492 research outputs found

    Wordle: A Microcosm of Life. Luck, Skill, Cheating, Loyalty, and Influence!

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    Wordle is a popular, online word game offered by the New York Times (nytimes.com). Currently there are some 2 million players of the English version worldwide. Players have 6 attempts to guess the daily word (target word) and after each attempt, the player receives color-coded information about the correctness and position of each letter in the guess. After either a successful completion of the puzzle or the final unsuccessful attempt, software can assess the player's luck and skill using Information Theory and can display data for the first, second, ..., sixth guesses of a random sample of all players. Recently, I discovered that the latter data is presented in a format that can easily be copied and pasted into a spreadsheet. I compiled data on Wordle players' first guesses from May 2023 - August 2023 and inferred some interesting information about Wordle players. A) Every day, about 0.2-0.5% of players solve the puzzle in one attempt. Because the odds of guessing the one of 2,315 possible target words at random is 0.043%, this implies that 4,000 - 10,000 players cheat by obtaining the target word outside of playing the game! B) At least 1/3 of the players have a favorite starting word, or cycle through several. And even though players should be aware that target words are never repeated, most players appear to remain loyal to their starting word even after its appearance as a target word. C) On August 15, 2023, about 30,000 players abruptly changed their starting word, presumably based on a crossword puzzle clue! Wordle players can be influenced! This study goes beyond social media postings, surveys, and Google Trends to provide solid, quantitative evidence about cheating in Wordle

    Are Audience Response Systems Worth the Cost? Comparing Question-Driven Teaching Strategies for Emergency Medical Technician Education

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    Purpose: As Emergency Medical Technician educators develop curricula to meet new national educational standards, effective teaching strategies validated for course content and unique student demographics are warranted. Three methods for answering multiple choice questions presented during lectures were compared: a) Audience Response System (ARS, clickers), b) hand-raising-with-eyes-closed (no-cost option), and c) passive response (no-cost option). The purpose was to determine if using the ARS resulted in improved exam scores. Method: 113 Emergency Medical Technician (EMT) students participated in this cross-over, block randomized, controlled trial, which was incorporated into their Cardiac Emergencies and Pulmonary Emergencies course lectures. Students took pretests, immediate post-tests, and delayed post-tests composed of multiple choice questions that targeted either lower or higher order thinking. Results: For both lectures, there were significant improvements on all immediate post-test scores compared to all pretest scores (p Conclusions: In this cohort, incorporation of no-cost question-driven teaching strategies into lectures was as effective as an ARS at encouraging significant, immediate and sustained improvements in answering multiple choice questions

    Susceptibility of Wild-Caught Lutzomyia longipalpis (Diptera: Psychodidae) Sand Flies to Insecticide After an Extended Period of Exposure in Western São Paulo, Brazil

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    Background In Brazil, members of the sand fly species complex Lutzomyia longipalpis transmit Leishmania infantum, a protist parasite that causes visceral leishmaniasis. Male Lu. longipalpis produce a sex pheromone that is attractive to both females and males. During a cluster randomised trial, to determine the combined effect of synthetic sex-aggregation pheromone and insecticide on Le. infantum transmission Lu. longipalpis had been continuously exposed to insecticide for 30 months. The objective of this study was to determine the effect of continuous exposure to the insecticides used in the trial on the susceptibility of Lu. longipalpis population. Methods During the trial the sand flies had been exposed to either lambda-cyhalothrin [pheromone + residual insecticide spray (PI)], deltamethrin [dog collars (DC)] or no insecticide [control (C)], for 30 months (November 2012 to April 2015). The insecticide treatment regime was kept in place for an additional 12 months (May 2015-April 2016) during this susceptibility study. Sand flies collected from the field were exposed to WHO insecticide-impregnated papers cyhalothrin (0.05%), deltamethrin (0.5%) and control (silicone oil) in a modified WHO insecticide exposure trial to determine their susceptibility. Results We collected 788 Lu. longipalpis using CDC-light traps in 31 municipalities across the three trial arms. Probit analysis showed that the knockdown times (KDTs) of Lu. longipalpis collected from the lambda-cyhalothrin exposed PI-arm [KDT50: 31.1 min, confidence interval (CI): 29.6–32.6 and KDT90: 44.2 min, CI: 42.1–46.7] were longer than the KDTs from the non-insecticide-treated C-arm (KDT50: 26.3 min, CI: 25.1–27.6 and KDT90: 38.2, CI: 36.5–40.2) (no-overlapping 95% CIs). KDTs of Lu. longipalpis collected from the deltamethrin exposed DC-arm had similar values (KDT50: 13.7 min, CI: 10.1–16.2 and KDT90: 26.7 min, CI: 21.8–30.6) to those for the C-arm (KDT50: 13.5 min; CI: 12.2–14.8 and KDT90: 23.2 min, CI: 21.4–25.4) (overlapping CIs). The wild-caught unexposed Lu. longipalpis (C-arm), took approximately twice as long to knock down as laboratory-colonised specimens for both insecticides. Conclusions Our study reveals slight changes in KDT, in sand flies after prolonged exposure to lambda-cyhalothrin in the presence of pheromone. These changes are not considered to have reached the reference levels indicative of resistance in sand flies suggesting that pheromone and insecticide treatment at the level indicated in this study do not constitute a significant risk of increased insecticide resistance. Prolonged exposure to deltamethrin in dog collars did not result in changes to KDT

    Exact solution (by algebraic methods) of the lattice Schwinger model in the strong-coupling regime

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    Using the monomer--dimer representation of the lattice Schwinger model, with Nf=1N_f =1 Wilson fermions in the strong--coupling regime (β=0\beta=0), we evaluate its partition function, ZZ, exactly on finite lattices. By studying the zeroes of Z(k)Z(k) in the complex plane (Re(k),Im(k))(Re(k),Im(k)) for a large number of small lattices, we find the zeroes closest to the real axis for infinite stripes in temporal direction and spatial extent S=2S=2 and 3. We find evidence for the existence of a critical value for the hopping parameter in the thermodynamic limit SS\rightarrow \infty on the real axis at about kc0.39k_c \simeq 0.39. By looking at the behaviour of quantities, such as the chiral condensate, the chiral susceptibility and the third derivative of ZZ with respect to 1/2k1/2k, close to the critical point kck_c, we find some indications for a continuous phase transition.Comment: 22 pages (6 figures

    A temporal comparison of sex-aggregation pheromone gland content and dynamics of release in three members of the Lutzomyia longipalpis (Diptera: Psychodidae) species complex

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    Background: Lutzomyia longipalpis is the South American vector of Leishmania infantum, the etiologic agent of visceral leishmaniasis (VL). Male L. longipalpis produce a sex-aggregation pheromone that is critical in mating, yet very little is known about its accumulation over time or factors involved in release. This laboratory study aimed to compare accumulation of pheromone over time and determine factors that might influence release in three members of the L. longipalpis species complex. Methodology/Principal findings: We investigated male sex-aggregation pheromone gland content at different ages and the release rate of pheromone in the presence or absence of females under different light conditions by gas chromatography-mass spectrometry (GC-MS). Pheromone gland content was determined by extraction of whole males and pheromone release rate was determined by collection of headspace volatiles. Pheromone gland content appeared age-related and pheromone began to accumulate between 6 to 12 h post eclosion and gradually increased until males were 7–9 days old. The greatest amount was detected in 9-day old Campo Grande males ((S)-9-methylgermacrene-B; X ± SE: 203.5 ± 57.4 ng/male) followed by Sobral 2S males (diterpene; 199.9 ± 34.3) and Jacobina males ((1S,3S,7R)-3-methyl-α-himachalene; 128.8 ± 30.3) at 7 days old. Pheromone release was not continuous over time. During a 4-hour period, the greatest quantities of pheromone were released during the first hour, when wing beating activity was most intense. It was then substantially diminished for the remainder of the time. During a 24 h period, 4–5 day old male sand flies released approximately 63 ± 11% of the pheromone content of their glands, depending on the chemotype. The presence of females significantly increased pheromone release rate. The light regime under which the sand flies were held had little influence on pheromone release except on Sobral 2S chemotype. Conclusions/Significance: Accumulation of pheromone appears to occur at different rates in the different chemotypes examined and results in differing amounts being present in glands over time. Release of accumulated pheromone is not passive, but depends on biotic (presence of females) and abiotic (light) circumstances. There are marked differences in content and release between the members of the complex suggesting important behavioural, biosynthetic and ecological differences between them. Author summary: The Dipteran subfamily Phlebotominae includes the genera Lutzomyia and Phlebotomus among which several species are important vectors of parasitic and bacterial pathogens. The sand fly Lutzomyia longipalpis is considered the main vector of visceral leishmaniasis (VL) in the New World. Based on the main component of the male sex-aggregation pheromone gland, different sex pheromone-producing populations (chemotypes) of L. longipalpis are recognized in Brazil. Given the importance of the sex-aggregation pheromones in the biology of this species complex, we present here the first attempt to study how pheromone accumulates in the glands over time and factors that might influence its release in the three most common chemotypes from Brazil. Our results demonstrated that pheromone first starts to accumulate a few hours post-eclosion (6–12 h) and this continues over 15 days. Pheromone release is a dynamic process which varies between the 3 chemotypes depending on biotic factors, such as light regime and presence/absence of conspecific females. This work provides valuable information, critical to our understanding of the behaviour and ecology of L. longipalpis sand flies and which will contribute to investigations to improve field-based pheromone control and monitoring of L. longipalpis sand flies

    Alternative shear reinforcement for reinforced concrete flat slabs

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    This paper presents the first series of validation tests for a patented shear reinforcement system for reinforced concrete flat slabs. The system, called “Shearband,” consists of elongated thin steel strips punched with holes, which undulate into the slab from the top surface. The main advantages of the new reinforcement system are structural effectiveness, flexibility, simplicity, and speed of construction. Four reinforced concrete slabs were tested in a specially designed test rig. The slabs reinforced in shear exhibited ductile behavior after achieving their full flexural potential, thus proving the effectiveness of the new reinforcement. This paper reviews briefly existing types of shear reinforcement and identifies the need for more efficient and economic solutions. Details of the experimental setup and results are given, including strain and deflection measurements as well as photographs of sections through the slabs. Finally, comparisons are made with the ACI 318 and BS8110 code predictions, which confirm that the system enabled the slabs to avoid punching shear failure and achieve their flexural potential. In addition, both codes are shown to lead to conservative estimates of flexural and punching shear capacities of reinforced concrete slabs
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