Accelerating Galaxy Winds During the Big Bang of Starbursts

We develop a new method to infer the temporal, geometric, and energetic properties of galaxy outflows, by combining stellar spectral modeling to infer starburst ages, and absorption lines to measure velocities. If winds are accelerated with time during a starburst event, then these two measurements enable us to solve for the wind radius, similarly to length scales and the Hubble parameter in Big Bang cosmology. This wind radius is the vital, but hard-to-constrain parameter in wind physics. We demonstrate the method using spectra of 87 starburst galaxies at z=0.05-0.44, finding that winds accelerate throughout the starburst phase and grow to typical radii of ~1 kpc in ~10 Myr. Mass flow rates increase rapidly with time, and the mass-loading factor exceeds unity at about 10 Myr - while still being accelerated, the gas will likely unbind from the local potential and enrich the circumgalactic medium. We model the mechanical energy available from stellar winds and supernovae, and estimate that a negligible amount is accounted for in the cool outflow at early times. However, the energy deposition increases rapidly and ~10% of the budget is accounted for in the cool flow at 10 Myr, similar to some recent hydrodynamical simulations. We discuss how this model can be developed, especially for high-redshift galaxies.Comment: Accepted for publication in MNRAS Letters. 6 pages, 5 figure

Artefact reduction in photoplethysmography

The use of optical techniques in biomedical monitoring and diagnosis is becoming increasingly widespread, primarily because of the non-invasive nature of optically derived measurements. Physiological analysis is usually achieved by characterisation of the spectral or temporal properties of the interaction between light and the anatomy. Although some optical measurements require complex instrumentation and protocols, recent technological advances have resulted in robust and compact equipment that is now used routinely in a multitude of clinical contexts. Unfortunately, these measurements are inherently sensitive to corruption from dynamic physical conditions or external sources of light, inducing signal artefact. Artefact is the primary restriction in the applicability of many optical measurements, especially for ambulatory monitoring and tele-medicine. The most widely used optical measurement is photoplethysmography, a technique that registers dynamic changes in blood volume throughout the peripheral vasculature and can be used to screen for a number of venous disorders, as well as monitoring the cardio-vascular pulse wave. Although photoplethysmographic devices are now incorporated into many patient-monitoring systems, the prevalent application is a measurement known as pulse oximetry, which utilises spectral analysis of the peripheral blood to estimate the arterial haernoglobin oxygen saturation. Pulse oximetry is well established as an early warning for hypoxia and is now mandatory under anaesthesia in many countries. The problem of artefact is prominent in these continuous monitoring techniques, where it is often impossible to control the physical conditions during use. This thesis investigates the possibility of reducing artefact corruption of photoplethysmographic signals in real time, using an electronic processing methodology that is based upon inversion of a physical artefact model. The consequences of this non-linear artefact reduction technique for subsequent signal analysis are discussed, culminating in a modified formulation for pulse oximetry that not only has reduced sensitivity to artefact but also possesses increased generality. The design and construction of a practical electronic system is then used to explore both the implementation issues and the scope of this technique. The performance of artefact reduction obtained is then quantified under realistic experimental conditions, demonstrating that this methodology is successful in removing or reducing a large proportion of artefact encountered in clinically relevant situations. It is concluded that non-linear artefact reduction can be applied to any photoplethysmographic technology, reducing interpretation inaccuracies that would otherwise be induced by signal artefact. It is also speculated that this technology could enable the use of photoplethysmographic systems in applications that are currently precluded by the inherent severity of artefact

Hindbrain Neurons as an Essential Hub in the Neuroanatomically Distributed Control of Energy Balance

This Review highlights the processing and integration performed by hindbrain nuclei, focusing on the inputs received by nucleus tractus solitarius (NTS) neurons. These inputs include vagally mediated gastrointestinal satiation signals, blood-borne energy-related hormonal and nutrient signals, and descending neural signals from the forebrain. We propose that NTS (and hindbrain neurons, more broadly) integrate these multiple energy status signals and issue-output commands controlling the behavioral, autonomic, and endocrine responses that collectively govern energy balance. These hindbrain-mediated controls are neuroanatomically distributed; they involve endemic hindbrain neurons and circuits, hindbrain projections to peripheral circuits, and projections to and from midbrain and forebrain nuclei

The Role of Narcissistic Hypocrisy in the Development of Accounting Estimates

In an experiment including experienced managers, we investigate how supervisor and subordinate narcissism influence a supervisor’s review of a subordinate’s accounting estimate. While narcissistic supervisors express greater liking for narcissistic subordinates (narcissistic tolerance), they nonetheless reject and revise the accounting estimates of narcissistic subordinates to a greater extent than they reject estimates of non‐narcissistic subordinates (narcissistic hypocrisy), even when doing so inhibits the supervisor’s ability to reach a profit target. Our findings contribute to extant research in accounting and psychology. We demonstrate that narcissistic hypocrisy extends beyond the evaluation of others and alters narcissists’ willingness to rely on other narcissists in a meaningful financial reporting decision. We also find that narcissistic hypocrisy is robust across age, gender, and supervisory experience.RÉSUMÉLe rôle de l’hypocrisie narcissique dans l’élaboration d’estimations comptablesLes auteurs mènent auprès de gestionnaires chevronnés une expérience visant à déterminer en quoi le narcissisme des supérieurs et des subalternes influe sur l’examen auquel les supérieurs soumettent les estimations comptables des subalternes. Bien que les supérieurs narcissiques semblent apprécier davantage les subalternes narcissiques (tolérance narcissique), ils rejettent et révisent néanmoins les estimations des subalternes narcissiques plus souvent qu’ils ne rejettent les estimations des subalternes non narcissiques (hypocrisie narcissique), même lorsque cette décision nuit à leur capacité d’atteindre un objectif de profit. Les résultats de l’étude viennent enrichir les recherches existantes en comptabilité et en psychologie. Les auteurs démontrent que l’hypocrisie narcissique s’étend au‐delà de l’évaluation d’autrui et modifie la mesure dans laquelle les narcissiques sont disposés à s’appuyer sur d’autres narcissiques dans une décision importante en matière d’information financière. Ils observent également que leurs conclusions quant à l’hypocrisie narcissique persistent quels que soient l’-ge, le sexe et l’expérience de supervision.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/155911/1/care12552-sup-0001-SupInfo.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155911/2/care12552.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/155911/3/care12552_am.pd

Who Sees Corruption? The Bases of Mass Perceptions of Political Corruption in Latin America

The capacity of citizens to see political corruption where it exists and to link such perceptions to evaluations of public officials constitutes an important test of political accountability. Although past research has established that perceived corruption influences political judgments, much less is known regarding the critical prefatory matter of who sees corruption. This article develops a multifaceted theoretical framework regarding the possible bases of perceived corruption. Experiential factors - personal experience and vicarious experience with bribery - mark the starting point for our account. We then incorporate psychological dispositions that may colour judgments about corruption and that may strengthen or weaken the links between experiences and perceptions. Expectations derived from this framework are tested in a series of multi-level models, with data from over 30,000 survey respondents from 17 nations and 84 regions in the Americas

Empirical Estimate of Lyman-alpha Escape Fraction in a Statistical Sample of Lyman-alpha Emitters

The Lyman-alpha (Lya) recombination line is a fundamental tool for galaxy evolution studies and modern observational cosmology. However, subsequent interpretations are still prone to a number of uncertainties. Besides numerical efforts, empirical data are urgently needed for a better understanding of Lya escape process. We empirically estimate the Lyman-alpha escape fraction fesc(Lya) in a statistically significant sample of z ~ 0 - 0.3 galaxies in order to calibrate high-redshift Lyman-alpha observations. An optical spectroscopic follow-up of a sub-sample of 24 Lyman-alpha emitters (LAEs) detected by GALEX at z ~ 0.2-0.3, combined with a UV-optical sample of local starbursts, both with matched apertures, allow us to quantify the dust extinction through Balmer lines, and to estimate the Lyman-alpha escape fraction from the Halpha flux corrected for extinction in the framework of the recombination theory. The global escape fraction of Lyman-alpha radiation spans nearly the entire range of values, from 0.5 to 100 %, and fesc(Lya) clearly decreases with increasing nebular dust extinction E(B-V). Several objects show fesc(Lya) greater than fesc(continuum) which may be an observational evidence for clumpy ISM geometry or for an aspherical ISM. Selection biases and aperture size effects may still prevail between z ~ 0.2-0.3 LAEs and local starbursts, which may explain the difference observed for fesc(Lya).Comment: 4 pages, 2 figures, accepted for publication in Astronomy and Astrophysic

On the influence of physical galaxy properties on Lyman-alpha escape in star-forming galaxies

[abridged] Among the different observational techniques used to select high-redshift galaxies, the hydrogen recombination line Lyman-alpha (Lya) is of particular interest as it gives access to the measurement of cosmological quantities such as the star formation rate of distant galaxy populations. However, the interpretation of this line and the calibration of such observables is still subject to serious uncertainties. Therefore, it important to understand under what conditions the Lya line can be used as a reliable star formation diagnostic tool. We use a sample of 24 Lya emitters at z ~ 0.3 with an optical spectroscopic follow-up to calculate the Lya escape fraction and its dependency upon different physical properties. We also examine the reliability of Lya as a star formation rate indicator. We combine these observations with a compilation of Lya emitters selected at z = 0 - 0.3 to assemble a larger sample. The Lya escape fraction depends clearly on the dust extinction following the relation fesc(Lya) = C(Lya) x 10^(-0.4 E(B-V) k(Lya)), but with a shallower slope than previously reported, with k(Lya) ~ 6.67 and C(Lya) = 0.22. However, the correlation does not follow the expected curve for a simple dust attenuation. We explore the various mechanisms than lead to fesc(Lya) values above the continuum extinction curve, i.e. to an enhancement of the Lya output. We also observe that the strength of Lya and the escape fraction appear unrelated to the galaxy metallicity. Regarding the reliability of Lya as a star formation rate (SFR) indicator, we show that the deviation of SFR(Lya) from the true SFR (as traced by the UV continuum) is a function of the observed SFR(UV), which can be seen as the decrease of fesc(Lya) with increasing UV luminosity. Moreover, we observe a redshift-dependence of this relationship revealing the underlying evolution of fesc(Lya) with redshift.Comment: 17 pages. Accepted for publicatio

Annexin A2 at the Interface of Actin and Membrane Dynamics: A Focus on Its Roles in Endocytosis and Cell Polarization

Annexins are a family of calcium- and phospholipid-binding proteins found in nearly all eukaryotes. They are structurally highly conserved and have been implicated in a wide range of cellular activities. In this paper, we focus on Annexin A2 (AnxA2). Altered expression of this protein has been identified in a wide variety of cancers, has also been found on the HIV particle, and has been implicated in the maturation of the virus. Recently, it has also been shown to have an important role in the establishment of normal apical polarity in epithelial cells. We synthesize here the known biochemical properties of this protein and the extensive literature concerning its involvement in the endocytic pathway. We stress the importance of AnxA2 as a platform for actin remodeling in the vicinity of dynamic cellular membranes, in the hope that this may shed light on the normal functions of the protein and its contribution to disease