Exact Tests for Two-Way Contingency Tables with Structural Zeros

Fisher's exact test, named for Sir Ronald Aylmer Fisher, tests contingency tables for homogeneity of proportion. This paper discusses a generalization of Fisher's exact test for the case where some of the table entries are constrained to be zero. The resulting test is useful for assessing cases where the null hypothesis of conditional multinomial distribution is suspected to be false. The test is implemented in the form of a new R package, aylmer.

Growth-induced mass flows in fungal networks

Cord-forming fungi form extensive networks that continuously adapt to maintain an efficient transport system. As osmotically driven water uptake is often distal from the tips, and aqueous fluids are incompressible, we propose that growth induces mass flows across the mycelium, whether or not there are intrahyphal concentration gradients. We imaged the temporal evolution of networks formed by Phanerochaete velutina, and at each stage calculated the unique set of currents that account for the observed changes in cord volume, while minimising the work required to overcome viscous drag. Predicted speeds were in reasonable agreement with experimental data, and the pressure gradients needed to produce these flows are small. Furthermore, cords that were predicted to carry fast-moving or large currents were significantly more likely to increase in size than cords with slow-moving or small currents. The incompressibility of the fluids within fungi means there is a rapid global response to local fluid movements. Hence velocity of fluid flow is a local signal that conveys quasi-global information about the role of a cord within the mycelium. We suggest that fluid incompressibility and the coupling of growth and mass flow are critical physical features that enable the development of efficient, adaptive, biological transport networks.Comment: To be published in PRSB. 20 pages, plus 8 pages of supplementary information, and 3 page bibliograph

Magnetic Ground State of Pr0.89_{0.89}LaCe0.11_{0.11}CuO4+α−δ_{4+\alpha-\delta} with Varied Oxygen Depletion Probed by Muon Spin Relaxation

The magnetic ground state of an electron-doped cuprate superconductor Pr$_{1-x}$LaCe$_x$CuO$_{4+\alpha-\delta}$ ($x=0.11, \alpha\simeq0.04$) has been studied by means of muon spin rotation/relaxation (\msr) over a wide variety of oxygen depletion, $0.03\le\delta\le0.12$. Appearance of weak random magnetism over entire crystal volume has been revealed by a slow exponential relaxation. The absence of $\delta$-dependence for the random magnetism and the multiplet pattern of muon Knight shift at higher fields strongly suggest that the random moments are associated with excited Pr$^{3+}$ ions under crystal electric field.Comment: 6 pages, 4 figures, submitted to J. Phys. Soc. Jp

Exact Tests for Two-Way Contingency Tables with Structural Zeros

Fisher's exact test, named for Sir Ronald Aylmer Fisher, tests contingency tables for homogeneity of proportion. This paper discusses a generalization of Fisher's exact test for the case where some of the table entries are constrained to be zero. The resulting test is useful for assessing cases where the null hypothesis of conditional multinomial distribution is suspected to be false. The test is implemented in the form of a new R package, aylmer

Evaluation of a Flipped Classroom in Mechanics of Materials

Recent interest towards the implementation of flipped (or inverted) classroom models parallelsthe wide availability of technology and the shift from lecture-based teaching methods towardsstudent-centered teaching methods in undergraduate engineering education. The flippedclassroom involves two components, computer-based video instruction outside of the classroomand interactive learning activities inside the classroom. The intent is to create an active andengaging classroom experience that can be tailored to meet the needs of students possessing awide range of learning styles. This can potentially reduce attrition, improve knowledge retention,and enhance skill development in engineering.The goals of this study are to compare and contrast the effectiveness of a flipped classroom and atraditional lecture-based classroom in a first course in mechanics of materials. Two 5-weeksummer session courses in mechanics of materials were used to perform the study. The firstcourse was taught in a traditional lecture-based format where, during face-to-face meetings, newconcepts were introduced during the lecture, example problems were performed by the instructorand in groups by students; outside of class students solved problems as part of homeworkassignments. The second course was taught using a flipped classroom approach where face-to-face sessions were used for active learning techniques involving group discussions, problemsolving sessions, and demonstrations. Outside of class students were required to watchscreencast tutorials on YouTube and answer concept questions as well as complete additionalhomework problems.Assessment on the effectiveness of the flipped classroom is based on performance of pre andpost quiz scores, student survey feedback, and instructor observations. Students in the flippedclassroom (test group) performed better on pre quiz scores (mean of 0.12 versus 0.03) and postquiz scores (mean of 0.58 versus 0.38) as compared to the traditional classroom (control group).Quizzes were scored 0 or 1 without partial credit, where a score of 1 indicated a correctnumerical answer and correct units. Controlling for prior academic achievement and initiallevels of content-specific achievement, a multiple linear regression analysis shows that 8% of thevariability in post quiz scores may be attributed to the instructional delivery approach. Theresults indicate that there is evidence to suggest that participation in the flipped classroom resultsin better performance than participation in the traditional lecture-based classroom

Psychological response to disaster: implications for Hawaii.

Given the frequency of natural disasters in Hawaii, it is important for practitioners to be aware of the numerous resulting psychological responses and risk factors, especially those unique to Hawaii. Practical guidelines are presented for practitioners, both in providing leadership during the disaster and in screening for psychopathology thereafter

Fragments of ML Decidable by Nested Data Class Memory Automata

The call-by-value language RML may be viewed as a canonical restriction of Standard ML to ground-type references, augmented by a "bad variable" construct in the sense of Reynolds. We consider the fragment of (finitary) RML terms of order at most 1 with free variables of order at most 2, and identify two subfragments of this for which we show observational equivalence to be decidable. The first subfragment consists of those terms in which the P-pointers in the game semantic representation are determined by the underlying sequence of moves. The second subfragment consists of terms in which the O-pointers of moves corresponding to free variables in the game semantic representation are determined by the underlying moves. These results are shown using a reduction to a form of automata over data words in which the data values have a tree-structure, reflecting the tree-structure of the threads in the game semantic plays. In addition we show that observational equivalence is undecidable at every third- or higher-order type, every second-order type which takes at least two first-order arguments, and every second-order type (of arity greater than one) that has a first-order argument which is not the final argument

Intimate partner violence exposure predicts antisocial behavior via pro‐violence attitudes among males with elevated levels of cortisol

The present study tested whether attitudes toward violence mediate the association between intimate partner violence exposure and antisocial behavior across adolescence, and whether cortisol level moderates these pathways in an ethnically diverse sample of 190 boys from low‐income, urban families. Results suggest that a pathway from intimate partner violence exposure at age 12 to antisocial behavior at age 17 is explained by pro‐violence attitudes at age 15. Boys with greater exposure to intimate partner violence endorsed stronger pro‐violence attitudes, which predicted increases in antisocial behavior. Further, the pro‐violence attitudes to antisocial behavior pathway were stronger among boys with heightened versus dampened cortisol levels. Results suggest that violent attitudes are important for understanding the cognitive underpinnings of antisocial behavior following intimate partner violence exposure, particularly in youth with high cortisol levels. Implications for prevention and intervention are discussed with respect to targeting malleable child behavior linked to later antisocial behavior.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/146367/1/sode12313.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/146367/2/sode12313_am.pd