Shape and spin distributions of asteroid populations from brightness variation estimates and large databases

Context. Many databases on asteroid brightnesses (e.g. ALCDEF, WISE) are potential sources for extensive asteroid shape and spin modelling. Individual lightcurve inversion models require several apparitions and hundreds of data points per target. However, we can analyse the coarse shape and spin distributions over populations of at least thousands of targets even if there are only a few points and one apparition per asteroid. This is done by examining the distribution of the brightness variations observed within the chosen population. Aims. Brightness variation has been proposed as a population-scale rather than individual-target observable in two studies so far. We aim to examine this approach rigorously to establish its theoretical validity, degree of ill-posedness, and practical applicability. Methods. We model the observed brightness variation of a target population by considering its cumulative distribution function (CDF) caused by the joint distribution function of two fundamental shape and spin indicators. These are the shape elongation and the spin latitude of a simple ellipsoidal model. The main advantage of the model is that we can derive analytical basis functions that yield the observed CDF as a function of the shape and spin distribution. The inverse problem can be treated linearly. Even though the inaccuracy of the model is considerable, databases of thousands of targets should yield some information on the distribution. Results. We establish the theoretical soundness and the typical accuracy limits of the approach both analytically and numerically. Using simulations, we derive a practical estimate of the model distribution in the (shape, spin)-plane. We show that databases such as Wide-field Infrared Survey Explorer (WISE) yield coarse but robust estimates of this distribution, and as an example compare various asteroid families with each other.Comment: 16 pages, 21 figures, manuscript accepted in Astronomy & Astrophysics, to be published in section 10. Planets and planetary system

Possible roles, positions, factors and components of dairying in organic farming – a rewiev, mapping, survey and comparison in the Czech Republic

The full-value experiment is questionable in evaluation organic dairying. It is problem to do a trial under comparable conditions for comparison of organic and conventional farming because of legislative reasons and necessity of long period of such event. Most of comparisons are carried out as practice descriptive observations and any of them has been carried out about milk production. That is main reason, why the aim of this work is to carry out a opening of monitoring of some production conditions and results of bio-dairying in the Czech Republic (CR). The quality aspects of sources, procedures and products are main topics of solution of projects about organic farming philosophy, in particular in solution of organic dairy foodstuff chain. There were choosen twelve organic dairy farms (survey II, 2006) for more detail research of production conditions according to results of exploratory questionnaire (2006, survey I, n = 85 pieces of questionnaire and 58 organic farms, which practicise dairying) in the CR. The climatology characteristics of selected organic dairy farms were as follows: (I) 562±149 m above sea level on the average (from 270 to 970 m a. s. l.); (II) 571.0±69.9 m above sea level, mean year temperature 6.0±1.1 ºC and average year rainfall sum 843.0±184.3 mm. It is clear according to previously mentioned figures that the organic (ecology) dairy farming is realized mostly in the mountain or sub-mountain areas (less favourable areas, LFAs) as compared to climatic conditions of CR mean profile. The results of investigation of organic farm (E) and breeder conditions and dairy cow health state, reproduction performance and milk quality in organic farms (I data file) as compared to conventional dairy cow herds (K) were: milk yield (E) was 14.2±3.4 kg of milk/cow/day on average and 5165±1112 kg/cow/year; E farms have 50 % free stables, some of them as different untraditional modifications (mostly in herds with low number of dairy cows); it is necessary to increase this amount for welfare improvement in the future; there are 52 % of binding stables in K herds; there (E) is high occurrence frequency of can milking equipments (46.4 %); there are 5.4 % cases of hand milking, 21.4 % of pipeline milking equipments and 26.8 % of milking parlours; there (K) are 3 % of can milking equipments, 50 % of pipeline milking equipments and 47 % of milking parlours; the average organic herd has 60±91 heads it means about 1/3 of K herd in the CR; geometrical average (xg) of organic herd size is 17 heads; daily milk deliveries were 1318±1475 kg in summer and 976±1368 kg in winter season (there is too high variability in the mentioned indicators); breed structure of E herds is 59.8 % of Bohemian Spotted cattle, 18.8 % of Holstein (H), 12.5 % of Jersey breed; H breed is dominating 47.5 % in K herds; average ratio of excluded milk (for secretion disorders or treatment) is 2.99 % in E herds and 4.6 % in K herds (P<0.01); also there (E) is lower occurrence of clinical mastitis 0.53±1.97 %; service period is 124.3 days in K and 98.7±46,1 days in E herds on average (P<0.01); there (E) is better insemination index 1.66±0.45 in comparison to K herds 2.07 (P<0.01); there is longer longevity as duration of production life of dairy cows in E herds (6.02 lactations, „about 141 % better”) in comparison to K herds (2.50 lactations, P<0.01); milk quality showed the average total mesophilic bacteria count (CPM) 36.0±26.8 ths. CFU/ml in organic farms (E), which is comparable to the conventional farms (K); somatic cell count (PSB) was 192±87 ths./ml in E herds and 256 ths./ml in K herds, which is in connection with the lower ratio of milk exclusion from delivery in E herds; an occurrence of residues of inhibitory substances (RIL) was not reported in E herds, which is more advantageous in comparison to the K herds (0.16 %) and it could be an impact of lowered antibiotica drug use; the average fat and lactose contents (T; 4.05±0.19 %) and (L; 4.83±0.15 %) are well comparable with K farms and the results show on higher energy deficiency in E herd nutrition. The water quality (II) is necessary in dairying as well. Drinking water is necessary for health of animals (their watering) and for milk quality (milking equipment sanitation) as well. Drinking water is asked in dairy farms by legislation. The E farm water quality: the nitrate level varied in the range from 1.63 to 28 mg/l with average 10.5 mg/l in ecological farms and standard limit 50 mg/l was not exceeded; the levels of nitrite and ammonia ions were mostly under detection limit of method; legislative limit <0.5 mg/l was not exceeded by nitrite and once by ammonia ions 0.81 mg/l. The microbiological indicators are more sensitive of course. In total the limits were exceeded 7× u in coliform bacteria, 3× in streptococci and Escherichia coli was confirmed 3× (in comparison to demand 0). Therefore it is necessary to take care of incidental water source sanitation. The effect of origin of water source (communal water pipes or own well in the organic farm area) which was used in the organic farming (II) was: the more marked result differences were not observed between own wells (S) and communal water supply (V) in E farms; an exception was stated in insignificantly better results of hygienic indicators of communal supply; therefore it is necessary to put the higher importance on sanitation of own water sources. There were identified eight own wells and four communal supply. E. g. nitrate levels were a little higher for wells 11.7 > 8.2 mg/l. The nitrites were not different. Chemical oxygen consumption was 0.45 and 0.52 mg/l. The more expressive differences were identified in chlorides, sulphates and Mg: 8.33 and 3.02 mg/l; 27.9 and 16.8 mg/l; 18.9 and 3.5 mg/l

New and updated convex shape models of asteroids based on optical data from a large collaboration network

Context. Asteroid modeling efforts in the last decade resulted in a comprehensive dataset of almost 400 convex shape models and their rotation states. These efforts already provided deep insight into physical properties of main-belt asteroids or large collisional families. Going into finer detail (e.g., smaller collisional families, asteroids with sizes 20 km) requires knowledge of physical parameters of more objects. Aims. We aim to increase the number of asteroid shape models and rotation states. Such results provide important input for further studies, such as analysis of asteroid physical properties in different populations, including smaller collisional families, thermophysical modeling, and scaling shape models by disk-resolved images, or stellar occultation data. This provides bulk density estimates in combination with known masses, but also constrains theoretical collisional and evolutional models of the solar system. Methods. We use all available disk-integrated optical data (i.e., classical dense-in-time photometry obtained from public databases and through a large collaboration network as well as sparse-in-time individual measurements from a few sky surveys) as input for the convex inversion method, and derive 3D shape models of asteroids together with their rotation periods and orientations of rotation axes. The key ingredient is the support of more that 100 observers who submit their optical data to publicly available databases. Results. We present updated shape models for 36 asteroids, for which mass estimates are currently available in the literature, or for which masses will most likely be determined from their gravitational influence on smaller bodies whose orbital deflections will be observed by the ESA Gaia astrometric mission. Moreover, we also present new shape model determinations for 250 asteroids, including 13 Hungarias and three near-Earth asteroids. The shape model revisions and determinations were enabled by using additional optical data from recent apparitions for shape optimization. © 2016 ESO.J.H. greatly appreciates the CNES post-doctoral fellowship program. J.H. and M.D. were supported by the project under the contract 11-BS56-008 (SHOCKS) of the French Agence National de la Recherche (ANR), JD by grant GACR 15-04816S of the Czech Science Foundation, DO by the grant NCN 2012/S/ST9/00022 of Polish National Science Center, and A. Marciniak by grant 2014/13/D/ST9/01818 of Polish National Science Center.Peer Reviewe

A COMPARISON OF SELECTED MILK INDICATORS IN ORGANIC HERDS WITH CONVENTIONAL HERD AS REFERENCE

In a historical sense, current organic farming is an old-new alternative under changed world conditions. Organic dairying (O) is an alternative of friendly use of the environment in time of presupposed global climate changes. Potential impact of organic farming on raw cow-milk quality, composition and properties, as conpared to conventional milk production (C), were evaluatedin this paper on the basis of selectedm ilk indicators (MIs). Total solids, whey volume, pH of milk fermentation ability (FAM-pH), FAM streptococci, FAM noble lactic acid bacteria, I and Cu were higher in C milk (P0.05) were observed in pH, rennet coagulation time, curd quality, FAM lactobacilli and streptococci/lactobacilli, Na, Mn and Zn. In general, the differences were a little more advantageous for O milk from both technological and nutritional point of view, particularly because of AS (0.461 .81m m), FAM-T (27.3 4.6 ) , Ca (1172 < l257 mg.kg-1)P, ( 950 < l004 mg. kg-1) and Mg 107.4<ll2.0mg.kg{) results. Organic milk can also produce better environment for yoghurt fermentation. Nevertheless, the results obtained should not be overestimated as both sources produced milk of good quality. Additional results are needed to prove organic milk benefits

An anisotropic distribution of spin vectors in asteroid families

Current amount of ~500 asteroid models derived from the disk-integrated photometry by the lightcurve inversion method allows us to study not only the spin-vector properties of the whole population of MBAs, but also of several individual collisional families. We create a data set of 152 asteroids that were identified by the HCM method as members of ten collisional families, among them are 31 newly derived unique models and 24 new models with well-constrained pole-ecliptic latitudes of the spin axes. The remaining models are adopted from the DAMIT database or the literature. We revise the preliminary family membership identification by the HCM method according to several additional criteria - taxonomic type, color, albedo, maximum Yarkovsky semi-major axis drift and the consistency with the size-frequency distribution of each family, and consequently we remove interlopers. We then present the spin-vector distributions for eight asteroidal families. We use a combined orbital- and spin-evolution model to explain the observed spin-vector properties of objects among collisional families. In general, we observe for studied families similar trends in the (a_p, \beta) space: (i) larger asteroids are situated in the proximity of the center of the family; (ii) asteroids with \beta>0{\deg} are usually found to the right from the family center; (iii) on the other hand, asteroids with \beta<0{\deg} to the left from the center; (iv) majority of asteroids have large pole-ecliptic latitudes (|\beta|\gtrsim 30{\deg}); and finally (v) some families have a statistically significant excess of asteroids with \beta>0{\deg} or \beta<0{\deg}. Our numerical simulation of the long-term evolution of a collisional family is capable of reproducing well the observed spin-vector properties. Using this simulation, we also independently constrain the age of families Flora (1.0\pm0.5 Gyr) and Koronis (2.5-4 Gyr).Comment: Accepted for publication in A&A (September 16, 2013

An advanced multipole model of the (130) Elektra quadruple system

The Ch-type asteroid (130) Elektra is orbited by three moons, making it the first quadruple system in the main asteroid belt. We aim to characterise the irregular shape of Elektra and construct a complete orbital model of its unique moon system. We applied the All-Data Asteroid Modelling (ADAM) algorithm to 60 light curves of Elektra, including our new measurements, 46 adaptive-optics (AO) images obtained by the VLT/SPHERE and Keck/Nirc2 instruments, and two stellar occultation profiles. For the orbital model, we used an advanced $N$-body integrator, which includes a multipole expansion of the central body (with terms up to the order $\ell = 6$), mutual perturbations, internal tides, as well as the external tide of the Sun acting on the orbits. We fitted the astrometry measured with respect to the central body and also relatively, with respect to the moons themselves. We obtained a revised shape model of Elektra with the volume-equivalent diameter $(201\pm 2)\,{\rm km}$. Out of two pole solutions, $(\lambda, \beta) = (189; -88)\,{\rm deg}$ is preferred, because the other one leads to an incorrect orbital evolution of the moons. We also identified the true orbital period of the third moon S/2014 (130) 2 as $P_2 = (1.642112 \pm 0.000400)\,{\rm d}$, which is in between the other periods, $P_1 \simeq 1.212\,{\rm d}$, $P_3 \simeq 5.300\,{\rm d}$, of S/2014 (130) 1 and S/2003 (130) 1, respectively. The resulting mass of Elektra, $(6.606 \substack{+0.007 \\ -0.013}) \times 10^{18}\,{\rm kg}$, is precisely constrained by all three orbits. Its bulk density is then $(1.536 \pm 0.038)\,{\rm g\,cm}^{-3}$. The expansion with the assumption of homogeneous interior leads to the oblateness $J_2 = -C_{20} \simeq 0.16$. However, the best-fit precession rates indicate a slightly higher value, ${\simeq}\,0.18$.Comment: 19 pages, 23 figure

Physical and dynamical properties of the main belt triple asteroid (87) Sylvia

We present the analysis of high angular resolution observations of the triple Asteroid (87) Sylvia collected with three 8-10 m class telescopes (Keck, VLT, Gemini North) and the Hubble Space Telescope. The moons' mutual orbits were derived individually using a purely Keplerian model. We computed the position of Romulus, the outer moon of the system, at the epoch of a recent stellar occultation which was successfully observed at less than 15 km from our predicted position, within the uncertainty of our model. The occultation data revealed that the Moon, with a surface-area equivalent diameter Ds=23.1$\pm$0.7km, is strongly elongated (axes ratio of 2.7$\pm$0.32.7$\pm$0.3), significantly more than single asteroids of similar size in the main-belt. We concluded that its shape is probably affected by the tides from the primary. A new shape model of the primary was calculated combining adaptive-optics observations with this occultation and 40 archived light-curves recorded since 1978. The difference between the J2=0.024-0.009+0.016 derived from the 3-D shape model assuming an homogeneous distribution of mass for the volume equivalent diameter Dv=273$\pm$10km primary and the null J2 implied by the Keplerian orbits suggests a non-homogeneous mass distribution in the asteroid's interior