Before and After Quizzes in One Shot Library Instruction

Short, informal paper describing a quiz given before and after a lecture or discussion, in this particular case, of the use of library article databases, to show prior knowledge, knowledge retention and gaps. The presentation associated with this article can be accessed at: http://archives.pdx.edu/ds/psu/2431

Location, orbit and energy of a meteoroid impacting the moon during the Lunar Eclipse of January 21, 2019

During lunar eclipse of January 21, 2019 a meteoroid impacted the Moon producing a visible light flash. The impact was witnessed by casual observers offering an opportunity to study the phenomenon from multiple geographical locations. We use images and videos collected by observers in 7 countries to estimate the location, impact parameters (speed and incoming direction) and energy of the meteoroid. Using parallax, we achieve determining the impact location at lat. $-29.43^{+0.30}_{-0.21}$, lon. $-67.89^{+0.07}_{-0.09}$ and geocentric distance as 356553 km. After devising and applying a photo-metric procedure for measuring flash standard magnitudes in multiple RGB images having different exposure times, we found that the flash, had an average G-magnitude $\langle G\rangle = 6.7\pm0.3$. We use gravitational ray tracing (GRT) to estimate the orbital properties and likely radiant of the impactor. We find that the meteoroid impacted the moon with a speed of $14^{+7}_{-6}$ km/s (70% C.L.) and at a shallow angle, $\theta < 38.2$ degrees. Assuming a normal error for our estimated flash brightness, educated priors for the luminous efficiency and object density, and using the GRT-computed probability distributions of impact speed and incoming directions, we calculate posterior probability distributions for the kinetic energy (median $K_{\rm med}$ = 0.8 kton), body mass ($M_{\rm med}$ = 27 kg) and diameter ($d_{\rm med}$ = 29 cm), and crater size ($D_{\rm med}$ = 9 m). If our assumptions are correct, the crater left by the impact could be detectable by prospecting lunar probes. These results arose from a timely collaboration between professional and amateur astronomers which highlight the potential importance of citizen science in astronomy.Comment: 19 pages, 11 figures, 4 tables. Data and scripts available in https://github.com/seap-udea/MoonFlashes. Accepted for publication in MNRA

High temporal variability in the occurrence of consumer-resource interactions in ecological networks

Ecological networks are theoretical abstractions that represent ecological communities. These networks are usually defined as static entities, in which the occurrence of a particular interaction between species is considered fixed despite the intrinsic dynamics of ecological systems. However, empirical analysis of the temporal variation of trophic interactions is constrained by the lack of data with high spatial, temporal, and taxonomic resolution. Here, we evaluate the spatiotemporal variability of multiple consumer-resource interactions of large marine networks. The tropic interactions of all of the analyzed networks had low temporal persistence, which was well described by a common exponential decay in the rank-frequency relationship of consumer-resource interactions. This common pattern of low temporal persistence was evident despite the dissimilarities of environmental conditions among sites. Between-site rank correlations of frequency of occurrence of interactions ranged from 0.59 to 0.73. After removing the interactions with <50% frequency, the between-site correlations decreased to values between 0.60 and 0.28, indicating that low-frequency interactions accounted for the apparent similarities between sites. Our results showed that the communities studied were characterized by few persistent interactions and a large number of transient trophic interactions. We suggest that consumer-resource temporal asynchrony in addition to varying local environmental conditions and opportunistic foraging could be among the mechanisms generating the observed rank-frequency relationship of trophic interactions. Therefore, our results question the analysis of ecological communities as static and persistent natural entities and stress the need for strengthening the analysis of temporal variability in ecological networks and long-term studies.Comment: 21 pages, 3 figure

Evaluating the utility of common-pool resource theory for understanding forest governance and outcomes in Indonesia between 1965 and 2012

While Common Pool Resource (CPR) theory has been widely applied to forestry, there are few examples of using the theory to study large-scale governance. In this paper we test the applicability of CPR theory to understanding forest governance and outcomes in Indonesia between 1965 and 2012. Indonesia contains one of the world’s largest tropical forests, and experienced rapid deforestation during this time frame, with forest cover dropping from close to 85% to less than 50%. Using a mixture of within case comparison and process tracing methods, we identify key variables that influenced the levels of deforestation during two time periods: before 1998, when governance was dominated by the dictatorship of President Suharto, and after 1998, when democratic governance and political decentralization were initiated, and deforestation rates fell and then rose again. Our results point to the value of CPR theory in identifying important variables that influence sustainability at large scales, however they also illustrate important limitations of CPR theory for the study of forests with large spatial extent and large numbers of users. The presence and absence of key variables from CPR theory did emerge as important causes of deforestation. However, some variables, such as strong leadership and local rule-making, appeared to work in the opposite direction as predicted by CPR theory. In addition, key variables that may have influenced deforestation rates are not well captured in CPR theory. These include the intention of the governance system, the presence of clientelistic politics, the influences of international politics and markets, and the influence of top-down governance. Given that CPR theory does not fully explain the case at hand, its applicability, as is, to large-scale commons should be treated with some caution

The pathophysiology of distal renal tubular acidosis

The kidneys have a central role in the control of acid-base homeostasis owing to bicarbonate reabsorption and production of ammonia and ammonium in the proximal tubule and active acid secretion along the collecting duct. Impaired acid excretion by the collecting duct system causes distal renal tubular acidosis (dRTA), which is characterized by the failure to acidify urine below pH 5.5. This defect originates from reduced function of acid-secretory type A intercalated cells. Inherited forms of dRTA are caused by variants in SLC4A1, ATP6V1B1, ATP6V0A4, FOXI1, WDR72 and probably in other genes that are yet to be discovered. Inheritance of dRTA follows autosomal-dominant and -recessive patterns. Acquired forms of dRTA are caused by various types of autoimmune diseases or adverse effects of some drugs. Incomplete dRTA is frequently found in patients with and without kidney stone disease. These patients fail to appropriately acidify their urine when challenged, suggesting that incomplete dRTA may represent an intermediate state in the spectrum of the ability to excrete acids. Unrecognized or insufficiently treated dRTA can cause rickets and failure to thrive in children, osteomalacia in adults, nephrolithiasis and nephrocalcinosis. Electrolyte disorders are also often present and poorly controlled dRTA can increase the risk of developing chronic kidney disease

Integrating the goal and business process perspectives in information system analysis

There are several motivations to promote investment and scientific effort in the integration of intentional and operational perspectives: organisational reengineering, continuous improvement of business processes, alignment among complementary analysis perspectives, information traceability, etc. In this paper we propose the integration of two modelling languages that support the creation of goal and business process models: the i* goal-oriented modelling method and Communication Analysis, a communication-oriented business process modelling method. We describe the methodological integration of the two modelling methods with the aim of fulfilling several criteria: i) to rely on appropriate theories; ii) to provide abstract and concrete syntaxes; iii) to provide scenarios of application; and iv) to develop tool support. We provide guidelines for using the two modelling methods in a top-down analysis scenario. We also present an illustrative case that demonstrates the feasibility of the approach.Peer ReviewedPostprint (author's final draft