Fragmenting Active Asteroid 331P/Gibbs

We describe active asteroid 331P/Gibbs (2012 F5) using archival Hubble Space Telescope (HST) data taken between 2015 and 2018. 331P is an outer main belt active asteroid with a long-lived debris trail that formed in 2011. Embedded in the debris trail we identify 19 fragments with radii between 0.04 and 0.11 km (albedo 0.05 assumed) containing about 1% of the mass of the primary nucleus. The largest shows a photometric range (∼1.5 mag), a V-shaped minimum, and a two-peaked lightcurve period near 9 hr, consistent with a symmetric contact binary. Less convincing explanations are that 331P-A is a monolithic, elongated splinter or that its surface shows hemispheric 4:1 albedo variations. The debris trail is composed of centimeter-sized and larger particles ejected with characteristic 10 cm s−1 speeds following a size distribution with index q = 3.7 ± 0.1 to 4.1 ± 0.2. The HST data show that earlier, ground-based measurements of the nucleus were contaminated by near-nucleus debris, which cleared by 2015. We find that the primary nucleus has effective radius 0.8 ± 0.1 km and is in rapid rotation (3.26 ± 0.01 hr), with a lightcurve range of 0.25 mag and a minimum density of 1600 kg m−3 if strengthless. The properties of 331P are consistent with (1) formation about 1.5 Myr ago by impact shattering of a precursor body, (2) spin-up by radiation torques to critical rotation, (3) ejection of about 1% of the nucleus mass in mid 2011 by rotational instability, and (4) subsequent evolution of the fragments and dispersal of the debris by radiation pressure.

IMPACT OF PHYSICAL MUTAGENS ON THE MALE GAMETOPHYTE OF THE TEA PLANT FOR ITS FURTHER USE IN HYBRIDIZATION

The migration of the radioisotopes - P32 and S35 from the soil to the tea plant (flowers) was studied. It is shown that their accumulation intensity in pollen sacs increases in proportion to the dose and reaches its maximum in the P32 variant after using a 8.0 MBq / ml dose. The migration intensity was the lowest in the 2.0 MBq / ml variant (0.14-0.223 MBq / 100 mg). It is estimated that P32 and S35 have significantly affected the vitality of tea plant pollens through the anomalies of their development. After using 2.0 and 4.0 MBq / ml doses, the vitality of the pollen is reduced in proportion to the dose and the development anomalies increase. Particulalry, the viability of pollen decrease compared to the control group, but the frequency and range of development anomalies increases. These include the slow development of the plant or the acceleration of the development of the primary nucleus, polyspermia, undeveloped pollen tube, etc. The use of processed P32 and S35 tea pollens in hybridization significantly increases the frequency of new formations and results in variability in the domination of signs. Among the new formations include the induction of haploids and triploids.

Search for the astrophysical sources of the Fly's Eye event with the highest to date cosmic ray energy E=3.2·1020 eV

Among the registered extremely high energy cosmic rays (EHECR, E=3.2·1020 eV) an event with the highest to date energy of E=3.2·1020 eV was detected by the Fly's Eye experiment (FE event) in 1991. With the use of the back-tracking method for the calculation of the EHECR trajectories in Galactic and extragalactic magnetic fields, we show that the galaxies UGC 03574 and UGC 03394 are the most promising candidates among the nearby extragalactic sources for the cases of iron and C-N-O group primary nucleus respectively. The most likely accelerating mechanisms are the newly-born millisecond pulsars, magnetar flares and tidal disruption events in these galaxies.

Influence of processing parameters on physicochemical properties of fractionated fish oil at low temperature crystallization

Purpose – The purpose of this study was to investigate the efficiency of low temperature fractional crystallization to increase polyunsaturated fatty acid (PUFA) content of fish oil. Effects of temperature, stages of crystallization, rate of cooling, agitation and addition of primary nucleus on separation efficiency were evaluated. Low temperature crystallization of triacylglycerols (TAGs) was used to increase PUFA content of fish oil (initial PUFA content ∼30 g/100 g oil). Design/methodology/approach – To optimize the fractionation process, the effect of fractionation temperature (7, 5, 0 and −5°C), crystallization procedures, cooling rate, agitation and addition of primary nucleus on PUFA content was evaluated. Findings – The best relationship between PUFA concentration (45.8 g/100 g oil) and PUFA yield (51.5 per cent) was attained by performing two-stage crystallization of TAGs at the final temperatures of 5 and 0°C under slow cooling rate (3°C h−1 for first fractionation procedure and 0.7°C h−1 for second stage, until the final fractionation temperature, 0°C, was reached) and slow agitation (3 rpm) and in the presence of primary nucleus, which resulted in 50 per cent increase in PUFA content over the original fish oil. Practical implications – Determination of iodine and saponification values, refractive index, solid fat content, melting point, cholesterol content of original oil and final fractionated product with the highest PUFA ratio showed that fractionation significantly alters physical and chemical properties of the fraction. Originality/value – Comparison of iodine value, saponification value, refractive index, solid fat content, melting point and cholesterol content of original oil and the final fractionated product (with the highest PUFA ratio) showed that the fractionation process significantly alters mentioned properties of the initial oil.

Multidisciplinary Teams in Health Care: Lessons from Oncology and Renal Teams

An indepth study conducted on units treating renal disease and cancer clinics determined that multidisciplinary teams are relatively commonplace in these areas. Developing four team organizational structures — sequential, primary, nucleus and dynamic — the authors hypothesize that each varies on a continuum in terms of how highly structured they are. The framework suggests that the ideology of equal participation on the team is the most difficult to sustain, and that difficulties typically arise as organization requirements become more complex. More research seems to be indicated to develop a comprehensive organizational framework, and the probable effect of organizational form on team performance. One of the key issues addressed is team leadership.