The Clock Paradox: Luise Lange's Discussion

In her articles on the clock paradox and the relativity of time Luise Lange (1891–1978) defends the theory of relativity against philosophical refutations, by showing that the apparent clock paradox is not a paradox, but merely conflicts with common sense and is based on a misunderstanding of the theory. The following study explores, contextualizes and analyzes Lange’s clear and sophisticated contribution to the debate on the clock paradox for the first time

Fibered spherical 3-orbifolds

In early 1930s Seifert and Threlfall classified up to conjugacy the finite subgroups of $\mathrm{SO}(4)$, this gives an algebraic classification of orientable spherical 3-orbifolds. For the most part, spherical 3-orbifolds are Seifert fibered. The underlying topological space and singular set of non-fibered spherical 3-orbifolds were described by Dunbar. In this paper we deal with the fibered case and in particular we give explicit formulae relating the finite subgroups of $\mathrm{SO}(4)$ with the invariants of the corresponding fibered 3-orbifolds. This allows to deduce directly from the algebraic classification topological properties of spherical 3-orbifolds.Comment: 27 pages, 6 figures. Several misprint corrected, improved expositio

Evaluating Methods of Correcting for Multiple Comparisons Implemented in SPM12 in Social Neuroscience fMRI Studies: An Example from Moral Psychology

In fMRI research, the goal of correcting for multiple comparisons is to identify areas of activity that reflect true effects, and thus would be expected to replicate in future studies. Finding an appropriate balance between trying to minimize false positives (Type I error) while not being too stringent and omitting true effects (Type II error) can be challenging. Furthermore, the advantages and disadvantages of these types of errors may differ for different areas of study. In many areas of social neuroscience that involve complex processes and considerable individual differences, such as the study of moral judgment, effects are typically smaller and statistical power weaker, leading to the suggestion that less stringent corrections that allow for more sensitivity may be beneficial, but also result in more false positives. Using moral judgment fMRI data, we evaluated four commonly used methods for multiple comparison correction implemented in SPM12 by examining which method produced the most precise overlap with results from a meta-analysis of relevant studies and with results from nonparametric permutation analyses. We found that voxel-wise thresholding with family-wise error correction based on Random Field Theory provides a more precise overlap (i.e., without omitting too few regions or encompassing too many additional regions) than either clusterwise thresholding, Bonferroni correction, or false discovery rate correction methods

D1 and D5-brane giant gravitons on AdS3×S3×S3×S1AdS_3 \times S^3 \times S^3 \times S^1

We construct various examples of 1/4-BPS giant gravitons embedded into the type IIB supergravity background $AdS_{3} \times S^{3}_{+} \times S^{3}_{-} \times S^{1}$ with pure R-R flux: two D1-brane giants wrapping 1-cycles in $AdS_{3}$ and $S^{3}_{+} \times S^{3}_{-}$, and one D5-brane giant wrapping a 4-cycle in $S^{3}_{+} \times S^{3}_{-}$ and the $S^{1}$. These D-branes are supported by angular momenta $\alpha$ P on one 3-sphere and $(1-\alpha)$ P on the other. We then construct a general class of 1/8-BPS D5-brane giant gravitons wrapping 4-cycles $\Sigma$ in $S^{3}_{+} \times S^{3}_{-}$ and the $S^{1}$. Here $\Sigma$ is the intersection of a holomorphic surface $\mathcal{C}$ in $\mathbb{C}^{2}_{+} \times \mathbb{C}^{2}_{-}$ with the $S^{3}_{+} \times S^{3}_{-}$ submanifold. The holomorphic surface $\mathcal{C}$ is defined by $f(y_{1}z_{1},y_{1}z_{2},y_{2}z_{1},y_{2}z_{2}) = 0$, with $y_{a}$ and $z_{a}$ the $\mathbb{C}^{2}_{\pm}$ complex coordinates. There is supersymmetry enhancement to 1/4-BPS in the special case $f(y_{1}z_{1}) = 0$ of which our original D5-brane giant graviton is an example.Comment: 30 pages, 4 figures. reference and figure added, minor change

New Zealand emergency nurses knowledge about forensic science and its application to practice

Violence is a major public health problem worldwide. Emergency nurses are often in a unique position to identify, assess, evaluate, and treat these patients, but there is limited forensic knowledge and skills to enable emergency nurses to feel confident to guide their practice in New Zealand. The purpose of this study was to establish the level of forensic knowledge and skills currently known and used by nurses in clinical practice working in New Zealand District Health Boards (DHB)’s emergency departments. The study aimed to develop a tertiary education course based on the needs and the knowledge required, to enable nurses to practice confidently and safely with Forensic patients in the emergency department setting. Methods A descriptive approach using online questionnaires including both quantitative and qualitative components was sent to all emergency departments in New Zealand DHB’s as well as the New Zealand Nurses Organisation (NZNO) emergency nurses’ section. Open-ended questions were analysed by thematic analysis. Closed questions were analysed by SPSS version 15 data analysis software (SPSS Inc, Chicago, IL). Themes identified focused on the knowledge and skills emergency nurses currently possess and the level of specialist education required to ensure patients receive the best medicolegal care. Results Results of the questionnaire revealed limited knowledge in being able to correctly identify all forensic patients, insufficient knowledge around evidence preservation and collection and limited knowledge around legislation or legal processes governing clinical care were discovered. However, 84% of all participants felt that having forensic knowledge was important for their practice, indicating a need for increased forensic education. Practice implications indicate that forensic education is warranted, needed and desired among ED nurses within the clinical setting. Discussion As forensic patients generally require emergency medical attention, it is important that nurses as part of the front-line first responders have forensic knowledge around preservation and collection of evidence during the provision of medical care. It was found that, emergency nurses do not have enough knowledge around forensic issues indicating that forensic education is warranted, needed and desired among ED nurses within the clinical setting. The study also provides support for the implementation of tertiary forensic science nursing postgraduate study in New Zealand

Integrable S matrix, mirror TBA and spectrum for the stringy AdS3×S3×S3×S1\text{AdS}_{3}\times\text{S}^3\times\text{S}^3\times\text{S}^1 WZW model

We compute the tree-level bosonic S matrix in light-cone gauge for superstrings on pure-NSNS $\text{AdS}_{3}\times\text{S}^3\times\text{S}^3\times\text{S}^1$. We show that it is proportional to the identity and that it takes the same form as for $\text{AdS}_{3} \times \text{S}^3\times\text{T}^4$ and for flat space. Based on this, we make a conjecture for the exact worldsheet S matrix and derive the mirror thermodynamic Bethe ansatz (TBA) equations describing the spectrum. Despite a non-trivial vacuum energy, they can be solved in closed form and coincide with a simple set of Bethe ansatz equations - again much like $\text{AdS}_{3}\times\text{S}^3\times\text{T}^4$ and flat space. This suggests that the model may have an integrable spin-chain interpretation. Finally, as a check of our proposal, we compute the spectrum from the worldsheet CFT in the case of highest-weight representations of the underlying Ka\v{c}-Moody algebras, and show that the mirror-TBA prediction matches it on the nose.Comment: 38 pages, Version accepted for publication in JHE