The late Neogene planktonic foraminifera genus Globigerinoidesella: taxonomy, biostratigraphy, evolution and palaeoecology

Planktonic foraminifera have one of the most complete fossil records of any group, and have proved invaluable in the fields of biostratigraphy, palaeoceanography and evolutionary studies. Gradual morphological change characterises their evolution, meaning that species delimitation for biostratigraphic purposes is typically artificial and arbitrary. Delimited taxa in the fossil record are ‘morphospecies’ rather than biological species. The late Neogene morphospecies Globigerinoidesella fistulosa is of considerable biostratigraphic utility because of its short stratigraphic range (mid-Pliocene to early Pleistocene) and unique morphology. It evolved distinctive protuberances on the final chamber(s), but morphospecies delimitation is problematic because of intergradation with its ancestor Trilobatus sacculifer. The fossil record of Globigerinoidesella fistulosa was investigated from multiple ocean basins, with research focused on four main areas: (1) Systematic taxonomy of G. fistulosa and the Trilobatus sacculifer plexus; (2) Biostratigraphy and biochronology of the extinction of G. fistulosa; (3) The role of heterochrony (i.e. changes in the timing and/or rate of development) in the morphological evolution of G. fistulosa; (4) Determination of the palaeoecology of G. fistulosa in relation to its ancestor T. sacculifer, to understand the mode of speciation and the potential palaeoceanographic applications of G. fistulosa. The taxonomic concepts of Globigerinoidesella fistulosa and the Trilobatus sacculifer plexus were revised, resolving numerous taxonomic issues in the group. Protuberance development was found to not only occur in Pliocene-Pleistocene T. sacculifer, but was also observed in Trilobatus immaturus, Trilobatus quadrilobatus and modern T. sacculifer specimens. New ages for the extinction of G. fistulosa and comparison with updated literature ages revealed that the currently used age of 1.88 Ma is only suitable locally and not applicable at other sites worldwide, where the extinction occurred between 1.716 and 1.74 Ma (~150,000 years later). The morphological evolution of G. fistulosa is demonstrated to be an example of the heterochronic process hypermorphosis. Stable isotope analyses (δ13C and δ18O) and palaeobiogeographic data reveal that G. fistulosa was a photosymbiotic, shallow-dwelling morphospecies with a distribution that tracked warm water oceanographic features. Geochemical depth profiles through test walls of G. fistulosa and T. sacculifer generated through laser ablation inductively coupled plasma mass spectrometry show heterogeneous Mg/Ca distribution, including cyclic high and low Mg/Ca banding and low Mg/Ca outer crust

Shrapnel motion

When a bomb explodes, the bomb-casing breaks up causing shrapnel fragments to scatter off with high velocity. Whilst study on penetration of the designated target has been addressed, the mechanics involved in the motion of the shrapnel have not been examined in great detail. This dissertation will address shrapnel motion using ideas from gasdynamics. The motivation for this problem comes from QinetiQ who, among other things, play an active role in modelling violent mechanics

Electronic and Transport Properties of Graphene Nanostructures.

Graphene --- a crystal of carbon atoms in a two-dimensional (2D) honeycomb lattice --- is a gapless semiconductor, and has attracted great interest since it was fabricated in 2004 [1-3]. This monolayer of graphite has been shown to have remarkable properties, such as a linear energy dispersion relation [4] and massless, chiral fermions [5]. This thesis discusses some of these properties, as well as those found in bilayer graphene [6- 8]. Bilayer graphene is the formation of two coupled layers of graphene, exhibiting Bernal stacking (to be discussed later), and features massive chiral fermions [9]. Chapter 1 discusses the tight binding model, and derives the Hamiltonians for monolayer and bilayer graphene, used in subsequent Chapters. We also review important phenomena that account for the results seen in later Chapters. In addition to the material discussed in this Chapter, several excellent review articles have been written that cover other features and phenomena in few-layer graphene systems [10-17]. Chapter 2 is original published work. We extend the low energy effective two-band Hamiltonian for electrons in bilayer graphene (McCann and Fal'ko [7]) to include a spatially dependent electrostatic potential. We find that this Hamiltonian contains additional terms, as compared to the one used earlier in the analysis of electronic transport in n-p junctions in bilayers (Katsnelson et al. [9]). However, for potential steps |it| < 7 i (where 71 is the interlayer coupling), corrections to the transmission probability due to such terms are small. For the angle-dependent transmission T(0) we find T(6) = sin2(2$) --- (2u/3/ji) sin(4$) sin($) which slightly increases the Fano factor: F = 0.241 for u = 40meV. Chapter 3 is original work which was carried out simultaneously with Barbier et al. [18]. Nevertheless, the method of analysis and parameters considered are different, and the results are reached independently. Agreement is found with [19-21]. The work focuses on the introduction of a periodic potential profile in monolayer and bilayer graphene systems, creating extra Dirac points in the energy dispersion for monolayer graphene. Classical catastrophe theory is then employed to describe caustics and cusps in a system with a periodic potential profile, for cusps forming at regular interfaces. The periodicity of the formation of cusps is matched with the periodicity of the superlattice. The energy at which this occurs is then mapped to the energy spectrum found when analysing monolayer graphene with a periodic potential profile. In Chapter 4 we create a model to characterise the angles and commensurability of a few layers of hexagonal lattice materials, seen in STM images in experiments. The model allows for different lattice constants and rotations for each layer, as well as selectively showing lattice sites that are nearly commensurate with sites in other layers. Two popular cases are turbostratic graphene (bilayer graphene where one layer is rotated relative to the other) and graphene on hBN (hexagonal boron nitride). Finally, appendices with complete source code to reproduce these results are given, with examples of their usage

An evaluation of the inflammatory time course response following traditional and blood flow restriction resistance exercise measured by peripheral quantitative computed tomography

Acute muscle swelling following resistance exercise can increase mCSA when assessed by pQCT. This swelling does not reflect muscle hypertrophy, but rather a fluid shift in and around the exercised musculature that may stimulate protein synthesis. This creates a need for determining the inflammatory time course response following a bout of resistance exercise to pinpoint the earliest a pQCT scan can be performed to predict mCSA with minimal error. Furthermore, the degree of muscle swelling following traditional resistance exercise and blood flow restriction resistance exercise has yet to be compared. PURPOSE: The purpose of this investigation was to determine the time course of increased intramuscular fluid following a traditional high-intensity resistance exercise bout and a low-intensity combined with blood flow restriction resistance exercise bout. METHODS: Ten men, aged 18-30 years, completed three experimental conditions in random order separated by at least one week: traditional resistance exercise [TRE], blood flow restriction resistance exercise [BFR], and a non-exercise control [CON]. For TRE subjects completed three sets of 8-10 repetitions on leg press, leg extension, and leg curl machines at an intensity of 75%-80% 1RM with two minutes of rest allowed between sets and exercises. For BFR, subjects wore five cm wide electronically controlled elastic pressure cuffs around their upper thighs during the exercise bout at a restrictive pressure of 160 mmHg. The same three exercises were completed during BFR but at an intensity of 20% 1RM. Subjects completed 30 repetitions for their first set, followed by three sets of 15 thereafter. Rest intervals were set at 30 seconds. For TRE, subjects remained in resting state, seated for approximately 20 minutes. Prior to exercise and 15 minutes, 75 minutes, 24h, 48h, 72h, and 96h after exercise in TRE and BFR protocols, subjects underwent a pQCT scan and thigh circumference measurement. Additionally, blood samples were collected via finger prick prior to, immediately after, and 1h after exercise to assess plasma volume. Muscle thickness of the quadriceps and hamstring were determined prior to exercise and immediately, 30 min, and 1h after exercise via ultrasound. RESULTS: MTQ for BFR was significantly greater immediately post-exercise (p < 0.001) and 30 minutes post-exercise (p = 0.001) when compared to pre-exercise. MTQ for TRE was significantly greater immediately post-exercise (p = 0.010), 30 minutes post-exercise (p = 0.007), and 60 minutes post-exercise (p = 0.019) when compared to pre-exercise. MTQ for BFR was significantly greater than TRE immediately post-exercise (p = 0.016). MTH for BFR was significantly greater immediately post-exercise (p = 0.036) when compared to pre-exercise. PV%Ä significantly decreased from pre- to immediately post-exercise in both BFR (p < 0.001) and TRE (p < 0.001) conditions. In BFR, mCSA was significantly greater at 15 minutes post-exercise (p < 0.001) and 75 minutes post-exercise when compared to pre-exercise mCSA. In TRE, mCSA was significantly greater at 15 minutes post-exercise compared to pre-exercise mCSA. Thigh circumference was significantly greater at 15 minutes post-exercise in BFR (p < 0.001), TRE (p = 0.002), and CON (p = 0.016) compared to their respective pre-exercise thigh circumference values. Additionally, thigh circumference was significantly greater at 75 minutes post-exercise in BFR (p = 0.032) and TRE (p = 0.007) compared to their respective pre-exercise thigh circumference values. CONCLUSION: Muscle swelling returns to pre-exercise levels within 24 hours after completing a moderate to high volume heavy-resistance exercise bout and a low-intensity coupled with blood flow restriction resistance exercise bout

Are Diffusion Models Vision-And-Language Reasoners?

Text-conditioned image generation models have recently shown immense qualitative success using denoising diffusion processes. However, unlike discriminative vision-and-language models, it is a non-trivial task to subject these diffusion-based generative models to automatic fine-grained quantitative evaluation of high-level phenomena such as compositionality. Towards this goal, we perform two innovations. First, we transform diffusion-based models (in our case, Stable Diffusion) for any image-text matching (ITM) task using a novel method called DiffusionITM. Second, we introduce the Generative-Discriminative Evaluation Benchmark (GDBench) benchmark with 7 complex vision-and-language tasks, bias evaluation and detailed analysis. We find that Stable Diffusion + DiffusionITM is competitive on many tasks and outperforms CLIP on compositional tasks like like CLEVR and Winoground. We further boost its compositional performance with a transfer setup by fine-tuning on MS-COCO while retaining generative capabilities. We also measure the stereotypical bias in diffusion models, and find that Stable Diffusion 2.1 is, for the most part, less biased than Stable Diffusion 1.5. Overall, our results point in an exciting direction bringing discriminative and generative model evaluation closer. We will release code and benchmark setup soon.Comment: Accepted to NeurIPS 202

Psychiatrists’ attitudes to professional boundaries concerning spirituality and religion: mixed-methods study

Aims and methodCalls for the integration of spirituality into psychiatric practice have raised concerns about boundary violations. We sought to develop a method to capture psychiatrists’ attitudes to professional boundaries and spirituality, explore consensus and understand what factors are considered. Case vignettes were developed, tested and refined. Three vignettes were presented to 80 mental health professionals (53% said they were psychiatrists; 39% did not identify their professional status). Participants recorded their reactions to the vignettes. Four researchers categorised these as identifying boundary violations or not and analysed the factors considered.ResultsIn 90% of cases, at least three of the four researchers agreed on classification (boundary violation; possible boundary violation; no boundary violation). Participants’ opinion about boundary violations was heterogeneous. There was consensus that psychiatrists should not proselytise in clinical settings. Reasoning emphasised pragmatic concerns. Few participants mentioned their religious beliefs. Equivocation was common.Clinical implicationsMental health professionals seem unsure about professional boundaries concerning religion and spirituality in psychiatric practice

Photo-catalytic carboxylate to sulfinamide switching delivers a divergent synthesis of sulfonamides and sulfonimidamides

Sulfinamides, sulfonamides, and sulfonimidamides are in-demand motifs in medicinal chemistry, yet methods for the synthesis of alkyl variants that start from simple, readily available feedstocks are scarce. In addition, bespoke syntheses of each class of molecules are usually needed. In this report, we detail the synthesis of these three distinct sulfur functional groups, using readily available and structurally diverse alkyl carboxylic acids as the starting materials. The method harnesses alkyl radical generation from carboxylic acids using acridine photocatalysts and 400 nm light with subsequent radical addition to sulfinylamine reagents, delivering sulfinamide products. Using the N-alkoxy sulfinylamine reagent t-BuO-NSO as the radical trap provides common N-alkoxy sulfinamide intermediates, which can be converted in a divergent manner to either sulfonamides or sulfonimidamides, by treatment with sodium hydroxide, or an amine, respectively. The reactions are scalable, tolerate a broad range of functional groups, and can be used for the diversification of complex biologically active compounds