Debt maturity, risk, and asymmetric information

We test the implications of Flannery’s (1986) and Diamond’s (1991) models concerning the effects of risk and asymmetric information in determining debt maturity, and we examine the overall importance of informational asymmetries in debt maturity choices. We employ data from more than 6,000 commercial loans from 53 large U.S. banks. Our results for low-risk firms are consistent with the predictions of both theoretical models, but our findings for high-risk firms conflict with the predictions of Diamond’s model and with much of the empirical literature. Our findings also suggest a strong quantitative role for asymmetric information in explaining debt maturity.

Why do borrowers pledge collateral? new empirical evidence on the role of asymmetric information

An important theoretical literature motivates collateral as a mechanism that mitigates adverse selection, credit rationing, and other inefficiencies that arise when borrowers hold ex ante private information. There is no clear empirical evidence regarding the central implication of this literature—that a reduction in asymmetric information reduces the incidence of collateral. We exploit exogenous variation in lender information related to the adoption of an information technology that reduces ex ante private information, and compare collateral outcomes before and after adoption. Our results are consistent with this central implication of the private-information models and support the empirical importance of this theory.

Teaching Chemistry in a Spiral Progression Approach: Lessons from Science Teachers in the Philippines

As the Philippines moves towards implementing the K-12 curriculum, there has been a mismatch in teacher preparation in science. The present teacher education curriculum prepares science teachers to specialise in a specific field (e.g. integrated science, biology, chemistry, and physics). However, in the K-12 curriculum, they are required to teach all the sciences in a spiral progression approach. Hence, this study analysed the experiences of science teachers in teaching chemistry in the K-12 curriculum in order to identify their challenges and how they are overcoming them. Findings suggest that the teacher’s content, pedagogy, and assessment in chemistry are problematic; specifically, challenges such as instruction-related factors, teacher competence, in-service training sufficiency, job satisfaction, support from upper management, laboratory adequacy, school resources, assessment tools, and others influence teacher success in teaching chemistry. These identified challenges greatly affect the ultimate beneficiaries of education, which is the learner

Perceptions of pre-service chemistry teachers on the utilization of productive lesson study as a framework for teaching and learning

The present study determined the perceptions of pre-service teachers on utilizing productive lesson study as a framework in teaching high school chemistry. Participants of the study were thirty (30) junior pre-service chemistry teachers from a state-funded teacher education institution in Manila, Philippines. Participants were exposed to a training-workshop on lesson study and productive pedagogy prior to getting their perception. Lesson study is a form of collaborative lesson planning while productive pedagogy is a framework for evaluating effectiveness of a teaching strategy based on intellectual quality, connectedness, recognition of difference and supportive classroom environment. Results of the study indicated that although most of the participants agreed to utilize the framework, most of them did not grasp the essential process of productive lesson study. On the other hand, all of them agreed that the framework will help improve the teaching skills of teachers and will therefore result to a greater achievement in chemistry among students. Disadvantages that they foresee in the framework include time element and exclusivity. The productive lesson study process will take much of their time and that formulated research lessons might be exclusive only to a group of students and may not be applicable to all

Exploring the current teaching and assessment practices of Australian Biochemistry and Molecular Biology academics

Biochemistry and Molecular Biology classes in Australia are usually held with large class sizes. Hence, some academics have started to innovate, explore and find novel ways to teach effectively in industrial-sized classes. However, it needs to be considered that most teaching and assessment practices being utilised by academics at present have not been formally evaluated for their effectiveness in their specific contexts or they might have been evaluated, but then the evaluation was not published. In addition, due to contextual constraints, simply transplanting some of these teaching and assessment practices from one university to another is not always possible without a study suggesting that they can be useful in a particular context. Therefore, this qualitative case study identifies current teaching and assessment practices by interviewing, observing and collecting documents utilised by Australian academics teaching in this field. The interview guide was prepared based on two established frameworks: the Productive Pedagogy (PP) and the Technological Pedagogical Content Knowledge (TPACK). The classroom observation guides are adapted and are anchored on the two frameworks as well. Interviews were transcribed and coded thematically. Five general themes emerged from the data analyses on the teaching and assessment practices of Australian Biochemistry and Molecular Biology academics: (1) They consider themselves to be traditional teachers; (2) They collaborate with their colleagues to design the course curriculum; (3) They adapt the curriculum to suit student’s background; (4) They are trying to shift their teaching from traditional to non-traditional; and (5) They practice reflective teaching. For each theme, two subthemes were identified and were classified as to pedagogical practice or assessment practice. In future studies, teaching and assessment practices that can be utilised or converted to a teaching strategy promoting conceptual change in a large class cohort will be identified by sending out free-response survey to academics across Australia

The Infrared Nuclear Emission of Seyfert Galaxies on Parsec Scales: Testing the Clumpy Torus models

We present subarcsecond resolution mid-infrared (mid-IR) photometry in the wavelength range from 8 to 20 micron of eighteen Seyfert galaxies, reporting high spatial resolution nuclear fluxes for the entire sample. We construct spectral energy distributions (SEDs) that the AGN dominates adding near-IR measurements from the literature at similar angular resolution. The IR SEDs of intermediate-type Seyferts are flatter and present higher 10 to 18 micron ratios than those of Seyfert 2. We fit the individual SEDs with clumpy torus models using the in-house-developed BayesClumpy tool. The models reproduce the high spatial resolution measurements. Regardless of the Seyfert type, even with high spatial resolution data, near- to mid-IR SED fitting poorly constrains the radial extent of the torus. For the Seyfert 2, we find that edge-on geometries are more probable than face-on views, with a number of clouds along equatorial rays of N = 5-15. The 10 micron silicate feature is generally modeled in shallow absorption. For the intermediate-type Seyferts, N and the inclination angle of the torus are lower than those of the Seyfert 2 nuclei, with the silicate feature appearing in weak emission or absent. The columns of material responsible for the X-ray absorption are larger than those inferred from the model fits for most of the galaxies, which is consistent with X-ray absorbing gas being located within the dust sublimation radius whereas the mid-IR flux arises from an area farther from the accretion disc. The fits yield both the bolometric luminosity of the intrinsic AGN and the torus integrated luminosity, from which we derive the reprocessing efficiency of the torus. In the models, the outer radial extent of the torus scales with the AGN luminosity, and we find the tori to be confined to scales less than 5 pc.Comment: 26 pages, 8 figures, 9 tables. Accepted for publication in Ap

Network model of immune responses reveals key effectors to single and co-infection dynamics by a respiratory bacterium and a gastrointestinal helminth

Co-infections alter the host immune response but how the systemic and local processes at the site of infection interact is still unclear. The majority of studies on co-infections concentrate on one of the infecting species, an immune function or group of cells and often focus on the initial phase of the infection. Here, we used a combination of experiments and mathematical modelling to investigate the network of immune responses against single and co-infections with the respiratory bacterium Bordetella bronchiseptica and the gastrointestinal helminth Trichostrongylus retortaeformis. Our goal was to identify representative mediators and functions that could capture the essence of the host immune response as a whole, and to assess how their relative contribution dynamically changed over time and between single and co-infected individuals. Network-based discrete dynamic models of single infections were built using current knowledge of bacterial and helminth immunology; the two single infection models were combined into a co-infection model that was then verified by our empirical findings. Simulations showed that a T helper cell mediated antibody and neutrophil response led to phagocytosis and clearance of B. bronchiseptica from the lungs. This was consistent in single and co-infection with no significant delay induced by the helminth. In contrast, T. retortaeformis intensity decreased faster when co-infected with the bacterium. Simulations suggested that the robust recruitment of neutrophils in the co-infection, added to the activation of IgG and eosinophil driven reduction of larvae, which also played an important role in single infection, contributed to this fast clearance. Perturbation analysis of the models, through the knockout of individual nodes (immune cells), identified the cells critical to parasite persistence and clearance both in single and co-infections. Our integrated approach captured the within-host immuno-dynamics of bacteria-helminth infection and identified key components that can be crucial for explaining individual variability between single and co-infections in natural populations

Unusually long path length for a nearly scatter-free solar particle event observed by Solar Orbiter at 0.43 au

Context: After their acceleration and release at the Sun, solar energetic particles (SEPs) are injected into the interplanetary medium and are bound to the interplanetary magnetic field (IMF) by the Lorentz force. The expansion of the IMF close to the Sun focuses the particle pitch-angle distribution, and scattering counteracts this focusing. Solar Orbiter observed an unusual solar particle event on 9 April 2022 when it was at 0.43 astronomical units (au) from the Sun. // Aims: We show that the inferred IMF along which the SEPs traveled was about three times longer than the nominal length of the Parker spiral and provide an explanation for this apparently long path. // Methods: We used velocity dispersion analysis (VDA) information to infer the spiral length along which the electrons and ions traveled and infer their solar release times and arrival direction. // Results: The path length inferred from VDA is approximately three times longer than the nominal Parker spiral. Nevertheless, the pitch-angle distribution of the particles of this event is highly anisotropic, and the electrons and ions appear to be streaming along the same IMF structures. The angular width of the streaming population is estimated to be approximately 30 degrees. The highly anisotropic ion beam was observed for more than 12 h. This may be due to the low level of fluctuations in the IMF, which in turn is very probably due to this event being inside an interplanetary coronal mass ejection The slow and small rotation in the IMF suggests a flux-rope structure. Small flux dropouts are associated with very small changes in pitch angle, which may be explained by different flux tubes connecting to different locations in the flare region. // Conclusions: The unusually long path length along which the electrons and ions have propagated virtually scatter-free together with the short-term flux dropouts offer excellent opportunities to study the transport of SEPs within interplanetary structures. The 9 April 2022 solar particle event offers an especially rich number of unique observations that can be used to limit SEP transport models