The Hip in Hip Hop: Toward a Discipline of Hip Hop Studies

Editorial

Cooling Radiation and the Lyman-alpha Luminosity of Forming Galaxies

We examine the cooling radiation from forming galaxies in hydrodynamic simulations of the LCDM model (cold dark matter with a cosmological constant), focusing on the Ly-alpha line luminosities of high-redshift systems. Primordial composition gas condenses within dark matter potential wells, forming objects with masses and sizes comparable to the luminous regions of observed galaxies. As expected, the energy radiated in this process is comparable to the gravitational binding energy of the baryons, and the total cooling luminosity of the galaxy population peaks at z ~= 2. However, in contrast to the classical picture of gas cooling from the \sim 10^6 K virial temperature of a typical dark matter halo, we find that most of the cooling radiation is emitted by gas with T < 20,000 K. As a consequence, roughly 50% of this cooling radiation emerges in the Ly-alpha line. While a galaxy's cooling luminosity is usually smaller than the ionizing continuum luminosity of its young stars, the two are comparable in the most massive systems, and the cooling radiation is produced at larger radii, where the Ly-alpha photons are less likely to be extinguished by dust. We suggest, in particular, that cooling radiation could explain the two large (\sim 100 kpc), luminous (L_{Ly-alpha} \sim 10^{44} erg s^{-1}) ``blobs'' of Ly-alpha emission found in Steidel et al.'s (1999) narrow band survey of a z = 3 proto-cluster. Our simulations predict objects of the observed luminosity at about the right space density, and radiative transfer effects can account for the observed sizes and line widths. We discuss observable tests of this hypothesis for the nature of the Ly-alpha blobs, and we present predictions for the contribution of cooling radiation to the Ly-alpha luminosity function of galaxies as a function of redshift.Comment: Submitted to ApJ. 28 pages including 9 PS figures. Version with color figures available at http://donald.astro.umass.edu/~fardal/papers/cooling/cooling.htm

Are steroid injections effective for tenosynovitis of the hand?

Yes. Steroid injections are an effective first-line therapy for flexor tenosynovitis of the hand, with a number needed to treat [NNT] of 2.3 for injection of steroids and lidocaine (strength of recommendation [SOR]: B, based on 1 prospective RCT and low- quality studies). Injection into the tendon sheath may not be critical to a successful outcome (SOR: B, based on 1 prospective uncontrolled trial)

Information flows and topic modeling in corporate governance

Purpose – Multiple disciplines such as finance, management and economics have contributed to governance research over time. However, the full intellectual structure of the governance “field” including the exchange of knowledge across disciplines and the large variety of governance topics remains to be uncovered. To appreciate the breadth of corporate governance research, it is necessary to understand the disciplinary sources from which the research stems. This manuscript focuses on the interdisciplinary underpinnings of corporate governance research. Design/methodology/approach – This paper employs bibliometric analysis to trace the evolution of corporate governance using articles included in the ISI Web of Science database between 1990 and 2015. Journals included in these categories encompass a full range of business disciplines and provide evidence of the multi-disciplinary nature of corporate governance. It also uncovers the topics treated by disciplines under the governance umbrella using a machine learning method called latent Dirichtlet allocation (LDA). Findings – Corporate governance research deals with a number of strategy-related topics. Unlike strategy topics that reside in a single discipline, corporate governance crosses disciplinary boundaries and includes contributions from accounting, finance, economics, law and management. Our analysis shows that over 80% of corporate governance articles come from outside the field of management. Our LDA solution indicates that the major topics in governance research include corporate governance theory, control of family firms, executive compensation and audit committees. Originality/value – The results illustrate that corporate governance is far more interdisciplinary than previously thought. This is an important insight for corporate governance academics and may lead to collaborative research. More importantly, this research illustrates the usefulness of LDA for investigating interdisciplinary fields. This method is easily transferable to other interdisciplinary fields and it provides a powerful alternative to existing bibliometric methods. We suggest a number of topic areas within library and information science where this method may be applied, including collection development, support for interdisciplinary faculty and basic research into emerging interdisciplinary areas

Ancilla-assisted quantum process tomography

Complete and precise characterization of a quantum dynamical process can be achieved via the method of quantum process tomography. Using a source of correlated photons, we have implemented several methods investigating a wide range of processes, e.g., unitary, decohering, and polarizing. One of these methods, ancilla-assisted process tomography (AAPT), makes use of an additional ``ancilla system,'' and we have theoretically determined the conditions when AAPT is possible. All prior schemes for AAPT make use of entangled states. Our results show that, surprisingly, entanglement is not required for AAPT, and we present process tomography data obtained using an input state that has no entanglement. However, the use of entanglement yields superior results.Comment: To appear in Physical Review Letter

Testing Cosmological Models Against the Abundance of Damped Lyman-Alpha Absorbers

We calculate the number of damped Lyman-alpha absorbers expected in various popular cosmological models as a function of redshift and compare our predictions with observed abundances. The Press-Schechter formalism is used to obtain the distribution of halos with circular velocity in different cosmologies, and we calibrate the relation between circular velocity and absorption cross-section using detailed gas dynamical simulations of a ``standard'' cold dark matter (CDM) model. Because of this calibration, our approach makes more realistic assumptions about the absorption properties of collapsed objects than previous, analytic calculations of the damped Lyman-alpha abundance. CDM models with Omega_0=1, H_0=50, baryon density Omega_b=0.05, and scale-invariant primeval fluctuations reproduce the observed incidence and redshift evolution of damped Lyman-alpha absorption to within observational uncertainty, for both COBE normalization (sigma_8=1.2) and a lower normalization (sigma_8=0.7) that better matches the observed cluster abundance at z=0. A tilted (n=0.8, sigma_8=0.7) CDM model tends to underproduce absorption, especially at z=4. With COBE normalization, a CDM model with Omega_0=0.4, Omega_{Lambda}=0.6 gives an acceptable fit to the observed absorption; an open CDM model is marginally acceptable if Omega_0 is at least 0.4 and strongly inconsistent with the z=4 data if Omega_0=0.3. Mixed dark matter models tend not to produce sufficient absorption, being roughly comparable to tilted CDM models if Omega_{nu} = 0.2 and failing drastically if Omega_{nu} = 0.3.Comment: AASlatex, 13 pages w/ 2 embedded ps figures. To be published in ApJ, Sept. 1, 199

Back to School in the Pandemic: Observations of the Influences of Prevention Measures on Relationships, Autonomy, and Learning of Preschool Children

Background: The COVID-19 pandemic has had a global impact on societies, economies, and education. In Spain, one of the countries most affected by the COVID-19 in the initial year, the virus began to spread at the end of February 2020. When the Spanish government declared a state of emergency, the first restrictive measure was the closure of all educational centers on the 14th of March. All schools and universities were closed until September 2020, when students returned to classes with preventative health measures in place to prevent the spread of the virus. Methods: This study focuses on the observation of children in pre-school education. Specifically, it focuses on studying how preventative health measures that were taken in the pre-schools may have influenced children’s social relationships, basic autonomy, and learning. We used a mixed method in which field notes were taken and observational scores were assigned. Results: The following prevention measures appear to have influenced children’s relationships, autonomy, and learning: bubble groups, handwashing, teachers wearing masks, divided playgrounds so different classes cannot mix, and no toys from home or shared personal objects. Conclusions: The results of the study suggest that new health measures such as the use of masks and social distancing do appear to be affecting the communication and development of pre-school children. Continued research is needed to understand and minimize the potential negative impacts of pandemic measures on children’s development

Measuring Discrimination Against Transgender People at the University of the Basque Country and in a Non-University Sample in Spain

Transgender people suffer from others&rsquo; negative attitudes in many situations. The university context is one environment where further progress has to be made to ensure the inclusion of transgender people. In this study, a sample of 376 undergraduate students was collected and their attitudes towards transgender people were analyzed. A comparison was made between number of years in university, and a sample from the general public. In addition, comparisons were made by gender, since the literature shows more negative attitudes toward transgender people in men than in women. The results show relatively positive attitudes toward transgender people among higher education students, but they have little knowledge of transgender identity. In turn, researchers found significant differences between different years in the university and between genders. These results support the need to expand knowledge about transgender people in the university environment

Improvement in Gender and Transgender Knowledge in University Students Through the Creative Factory Methodology

In Spain, Social Educators, similar to both social workers and educators in the United States, help coordinate social change through educational interventions and mobilization of social groups to benefit marginalized people and overall societal welfare. They are trained to work with diverse populations, and it is important that they have awareness and training on gender and transgender issues given the extensive discrimination that transgender people endue. Research has begun to identify the important role that knowledge and attitudes of health and educational professionals may play in providing a supportive, healing context to combat the harmful effects of this discrimination and how educational trainings may foster improved knowledge and attitudes in helping professions. This study describes a program to improve knowledge and positive attitudes toward gender and especially transgender people in university students who study Social Education. The researchers measured knowledge and attitudes toward gender and transgender people issues of 64 students before and after receiving a 4-month interactive training. They used the Short Form of the Genderism and Transphobia Scale, a 12-item scale of transphobia and gender ideology variables. The researchers also asked participants about their knowledge of gender and transgender issues before and after training. The methodological experience "Creative Factory" was employed as an interactive training program. The main goal of this methodology is to enable students in a formative context to analyze social realities to generate discussion and innovate ideas to design successful practices. After 4 months of training with a weekly session on gender and transgender learning, students showed improvements in knowledge and attitudes toward both gender and transgender people. Specifically, students demonstrated more knowledge about gender and transgender issues and more positive attitudes toward transgender people. The study demonstrates that training in gender education using the Creative Factory methodology improved knowledge and attitudes in students