scholarly journals Asteroid cratering families: recognition and collisional interpretation

2019 ◽  
Vol 622 ◽  
pp. A47 ◽  
Author(s):  
A. Milani ◽  
Z. Knežević ◽  
F. Spoto ◽  
P. Paolicchi

Aims. We continue our investigation of the bulk properties of asteroid dynamical families identified using only asteroid proper elements to provide plausible collisional interpretations. We focus on cratering families consisting of a substantial parent body and many small fragments. Methods. We propose a quantitative definition of cratering families based on the fraction in volume of the fragments with respect to the parent body; fragmentation families are above this empirical boundary. We assess the compositional homogeneity of the families and their shape in proper element space by computing the differences of the proper elements of the fragments with respect to the ones of the major body, looking for anomalous asymmetries produced either by post-formation dynamical evolution, or by multiple collisional/cratering events, or by a failure of the hierarchical clustering method (HCM) for family identification. Results. We identified a total of 25 dynamical families with more than 100 members ranging from moderate to heavy cratering. For three families (4, 15 and 283) we confirm the occurrence of two separate cratering events, while family (569) Misa is a mixed case, with one cratering event and one fragmentation event. The case of family 3 remains dubious, in that there could be either one or two collisions. For family 20, we propose a double collision origin, not previously identified. In four cases (31, 480, 163 and 179) we performed a dedicated search for dynamical resonant transport mechanisms that could have substantially changed the shape of the family. By using a new synthetic method for computation of secular frequencies, we found possible solutions for families 31, 480, and 163, but not for family 179, for which we propose a new interpretation, based on a secular resonance contaminating this family: the family of 179 should be split into two separate clusters, one containing (179) itself and the other, family (9506) Telramund, of fragmentation type, for which we have computed an age.

1989 ◽  
Vol 8 ◽  
pp. 273-279
Author(s):  
V. Zappala’

AbstractAsteroid families are considered for the most to represent fragments of collisional breakup of precursor bodies. If true, this offers the unique possibility to examine the interiors of large bodies and to study the processes of collision on a scale much larger than can be done in laboratory. Indeed, the general features of the mass distributions and of the ejection velocities of the family members can be interpreted in terms of collisional disruption of a parent body followed by self-gravitational reaccumulation on the largest remnant. However, several problems remain open: a) the degree of fragmentation in real families is generally lower than that observed for experimental targets; b) the relative velocities computed including also proper eccentricity and inclination differences are higher by about a factor 4 than those derived from semiaxes differences only; c) only very few of the presently proposed families have distributions of inferred mineralogies consistent with cosmochemistry. Further studies are needed, including better proper elements computation, classification methods, and new investigations on the physics of hypervelocity impacts.


2015 ◽  
Vol 71 (1) ◽  
Author(s):  
Kyu Seop Kim

Recent scholars focus mainly on Paul’s use of ‘brothers (and sisters)’ or ‘brother (and sister)’ in Greco-Roman epistolary conventions and cultural backdrops. However, Jewish dimensions (particularly ethnic dimensions) of Paul’s sibling language still remain unexplored in current scholarship. Furthermore, scholars have not drawn much attention to how Jewish letter writers use sibling terms in their letters. This article offers a new interpretation on Paul’s sibling language in light of its Jewish usage. We should note that Jewish letter writers did not address their Gentile letter recipients as ‘brother(s)’. However, Paul did call his recipients ‘brothers’. It is unlikely that Paul employed sibling language without being aware of its common Jewish usage. The author proposes that Paul’s sibling language is used in the context of an ethnic insider designation (shared ethnicity), and that ascribing the title of brother to believers including Gentiles signals the re-definition of the family of Abraham.


2020 ◽  
Vol 643 ◽  
pp. A38
Author(s):  
B. Yang ◽  
J. Hanuš ◽  
M. Brož ◽  
O. Chrenko ◽  
M. Willman ◽  
...  

Aims. The Euphrosyne asteroid family occupies a unique zone in orbital element space around 3.15 au and may be an important source of the low-albedo near-Earth objects. The parent body of this family may have been one of the planetesimals that delivered water and organic materials onto the growing terrestrial planets. We aim to characterize the compositional properties as well as the dynamical properties of the family. Methods. We performed a systematic study to characterize the physical properties of the Euphrosyne family members via low-resolution spectroscopy using the NASA Infrared Telescope Facility. In addition, we performed smoothed-particle hydrodynamics (SPH) simulations and N-body simulations to investigate the collisional origin, determine a realistic velocity field, study the orbital evolution, and constrain the age of the Euphrosyne family. Results. Our spectroscopy survey shows that the family members exhibit a tight taxonomic distribution, suggesting a homogeneous composition of the parent body. Our SPH simulations are consistent with the Euphrosyne family having formed via a reaccumulation process instead of a cratering event. Finally, our N-body simulations indicate that the age of the family is 280−80+180 Myr, which is younger than previous estimates.


2020 ◽  
Vol 501 (1) ◽  
pp. 356-366
Author(s):  
Debora Pavela ◽  
Bojan Novaković ◽  
Valerio Carruba ◽  
Viktor Radović

ABSTRACT The Karma asteroid family is a group of primitive asteroids in the middle part of the main belt, just at the outer edge of the 3J:1A mean-motion resonance. We obtained the list of the family members with 317 asteroids, and estimated that it was formed by the catastrophic disruption of a parent body that was between 34 and 41 km in diameter. Based on the V-shape method, age of the Karma family is estimated to be about 137 Myr. A detailed dynamical map of the region combined with numerical simulations allowed us to reconstruct the long-term dynamical evolution of the family, and to identify the mechanisms responsible for this evolution. The numerical simulations successfully reproduced the main features in the orbital distribution of the family members but also showed that some regions of the Karma family could be missing. A more detailed analysis revealed that these regions likely consist of very dark objects, fainter than absolute magnitude H = 17, that have not yet been detected. Based on the obtained results, we concluded that magnitude–frequency distribution of family members up to H = 16 mag is neither affected by dynamical erosion nor observational incompleteness, and therefore represents the result of collisional grinding of the original family population. Finally, we found that the Karma family have been supplying some asteroids to the near-Earth region via the 3J:1A resonance. Currently, there should about 10 family members larger than 1 km in diameter, orbiting in the near-Earth space.


2019 ◽  
Vol 22 (2) ◽  
pp. 27-32
Author(s):  
Khurshida Tillahodjaeva ◽  

In this article we will talk about the scale of family and marriage relations in the early XX century in the Turkestan region, their regulation, legislation. Clearly reveals the role of women and men in the family, the definition of which is based on the material conditions of society, equality of rights and freedoms and its features.


2021 ◽  
Vol 22 (9) ◽  
pp. 4716
Author(s):  
Francesco Ciscato ◽  
Lavinia Ferrone ◽  
Ionica Masgras ◽  
Claudio Laquatra ◽  
Andrea Rasola

Hexokinases are a family of ubiquitous exose-phosphorylating enzymes that prime glucose for intracellular utilization. Hexokinase 2 (HK2) is the most active isozyme of the family, mainly expressed in insulin-sensitive tissues. HK2 induction in most neoplastic cells contributes to their metabolic rewiring towards aerobic glycolysis, and its genetic ablation inhibits malignant growth in mouse models. HK2 can dock to mitochondria, where it performs additional functions in autophagy regulation and cell death inhibition that are independent of its enzymatic activity. The recent definition of HK2 localization to contact points between mitochondria and endoplasmic reticulum called Mitochondria Associated Membranes (MAMs) has unveiled a novel HK2 role in regulating intracellular Ca2+ fluxes. Here, we propose that HK2 localization in MAMs of tumor cells is key in sustaining neoplastic progression, as it acts as an intersection node between metabolic and survival pathways. Disrupting these functions by targeting HK2 subcellular localization can constitute a promising anti-tumor strategy.


2021 ◽  
pp. tobaccocontrol-2020-056145 ◽  
Author(s):  
Ollie Ganz ◽  
Mary Hrywna ◽  
Kevin R J Schroth ◽  
Cristine D Delnevo

In 2009, the Family Smoking Prevention and Tobacco Control Act (TCA) granted the U.S. Food and Drug Administration (FDA) regulatory authority over tobacco products, although initially this only included cigarettes, smokeless tobacco and roll-your-own tobacco. In 2016, the deeming rule extended regulatory authority to include all tobacco products, including cigars. The deeming rule prohibited the introduction of new tobacco products into the marketplace without proper marketing authorisation and laid out pathways for tobacco companies to follow. The deeming rule should have frozen the cigar marketplace in 2016. In this paper, we describe how the cigarillo marketplace, nevertheless, continues to diversify with new brands, flavors, styles and packaging sizes entering the market regularly. As an example, we highlight recent promotional efforts by Swedish Match North America (Swedish Match) for their popular cigarillo brands, including White Owl, Night Owl and Garcia y Vega’s Game brand. We argue that ambiguities in the TCA make it unclear whether Swedish Match’s seemingly new cigarillos fit the definition of new tobacco products and, if so, whether they are on the market legally. Swedish Match and other cigarillo companies may be taking advantage of these ambiguities to promote a variety of cigarillo flavors and styles in innovative ways. Given that cigars are combustible tobacco products that pose many of the same risks as cigarettes, this business practice raises significant concerns regarding the protection of public health, particularly among young people.


Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3366
Author(s):  
Daniel Suchet ◽  
Adrien Jeantet ◽  
Thomas Elghozi ◽  
Zacharie Jehl

The lack of a systematic definition of intermittency in the power sector blurs the use of this term in the public debate: the same power source can be described as stable or intermittent, depending on the standpoint of the authors. This work tackles a quantitative definition of intermittency adapted to the power sector, linked to the nature of the source, and not to the current state of the energy mix or the production predictive capacity. A quantitative indicator is devised, discussed and graphically depicted. A case study is illustrated by the analysis of the 2018 production data in France and then developed further to evaluate the impact of two methods often considered to reduce intermittency: aggregation and complementarity between wind and solar productions.


2002 ◽  
Vol 33 (1) ◽  
pp. 23-34 ◽  
Author(s):  
Hasan H. Basibuyuk ◽  
Mike G. Fitton ◽  
Alexandr P. Rasnitsyn ◽  
Donald L.J. Quicke

AbstractThe definition of the family Evaniidae is revised and Cretevaniidae are synonymised with Evaniidae based on evidence derived from recently described Mesozoic taxa and a new genus and species, Lebanevania azari, described here from Lebanese amber. A fore leg with a long trochanter and a 12-segmented antenna are autapomorphies of the new genus. A large, high and wide head and a high and short mesosoma are derived characters shared with other Evaniidae. The new genus also has complete fore wing venation and lacks a tubular petiole, which are ground plan features of the Evanioidea. A cladistic analysis of fossil and extant members of the superfamily Evanioidea and notes on fossil taxa are presented.


Author(s):  
Roger S. Miles

SynopsisThe holotype and only known specimen of Rhachiosteus pterygiatus Gross is partially redescribed and new restorations are given. Attention is drawn to important points in its osteology and the possible development of a cutaneous sensory system. A definition of the family Rhachiosteidsæ Stensiö is given. This family differs from all other described groups of euarthrodires in the lack of posterior lateral and posterior dorsolateral flank plates. Rhachiosteus is a pachyosteomorph brachythoracid, as defined in the text, and may be fairly closely related in some way to the (coccosteomorph) family Coccosteidsæ. There is no indication that it is closely related to any other known pachyosteomorph, or to other groups of arthrodires, such as the Rhenanida and Ptyctodontida, in which there are no posterior flank plates.


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