Using Annual Panel Data To Examine The Monday Effect

The Monday effect is a well-known anomaly in which Monday stocks returns are significantly different from other days. Recent research suggests that small-cap stocks exhibit negative and significant Monday returns, mid-cap stocks show no Monday effect and large-cap stocks have positive and significant Monday returns. In this short paper we re-examine the Monday effect using a somewhat different approach that the rest of the literature. Specifically, we examine the U.S. mean Monday returns for each market capitalization decile and for each year over the period 1966-2007. We then examine the patterns of these annual Monday returns. Using this method, we find that the Monday effect has dissipated for all sizes of stocks so much that, by the middle 1990s, the Monday returns are generally not significant from zero

The Use of Epidural Corticosteroids for Cervical Radiculopathy: An Interlaminar Versus Transforaminal Approach

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146929/1/pmr2178.pd

The Impact of CEO Turnover on Equity Volatility

A change in executive leadership is a significant event in the life of a firm. Our paper investigates a potentially significant consequence of a CEO turnover: a change in equity volatility. We develop several hypotheses about how CEO changes might affect stock price volatility, and test these hypotheses using a sample of 872 CEO changes over the 1979-1995 period. We find that volatility increases following a CEO turnover, even for the most frequent type, when a CEO leaves voluntarily and is replaced by someone from inside the firm. Our results indicate that forced turnovers, which are expected to result in large strategy changes, increase volatility more than voluntary turnovers. Outside successions, which are expected to result in a successor CEO with less certain skill in managing the firm's operations, increase volatility more than inside turnovers. We also document a greater stock-price response to earnings announcements around CEO turnover, consistent with more informative signals of value driving the increased volatility. Controls for firm-specific characteristics indicate that the volatility changes cannot be entirely attributed to factors such as changes in firm operations, firm size, and both volatility change and performance prior to the turnover

The Diverse Infrared Properties of a Complete Sample of Star-Forming Dwarf Galaxies

We present mid-infrared Spitzer Space Telescope observations of a complete sample of star-forming dwarf galaxies selected from the KPNO International Spectroscopic Survey. The galaxies span a wide range in mid-infrared properties. Contrary to expectations, some of the galaxies emit strongly at 8 micron indicating the presence of hot dust and/or PAHs. The ratio of this mid-infrared dust emission to the stellar emission is compared with the galaxies' luminosity, star-formation rate, metallicity, and optical reddening. We find that the strength of the 8.0 micron dust emission to the stellar emission ratio is more strongly correlated with the star-formation rate than it is with the metallicity or the optical reddening in these systems. Nonetheless, there is a correlation between the 8.0 micron luminosity and metallicity. The slope of this luminosity-metallicity correlation is shallower than corresponding ones in the B-band and 3.6 micron. The precise nature of the 8.0 micron emission seen in these galaxies (i.e., PAH versus hot dust or some combination of the two) will require future study, including deep mid-IR spectroscopy.Comment: 14 pages, accepted Ap

Mice in a labyrinth: Rapid learning, sudden insight, and efficient exploration

Animals learn certain complex tasks remarkably fast, sometimes after a single experience. What behavioral algorithms support this efficiency? Many contemporary studies based on two-alternative-forced-choice (2AFC) tasks observe only slow or incomplete learning. As an alternative, we study the unconstrained behavior of mice in a complex labyrinth and measure the dynamics of learning and the behaviors that enable it. A mouse in the labyrinth makes ~2000 navigation decisions per hour. The animal quickly discovers the location of a reward in the maze and executes correct 10-bit choices after only 10 reward experiences – a learning rate 1000-fold higher than in 2AFC experiments. Many mice improve discontinuously from one minute to the next, suggesting moments of sudden insight about the structure of the labyrinth. The underlying search algorithm does not require a global memory of places visited and is largely explained by purely local turning rules

Trends and economic drivers for United States naloxone pricing, January T 2006 to February 2017

Anecdotal evidence indicates that naloxone prices have risen in recent years, but limited research has examined the magnitude of these increases and potential causes. We contribute nationally representative evidence to help answer each of these questions, including wholesale pricing data from a proprietary drug sales database span- ning January 2006 to February 2017. We find that all formulations of naloxone increased in price since 2006 except for Narcan Nasal Spray. These cumulative increases totaled 2281% for the 0.4 MG single-dose products, 244% for the 2 MG single-dose products, 3797% for the 4 MG multi-dose products, and 469% for the 0.4 MG Evzio auto-injector. We believe that increased demand for naloxone from the opioid epidemic may explain the more gradual price increases for the 0.4 MG single-dose and 4 MG multi-dose products prior to 2012. On the other hand, we believe that the sudden, sustained prices increases occurring for all of the products since 2012 may be the result of a drug shortage for the 0.4 MG single-dose products and the fact that each naloxone product has historically been sold by only a single competitor

The Beck Initiative : training school-based mental health staff in cognitive therapy

A growing literature supports cognitive therapy (CT) as an efficacious treatment for youth struggling with emotional or behavioral problems. Recently, work in this area has extended the dissemination of CT to school-based settings. The current study has two aims: 1) to examine the development of therapists’ knowledge and skills in CT, an evidence-based approach to promoting student well-being, and 2) to examine patterns of narrative feedback provided to therapists participating in the program. As expected, school therapists trained in CT demonstrated significant gains in their knowledge of CT theory and in their demonstration of CT skills, with the majority of therapists surpassing the accepted threshold of competency in CT. In addition, an examination of feedback content suggested that narrative feedback provided to therapists most frequently consisted of positive feedback and instructions for future sessions. Suggestions for future research regarding dissemination of CT are discussed in light of increasing broad access to evidence based practices.peer-reviewe

Determination of calcium, magnesium, and aluminum in red spruce (Picea rubens) foliage and surrounding soil from the Great Smoky Mountains National Park, Blue Ridge Parkway, and Mount Mitchell State Park using inductively coupled plasma optical emission spectrometry

Red spruce (Picea rubens) trees are medium size conifers found in the Appalachian Mountains at high elevations (above 4500 ft.). Since the 1970’s, several reports indicate a decline of spruce-fir forests in the Southern Appalachian Mountains caused by acid deposition. Acid deposition leaches essential nutrients out of the soil, such as calcium (Ca2+) and magnesium (Mg2+) cations, and increases the availability of toxic metals to plants, such as aluminum cations (Al3+). Investigation of acid deposition effects on red spruce forests was achieved by analyzing calcium, magnesium, and aluminum in foliage and soils of these forests. Samples were collected from various locations on the Blue Ridge Parkway (NC), within the Great Smoky Mountains National Park (NC/TN) and Mt. Mitchell State Park (NC). Foliar and soil samples were collected from 30 red spruce trees (each consisted of 10 matures, 10 saplings, and 10 seedlings,) at each sample site. The concentrations of calcium, magnesium, and aluminum in the foliage and surrounding soils of red spruce trees were determined by using an acid digestion and cation exchange method, respectively. Foliar and soil samples were analyzed using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). Statistical (Student's t – test, analysis of variance, and linear regression analysis) and geospatial analysis were performed on the results. There was some correlation in nutrient or toxic metal concentrations found in the foliage or surrounding soils of red spruce trees with respect to elevation of red spruce forests located in the Southern Appalachian Mountains. In spite of the proximity of coal burning power plants located in eastern Tennessee, the majority of western samples sites did not exhibit lower nutrient and higher toxic metal concentrations when compared to eastern sample sites. Inconclusive evidence suggested that soil pH did not influence the nutrient or toxic metal concentrations found in the foliage or surrounding soils of red spruce forests. When foliar nutrient or toxic metal concentrations from red spruce trees were investigated as a function of soil metal concentrations, the majority of the results did not follow the hypothesis that the concentration of nutrients or toxic metals found in the surrounding soils of red spruce trees would correlate with the quantity found within the red spruce tree's foliage. The majority of the results indicated that foliar or soil metal concentrations in mature red spruce, red spruce saplings, and red spruce seedlings were not significantly different. Soil calcium/aluminum molar ratios taken from red spruce trees located in the Southern Appalachian Mountains suggested that almost all sample sites are at high risk of adverse forests health effects. A comparison of previous studies of foliar calcium/aluminum ratios taken from red spruce saplings located at Clingman’s Dome, NC/TN suggested a possible improvement, since in the 1980's, in red spruce forest health. A comparison with previous studies, which spanned 40 years, at Richland Balsam, NC of foliar calcium and magnesium concentrations taken from saplings red spruce trees, suggested a possible improvement in red spruce health at that site since 1994

TPCK/TPACK Research and Development: Past, Present, and Future Directions

Scholarship addressing technological pedagogical content knowledge (TPCK or TPACK) has examined how to develop, apply, and assess it in diverse educational settings and content areas. During the last 12 years, multiple ways to understand this knowledge and support its development have emerged, generating approximately 1,200 publications that utilise the construct, impacting the practice of postsecondary faculty, administrators, and others invested in meaningful educational uses of technology. Perhaps inevitably, TPACK’s enthusiastic reception and rapid dissemination have generated multiple points of divergence, which in turn need further study; especially the construct\u27s accurate measurement and validation; how to assist preservice and in-service teachers\u27 TPACK development; contextual influences upon teachers\u27 TPACK; and the relationship of TPACK-based knowledge to teachers\u27 decision-making and action. Given the widespread diffusion of TPACK, research focusing on these and related issues will help to determine the direction of future postsecondary learning and teaching with technologies. Therefore, this special issue of AJET addresses future directions in TPCK/TPACK research and development

A Weil-Barsotti formula for Drinfeld modules

We study the group of extensions in the category of Drinfeld modules and Anderson's t-modules, and we show in certain cases that this group can itself be given the structure of a t-module. Our main result is a Drinfeld module analogue of the Weil-Barsotti formula for abelian varieties. Extensions of general t-modules are also considered, in particular extensions of tensor powers of the Carlitz module. We motivate these results from various directions and compare to the situation of elliptic curves.Comment: 20 pages, latex file. To appear in Journal of Number Theor