2,417 research outputs found
Locomotor characterization of the sub-fossil lemur Babakotia
No full textPalaeopropithecids or “sloth lemurs” are a diverse clade of large-bodied Malagasy subfossil primates characterized by their suspensory positional behaviors. The most recently discovered genus of the family is Babakotia. This species has been described as more arboreal than Mesopropithecus but less than Palaeopropithecus. A remarkably complete skeleton of Babakotia is housed at the Division of Fossil Primates of the Duke University Primate Center. To further understand arboreal adaptations of Babakotia we compared within bone and between bones articular and cross-sectional diaphyseal proportions of limb long bones of this specimen to suspensory primates (hominoids and monkeys) and true sloths (Choloepus and Bradypus). Results show that Babakotia humeral articular to diaphyseal proportions are generally similar to those of true sloths than to those of apes. Babakotia femoral proportions are also similar to true sloth distributions, but are also similar to lesser apes in their proximal ends (i.e., relative femoral head surface area and superoinferior breadth). Distally, Babakotia is closer to great apes and lesser apes than to monkeys; unfortunately true sloth comparative data are missing for this comparison. Interlimb proportions show that Babakotia’s relative diaphyseal strengths are similar to the mean value for orangutans and in the range of true sloths. As for interlimb articular proportions, Babakotia overlaps with great apes for proximal articulations, but with true sloths for distal articulations. These results provide new evidence on the arboreal adaptations of Babakotia and further highlight similarities with both extant suspensory primates and non-primate slow arboreal climbers and hangers, i.e., true sloths
A historical comment about the GVT in short interval
No full textIn this article, the author introduces the history, progress and method in the Goldbach-Vinogradov Theorem in short interval by which every sufficiently large odd integer could be expressed as the sum of three almost equal prime numbers.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000183488400018&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701MathematicsCPCI-S(ISTP)
Investigation on the DC CB Performance during a Current Interruption Failure at First Current Zero
No full textThe vacuum interrupter is used as the key component of an active DCCB due to its excellent interruption and dielectric recovery characteristics after current zero. The vacuum interrupter can only interrupt the fault currents below the limitation of a critical di/dt and TIV, otherwise it causes a reignition and the interruption failure. In this paper, a detailed active injection DC CB model is developed, considering operation delay of switches, parasitic parameters of switches and thorough control logic. The limitation dielectric strength between the vacuum gap is defined by the cold break down voltage. Based on the numerical modelling, investigation will be performed to see the performance of DC CB with a failure interruption on the first current zero. The simulation results can help to optimize the injection circuit parameters when DC CB has a failure on the first current zero and has to interrupt in the next current zeros. This algorithm will consider predefined threshold of di/dt, chopping current and variable operation time in different scenarios.Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Intelligent Electrical Power Grid
Technical performance of different DC CB technologies for future HVDC Grids
No full textMultiterminal dc (MTDC) network is preferred due to its reliability, security of supply and flexibility. However, MTDC network also comes with the protection challenges resulting from dc faults. Hence, the dc circuit breaker (DC CB) is imperative in such a network. In these recent years, several DC CB technologies have been proposed and demonstrated by different manufacturers. Besides, these DC CB technologies differ from each other in terms of the speed of operation, interruption capability and costs. Hence, for the optimal performance of the MTDC network, a study of the co-ordinative operation of different DC CB technologies is required. In this thesis, two typical types of DC CBs are modelled in detail and implemented in a 4-terminal MTDC network in PSCAD environment, by considering operation time, interruption capability and interruption characteristics. The obtained results are used for DC CB’s selection optimization methodology for the future MTDC networks. Similarly, a scaled model of DC CB has to be analysed in terms of its interruption capability in MTDC network considering various scenarios. Therefore, in this master thesis, technical performance of DC CB technologies is conducted for a test and multiterminal dc network in EMT based software environment.The DC CB is the key to unlock the reliable operation of a Multi-terminal direct current network, whereas fast, effective and accurate models are frequently needed for system-level studies. Due to higher subsystem components in DC CB, a detailed DC CB model creates a bottleneck in the network analysis. This thesis also proposes and compares, an average model with a detailed model of Voltage source converter Assisted Resonant Current (VARC) and Mechanical DC CB in MTDC Network in terms of their performance and computation time for two typical simulation cases. The average and detailed model is modelled and simulated on the PSCAD/EMTDC electromagnetic transient platform. Decisively, this thesis concludes by presenting an accurate response of the average model during the fast transient event, showing additional computational advantage.<br/
Xenon exposure in the neonatal rat brain: effects on genes that regulate apoptosis.
No full textBACKGROUND:
In the developing rodent brain, exposure to volatile anesthetics causes widespread neuronal apoptosis in several regions of the brain. Increasing evidence points to a possible neuroprotective role for the anesthetic gas xenon, following neuronal injury. To address this gap in understanding, we explored the transcriptional consequences of xenon in the brains of postnatal day 7 (P7) rats exposed to xenon compared to those of air-breathing animals, with particular emphasis on the mRNA transcript levels of Akt and c-Jun N-terminal kinase kinase 1 (JNKK1), which are important for cell survival and the activation of extrinsic neuroapoptotic pathways, respectively.
METHODS:
P7 Sprague/Dawley rats were exposed to air (75% nitrogen, 25% oxygen) or xenon (75% xenon, 25% oxygen) for 120 min (N=6/group). Forebrains were harvested for reverse transcription polymerase chain reaction, which enabled quantification of Akt and JNKK1 mRNA transcripts. Suppression subtractive hybridization was used to explore the "genetic signature" of xenon exposure.
RESULTS:
Compared to control air-breathing animals, xenon-breathing rats exhibited a 0.7-fold decrease in Akt mRNA expression (P<0.01) and a 1.6-fold increase in JNKK1 mRNA levels (P<0.05).
CONCLUSION:
The concomitant decrease in the Akt mRNA expression level and increase in the JNKK1 mRNA transcript level provide evidence that xenon has a neuroapoptotic effect in the developing rodent forebrain. Given these results, further study into the paradoxical neuroprotective and neuroapoptotic effects of xenon is warranted
The characteristics of the polish CB-language
No full textThe paper analyzes the language used by drivers on the Citizens’ Band radio (CB radio). The
users of the radio communicate only in speech, their communication is highly pragmatic and
based on partnership. The utterances alternate between formal and informal ones, which
determines the range and register of vocabulary. Drivers often use diminutives and polite
addresses thus creating the atmosphere of mutual respect and cordiality, which can be
comforting and reassuring for strangers who happen to establish a casual contact. The specific
language used on the CB radio fulfils two basic functions: it creates a sense of community
among drivers and protects the information passed on as warnings. At the end of the paper,
the author appends a comprehensive glossary of the CB language
Modelling of GO/PPy/CB and rGO/PPy/CB nanocomposite supercapacitors using an electrical equivalent circuit
No full textIn this study, supercapacitor device performances of graphene oxide (GO), reduced graphene oxide (rGO), polypyrrole (PPy), and ternary nanocomposites of GO, PPy, and carbon black (CB) as GO/PPy/CB and rGO/PPy/CB were firstly prepared using the in situ polymerization method. The obtained composite materials were characterized by scanning electron microscopy energy–dispersive X-ray (SEM–EDX), Fourier-transform infrared-attenuated transmission reflectance (FTIR-ATR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), atomic force microscopy (AFM), Brunauer–Emmett–Teller (BET) surface area analysis, cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopic (EIS) methods. The highest specific capacitance (Csp) of the rGO/PPy/CB nanocomposite was obtained as Csp = 39, 48, and 27.86 F × g?1 by three methods of CV, GCD, and EIS, respectively. Two equivalent circuit models of Rs(CdlRct) and LRs(QRct) were presented to compare equivalent circuit parameters. Theoretical and experimental values are compatible with each other. Graphical abstract: [Figure not available: see fulltext.]. © 2021, The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.Trakya ÜniversitesiThis work is a part of the research project NKUBAP.01.?NAP.19.213 approved by the Scientific and Research Project Unit (Tekirdag Namik Kemal University). This research grant is gratefully acknowledged. We thank Prof. Dr. Murat Turkyilmaz and Ozan Yoruk (PhD student) for TGA and BET measurements (TUTAGEM, Trakya University, Turkey)
„Misiek z okularami na hulajnodze”, czyli o CB-polszczyźnie
No full textThe paper analyzes the language used by drivers on the Citizens’ Band radio (CB radio). The users of the radio communicate only in speech, their communication is highly pragmatic and based on partnership. The utterances alternate between formal and informal ones, which determines the range and register of vocabulary. Drivers often use diminutives and polite addresses thus creating the atmosphere of mutual respect and cordiality, which can be comforting and reassuring for strangers who happen to establish a casual contact. The specific language used on the CB radio fulfils two basic functions: it creates a sense of community among drivers and protects the information passed on as warnings. At the end of the paper, the author appends a comprehensive glossary of the CB language
Fast bug finding in lock-free data structures with CB-DPOR
No full textThesis: M. Eng., Massachusetts Institute of Technology, Department of Electrical Engineering and Computer Science, 2014.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student-submitted PDF version of thesis.Includes bibliographical references (pages 39-40).This thesis describes CB-DPOR, an algorithm for quickly finding bugs in lock-free data structures. CB-DPOR is a combination of the CHESS and DPOR model checking algorithms. CB-DPOR performs similar to the concurrently developed preemption-bounded BPOR algorithm. CODEX is a tool for finding bugs in lock-free data structures. CODEX implements CBDPOR and this thesis demonstrates how to use CODEX to find bugs. This thesis describes new bugs in open-source lock-free data structures, and compares the performance of CBDPOR with the earlier model checking algorithms CHESS, DPOR, and PCT. CB-DPOR find bugs one to two orders of magnitude faster than earlier algorithms.by Jelle van den Hooff.M. Eng
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