Measuring welfare changes from commodity price stabilization in small open economies

The authors extend the widely used Newbery and Stiglitz (1981) approach to measuring welfare changes from commodity price stabilization to a general equilibrium setting. They derive the welfare changes in terms of net consumer and producer surplus, rather than in terms of producer income as in the Newbery and Stiglitz approach. The authors present formulas for measuring the welfare changes for domestic price stabilization achieved through profitable storage (as assumed by Newbery and Stiglitz) and for stabilization through a variable tariff scheme. These formulas differ significantly, so it is inappropriate to use the Newbery and Stiglitz formula to justify the use of domestic price controls such as a variable levy. In recent years, governments in many developing countries have liberalized their trade policies in the pursuit of improved economic performance. But this has exposed their economies to variations in international prices and raised questions about the desirability of domestic price stabilization programs. A popular mechanism for this purpose is a variable import levy scheme. The authors'analysis confirms that domestic welfare is lower under trade policies that stabilize domestic prices, as such policies serve only to shift the price uncertainty from producers and consumers to the government budget - while incurring the social costs of the distortionary tariffs and subsidies. The authors focus on a comparison of the welfare effects of price stabilization under a variable tariff scheme and storage, but suggest a better option: to use financial instruments for hedging against commodity price risks. This requires that there be no capital controls - one of the main reasons private insurance is seldom undertaken in developing countries.Economic Theory&Research,Insurance&Risk Mitigation,Markets and Market Access,Access to Markets,Environmental Economics&Policies

Effects of negative keying and wording in attitude measures: A mixed-methods study

Researchers often collect data on attitudes using “balanced” measurement scales—that is, scales with comparable numbers of positive and negative (i.e., reverse-scored) items. Many previous measurement studies have found the inclusion of negative items to be detrimental to scale reliability and validity. However, these studies have rarely distinguished among negatively-worded items, negatively-keyed items, and items with negative wording and keying. The purpose of the current study was to make those distinctions and investigate why the psychometric properties of balanced scales tend to be worse than those of scales with uniformly positive wording/keying. A mixed-methods approach was employed. In Study 1 (quantitative), item wording and keying were systematically varied in adaptations of two published attitude measures that were administered to a large college student sample. Reliability and dimensionality of the resulting data were examined across the measures in each of four wording/keying configurations. Study 2 (qualitative) incorporated a mix of the same four wording/keying conditions in an adapted measure that was administered individually to a small sample of college students. A think-aloud design was implemented to elicit verbalizations that were subsequently analyzed using a thematic networks approach. Study 1 findings indicated that reliability estimates were generally highest for scales where all items were positively worded/keyed and lowest for scales with balanced keying (or balanced keying and wording). Regarding dimensionality, method variance was more evident when keying was balanced than when keying was consistent. This tended to be the case whether wording was balanced or consistent. Study 2 revealed a number of factors that could contribute to differences in the response patterns elicited by negative and positive items. These factors included the relative difficulty of processing negatively-worded statements, respondent characteristics such as reading skill and frustration tolerance, and idiosyncratic response styles. Among previously posited explanations for the differential functioning of negative and positive items, results from the studies supported some explanations (e.g., method variance; careless responding) more than others (e.g., the substantive explanation). Overall, it appeared that the psychometric consequences of balanced keying are no less substantial than those of balanced wording. An important question raised by the findings is whether the apparent advantage of consistent keying (in terms of reliability and dimensionality) came at the expense of validity, since careless responding and other forms of satisficing may be masked when keying is not balanced

Maximum Entropy Estimation of the Galactic Bulge Morphology via the VVV Red Clump

The abundance and narrow magnitude dispersion of Red Clump (RC) stars make them a popular candidate for mapping the morphology of the bulge region of the Milky Way. Using an estimate of the RC's intrinsic luminosity function, we extracted the three-dimensional density distribution of the RC from deep photometric catalogues of the VISTA Variables in the Via Lactea (VVV) survey. We used maximum entropy based deconvolution to extract the spatial distribution of the bulge from Ks-band star counts. We obtained our extrapolated non-parametric model of the bulge over the inner 40 by 40 degrees squared region of the Galactic centre. Our reconstruction also naturally matches onto a parametric fit to the bulge outside the VVV region and inpaints overcrowded and high extinction regions. We found a range of bulge properties consistent with other recent investigations based on the VVV data. In particular, we estimated the bulge mass to be in the range 13 to 17 billion solar masses, the X-component to be between 18% and 25% of the bulge mass, and the bulge angle with respect to the Sun-Galactic centre line to be between 18 and 32 degrees. Studies of the Fermi Large Area Telescope (LAT) gamma-ray Galactic centre excess suggests that the excess may be traced by Galactic bulge distributed sources. We applied our deconvolved density in a template fitting analysis of this Fermi-LAT GeV excess and found an improvement in the fit compared to previous parametric based templates.Comment: 25 pages, 27 figures, minor typo correcte

Axiomatic design of a manually powered wheelchair lift mechanism

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Includes bibliographical references (leaves 65-66).The objective of this research is to create an inexpensive mechanism which gives wheelchair users the ability to adjust the vertical height of their chair while seated. There are currently 1.5 million manual wheelchair users in the United States. However, no manual height adjust mechanisms are available in the current marketplace. Increased vertical range of sight and reach will result in unprecedented levels of independence for wheelchair users. We applied the theory of axiomatic design as a methodology for designing a mechanism to fill this compelling unmet need. Careful consideration of the functional and physical domains guided us to an effective solution to this design problem. A proof of concept prototype was created to demonstrate the potential of this design solution. This prototype is capable of lifting a person of 2501bs weight 15 inches off of the ground while seated in the wheelchair. This design solution is viable, and with continued work we hope that it may someday come to fruition as an effective and useful product.by Kevin DiGenova and Chris Coleman.S.B

'Kindness and empathy beyond all else' : Challenges to professional identities of Higher Education teachers during COVID-19 times

COVID-19 has continued to effect higher education globally in significant ways. During 2020, many institutions shifted learning online overnight as the sector closed its doors and opened new sites for remote teaching. This article reports on an international study [Phillips et al., 2021] that sought to capture how cross-sectoral teachers experienced these emergency changes during the first months of restrictions. The data, analysed using narrative identity theory, revealed concerns that fall into two broad categories: technologies and relationships. Significantly, it was not a loss of content delivery or changes to assessment that prompted the greatest anxiety for our colleagues, but that they held significant concerns about their students’ mental health; inequities of access to a range of services including technological; and challenges connecting emotionally with their students at a distance. The results provide actionable strategies for higher education institutions to apply in future emergencies where remote teaching is necessary

Non-Parametric Density Reconstruction of the Galactic Bulge Area using Red Clump Stars in the VVV Survey

Studies of the red clump giant population in the inner Milky Way suggest the Galactic bulge/bar has a boxy/peanut/X-shaped structure as predicted by its formation via a disc buckling instability. We used a non-parametric method of estimating the Galactic bulge morphology that is based on maximum entropy regularisation. This enabled us to extract the three-dimensional distribution of the red giant stars in the bulge from deep photometric catalogues of the VISTA Variables in the Via Lactea (VVV) survey. Our high-resolution reconstruction confirms the well-known boxy/peanut/X-shaped structure of the bulge. We also find spiral arm structures that extend to around three kpc in front of and behind the bulge and are on different sides of the bulge major axis. We show that the detection of these structures is robust to the uncertainties in the luminosity function.Comment: 12 pages, 8 figures, V4: MNRAS accepted versio

STORIES FOUND WITHIN THE LEARNINGS OF TEACHING IN COVID-19

COVID-19 has disrupted the educational landscape around the world, putting new pressures on schools, colleges and universities, and more specifically on teaching, learning and assessment. Educators feel fragmented, as their identities as well as their roles pivoted when the pandemic directed them home to teach. This paper explores a global story-based educational research project that sought to capture the pressures, stress and self-efficacy of educators across the world. Our digital ethnographic study sought to explore what educators were experiencing; to archive the worries, hopes, concerns and issues encountered by teachers in new spaces and sites as remote emergency practice began. What has emerged from the 635-educator participant study that includes 105 respondents in the higher education/tertiary sector that we have chosen to focus on here, is an attentiveness to the place of learning and teaching. More importantly, the relations between people and place, and the teachers and their students. This paper explores four stories from the higher education data that have been re-storied as an opening to this pandemic and the effects of the pivot on teaching practice to indicate the times and provide voice to our participants

Support for the Research Process, an academic library manifesto

When we shift our attention from 'save libraries' to 'save scholarship', the imperative changes from 'preserve the current institutions' to 'do whatever works' [adapted from Clay Shirky]OCLC Research (Online Computer Library Center, Dublin, Ohio, USA); Research Libraries Grou

The Vibration Spectrum of Two Euler–Bernoulli Beams Coupled Via a Dissipative Joint

The asymptotic estimation of the vibration spectrum for a system of two identical Euler–Bernoulli beams coupled via each of the four standard types of linear dissipative joint has been solved for the case when one beam is clamped and the other beam is free at the outer ends. Here, we generalize those results and solve the problem for all 40 combinations of energy-conserving end conditions. We provide both asymptotic and numerical results, and we compare the various systems with an eye toward determining which configurations lead to asymptotically equivalent vibration spectra