Increasing security of supply by the use of a local power controller during large system disturbances

This paper describes intelligent ways in which distributed generation and local loads can be controlled during large system disturbances, using Local Power Controllers. When distributed generation is available, and a system disturbance is detected early enough, the generation can be dispatched, and its output power can be matched as closely as possible to local microgrid demand levels. Priority-based load shedding can be implemented to aid this process. In this state, the local microgrid supports the wider network by relieving the wider network of the micro-grid load. Should grid performance degrade further, the local microgrid can separate itself from the network and maintain power to the most important local loads, re-synchronising to the grid only after more normal performance is regained. Such an intelligent system would be a suitable for hospitals, data centres, or any other industrial facility where there are critical loads. The paper demonstrates the actions of such Local Power Controllers using laboratory experiments at the 10kVA scale

Discourse and identity in a corpus of lesbian erotica

This article uses corpus linguistic methodologies to explore representations of lesbian desires and identities in a corpus of lesbian erotica from the 1980s and 1990s. We provide a critical examination of the ways in which “lesbian gender,” power, and desire are represented, (re-)produced, and enacted, often in ways that challenge hegemonic discourses of gender and sexuality. By examining word frequencies and collocations, we critically analyze some of the themes, processes, and patterns of representation in the texts. Although rooted in linguistics, we hope this article provides an accessible, interdisciplinary, and timely contribution toward developing understandings of discursive practices surrounding gender and sexuality

How Do Individuals in a Radical Echo Chamber React to Opposing Views? Evidence from a Content Analysis of Stormfront

Calls to “break up” radical echo chambers by injecting them with alternative viewpoints are common. Yet, thus far there is little evidence about the impact of such counter-messaging. To what extent and how do individuals who inhabit a radical echo chamber engage with messages that challenge their core beliefs? Drawing on data from the radical right forum Stormfront we address this question with a large-scale content and longitudinal analysis of users’ posting behavior, which analyses more than 35,000 English language contributions to the forum spanning 2011 through 2013. Our findings show that engaging with oppositional views is actually a core practice among Stromfront users which invites active participation and encourages engagement. Indeed, many “echoes” in the echo chamber we studied were not core beliefs being restated, but the sound of opposing viewpoints being undermined and marginalized. These findings underscore the limited potential for counter-messages to undermine radical echo chambers

The RCB star V854 Cen is surrounded by a hot dusty shell

Aims : The hydrogen-deficient supergiants known as R Coronae Borealis (RCB) stars might be the result of a double-degenerate merger of two white dwarfs (WDs), or a final helium shell flash in a planetary nebula central star. In this context, any information on the geometry of their circumstellar environment and, in particular, the potential detection of elongated structures, is of great importance. Methods : We obtained near-IR observations of V854 Cen with the AMBER recombiner located at the Very Large Telescope Interferometer (VLTI) array with the compact array (B$\leq$35m) in 2013 and the long array (B$\leq$140m) in 2014. At each time, V854 Cen was at maximum light. The $H$- and $K$-band continua were investigated by means of spectrally dependant geometric models. These data were supplemented with mid-IR VISIR/VLT images. Results : A dusty slightly elongated over density is discovered both in the $H$- and $K$-band images. With the compact array, the central star is unresolved ($\Theta\leq2.5$\,mas), but a flattened dusty environment of $8 \times 11$ mas is discovered whose flux increases from about $\sim$20% in the $H$ band to reach about $\sim$50% at 2.3\micron, which indicates hot (T$\sim$1500\,K) dust in the close vicinity of the star. The major axis is oriented at a position angle (P.A.) of 126$\pm$29$\deg$. Adding the long-array configuration dataset provides tighter constraints on the star diameter ($\Theta\leq1.0$ mas), a slight increase of the overdensity to $12 \times 15$ mas and a consistent P.A. of 133$\pm$49$\deg$. The closure phases, sensitive to asymmetries, are null and compatible with a centro-symmetric, unperturbed environment excluding point sources at the level of 3% of the total flux in 2013 and 2014. The VISIR images exhibit a flattened aspect ratio at the 15-20% level at larger distances ($\sim$1\arcsec) with a position angle of 92$\pm$19$\deg$, marginally consistent with the interferometric observations. Conclusions : This is the first time that a moderately elongated structure has been observed around an RCB star. These observations confirm the numerous suggestions for a bipolar structure proposed for this star in the literature, which were mainly based on polarimetric and spectroscopic observations.Comment: Accepted by A\&A, new version after language editing, Astronomy and Astrophysics (2014

Effective Hamiltonian Approach to Hyperon Beta Decay with Final-State Baryon Polarization

Using an effective Hamiltonian approach, we obtain expressions for hyperon beta decay final-state baryon polarization. Terms through second order in the energy release are retained. The resulting approximate expressions are much simpler and more compact than the exact expressions, and they agree closely with them.Comment: 1 Figure Will appear in Phys Rev D 60 Article 117505 (Dec 1, 1999

High-precision ID-TIMS cassiterite U–Pb systematics using a low-contamination hydrothermal decomposition: implications for LA-ICP-MS and ore deposit geochronology

Cassiterite (SnO2) is the most common ore phase of Sn. Typically containing 1–100 µg g−1 of uranium and relatively low concentrations of common Pb, cassiterite has been increasingly targeted for U–Pb geochronology, principally via microbeam methods, to understand the timing and durations of granite-related magmatic–hydrothermal systems throughout geological time. However, due to the extreme resistance of cassiterite to most forms of acid digestion, there has been no published method permitting the complete, closed-system decomposition of cassiterite under conditions in which the basic necessities of measurement by isotope dilution can be met, leading to a paucity of reference and validation materials. To address this a new low blank (&lt; 1 pg Pb) method for the complete acid decomposition of cassiterite utilising HBr in the presence of a mixed U–Pb tracer, U and Pb purification, and thermal ionisation mass spectrometry (TIMS) analyses has been developed. Decomposition rates have been experimentally evaluated under a range of conditions. A careful balance of time and temperature is required due to competing effects (e.g. HBr oxidation), yet the decomposition of 500 µm diameter fragments of cassiterite is readily achievable over periods comparable to zircon decomposition. Its acid-resistant nature can be turned into an advantage by leaching common Pb-bearing phases (e.g. sulfides, silicates) without disturbing the U–Pb systematics of the cassiterite lattice. The archetypal Sn–W greisen deposit of Cligga Head, SW England, is used to define accuracy relative to chemical abrasion–isotope dilution–thermal ionisation mass spectrometry (CA-ID-TIMS) zircon U–Pb ages and demonstrates the potential of this new method for resolving high-resolution timescales (&lt;0.1 %) of magmatic–hydrothermal systems. However, data also indicate that the isotopic composition of initial common Pb varies significantly, both between crystals and within a single crystal. This is attributed to significant fluid–rock interactions and the highly F-rich acidic nature of the hydrothermal system. At microbeam precision levels, this issue is largely unresolvable and can result in significant inaccuracy in interpreted ages. The ID-TIMS U–Pb method described herein can, for the first time, be used to properly characterise suitable reference materials for microbeam cassiterite U–Pb analyses, thus improving the accuracy of the U–Pb cassiterite chronometer as a whole.</p

A multidomain relational framework to guide institutional AI research and adoption

Calls for new metrics, technical standards and governance mechanisms to guide the adoption of Artificial Intelligence (AI) in institutions and public administration are now commonplace. Yet, most research and policy efforts aimed at understanding the implications of adopting AI tend to prioritize only a handful of ideas; they do not fully connect all the different perspectives and topics that are potentially relevant. In this position paper, we contend that this omission stems, in part, from what we call the ‘relational problem’ in socio-technical discourse: fundamental ontological issues have not yet been settled—including semantic ambiguity, a lack of clear relations between concepts and differing standard terminologies. This contributes to the persistence of disparate modes of reasoning to assess institutional AI systems, and the prevalence of conceptual isolation in the fields that study them including ML, human factors, social science and policy. After developing this critique, we offer a way forward by proposing a simple policy and research design tool in the form of a conceptual framework to organize terms across fields—consisting of three horizontal domains for grouping relevant concepts and related methods: Operational, Epistemic, and Normative. We first situate this framework against the backdrop of recent socio-technical discourse at two premier academic venues, AIES and FAccT, before illustrating how developing suitable metrics, standards, and mechanisms can be aided by operationalizing relevant concepts in each of these domains. Finally, we outline outstanding questions for developing this relational approach to institutional AI research and adoption

Wind Power Frequency Control in Doubly FED Induction Generator Using CFMPC-FOPID Controller Scheme

Because the majority of wind turbines operate in maximum output power tracking mode, power system frequency cannot be supported. However, if the penetration rate of wind power increases, the system inertia related to frequency modulation may decrease. In addition, frequency stability will be severely affected in the event of significant disturbances to the system load. Due to the high penetration of wind power in isolated power systems, this study suggests a coordinated frequency management approach for emergency frequency regulation. In order to prevent the phenomenon of load frequency control in doubly fed induction generators (DFIGs), a unique efficient control scheme is developed. The Cascaded Fractional Model Predictive Controller coupled with Fractional-Order PID controller (CFMPC-FOPID) is developed to provide the DFIG system with an efficient reaction to changes in load and system parameters. The proposed controller must have a robust tendency to respond quickly in terms of minimum settling time, undershoot, and overshoot. Nonlinear feedback controllers are designed using frequency deviations and power imbalances to achieve the reserve power distribution between generators and DFIGs in a variety of wind speed conditions. It makes upgrading quick and easy. In Matlab/Simulink, a simulation model is built to test the viability of the suggested approach

Theory of Mind Performance in Younger and Older Adults with Elevated Autistic Traits

Little is known about the impact of aging with Autism Spectrum Disorder on theory of mind (ToM). While ToM difficulties appear to abate with age in older autistic populations, this has yet to be explored in the Broad Autism Phenotype (BAP). The current study examined ToM performance among younger (n = 49, aged 18–46) and older adults (n = 47, aged 60–91) who were classified as on the BAP (younger n = 18; older n = 21) or not (younger n = 31; older n = 26) using the BAP Questionnaire. ToM was assessed using the ecologically valid Strange Stories Film Task (SSFT) and the dynamic Happé–Frith Triangle Animations task (TA). A 2 × 2 analysis of variance examined the effects of autistic traits (BAP vs. non‐BAP) and age (young vs. old). For both SSFT and TA, results showed autistic trait main effects on task performance (non‐BAP > BAP). Age main effects were observed for some but not all metrics on TA (younger better than older), with no differences in SSFT. An interaction of autistic traits and age was observed in TA Intentionality, with younger non‐BAP and younger BAP performing similarly but older non‐BAP performing better than older BAP. Results show that younger and older adults with elevated autistic traits show poorer ToM performance. Despite ToM difficulties being common in later life in the general population, this effect was not observed when using a ToM task designed to reflect real‐world scenarios. However, results suggest that autistic traits and age could interact to increase risk for poor ToM performance in older adults who endorse elevated autistic traits

Streptococcus mutans Levels and Biotypes in Egyptian and Saudi Arabian Students During the First Months of Residency in the United States

Several studies indicated that serotype/biotype c strains are the most common on a global basis, but that regional differences may occur relative to other serotype/biotypes. Of particular interest is the observation that individuals residing in the Middle East have higher incidences of serotype e and d strains relative to their levels in American citizens. This could reflect exposure to different Streptococcus mutans serotypes during the period in which the teeth are colonized, or might reflect other factors local to the region, such as diet. The purpose of the present study was to observe Egyptian and Saudi Arabian students during the first four months after their arrival in the United States, in order to determine whether this change in habitat affected the levels and biotypes of S. mutans. The results of this study showed that biotype c strains were the most prevalent in saliva and plaque of these Egyptians and Saudi Arabian students, followed by biotype e and biotype d. There was a drop in the number of S. mutans in the saliva and the proportions of S. mutans in the plaque after two months of residence in the United States, followed by a significant increase after four months of residence. This increase was most noticeable in subjects who had a higher number of decayed surfaces. In these subjects, the percentage of S. mutans in pooled occlusal plaque increased significantly, from 6.1 to 13.2%.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66894/2/10.1177_00220345840630011201.pd