Government policy towards multi-national corporations

We analyze an environment with asymmetric information where a country tries to attract a multi-national corporation. The country can use both taxes and grants to meet its objective of maximizing net revenues. We show that when the country has private information it can often convey it via its choice of a tax-grant pair. When the tax rates are unbounded the country is able to extract the full surplus. The existence of an upper bound can in some cases reduce the payoff to a stronger country.Foreign Direct Investment

The X-ray spectrum of RX J1914.4+2456 revisited

It has been proposed that RX J1914.4+2456 is a stellar binary system with an orbital period of 9.5 mins. As such it shares many similar properties with RX J0806.3+1527 (5.4 mins). However, while the X-ray spectrum of RX J0806.3+1527 can be modelled using a simple absorbed blackbody, the X-ray spectrum of RX J1914.4+2456 has proved difficult to fit using a physically plausible model. In this paper we re-examine the available X-ray spectra of RX J1914.4+2456 taken using XMM-Newton. We find that the X-ray spectra can be fitted using a simple blackbody and an absorption component which has a significant enhancement of neon compared to the solar value. We propose that the material in the inter-binary system is significantly enhanced with neon. This makes its intrinsic X-ray spectrum virtually identical to RX J0806.3+1527. We re-access the X-ray luminosity of RX J1914.4+2456 and the implications of these results.Comment: Accepted for publication in MNRA

Government policy towards multi-national corporations

We analyze an environment with asymmetric information where a country tries to attract a multi-national corporation. The country can use both taxes and grants to meet its objective of maximizing net revenues. We show that when the country has private information it can often convey it via its choice of a tax-grant pair. When the tax rates are unbounded the country is able to extract the full surplus. The existence of an upper bound can in some cases reduce the payoff to a stronger country

Is a Good Student Also a Happier One? Traditional Measures of School Functioning as Predictors of Students\u27 Well-Being

Academic achievement, behavior, and school connectedness have long been considered central measures for assessing students’ optimal functioning in school. With the growing interest in positive education and its’ inclusion of well-being as a central educational goal, attention has been turned to the extent to which these traditional measures of school functioning are related to students’ well-being. Based on a sample of 314 Israeli middle school students from one school, this study focuses on the relationship between the latter measures of school functioning and students’ well-being, operationalized as life satisfaction, positive and negative affect, hope, and gratitude. Using structural equational modelling, our findings revealed that GPA, teachers’ reports of disruptive behavior, and students’ reports of school connectedness predict students’ well-being, with school connectedness as the strongest predictor of all five well-being measures. This suggests that a sense of connectedness is more crucial to students’ well-being than their academic achievements or behavior in school. Surprisingly, students’ disruptive behavior as reported by teachers was slightly, but significantly, positively associated with life satisfaction, hope and positive affect. Further inquiry into this curious finding revealed that disruptive behavior is related to higher well-being primarily for students of middle range academic attainment (GPA of 64-84) when controlling for connectedness to school. Based on this finding, we suggest that within the school context better behavior among average achievers may be a potential sign of a maladaptive response to being left outside the schools’ radar while disruptive behavior among average achievers may in fact be the more resilient response. Attention is given to this interpretation of the finding as well as to more general implications of the importance of school connectedness for students’ well-being

All-pay auctions with variable rewards

Available online from Blackwell SynergyWe study all–pay auctions with variable rewards under incomplete information. In standard models, a reward depends on a bidder’s privately known type; however, in our model it is also a function of his bid. We show that in such models there is a potential for paradoxical behavior where a reduction in the rewards or an increase in costs may increase the expected sum of bids or alternatively the expected highest bid

A Tagging Solution to Discover IoT Devices in Apartments

The number of IoT devices in smart homes is increasing. This broad adoption facilitates users' lives, but it also brings problems. One such issue is that some IoT devices may invade users' privacy. Some reasons for this invasion can stem from obscure data collection practices or hidden devices. Specific IoT devices can exist out of sight and still collect user data to send to third parties via the Internet. Owners can easily forget the location or even the existence of these devices, especially if the owner is a landlord who manages several properties. The landlord-owner scenario creates multi-user problems as designers build machines for single users. We developed tags that use wireless protocols, buzzers, and LED lighting to lead users to solve the issue of device discovery in shared spaces and accommodate multi-user scenarios. They are attached to IoT devices inside a unit during their installation to be later discovered by a tenant. These tags have similar functionalities as the popular Tile models or Airtag, but our tags have different features based on our privacy use case. Our tags do not require pairing; multiple users can interact with them through our Android application. Although researchers developed several other tools, such as thermal cameras or virtual reality (VR), for discovering devices in environments, they have not used wireless protocols as a solution. We measured specific performance metrics of our tags to analyze their feasibility for this problem. We also conducted a user study to measure the participants' comfort levels while finding objects with our tags attached. Our results indicate that wireless tags can be viable for device tracking in residential properties

Accurate X-ray position and multiwavelength observations of the isolated neutron star RBS 1774

We report on X-ray, optical, infrared and radio observations of the X-ray dim isolated neutron star (XDINS) 1RXS J214303.7+065419 (also known as RBS 1774). The X-ray observation was performed with the High Resolution Camera on board of the Chandra X-ray Observatory, allowing us to derive the most accurate position for this source (alpha = 21h43m3.38s, delta= +6deg54'17".53; 90% uncertainty of 0."6). Furthermore, we confirmed with a higher spatial accuracy the point-like nature of this X-ray source. Optical and infrared observations were taken in B, V, r', i', J, H and Ks filters using the Keck, VLT, Blanco and Magellan telescopes, while radio observations were obtained from the ATNF Parkes single dish at 2.9GHz and 708MHz. No plausible optical and/or infrared counterpart for RBS 1774 was detected within the refined sub-arsecond Chandra X-ray error circle. Present upper limits to the optical and infrared magnitudes are r'>25.7 and J>22.6 (5 sigma confidence level). Radio observations did not show evidence for radio pulsations down to a luminosity at 1.4 GHz of L < 0.02 mJy kpc^2, the deepest limit up to date for any XDINS, and lower than what expected for the majority of radio pulsars. We can hence conclude that, if RBS 1774 is active as radio pulsar, its non detection is more probably due to a geometrical bias rather than to a luminosity bias. Furthermore, no convincing evidence for RRAT-like radio bursts have been found. Our results on RBS 1774 are discussed and compared with the known properties of other thermally emitting neutron stars and of the radio pulsar population.Comment: 8 pages, 9 figures, accepted for publication on MNRA

A study of subjective well-being, resilience, and risk of PTSD among Israeli adolescents exposed to terrorism

While many studies have analyzed the role of subjective well-being components in building psychological resilience in times of stress, there is also evidence that certain aspects of well-being may be tied to increased risk of psychological distress in the aftermath of a traumatic event. Based on a sample of 368 Israeli adolescents surveyed before and after a bout of missile attacks on their city, this study investigates (a) the relationship between subjective well-being components (hope, life satisfaction, and positive and negative affect) and PTSD, thereby assessing their role as protective or risk factors, and (b) changes in the latter well-being measures from before to after the attacks, thereby assessing individuals’ ability to “bounce back” to prior levels of well-being. Using structural educational modeling, our study revealed that life satisfaction was the only subjective well-being factor before the attacks to serve as a protective factor against PTSD symptoms. Negative affect and hope before the attacks served as direct risk factors, while positive affect served as an indirect risk factor. There was a significant increase in hope from before to after the missile attacks, with no change in other well-being measures. Implications of these finding are discussed

Mid-infrared VISIR and Spitzer observations of the surroundings of the magnetar SGR 1806-20

We report mid-infrared observations of SGR 1806-20 and its environment - with the highest spatial resolution in this domain to date - using ESO/VISIR in 2005 and 2006, and we retrieved Spitzer/IRAC-MIPS archival data of the same field. We aimed at studying the mid-infrared emission of the stars associated with the same cluster as SGR 1806-20, to detect variations that could be due to the high-energy activity of the magnetar through interaction with the dust. We also aimed at studying the morphology of the cloud close to the centre of the cluster. We performed broadband photometry of three stars - LBV 1806-20, a WC9 and an O/B supergiant - on our VISIR images, as well as on the IRAC data. We then built and fitted their broadband spectral energy distributions with a combination of two absorbed black bodies, representing their stellar components, as well as a possible mid-infrared excess, in order to derive their physical parameters. We show that LBV 1806-20 and the WC9 star exhibit a mid-infrared excess, likely because of the presence of circumstellar dust related to their winds. We also show that only LBV 1806-20 had a variable flux over a period of two years, variability which is due to its LBV nature rather than to a heating of the gas and dust cloud by the high-energy emission of SGR 1806-20. Finally, differences in the intrinsic absorptions of the three stars show an inhomogeneous structure of the density of the gas and dust cloud in the massive star cluster.Comment: 9 pages, 5 figures, 4 tables, accepted in A&

Orbital Evolution of Compact White Dwarf Binaries

The new-found prevalence of extremely low mass (ELM, Mhe<0.2 Msun) helium white dwarfs (WDs) in tight binaries with more massive WDs has raised our interest in understanding the nature of their mass transfer. Possessing small (Menv~1e-3 Msun) but thick hydrogen envelopes, these objects have larger radii than cold WDs and so initiate mass transfer of H-rich material at orbital periods of 6-10 minutes. Building on the original work of D'Antona et al., we confirm the 1e6 yr period of continued inspiral with mass transfer of H-rich matter and highlight that the inspiraling direct-impact double WD binary HM Cancri likely has an ELM WD donor. The ELM WDs have less of a radius expansion under mass loss, thus enabling a larger range of donor masses that can stably transfer matter and become a He mass transferring AM CVn binary. Even once in the long-lived AM CVn mass transferring stage, these He WDs have larger radii due to their higher entropy from the prolonged H burning stage.Comment: 9 pages, 8 figures. Accepted for publication in the Astrophysical Journa