A photometric monitoring of bright high-amplitude delta Scuti stars. II. Period updates for seven stars

We present new photometric data for seven high-amplitude delta Scuti stars. The observations were acquired between 1996 and 2002, mostly in the Johnson photometric system. For one star (GW UMa), our observations are the first since the discovery of its pulsational nature from the Hipparcos data.The primary goal of this project was to update our knowledge on the period variations of the target stars. For this, we have collected all available photometric observations from the literature and constructed decades-long O-C diagrams of the stars. This traditional method is useful because of the single-periodic nature of the light variations. Text-book examples of slow period evolution (XX Cyg, DY Her, DY Peg) and cyclic period changes due to light-time effect (LITE) in a binary system (SZ Lyn) are updated with the new observations. For YZ Boo, we find a period decrease instead of increase. The previously suggested LITE-solution of BE Lyn (Kiss & Szatmary 1995) is not supported with the new O-C diagram. Instead of that, we suspect the presence of transient light curve shape variations mimicking small period changes.Comment: 11 pages, 15 figures, accepted for publication in A&

Effects of Blood Pressure and Intraocular Pressure on Ocular Arterial Blood Flow: Studies on in vitro Models

Placed in 1st Place in the category of Cell Biology and Physiology, Denman ForumGlaucoma is the second leading cause of blindness around the world. Diagnosis of this disease often occurs after the detection of noticeable symptoms, by which point irreversible damage has already been incurred. Glaucoma develops when stress factors induce retinal ganglion cell death, resulting in vision loss. In particular, prolonged reduction in blood flow into the eye may lead to ocular tissue malnutrition and hypoxia, eventually leading to cell death. The posterior ciliary arteries are the main blood supply to the optic nerve head, where glaucoma damages occur first. These arteries traverse the posterior peripapillary sclera to penetrate the eye. This study aims to investigate the effects that different combinations of intraocular pressure, blood pressure, and scleral stiffness have on blood flow of in vitro posterior ciliary artery models. To perform this study, a modeling system of the peripapillary sclera was developed. A number of different polymers (including agarose, polydimethylsiloxane, and industrial TC-5005 gels) were explored to model scleral tissues with various compressive moduli. Multiple models of industrial TC-5005 and agarose were made to mimic sclera of increasing stiffness. The polymers were molded and cured into wall-less vessels and placed into a perfusion chamber where pressure was separately applied to the outside (intraocular) and inside (blood) the vessel at different combinations. Five models of stiffness ranging from 30 – 415 kPa were fabricated for flow tests. The resulting change in fluid flow rate was recorded to determine the combinatory effects of the two pressures through these phantoms. It was found that across all combinations of pressures, the fluid flow would initially increase with stiffness, then upon reaching ~60 kPa achieve a maximum flow. For models much stiffer than 60 kPa, a significant decrease in fluid flow as much as 87% was observed. The initial increase in fluid flow from 30 to 60 kPa may be evidence of the protective effects of scleral stiffening predicted in previous research. This study represents a first step in understanding the potential impacts of the scleral compressive modulus on the fluid flow rate under biological effects by IOP and BP, supporting the hypothesis that sclera stiffness may play an important role in glaucomatous development.Research is partially supported by NIHRO1EY020929A one-year embargo was granted for this item.Academic Major: Biomedical Engineerin

Koruna Exchange Rate Turbulence in May 1997

The study has been written by the team of the CNB experts in order to provide evidence about the exchange-rate turbulence of koruna in 1997. First, it provides analysis of the root causes of the exchange rate turbulence in May 1997. Secondly, it takes an in-depth look at the attempts to solve the problem of turbulence, from the CNB strategy in the first days, the escalation, up to and including the changes in the exchange rate regime and the rationale behind these changes. Finally, it concentrates on the eventual easing of the turbulence and the CNB's strategy aimed at interest rate landing.exchange rate crisis turbulence Czech koruna 1997

The evolution of the Mira variable R Hydrae

The Mira variable R Hydrae is well known for its declining period, which Wood & Zarro (1981) attributed to a possible recent thermal pulse. Here we investigate the long-term period evolution, covering 340 years, going back to its discovery in AD 1662. Wavelets are used to determine both the period and semi-amplitude. We show that the period decreased linearly between 1770 and 1950; since 1950 the period has stabilized at 385 days. The semi-amplitude closely follows the period evolution. Detailed analysis of the oldest data shows that before 1770 the period was about 495 days. We find no evidence for an increasing period during this time as found by Wood & Zarro. IRAS data shows that the mass loss dropped dramatically around AD 1750. The decline agrees with the mass-loss formalism from Vassiliadis & Wood, but is much larger than predicted by the Bloecker mass-loss law. An outer detached IRAS shell suggests that R Hya has experienced such mass-loss interruptions before. The period evolution can be explained by a thermal pulse occuring around AD 1600, or by an non-linear instability leading to an internal relaxation of the stellar structure. The elapsed time between the mass-loss decline giving rise to the outer detached shell, and the recent event, of approximately 5000 yr suggests that only one of these events could be due to a thermal pulse. Further monitoring of R Hya is recommended, as both models make strong predictions for the future period evolution. R Hya-type events, on time scales of 10^2-10^3 yr, could provide part of the explanation for the rings seen around some AGB and post-AGB stars.Comment: 13 pages. MNRAS, accepted for publicatio

Relieving pain using dose-extending placebos

Placebos are often used by clinicians, usually deceptively and with little rationale or evidence of benefit, making their use ethically problematic. In contrast with their typical current use, a provocative line of research suggests that placebos can be intentionally exploited to extend analgesic therapeutic effects. Is it possible to extend the effects of drug treatments by interspersing placebos? We reviewed a database of placebo studies, searching for studies that indicate that placebos given after repeated administration of active treatments acquire medication-like effects. We found a total of 22studies in both animals and humans hinting of evidence that placebos may work as a sort of dose extender of active painkillers. Wherever effective in relieving clinical pain, such placebo use would offer several advantages. First, extending the effects of a painkiller through the use of placebos may reduce total drug intake and side effects. Second, dose-extending placebos may decrease patient dependence. Third, using placebos along with active medication, for part of the course of treatment, should limit dose escalation and lower costs. Importantly, provided that nondisclosure is pre-authorized in the informed consent process and that robust evidence indicates therapeutic benefit comparable to that of standard full-dose therapeutic regimens, introducing dose-extending placebos into the clinical arsenal should be considered. This novel prospect of placebo use has the potential to change our general thinking about painkiller treatments, the typical regimens of painkiller applications, and the ways in which treatments are evaluated

Too Informal? How a Chatbot’s Communication Style Affects Brand Attitude and Quality of Interaction

This study investigated the effects of (in)formal chatbot responses and brand familiarity on social presence, appropriateness, brand attitude, and quality of interaction. An online experiment using a 2 (Communication Style: informal vs. formal) by 2 (Brand: familiar vs. unfamiliar) between subject design was conducted in which participants performed customer service tasks with the assistance of chatbots developed for the study. Subsequently, they filled out an online questionnaire. An indirect effect of communication style on brand attitude and quality of interaction through social presence was found. Thus, a chatbot’s informal communication style induced a higher perceived social presence which in turn positively influenced quality of the interaction and brand attitude. However, brand familiarity did not enhance perceptions of appropriateness, indicating participants do not assign different roles to chatbots as communication partner

Phonetic accommodation in non‑native directed speech supports L2 word learning and pronunciation

Published: 02 December 2023This study assessed whether Non-native Directed Speech (NNDS) facilitates second language (L2) learning, specifically L2 word learning and production. Spanish participants (N = 50) learned novel English words, presented either in NNDS or Native-Directed Speech (NDS), in two tasks: Recognition and Production. Recognition involved matching novel objects to their labels produced in NNDS or NDS. Production required participants to pronounce these objects’ labels. The novel words contained English vowel contrasts, which approximated Spanish vowel categories more (/i-ɪ/) or less (/ʌ-æ/). Participants in the NNDS group exhibited faster recognition of novel words, improved learning, and produced the /i-ɪ/ contrast with greater distinctiveness in comparison to the NDS group. Participants’ ability to discriminate the target vowel contrasts was also assessed before and after the tasks, with no improvement detected in the two groups. These findings support the didactic assumption of NNDS, indicating the relevance of the phonetic adaptations in this register for successful L2 acquisition.This research was supported by a Doctoral Fellowship (LCF/BQ/DI19/11730045) from “La Caixa” Foundation (ID 100010434) to G.P., and by the Spanish Ministry of Science and Innovation through the Ramon y Cajal Research Fellowship (RYC2018-024284-I) to M.K. This research was supported by the Basque Government through the BERC 2022-2025 program and by the Spanish State Research Agency through BCBL Severo Ochoa excellence accreditation CEX2020-001010-S. The research was also supported by the Spanish Ministry of Economy and Competitiveness (PID2020-113926GB-I00 to C.D.M.), and the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation programme (grant agreement No 819093 to C.D.M.)

Biological Inflammatory and Metabolic Effects of Petro- and Bio-diesel Exhaust Particulate Matter Emissions from a LightDuty Diesel Engine

Sustainability of our transportation system depends on making well-informed choices on vehicle energy sources for human and goods mobility. Motor vehicles operating on fossil fuels are a significant source of air pollution risk and challenge the ability of humans to mitigate climate change. Biodiesel is a low carbon fuel substitute for petroleum diesel, but relatively little is known about how exposure to biodiesel combustion particles affects chronic diseases such as asthma and type II diabetes mellitus (T2DM). This study examined the effect of particulate matter (PM) generated by the combustion of commercially available petrodiesel and soybean biodiesel fuels on inflammation and metabolic dysfunction using two types of in vivo experiments. To evaluate inflammation response, oropharyngeal 3-day exposures of females to B20 (20% biodiesel/80% petrodiesel by volume) and B0 (100% petrodiesel) particles from a light-duty diesel engine operating on a semi-transient cycle were followed by lung fluid and tissue biochemical analysis. Prenatal exposure effects on offspring growth and metabolism were evaluated by maternal exposure during gestational days 9-17 (delivery 18-20 days) and monitoring offspring for 12 months. Prenatal exposure to exhaust PM from petrodiesel fuel combustion had different metabolic effects in male vs. female offspring. For B20 exhaust PM, the number of offspring was too low to detect differences. The results of this study suggest that males and females may have differential risk for metabolic dysfunction after prenatal exposure during gestation. Future studies should be conducted to quantify sex-specific effects on exposure to vehicle exhaust PM from biodiesel fuel blends

Characterization of Sirt2 using conditional RNAi in mice

Within the past eight years, RNA interference (RNAi) has emerged as a powerful experimental tool for gene function analysis in mice. Reversible control of shRNA mediated RNAi has been achieved by using a tetracycline (tet)-inducible promoter. In the presence of the inductor doxycycline (dox), shRNA mediated gene silencing is initiated, whereas RNAi mechanism is blocked in the absence of dox. To achieve spatially and temporally regulated RNAi, the tet inducible system was combined with a Cre/loxP based strategy for tissue specific activation of shRNA constructs. To this end, a loxP-flanked "promoter inhibitory element" (PIE) was placed between the proximal (PSE) and distal sequence element (DSE) of a dox inducible promoter such that promoter function is completely blocked. Re-activation can be achieved through Cre mediated excision of PIE. To allow for gene silencing in a selected tissue, Cre expression can be regulated by a tissue-specific promoter. In mouse ES cells, the system mediated tight regulation of shRNA expression upon Cre mediated activation and dox administration, reaching knockdown efficiencies of >80%. Unexpectedly, the system showed a limited activity in transgenic mice when applied for conditional silencing of two different targets, LacZ and Sirt2. Sirt2 is a member of the sirtuin family which has considerably gained attention in vitro for its possible role in many physiological processes, including adipogenesis and neurodegenerative diseases. To investigate the function of Sirt2 in vivo, the unmodified dox-responsive and tet-inducible promoter was further used for conditional RNAi in transgenic mice. Inducible shRNA expression resulted in efficient silencing of Sirt2 (>90%) in all tissues which have been analyzed. Suppression of Sirt2 during embryogenesis resulted in offspring consisting of equal ratios of wild type and transgenic pups, indicating that Sirt2 is not indispensable for development. In adult animals, glucose metabolism, insulin sensitivity and energy balance appeared to be unaffected by Sirt2 deficiency. Likewise, expression of PPARγ, a downstream target of Sirt2, was not found to be altered upon Sirt2 inhibition. Finally, Sirt2 silencing was induced in an experimental model of Parkinson disease (PD). Data from Rotarod performances to study motor behaviour did not provide any evidence for a role of Sirt2 in PD pathogenesis as suggested by previous in vitro studies. Taken together, conditional Sirt2 silencing in vivo does not support speculation concerning a central role of Sirt2 in physiological processes, embryogenesis and in a mouse model of Parkinson disease