scholarly journals The imprint of the protoplanetary disc in the accretion of super-Earth envelopes

2020 ◽  
Vol 494 (2) ◽  
pp. 2440-2448 ◽  
Author(s):  
Mohamad Ali-Dib ◽  
Andrew Cumming ◽  
Douglas N C Lin
Keyword(s):  
Energy Transport ◽  
Thermal State ◽  
Relative Size ◽  
Outer Envelope ◽  
Dominant Type ◽  
The Core ◽  
Lower Entropy ◽  
Gas Accretion ◽  
The Hill

ABSTRACT Super-Earths are by far the most dominant type of exoplanet, yet their formation is still not well understood. In particular, planet formation models predict that many of them should have accreted enough gas to become gas giants. Here, we examine the role of the protoplanetary disc in the cooling and contraction of the protoplanetary envelope. In particular, we investigate the effects of (1) the thermal state of the disc as set by the relative size of heating by accretion or irradiation, and whether its energy is transported by radiation or convection, and (2) advection of entropy into the outer envelope by disc flows that penetrate the Hill sphere, as found in 3D global simulations. We find that, at 5 and 1 au, this flow at the level reported in the non-isothermal simulations where it penetrates only to ∼0.3 times the Hill radius has little effect on the cooling rate since most of the envelope mass is concentrated close to the core, and far from the flow. On the other hand, at 0.1 au, the envelope quickly becomes fully radiative, nearly isothermal, and thus cannot cool down, stalling gas accretion. This effect is significantly more pronounced in convective discs, leading to envelope mass orders of magnitude lower. Entropy advection at 0.1 au in either radiative or convective discs could therefore explain why super-Earths failed to undergo runaway accretion. These results highlight the importance of the conditions and energy transport in the protoplanetary disc for the accretion of planetary envelopes.

Stopping Super-Earths from growing into Jupiters

2020 ◽  
Author(s):  
Mohamad Ali-Dib ◽  
Andrew Cumming ◽  
Doug Lin
Keyword(s):  
Planet Formation ◽  
Thermal State ◽  
Relative Size ◽  
Protoplanetary Disk ◽  
Outer Envelope ◽  
Dominant Type ◽  
Lower Entropy ◽  
Gas Accretion ◽  
The Hill

<p>Super-Earths are by far the most dominant type of exoplanet, yet their formation is<br />still not well understood. In particular, planet formation models predict that many<br />of them should have accreted enough gas to become gas giants. Here we examine the<br />role of the protoplanetary disk in the cooling and contraction of the protoplanetary<br />envelope. In particular, we investigate the effects of 1) the thermal state of the disk as<br />set by the relative size of heating by accretion or irradiation, and whether its energy is<br />transported by radiation or convection, and 2) advection of entropy into the outer envelope by disk flows that penetrate the Hill sphere, as found in 3D global simulations.<br />We find that, at 0.1 AU, the envelope quickly becomes fully radiative, nearly isothermal, and thus cannot cool down, stalling gas accretion. This<br />effect is significantly more pronounced in convective disks, leading to envelope mass or-<br />ders of magnitude lower. Entropy advection at 0.1 AU in either radiative or convective<br />disks could therefore explain why super-Earths failed to undergo runaway accretion.</p> <p>Ali-Dib, Cumming, & Lin (MNRAS 2020)</p>

Does a Ribosome Really Read? On the Cognitive Roots and Heuristic Value of Linguistic Metaphors in Molecular Genetics. Part 2

2020 ◽  
Vol 63 (2) ◽  
pp. 46-62
Author(s):  
Suren T. Zolyan
Keyword(s):  
Information Processing ◽  
Genetic Information ◽  
Formal Organization ◽  
Dual Nature ◽  
Reading Frame ◽  
The Core ◽  
Genetic Information Processing ◽  
Cognitive Frame ◽  
Effective Instrument

We discuss the role of linguistic metaphors as a cognitive frame for the understanding of genetic information processing. The essential similarity between language and genetic information processing has been recognized since the very beginning, and many prominent scholars have noted the possibility of considering genes and genomes as texts or languages. Most of the core terms in molecular biology are based on linguistic metaphors. The processing of genetic information is understood as some operations on text – writing, reading and editing and their specification (encoding/decoding, proofreading, transcription, translation, reading frame). The concept of gene reading can be traced from the archaic idea of the equation of Life and Nature with the Book. Thus, the genetics itself can be metaphorically represented as some operations on text (deciphering, understanding, code-breaking, transcribing, editing, etc.), which are performed by scientists. At the same time linguistic metaphors portrayed gene entities also as having the ability of reading. In the case of such “bio-reading” some essential features similar to the processes of human reading can be revealed: this is an ability to identify the biochemical sequences based on their function in an abstract system and distinguish between type and its contextual tokens of the same type. Metaphors seem to be an effective instrument for representation, as they make possible a two-dimensional description: biochemical by its experimental empirical results and textual based on the cognitive models of comprehension. In addition to their heuristic value, linguistic metaphors are based on the essential characteristics of genetic information derived from its dual nature: biochemical by its substance, textual (or quasi-textual) by its formal organization. It can be concluded that linguistic metaphors denoting biochemical objects and processes seem to be a method of description and explanation of these heterogeneous properties.

Exploring the Mechanism of Lingzhu San in Treating Febrile Seizures by Using Network Pharmacology

2020 ◽  
Vol 23 ◽  
Author(s):  
Xiao Zhou ◽  
Xiao-Fei Zhang ◽  
Dong-Yan Guo ◽  
Yan-Jun Yang ◽  
Lin Liu ◽  
...  
Keyword(s):  
Febrile Seizures ◽  
Network Pharmacology ◽  
Biological Processes ◽  
Active Compounds ◽  
Potential Core ◽  
R Language ◽  
The Core ◽  
Multiple Factors ◽  
Therapeutic Mechanism

Objective: Lingzhu San (LZS) is a traditional Chinese medicine (TCM) prescription which can be effective in treating febrile seizures (FS) and has few researches on the mechanisms. In order to better guide the clinical use of LZS, we used the research ideas and methods of network pharmacology to find the potential core compounds, targets and pathways of LZS in the complex TCM system for the treatment of FS, and predict the mechanism. Materials and Methods: Databases such as BATMAN, TCMSP, TCMID, and SWISS TARGET are used to mine the active compounds and targets of LZS, and the target information of FS was obtained through GENECARDS and OMIM. Using Venny2.1.0 and Cytoscape software to locked the potential core compounds and targets of FS. The R language and ClusterProfiler software package were adopt to enrich and analyze the KEGG and GO pathways of the core targets and the biological processes and potential mechanisms of the core targets were revealed. Results: 187 active compounds and 2113 target proteins of LZS were collected. And 38 potential core compounds, 35 core targets and 775 metabolic and functional pathways were screened which involved in mediating FS. Finally, the role of the core compounds, targets and pivotal pathways of LZS regulated FS in the pathogenesis and therapeutic mechanism of FS was discussed and clarified. Conclusions: In this paper, the multi-compounds, multi-targets and multi-pathways mechanism of LZS in the treatment of FS was preliminarily revealed through the analysis of network pharmacology data, which is consistent with the principle of multi-compounds compatibility of TCM prescriptions and unified treatment of diseases from multiple angles, and it provides a new way for TCM to treat complex diseases caused by multiple factors.

Acid ceramidase, a double-edged sword in cancer aggression: A minireview

2020 ◽  
Vol 20 ◽  
Author(s):  
Helen Shiphrah Vethakanraj ◽  
Niveditha Chandrasekaran ◽  
Ashok Kumar Sekar
Keyword(s):  
Cell Fate ◽  
Cancer Progression ◽  
Potential Role ◽  
Tumour Progression ◽  
Acid Ceramidase ◽  
The Core ◽  
The Past ◽  
Sphingosine 1 Phosphate ◽  
Key Enzyme

: Acid ceramidase (AC), the key enzyme of the ceramide metabolic pathway hydrolyzes pro-apoptotic ceramide to sphingosine, which by the action of sphingosine-1-kinase is metabolized to mitogenic sphingosine-1-phosphate. The intracellular level of AC determines ceramide/sphingosine-1-phosphate rheostat which in turn decides the cell fate. The upregulated AC expression during cancerous condition acts as a “double-edged sword” by converting pro-apoptotic ceramide to anti-apoptotic sphingosine-1-phosphate, wherein on one end, the level of ceramide is decreased and on the other end, the level of sphingosine-1-phosphate is increased, thus altogether aggravating the cancer progression. In addition, cancer cells with upregulated AC expression exhibited increased cell proliferation, metastasis, chemoresistance, radioresistance and numerous strategies were developed in the past to effectively target the enzyme. Gene silencing and pharmacological inhibition of AC sensitized the resistant cells to chemo/radiotherapy thereby promoting cell death. The core objective of this review is to explore AC mediated tumour progression and the potential role of AC inhibitors in various cancer cell lines/models.

Rural Dalit Women Entrepreneurs and Development Scenario: A Study

2016 ◽  
Vol 5 (1) ◽  
Author(s):  
Amaldass M. ◽  
Neema Gnanadev
Keyword(s):  
Rural Women ◽  
Women Entrepreneurs ◽  
Cultural Aspects ◽  
Self Employment ◽  
Dalit Women ◽  
Integral Development ◽  
Entrepreneurial Activities ◽  
The Hill ◽  
The Village

Pandit Nehru affirmed that women development/ empowerment is the basis for the substantial growth of a family, a village, or a nation. Development/upliftment of women is an essential ingredient of human development. Entrepreneurship development among the rural women folk would strengthen the village economy and promote regional development. The women entrepreneurs have proved that there is a source of immense untapped power in the womanhood of India (Margaret, 1992). Women undoubtedly are the backbone of the socio-economic-cultural aspects in the hill scenario. The subsistence agriculture which leads to low and unstable incomes, which in turn lead to a sizeable out-migration of male members that leads to only women headed families behind, and the role of women in the household economy becomes more important (Rawat, 2004). In the midst of limited opportunities, tough terrains and lack of resources, the contribution of women entrepreneurs to the society is enormous. An attempt was made to highlight the strategies and development aspects of rural women entrepreneurs in Almora district. Entrepreneurs who are engaged in self-employment and innovative entrepreneurial activities were selected for the study. A total of 50 samples were selected and the data were collected through interviews and focus groups. The study reveals various aspects related to rural women entrepreneurship and constraints that need attention so to empower women in their efforts toward integral development.

The Fox Diet

2018 ◽  
Author(s):  
Yochai Benkler ◽  
Robert Faris ◽  
Hal Roberts
Keyword(s):  
First Year ◽  
Right Wing ◽  
Justice Department ◽  
Fox News ◽  
The Core ◽  
Deep State ◽  
Media Ecosystem ◽  
Conservative Media ◽  
The Right

This chapter focuses on the role of the dominant player in conservative media, Fox News, during the first year of Donald Trump’s presidency. It looks at three case studies to illustrate how Fox News used its position at the core of the right-wing media ecosystem repeatedly to mount propaganda attacks in support of Trump: the Michael Flynn firing in March 2017, when Fox adopted the “deep state” framing of the entire controversy; the James Comey firing and Robert Mueller appointment in May 2017; when Fox propagated the Seth Rich murder conspiracy; and in October and November, when the arrests of Paul Manafort and guilty plea of Flynn seemed to mark a new level of threat to the president, Fox reframed the Uranium One story as an attack on the integrity of the FBI and Justice Department officials in charge of the investigation.

scholarly journals The role of AGN activity in the building up of the BCG at z ∼ 1.6

2019 ◽  
Vol 15 (S356) ◽  
pp. 280-284
Author(s):  
Angela Bongiorno ◽  
Andrea Travascio
Keyword(s):  
Galaxy Cluster ◽  
Cluster Galaxy ◽  
X Ray ◽  
Groups Of Galaxies ◽  
Star Forming ◽  
The Core ◽  
The Galaxy ◽  
Multi Wavelength

AbstractXDCPJ0044.0-2033 is one of the most massive galaxy cluster at z ∼1.6, for which a wealth of multi-wavelength photometric and spectroscopic data have been collected during the last years. I have reported on the properties of the galaxy members in the very central region (∼ 70kpc × 70kpc) of the cluster, derived through deep HST photometry, SINFONI and KMOS IFU spectroscopy, together with Chandra X-ray, ALMA and JVLA radio data.In the core of the cluster, we have identified two groups of galaxies (Complex A and Complex B), seven of them confirmed to be cluster members, with signatures of ongoing merging. These galaxies show perturbed morphologies and, three of them show signs of AGN activity. In particular, two of them, located at the center of each complex, have been found to host luminous, obscured and highly accreting AGN (λ = 0.4−0.6) exhibiting broad Hα line. Moreover, a third optically obscured type-2 AGN, has been discovered through BPT diagram in Complex A. The AGN at the center of Complex B is detected in X-ray while the other two, and their companions, are spatially related to radio emission. The three AGN provide one of the closest AGN triple at z > 1 revealed so far with a minimum (maximum) projected distance of 10 kpc (40 kpc). The discovery of multiple AGN activity in a highly star-forming region associated to the crowded core of a galaxy cluster at z ∼ 1.6, suggests that these processes have a key role in shaping the nascent Brightest Cluster Galaxy, observed at the center of local clusters. According to our data, all galaxies in the core of XDCPJ0044.0-2033 could form a BCG of M* ∼ 1012Mȯ hosting a BH of 2 × 108−109Mȯ, in a time scale of the order of 2.5 Gyrs.

The Germans and Air Power at Dieppe: The Raid and its Lessons from the ‘Other Side of the Hill’

2021 ◽  
pp. 096834452199586
Author(s):  
James Shelley
Keyword(s):  
Armed Forces ◽  
The Other ◽  
Air Power ◽  
Coastal Defence ◽  
German Armed Forces ◽  
Popular Interest ◽  
The Hill

Despite the vast academic and popular interest in the Dieppe raid of 19 August 1942, there remains a curious oversight of the German side of the story. This contribution interrogates German sources in order to explore the Dieppe air battle and its consequences from the perspective of the German armed forces. The paper ultimately demonstrates that the Germans learnt much about the role of air power in coastal defence from their experiences at Dieppe, but that the implementation of those lessons was lacking.

scholarly journals A militant defence of democracy: A few replies to my critics

2020 ◽  
pp. 019145372097472
Author(s):  
Cristina Lafont
Keyword(s):  
Deliberative Democracy ◽  
Special Issue ◽  
The Core ◽  
Difficult Question ◽  
Proper Role

In this essay, I address some questions and challenges brought about by the contributors to this special issue on my book ‘ Democracy without Shortcuts’. First, I clarify different aspects of my critique of deep pluralist conceptions of democracy to highlight the core incompatibilities with the participatory conception of deliberative democracy that I defend in the book. Second, I distinguish different senses of the concept of ‘blind deference’ that I use in the book to clarify several aspects and consequences of my critique of epistocratic conceptions of democracy and their search for ‘expertocratic shortcuts’. This in turn helps me briefly address the difficult question of the proper role of experts in a democracy. Third, I address potential uses of empowered minipublics that I did not discuss in the book and highlight some reasons to worry about their lack of accountability. This discussion in turn leads me to address the difficult question of which institutions are best suited to represent the transgenerational collective people who are supposed to own a constitutional project. Finally, I address some interesting suggestions for how to move the book’s project forward.

Genealogy of Colonial Discourse: Hindu Traditions and the Limits of European Representation

2009 ◽  
Vol 51 (3) ◽  
pp. 563-589 ◽  
Author(s):  
Raf Gelders
Keyword(s):  
Nineteenth Century ◽  
South Asian ◽  
Colonial Discourse ◽  
Colonial State ◽  
The Core ◽  
European Culture ◽  
Eastern Cultures ◽  
The Subject ◽  
Core Issues

In the aftermath of Edward Said's Orientalism (1978), European representations of Eastern cultures have returned to preoccupy the Western academy. Much of this work reiterates the point that nineteenth-century Orientalist scholarship was a corpus of knowledge that was implicated in and reinforced colonial state formation in India. The pivotal role of native informants in the production of colonial discourse and its subsequent use in servicing the material adjuncts of the colonial state notwithstanding, there has been some recognition in South Asian scholarship of the moot point that the colonial constructs themselves built upon an existing, precolonial European discourse on India and its indigenous culture. However, there is as yet little scholarly consensus or indeed literature on the core issues of how and when these edifices came to be formed, or the intellectual and cultural axes they drew from. This genealogy of colonial discourse is the subject of this essay. Its principal concerns are the formalization of a conceptual unit in the sixteenth and seventeenth centuries, called “Hinduism” today, and the larger reality of European culture and religion that shaped the contours of representation.

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