spherical, as the angular difference between the branches is a measure of the precession of the orbital plane.Comment: ApJ, in pres

New UltraCool and Halo White Dwarf Candidates in SDSS Stripe 82

A 2.5 x 100 degree region along the celestial equator (Stripe 82) has been imaged repeatedly from 1998 to 2005 by the Sloan Digital Sky Survey. A new catalogue of ~4 million light-motion curves, together with over 200 derived statistical quantities, for objects in Stripe 82 brighter than r~21.5 has been constructed by combining these data by Bramich et al. (2007). This catalogue is at present the deepest catalogue of its kind. Extracting the ~130000 objects with highest signal-to-noise ratio proper motions, we build a reduced proper motion diagram to illustrate the scientific promise of the catalogue. In this diagram disk and halo subdwarfs are well-separated from the cool white dwarf sequence. Our sample of 1049 cool white dwarf candidates includes at least 8 and possibly 21 new ultracool H-rich white dwarfs (T_eff < 4000K) and one new ultracool He-rich white dwarf candidate identified from their SDSS optical and UKIDSS infrared photometry. At least 10 new halo white dwarfs are also identified from their kinematics.Comment: 10 pages, 5 figures, published in MNRAS, minor text changes, final versio

Substructure revealed by RR Lyraes in SDSS Stripe 82

We present an analysis of the substructure revealed by 407 RR Lyraes in Sloan Digital Sky Survey (SDSS) Stripe 82. Period estimates are determined to high accuracy using a string-length method. A subset of 178 RR Lyraes with spectrally derived metallicities are employed to derive metallicity-period-amplitude relations, which are then used to find metallicities and distances for the entire sample. The RR Lyraes lie between 5 and 115 kpc from the Galactic center. They are divided into subsets of 316 RRab types and 91 RRc types based on their period, colour and metallicity. The density distribution is not smooth, but dominated by clumps and substructure. Samples of 55 and 237 RR Lyraes associated with the Sagittarius Stream and the Hercules-Aquila Cloud respectively are identified. Hence, ~ 70 % of the RR Lyraes in Stripe 82 belong to known substructure. There is a sharp break in the density distribution at Galactocentric radii of 40 kpc, reflecting the fact that the dominant substructure in Stripe 82 - the Hercules-Aquila Cloud and the Sagittarius Stream - lies within 40 kpc. In fact, almost 60 % of all the RR Lyraes in Stripe 82 are associated with the Hercules-Aquila Cloud alone, which emphasises its pre-eminence. Additionally, evidence of a new and distant substructure - the Pisces Overdensity - is found, consisting of 28 faint RR Lyraes centered on Galactic coordinates (80 deg, -55 deg) and with distances of ~ 80 kpc. The total stellar mass in the Pisces Overdensity is ~10000 solar masses and its metallicity is [Fe/H] ~ -1.5.Comment: 15 pages, submitted to MNRA

The Hercules-Aquila Cloud

We present evidence for a substantial overdensity of stars in the direction of the constellations of Hercules and Aquila. The Cloud is centered at a Galactic longitude of about 40 degrees and extends above and below the Galactic plane by at least 50 degrees. Given its off-centeredness and height, it is unlikely that the Hercules-Aquila Cloud is related to the bulge or thick disk. More likely, this is a new structural component of the Galaxy that passes through the disk. The Cloud stretches about 80 degrees in longitude. Its heliocentric distance lies between 10 and 20 kpc so that the extent of the Cloud in projection is roughly 20 kpc by 15 kpc. It has an absolute magnitude of -13 and its stellar population appears to be comparable to, but somewhat more metal-rich than, M92.Comment: ApJ (Letters), in pres

Crab Pulsar Photometry and the Signature of Free Precession

Optical photometry for the pulsar PSR0531+21 has been extended with new observations that strengthen evidence for a previously observed 60 seconds periodicity. This period is found to be increasing with time at approximately the same rate as the rotational period of the pulsar. The observed period and its time dependence fit a simple free precession model.Comment: 6 pages, 7 figures. Published in A&