517 research outputs found
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Gastric Outlet Obstruction Due to Malposition of Replacement Gastrostomy Tube
A 78-year old male presented to the emergency department after accidental dislodgement of his chronic gastrostomy tube. A replacement gastrostomy tube was passed easily through the existing stoma and flushed without difficulty. Confirmatory abdominal radiography demonstrated contrast in the proximal small bowel, but the patient subsequently developed epigastric pain and refractory vomiting. Computed tomography revealed the tip of the gastrostomy tube terminating in the pylorus or proximal duodenum. This case highlights gastric outlet obstruction complicating the replacement of a gastrostomy tube and the associated radiographic findings
Optical Measurements On The BP III To Isotropic Phase Transition In Highly Chiral Liquid Crystals
Optical activity and light scattering measurements in the chiral-racemic system of 4-(2-methylbutyl) phenyl-4-hexyloxybenzoate (CE4) reveal a much larger decrease in the discontinuity at the third blue phase (BP III) to isotropic phase transition than reported previously using adiabatic scanning calorimetry on another compound. Whereas these new data show that the transition is still slightly discontinuous for the pure optical isomer of CE4, similar light scattering measurements on the pure optical isomer of 4″-(2- methylbutylphenyl)-4′-(2-methylbutyl)-4-biphenyl-carboxylate (CE2), which is more chiral than CE4, show no discontinuity at all
Prompt Problems: A New Programming Exercise for the Generative AI Era
Large Language Models (LLMs) are revolutionizing the field of computing
education with their powerful code-generating capabilities. Traditional
pedagogical practices have focused on code writing tasks, but there is now a
shift in importance towards code reading, comprehension and evaluation of
LLM-generated code. Alongside this shift, an important new skill is emerging --
the ability to solve programming tasks by constructing good prompts for
code-generating models. In this work we introduce a new type of programming
exercise to hone this nascent skill: 'Prompt Problems'. Prompt Problems are
designed to help students learn how to write effective prompts for AI code
generators. A student solves a Prompt Problem by crafting a natural language
prompt which, when provided as input to an LLM, outputs code that successfully
solves a specified programming task. We also present a new web-based tool
called Promptly which hosts a repository of Prompt Problems and supports the
automated evaluation of prompt-generated code. We deploy Promptly for the first
time in one CS1 and one CS2 course and describe our experiences, which include
student perceptions of this new type of activity and their interactions with
the tool. We find that students are enthusiastic about Prompt Problems, and
appreciate how the problems engage their computational thinking skills and
expose them to new programming constructs. We discuss ideas for the future
development of new variations of Prompt Problems, and the need to carefully
study their integration into classroom practice.Comment: Accepted to SIGCSE'24. arXiv admin note: substantial text overlap
with arXiv:2307.1636
Kahler Stabilized, Modular Invariant Heterotic String Models
We review the theory and phenomenology of effective supergravity theories
based on orbifold compactifications of the weakly-coupled heterotic string. In
particular, we consider theories in which the four-dimensional theory displays
target space modular invariance and where the dilatonic mode undergoes Kahler
stabilization. A self-contained exposition of effective Lagrangian approaches
to gaugino condensation and heterotic string theory is presented, leading to
the development of the models of Binetruy, Gaillard and Wu. Various aspects of
the phenomenology of this class of models are considered. These include issues
of supersymmetry breaking and superpartner spectra, the role of anomalous U(1)
factors, issues of flavor and R-parity conservation, collider signatures, axion
physics, and early universe cosmology. For the vast majority of
phenomenological considerations the theories reviewed here compare quite
favorably to other string-derived models in the literature. Theoretical
objections to the framework and directions for further research are identified
and discussed.Comment: Invited review article for International Journal of Modern Physic
"It's Weird That it Knows What I Want": Usability and Interactions with Copilot for Novice Programmers
Recent developments in deep learning have resulted in code-generation models
that produce source code from natural language and code-based prompts with high
accuracy. This is likely to have profound effects in the classroom, where
novices learning to code can now use free tools to automatically suggest
solutions to programming exercises and assignments. However, little is
currently known about how novices interact with these tools in practice. We
present the first study that observes students at the introductory level using
one such code auto-generating tool, Github Copilot, on a typical introductory
programming (CS1) assignment. Through observations and interviews we explore
student perceptions of the benefits and pitfalls of this technology for
learning, present new observed interaction patterns, and discuss cognitive and
metacognitive difficulties faced by students. We consider design implications
of these findings, specifically in terms of how tools like Copilot can better
support and scaffold the novice programming experience.Comment: 26 pages, 2 figures, TOCH
α-Amino-β-sulphone hydroxamates as potent MMP-13 inhibitors that spare MMP-1
A series of α-amino-β-sulphone hydroxamates was prepared and evaluated for potency versus MMP-13 and selectivity versus MMP-1. Various substituents were employed on the α-amino group (P1 position), as well as different groups attached to the sulphone group extending into P1′. Low nanomolar potency was obtained for MMP-13 with selectivity versus MMP-1 of \u3e1000× for a number of analogues.
α-Amino-β-sulphone hydroxamates were prepared, which are potent MMP-13 inhibitors with selectivity versus MMP-1 of \u3e1000× for a number of analogues. Selected compounds exhibited oral bioavailability
Candidate Screening of the TRPC3 Gene in Cerebellar Ataxia
The hereditary cerebellar ataxias are a diverse group of neurodegenerative disorders primarily characterised by loss of balance and coordination due to dysfunction of the cerebellum and its associated pathways. Although many genetic mutations causing inherited cerebellar ataxia have been identified, a significant percentage of patients remain whose cause is unknown. The transient receptor potential (TRP) family member TRPC3 is a non-selective cation channel linked to key signalling pathways that are affected in cerebellar ataxia. Furthermore, genetic mouse models of TRPC3 dysfunction display cerebellar ataxia, making the TRPC3 gene an excellent candidate for screening ataxic patients with unknown genetic aetiology. Here, we report a genetic screen for TRPC3 mutations in a cohort of 98 patients with genetically undefined late-onset cerebellar ataxia and further ten patients with undefined episodic ataxia. We identified a number of variants but no causative mutations in TRPC3. Our findings suggest that mutations in TRPC3 do not significantly contribute to the cause of late-onset and episodic human cerebellar ataxias
Multi-wavelength diagnostic properties of Galactic Planetary Nebulae detected by GLIMPSE-I
We uniformly analyze 136 optically detected PNe and candidates from the
GLIMPSE-I survey in order to to develop robust, multi-wavelength,
classification criteria to augment existing diagnostics and provide pure PN
samples. PNe represent powerful astrophysical probes. They are important
dynamical tracers, key sources of ISM chemical enrichment, windows into late
stellar evolution, and potent cosmological yardsticks. But their utility
depends on separating them unequivocally from the many nebular mimics which can
strongly resemble bona fide PNe in traditional optical images and spectra. We
merge new PNe from the carefully evaluated, homogeneous MASH-I and MASH-II
surveys, which offer a wider evolutionary range of PNe than hitherto available,
with previously known PNe classified by SIMBAD. Mid-infrared (MIR) measurements
vitally complement optical data because they reveal other physical processes
and morphologies via fine-structure lines, molecular bands and dust. MIR
colour-colour planes, optical emission line ratios and radio fluxes show the
unambiguous classification of PNe to be complex, requiring all available
evidence. Statistical trends provide predictive value and we offer quantitative
MIR criteria to determine whether an emission nebula is most likely to be a PN
or one of the frequent contaminants such as compact HII regions or symbiotic
systems. Prerequisites have been optical images and spectra but MIR morphology,
colours, environment and a candidate's MIR/radio flux ratio provide a more
rigorous classification. Our ultimate goal is to recognize PNe using only MIR
and radio characteristics, enabling us to trawl for PNe effectively even in
heavily obscured regions of the Galaxy.Comment: 32 pages, 18 figures, 10 table
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