Trepostomate bryozoans from the upper Katian (Upper Ordovician) of Morocco: gigantism in high latitude Gondwana platforms

2015 ◽  
Vol 89 (2) ◽  
pp. 195-221 ◽  
Author(s):  
Andrea Jiménez-Sánchez ◽  
Enmanuelle Vennin ◽  
Enrique Villas
Keyword(s):  
Depositional Environments ◽  
Congeneric Species ◽  
Upper Ordovician ◽  
Supporting Surface ◽  
Great Stability ◽  
Fine Grained ◽  
Intermediate Unit ◽  
Alternative Proposal ◽  
The One ◽  
Giant Size

AbstractA study of the Upper Ordovician trepostomate bryozoans belonging to the families Amplexoporidae and Monticuliporidae, from the eastern Anti-Atlas of Morocco, is presented here. They occur in the marly to fine-grained limestone, intermediate unit of the Khabt-el-Hajar Formation, late Katian in age, representing outer-ramp depositional environments. They inhabited the highest paleolatitude known for a bryozoan fauna during the Ordovician, estimated at more than 65–70ºS. A total of 11 species of the generaAnaphragma,Atactoporella,Homotrypa,Monotrypa,Monticulipora, andPrasoporaare described. Three species are already known from the equatorial-tropical paleocontinents of Baltica, Laurentia, and Siberia:Anaphragma mirabile,Monotrypa jewensis, andPrasopora falesi. Four new taxa are described:Anaphragma undulata,Atactoporella moroccoensis,Monticulipora globulata, andMonticulipora irregularis.The two species ofAnaphragmaand the one ofAtactoporelladisplay significantly larger zoarial sizes than congeneric species, representing gigantism among bryozoans. Polar gigantism is rejected for the two species ofAnaphragmaas is gigantism related to photosynthetic endosymbionts. An alternative proposal for their giant size is their long zoarial life span due to their well-balanced, robust branching form, with a relatively wide basal supporting surface, adapted to unconsolidated substrates in environments below wave base. Their great stability in outer-ramp environments, with infrequent storms, would allow the zoaria to grow for an extended time and reach large sizes before being overturned and buried.Atactoporella moroccoensis, has both zoaria and zooecia gigantic, suggesting a hypothesis of polar gigantism.

scholarly journals Mineralogy, Geochemistry and Provenance of Coastal Sands from Greece: New Insights on the REE Content of Black Coastal Sands from Aggelochori Area, N.-Greece

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 693
Author(s):  
Argyrios Papadopoulos ◽  
Stylianos Lazaridis ◽  
Afroditi Kipourou-Panagiotou ◽  
Nikolaos Kantiranis ◽  
Antonios Koroneos ◽  
...  
Keyword(s):  
Major And Trace Elements ◽  
Heavy Minerals ◽  
Sea Waves ◽  
Complex Flow ◽  
Fine Grained ◽  
Microscopy Analysis ◽  
Beach Sands ◽  
Geochemical Analyses ◽  
The One ◽  
Black Color

Beach sands from Aggelochori coast line are investigated for their geochemistry and REE content, mineralogy and their provenance. These fluvial sands bear heavy minerals enriched horizons (containing minerals such as magnetite, zircon, ilmenite, hematite, rutile and titanite) that can be distinguished due to their black color and are formed usually due to the action of sea waves that deposit the heavy minerals and remove the lighter ones. After a suitable processing (washing, sieving, drying and magnetic separation) of the samples, the mineral constituents and their presence (wt.%) were estimated by XRD. Among the samples, the one being simultaneously the more fine grained and the more zircon-enriched (as suggested by XRPD data and optical microscopy analysis) has been selected for further geochemical analyses. The major and trace elements contents were compared to previously studied REE enriched beach sands from Kavala and Sithonia. Beach sands from Aggelochori area appear to have relatively low REE contents. Considering the provenance of these sediments, we suggest that these sands, are a product of the erosion of multi-sources, including the near-by Monopigado granite, as well as metamorphic rocks, as indicated by the presence of rutile and both ilmenite and magnetite in some samples. Therefore, there are indications of a complex flow pattern that existed at the paleo-catchment area of the deposition.

Improving the Mechanical Properties of AZ31 Mg Alloy by High Ratio Extrusion

2006 ◽  
Vol 503-504 ◽  
pp. 865-870 ◽  
Author(s):  
Yongjun Chen ◽  
Qu Dong Wang ◽  
Jianguo Peng ◽  
Chun Quan Zhai
Keyword(s):  
Mechanical Properties ◽  
High Strength ◽  
High Ratio ◽  
Extrusion Ratio ◽  
Mg Alloy ◽  
Fine Grained ◽  
Az31 Mg Alloy ◽  
Industry Applications ◽  
One Step ◽  
The One

Experiments were conducted both to evaluate the potential for grain refinement, the subsequent mechanical properties at room temperature in samples of AZ31 Mg alloy and also to investigate the relationship between one-step and two-step high ratio extrusion (HRE). The one-step HRE was undertaken using a high extrusion ratio of 70:1 at 250, 300 and 350°C. And the two-step HRE was conducted with an extrusion ratio of 7 for the first step at 250, 300 and 350°C, followed by a second-step extrusion with an extrusion ratio of 10 at 250, 300 and 350°C. The initial grain size in the AZ31 ingot was 100μm and that after one-step HRE became similar to 5μm, after two-step HRE at 250, 300 and 350°C were 2, 4, 7μm, respectively, resulting in superior mechanical properties at ambient temperature. The microstructure of two-step HRE was finer and uniformer than that of one-step HRE and the strength of one-step and two-step HRE were similar, moreover, the elongation of one-step HRE was improved markedly than that of two-step HRE. Dynamic recrystallization and adjacent grain broking during HRE is introduced to explain the effects of one-step and two-step HRE on the microstructure and mechanical properties of AZ31 Mg alloy. The current results imply that the simple HRE method might be a feasible processing method for industry applications, and the multiply steps extrusion are effective to fabricate high strength of fine grained hcp metals.

scholarly journals Additive-error fine-grained quantum supremacy

Quantum ◽  
2020 ◽  
Vol 4 ◽  
pp. 329
Author(s):  
Tomoyuki Morimae ◽  
Suguru Tamaki
Keyword(s):  
Quantum Computing ◽  
Complexity Theory ◽  
Polynomial Time ◽  
Boolean Circuits ◽  
Exponential Time ◽  
Fine Grained ◽  
Additive Error ◽  
Universal Quantum ◽  
The One ◽  
Computing Models

It is known that several sub-universal quantum computing models, such as the IQP model, the Boson sampling model, the one-clean qubit model, and the random circuit model, cannot be classically simulated in polynomial time under certain conjectures in classical complexity theory. Recently, these results have been improved to ``fine-grained" versions where even exponential-time classical simulations are excluded assuming certain classical fine-grained complexity conjectures. All these fine-grained results are, however, about the hardness of strong simulations or multiplicative-error sampling. It was open whether any fine-grained quantum supremacy result can be shown for a more realistic setup, namely, additive-error sampling. In this paper, we show the additive-error fine-grained quantum supremacy (under certain complexity assumptions). As examples, we consider the IQP model, a mixture of the IQP model and log-depth Boolean circuits, and Clifford+T circuits. Similar results should hold for other sub-universal models.

scholarly journals Radionuclides as tracers of coastal processes in Brazil: review, synthesis, and perspectives

2008 ◽  
Vol 56 (2) ◽  
pp. 115-130 ◽  
Author(s):  
Isaac R. Santos ◽  
William C. Burnett ◽  
José M. Godoy
Keyword(s):  
Coastal Lagoons ◽  
Phosphate Fertilizer ◽  
Depositional Environments ◽  
Brazilian Coast ◽  
Petroleum Processing ◽  
Artificial Radionuclide ◽  
Economic Activities ◽  
Radium Isotopes ◽  
Erosion Processes ◽  
The One

We review the usefulness, limitations, significance, and coastal management implications of radionuclide measurements in Brazilian coastal environments. We focus on the use of radionuclides as tracers of sedimentary processes and submarine groundwater discharge (SGD). We also discuss artificial radionuclide contamination and high natural radioactivity areas. The interpretation of 14C-, 137Cs-, and 210Pb-derived sedimentation rates has provided evidence that inappropriate soil use by urban and agricultural activities has intensified erosion processes on land, which is reflected in depositional environments, such as coastal lagoons, estuaries and mangroves. Of the processes discussed in this paper, SGD is the one that requires the most scientific effort in the short-term. There have been only two case studies using 222Rn and radium isotopes as groundwater tracers in Brazil. These investigations showed that SGD can be a major source of nutrients and other dissolved species to the coastal ocean. Baseline 137Cs, 90Sr, 239+240Pu, and 238Pu concentrations in seawater from the whole Brazilian coastal zone are very low. Therefore, in spite of contamination problems in many ecosystems in the northern hemisphere, artificial radionuclide pollution appears to be negligible along the Brazilian coast. Phosphate fertilizer industries and petroleum processing facilities are the main economic activities producing Technologically Enhanced Naturally Occurring Radioactive Materials (TENORM). Even though a few attempts have been made to assess the radiological effects of these activities, their potential threats indicate a need for the radiological control of their wastes. This review showed that the number of studies within the field of environmental radioactivity is still small in Brazil and much more research is needed to understand processes of high interest for environmental managers. In the near future, it is likely that such studies in Brazil will move from descriptive, environmental quality-based assessments to approaches that attempt to quantify chemical, physical, and biological processes in the environment.

Les élections législatives du 13 décembre 1987 : Analyse des résultats

Res Publica ◽  
1988 ◽  
Vol 30 (1) ◽  
pp. 3-24
Author(s):  
William Fraeys
Keyword(s):  
The Other ◽  
Great Stability ◽  
Political Situation ◽  
Universal Suffrage ◽  
Political Impact ◽  
Economic Background ◽  
French Speaking ◽  
The Face ◽  
General Elections ◽  
The One

Organized only two years after the previous genera! elections, the 1987 poll, characterized by a great stability of the electorale, wilt probably have a deep political impact on the country's future.If the rate of external mobility suitably gauges the extent of the citizens' shifts in votes, the 1987 elections will have ranged among the four most stable general elections out of the twenty-two that have taken place since universal suffrage has been introduced. And yet, because of the decline of the outgoing coalition, on the one hand, which is mainly due to the loss suffered by the CVP, and because of the change of majority within the Walloon Regional Council and the French-speaking Community Council, on the other, the political situation appears very different after the 13th December 1987 elections. The observer can only be struck by the asymmetrical behaviour of the voters in the northern and southern parts of the country. In Flanders, the main party is on the decline white all other parties are winning votes.However, everything seems to show that the motivation of the voters who did not vote twice for the same party in 1985 and 1987, but who, as we said, are not very numerous, was an economic and social motivationrather than a language or community-related one. The gains of Agalev, the PVV and the SP in the face of the Volksunie's status quo cannot be explained otherwise. The gains of the Vlaams Blok, notably in Antwerp, are probably due to social (attitude towards immigrants) rather than community-linked motivations too. In the W alloon Region, on the contrary, the main party is registering an obvious gain, white the other parties are declining or stagnating. In this case, the motivations seem to be numerous : they have a social and economic background on the part of voters who trusted the main opposition party, but they are also community linked and inspired by considerations that have to do with the relationships between the Walloon and Flemish people in the Belgian State under transformation.The political prospects then appear uncertain. This is even more true that two other elections are to take place in the next eighteen months.These concern the opposite levels of the elected Assemblies: the municipal Council and the European Parliament.

Conclusion

2020 ◽  
pp. 243-252
Author(s):  
Ted Nannicelli
Keyword(s):  
Moral Psychology ◽  
Applied Ethics ◽  
The Other ◽  
Ethical Criticism ◽  
Artistic Creation ◽  
Fine Grained ◽  
Parallel Path ◽  
Ethical Context ◽  
The One ◽  
Future Work

This chapter summarizes the book’s central claims and looks at paths for future work on the applied ethics of artistic creation and ethical criticism. It suggests the need for two parallel strands of inquiry: On the one hand, as the term “applied ethics” suggests, there is a need for a finer-grained understanding of both the artistic and ethical contexts of artistic creation—an understanding that will need to be informed by research across a number of fields, including anthropology, art history, and moral psychology. On the other hand, whatever details of that context are revealed by this fine-grained analysis, there will be a more abstract conceptual challenge about how to reconcile the norms of that art-historical and ethical context with those in currency in the art-historical and ethical context from which one is judging the work. So, the parallel path of inquiry is in metaethics.

scholarly journals Traceable Attribute-Based Secure Data Sharing with Hidden Policies in Mobile Health Networks

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Xueyan Liu ◽  
Yukun Luo ◽  
Xiaotao Yang
Keyword(s):  
Bilinear Pairing ◽  
Health Networks ◽  
Access Policy ◽  
Fine Grained ◽  
Attribute Based Encryption ◽  
Data Owner ◽  
Data User ◽  
Efficient Scheme ◽  
And Performance ◽  
The One

The growing need to store, share, and manage medical and health records has resulted in electronic medical health sharing system (mHealth), which provides intelligent medical treatment for people. Attribute-based encryption (ABE) is regarded as a new cryptology to enhance fine-grained access control over encrypted sharing data in mHealth. However, some existing attribute-based mHealth systems not only violate the one-to-many application characteristics of attribute-based encryption mechanism but also destroy the anonymity of user. In this study, an efficient scheme is proposed to tackle the above defaults and offer two-way anonymity of data owner and data user by introducing a pseudoidentity. The computation of hidden access policy is reduced by removing the bilinear pairing, whereas the interaction between cloud storage and data user is avoided to save bandwidth during trapdoor generation. We also consider the temporal factor of the uploaded information by introducing access validity. Security and performance analyses show that the proposed scheme is efficient without reducing security.

scholarly journals Attribute-Guard: Attribute-Based Flow Access Control Framework in Software-Defined Networking

2020 ◽  
Vol 2020 ◽  
pp. 1-18 ◽  
Author(s):  
Xianwei Zhu ◽  
ChaoWen Chang ◽  
Qin Xi ◽  
ZhiBin Zuo
Keyword(s):  
Access Control ◽  
Software Defined Networking ◽  
Authentication Protocol ◽  
Network Characteristics ◽  
Fine Grained ◽  
Control Framework ◽  
Data Plane ◽  
Data Validity ◽  
The One ◽  
Matching Field

Software-defined networking (SDN) decouples the control plane from the data plane, offering flexible network configuration and management. Because of this architecture, some security features are missing. On the one hand, because the data plane only has the packet forwarding function, it is impossible to effectively authenticate the data validity. On the other hand, OpenFlow can only match based on network characteristics, and it is impossible to achieve fine-grained access control. In this paper, we aim to develop solutions to guarantee the validity of flow in SDN and present Attribute-Guard, a fine-grained access control and authentication scheme for flow in SDN. We design an attribute-based flow authentication protocol to verify the legitimacy of the validity flow. The attribute identifier is used as a matching field to define a forwarding control. The flow matching based on the attribute identifier and the flow authentication protocol jointly implement fine-grained access control. We conduct theoretical analysis and simulation-based evaluation of Attribute-Guard. The results show that Attribute-Guard can efficiently identify and reject fake flow.

Ontology-Based Data Warehousing and Mining Approaches in Petroleum Industries

2011 ◽  
pp. 211-236 ◽  
Author(s):  
Shastri L. Nimmagadda ◽  
Heinz Dreher
Keyword(s):  
Data Structures ◽  
Data Warehousing ◽  
Heterogeneous Data ◽  
Knowledge Mapping ◽  
Financial Decisions ◽  
Fine Grained ◽  
Knowledge Models ◽  
Visualization Of Data ◽  
The One ◽  
Commercial Organizations

Several issues of database organization of petroleum industries have been highlighted. Complex geo-spatial heterogeneous data structures complicate the accessibility and presentation of data in petroleum industries. Objectives of the current research are to integrate the data from different sources and connecting them intelligently. Data warehousing approach supported by ontology, has been described for effective data mining of petroleum data sources. Petroleum ontology framework, narrating the conceptualization of petroleum ontology and methodological architectural views, has been described. Ontology based data warehousing with fine-grained multidimensional data structures, facilitate to mining and visualization of data patterns, trends, and correlations, hidden under massive volumes of data. Data structural designs and implementations deduced, through ontology supportive data warehousing approaches, will enable the researchers in commercial organizations, such as, the one of Western Australian petroleum industries, for knowledge mapping and thus interpret knowledge models for making million dollar financial decisions.

scholarly journals Visual attention is available at a task-relevant location rapidly after a saccade

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Tao Yao ◽  
Madhura Ketkar ◽  
Stefan Treue ◽  
B Suresh Krishna
Keyword(s):  
Eye Movements ◽  
Spatial Attention ◽  
Spatial Location ◽  
Temporal Analysis ◽  
Neuronal Population ◽  
Attentional Modulation ◽  
Attention Task ◽  
Fine Grained ◽  
The One ◽  
Precise Time

Maintaining attention at a task-relevant spatial location while making eye-movements necessitates a rapid, saccade-synchronized shift of attentional modulation from the neuronal population representing the task-relevant location before the saccade to the one representing it after the saccade. Currently, the precise time at which spatial attention becomes fully allocated to the task-relevant location after the saccade remains unclear. Using a fine-grained temporal analysis of human peri-saccadic detection performance in an attention task, we show that spatial attention is fully available at the task-relevant location within 30 milliseconds after the saccade. Subjects tracked the attentional target veridically throughout our task: i.e. they almost never responded to non-target stimuli. Spatial attention and saccadic processing therefore co-ordinate well to ensure that relevant locations are attentionally enhanced soon after the beginning of each eye fixation.

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