1,860 research outputs found
P-V Criticality in Quasitopological Gravity
We investigate the thermodynamic behaviour of AdS quasitopological black hole
solutions in the context of extended thermodynamic phase space, in which the
cosmological constant induces a pressure with a conjugate volume. We find that
the third order exact quasitopological solution exhibits features consistent
with the third order Lovelock solutions for positive quasitopological coupling,
including multiple reentrant phase transitions and isolated critical points.
For negative coupling we find the first instances of both reentrant phase
transitions and thermodynamic singularities in five dimensions, along with
other modified thermodynamic behaviour compared to Einstein-AdS-Gauss Bonnet
gravity.Comment: 20 pages, 15 figures, REVTeX 4-1; updated to match published versio
Returning to the Novel Planet of Death : A Chronotopic Exploration
A rereading of Robert Silverberg\u27s (1967) young adult novel Planet of Death, occurring as part of a qualitative self-study four decades after this book had been a site of independent repeated reading over the course of my Grade Five school year, offers a chronotopic perspective of the literary motivations and habits in one young girl. Mikhail Bakhtin\u27s conceptualization of the literary chronotope is used to identify elements of time and space related to my transaction with Silverberg\u27s book. Seen through a chronotopic lens, reading appears as a compelling travel opportunity in terms of gender, culture, ability, and age. Rather than developing deeper insights through rereading, it is argued that the threshold of understanding that was reached in an initial reading of this novel was replicated through a series of time-travel experiences that were otherwise rewarding across a span of at least 12 readings during a single school year. Rereading is identified here as an internal chronotope that operates as a mechanism for cruise-controlled intellectual travel through which to safely observe, enjoy and repeatedly entertain perspectives other than one\u27s own. Rereading is also identified here as an opportunity to access an external chronotope that presents earlier versions of the reader, increasing motivation for reading as well as providing material to support identity studies. Implications from this self-study relate to the importance of offering opportunities for in-school rereading and deeper understandings about the value of this activity
Resident Advisors React: Autoethnographic Reflections on High-Intensity Situations
Resident Advisors (RAs) are paraprofessional peer leaders who are trained to respond to high-intensity incidents. Upon witnessing a crisis situation, I found it difficult to reflect and maintain my own personal wellness. The intent of this research has been to learn of and to give voice to the multiple ways in which RAs respond to such scenarios.
Utilizing autoethnography, I incorporate my experience with the perspectives of my coworkers and multidisciplinary literature. Seven current RAs, who had self-identified experiencing such an incident, volunteered to be interviewed. These narratives are embodied in the text in order to establish a dialogue between researcher, participants, and readers.
The data reflected here synthesizes the reactions of eight different RAs.Given the qualitative methodology, broad generalizations cannot be made. However, it is evident that we exhibit helpful and inhibiting behaviors as a means to be personally well after professionally engaging in highly emotional experiences
The Effects of Superovulation and Embryo Culture on Genomic Imprinting in a Mouse Model System
Genomic imprinting is a specialized transcriptional mechanism resulting in the unequal expression of alleles based on their parent-of-origin. Imprinted genes are critical for embryonic and fetal development and their dysregulation is linked to a group of human diseases called imprinting disorders, including Beckwith-Wiedemann Syndrome, Angelman Syndrome and Silver-Russell Syndrome. Two critical phases of genomic imprinting exist. The acquisition phase occurs in developing germ cells, asynchronously for different imprinted loci, while the maintenance phase takes place during preimplantation development, while the rest of the genome is undergoing demethylation. Increased frequencies of human imprinting disorders are observed in children following the use of assisted reproductive technologies (ARTs). The timing of ARTs during the critical periods of imprint acquisition and maintenance provides a mechanism for their disruption. At the onset of this project, I hypothesized that superovulation alone, and embryo culture alone, disrupt imprinting acquisition and maintenance mechanisms, respectively, and that disruption of genomic imprinting correlates with rates of preimplantation embryo development. I have determined the effects of superovulation, and embryo culture using five commercially available media, on the key imprinted loci H19, Snrpn, Peg3, Kcnq1ot1 and Peg1/Mest, and correlated rates of preimplantation development with loss of genomic imprinting. Superovulation alone disrupted genomic imprinting, in a dose-dependent manner. Embryo culture in all media was sub-optimal in maintaining genomic imprints. Embryos developing at a moderate pace showed levels of imprinted methylation most similar to in vivo-derived controls. In addition, these studies suggest that superovulation does not affect the acquisition of imprinted methylation, but rather maintenance throughout preimplantation development. Data presented in this thesis suggests that superovulation disrupts one or more key maternal-effects genes necessary for imprint maintenance, and that superovulation and embryo culture disrupt the same pathway. Future studies delineating the mechanisms mediating embryonic adaptation to the environmental insult caused by ARTs, and improving current techniques to minimize the amount of adaptation required for embryo growth and survival outside the female reproductive tract, will lead to a decreased incidence of disease and improve the long term health of children born following ARTs
Wc-1 and the proximal gata sequence mediate a cis-/trans-acting repressive regulation of light-dependent gene transcription in the dark
Light influences a wide range of physiological processes from prokaryotes to mammals. Neurospora crassa represents an important model system used for studying this signal pathway. At molecular levels, the WHITE COLLAR Complex (WCC), a heterodimer formed by WC-1 (the blue light photo-sensor) and WC-2 (the transcriptional activator), is the critical positive regulator of light-dependent gene expression. GATN (N indicates any other nucleotide) repeats are consensus sequences within the promoters of light-dependent genes recognized by the WCC. The distal GATN is also known as C-box since it is involved in the circadian clock. However, we know very little about the role of the proximal GATN, and the molecular mechanism that controls the transcription of light-induced genes during the dark/light transition it is still unclear. Here we showed a first indication that mutagenesis of the proximal GATA sequence within the target promoter of the albino-3 gene or deletion of the WC-1 zinc finger domain led to a rise in expression of light-dependent genes already in the dark, effectively decoupling light stimuli and transcriptional activation. This is the first observation of cis-/trans-acting repressive machinery, which is not consistent with the light-dependent regulatory mechanism observed in the eukaryotic world so far
EVALUATION OF ELECTRODE SURFACE TREATMENTS IN SLUDGE ELECTRO-OSMOSIS DEWATERING”
The drying of sludge produced by Wastewater Treatment Plants (WWTPs) is a very hard process due to the presence of the colloid fraction. Electro-osmosis could be a suitable technique to reduce the water content of the final sludge. Electrical fields of 10 V/cm, 15 V/cm and 20 V/cm have been studied for electro-osmosis tests in a static or dynamic apparatus, obtaining a dry solids content up to 40-45%, with respect to 25-30% obtained by mechanical methods. In order to optimise the apparatus, the corrosion behaviour of the anodic material appears the main critical aspect, due to the high circulating current density. Moreover, wear may be detrimental for the surface of rotating electrodes. We then investigated the behaviour of materials used as electrodes mainly by evaluating the efficiency of the process and their surface aspect after treatment. The full understanding of the electrochemical reactions developed at the anode are a key factor for the material choice. We compared the efficiency and the corrosion resistance of anodes made of titanium MMO with respect to bare stainless steel (AISI 304) and stainless steel coated by PVD technique with TiN, AlTiN and DLC. Characterization of the anodes samples by roughness tests and by AFM show that corrosion resistance of the DSA was the most suitable for our application. However, efficiencies of the electro-osmosis process for all the materials used have been found comparable, in terms of developed current densities and total energy consumptions, for low-test duration
Impianti di ionizzazione Cu-Ag per la di disinfezione delle acque e rischi di corrosione per spostamento
The copper and silver ionization system is one of the water sanitation treatments. Effective ionization occurs if the
content of copper ions in solution is 0.2-0.4 mg/L and that of silver ions is 0.02-0.04 mg/L. An excess of copper
and silver ions can react with other metal surfaces, triggering a deposition reaction, allowing the formation of
deposits of more noble metals, and then promoting a localized corrosion phenomenon due to galvanic coupling.
In the present paper, two case histories will be presented: one related to a legionella sanitizing plant system of a
hospital; the second related to a system of water purification of a vessel on a boat. In both cases, working
conditions are illustrated, corrosion morphology is described, focusing on the presence of copper and silver
deposits, and the cause of corrosion is presented, estimating a reliable corrosion rate
Strategic Approach for Electric Vehicle Charging Infrastructure for Efficient Mobility along Highways: A Real Case Study in Spain
The Electric Vehicle (EV) market has been growing exponentially in recent years, which is why the distribution network of public charging stations will be subject to expansion and upgrading. In order to improve the public charging infrastructure, this paper aims to develop a model capable of analyzing the current situation of a stretch of highway, identifying the congestion points, created by the formation of queues at the charging points. A specific section of a highway in Spain was selected as a case study to evaluate the performance of the model, allowing for rigorous testing and thorough analysis of its performance in a real-world scenario. The first step is to define and evaluate the effects of factors affecting EV consumption, such as the slope of the road, weather conditions, and driving style. Subsequently, a simulation model is developed using the agent-based simulation software AnyLogic, which simulates the journey of a fleet of electric vehicles, taking into account the battery charging and discharging process. Based on the obtained results, the charging infrastructure is improved to minimize the total travel time of an electric vehicle on a long-distance trip
Fundamental Power Limits of SAR and ΔΣ Analog-to-Digital Converters
This work aims at estimating and comparing the power limits of ΔΣ and charge-redistribution successiveapproximation register (CR-SAR) analog-to-digital converters (ADCs), in order to identify which topology is the most powerefficient for a target resolution. A power consumption model for mismatch-limited SAR ADCs and for discrete-time (DT) ΔΣ modulators is presented and validated against experimental data.
SAR ADCs are found to be the best choice for low-to-medium resolutions, up to roughly 80 dB of dynamic range (DR). At high resolutions, on the other hand, ΔΣ modulators become more power-efficient. This is due to the intrinsic robustness of the ΔΣ modulation principle against circuit imperfections and nonidealities.
Furthermore, a comparison of the area occupation of such topologies reveals that, at high resolutions and for a given dynamic range, ΔΣ ADCs result more area-efficient as well
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