538 research outputs found
Right Hand Fork Pedestrian Bridge Final Report
Right Hand Fork is a tributary canyon whose stream enters the Logan River nine miles east of the mouth of Logan Canyon near Logan, Utah. The access bridge to a popular recreational area, the Hobbit Caves, was damaged in 2011 by flooding. We propose that a new bridge be designed and constructed for the Forest Service to replace the current structure to ensure public safety and minimize environmental impact. We plan to use a longer bridge span that will situate the abutments higher on the stream bank and reduce possible water damage during flood events. Bridge costs will be minimized and will meet required construction and aesthetic standards required by the Forest Service.
The current bridge is a 15-foot timber span placed on existing earth footings. High runoff discharges in 2011 caused the northern earth abutment to shear and settle due to scour. The bridge span now sags at approximately 20°. While still usable, the bridge\u27s structural integrity has been compromised, and the footing will presumably continue to settle until the bridge fails. Figure 1 shows the extent of the damage done to the bridge.
We have completed a topographical survey and hydrological report to determine the best location for the structure to prevent future water damage. We performed structural analysis and design for a safe and cost-effective replacement pedestrian bridge. We independently prepared a steel bridge and a timber bridge design. The preferred alternative for structural materials is a 40-ft timber glulam girder span and Gabion foundations. We propose that construction will begin as early as fall 2015. We also propose biannual inspections beginning once construction is complete to ensure proper maintenance and a 50-year life as required by the Forest Service
Crystallisation of Aspirin via Simulated Pulmonary Surfactant Monolayers and Lung-Specific Additives
Pain is a prevalent condition that can have a serious impact upon the socioeconomic function of a population. Numerous methods exist to administer analgesic medication (e.g. aspirin) to the body however inherent drawbacks limit patient acceptability. The inhaled route offers promise to facilitate the administration of medication to the body. Here, we consider the crystallisation behaviour of aspirin, our model therapeutic agent, when in contact with material of relevance to the lung. Thus, our approach aims to better understand the interaction between drug substances and the respiratory tract. Langmuir monolayers composed of a mixed surfactant system were supported on an aqueous subphase containing aspirin (7.5mg/ml). The surfactant film was compressed to either 5mN/m (i.e. inhalation end point) or 50mN/m (i.e. exhalation end point), whilst located within a humid environment for 16 hours. Standard cooling crystallisation procedures were employed to produce control samples. Antisolvent crystallisation in the presence or absence of lung-specific additives was conducted. All samples were analysed via scanning electron microscopy (SEM) and X-ray diffraction (XRD). Drug-surfactant interactions were confirmed via condensed Langmuir isotherms. SEM analysis revealed plate-like morphology. The crystallisation route dictated both the crystal habit and particle size distribution. Dominant reflections were the (100) and (200) aspects. The main modes of interaction were hydrogen bonding, hydrophobic associations and van der Waals forces. Here, we have demonstrated the potential of antisolvent crystallisation with lung-specific additives to achieve control over drug crystal morphology. The approach taken can be applied in respirable formulation engineering
The temperature in Hawking radiation as tunneling
The quasi-classical method of deriving Hawking radiation under the
consideration of canonical invariance is investigated. We find that the horizon
should be regarded as a two-way barrier and the ingoing amplitude should be
calculated according to the negative energy particles tunneling into the black
hole because of the whole space-time interchange and thus the standard Hawking
temperature is recovered. We also discuss the advantage of the Painlev\'{e}
coordinates in Hawking radiation as tunneling
A comparative study on communication structures of Chinese journals in the social sciences
We argue that the communication structures in the Chinese social sciences
have not yet been sufficiently reformed. Citation patterns among Chinese
domestic journals in three subject areas -- political science and marxism,
library and information science, and economics -- are compared with their
counterparts internationally. Like their colleagues in the natural and life
sciences, Chinese scholars in the social sciences provide fewer references to
journal publications than their international counterparts; like their
international colleagues, social scientists provide fewer references than
natural sciences. The resulting citation networks, therefore, are sparse.
Nevertheless, the citation structures clearly suggest that the Chinese social
sciences are far less specialized in terms of disciplinary delineations than
their international counterparts. Marxism studies are more established than
political science in China. In terms of the impact of the Chinese political
system on academic fields, disciplines closely related to the political system
are less specialized than those weakly related. In the discussion section, we
explore reasons that may cause the current stagnation and provide policy
recommendations
On drug-base incompatibilities during extrudate manufacture and fused deposition 3D printing
Aim: 3D printing can be applied for point-of-care personalized treatment. This study aimed to determine the manufacturability and characteristics of 3D printed, drug loaded implants for alcohol misuse. Materials & methods: Disulfiram was the drug substance used and polylactic acid (PLA) the base material. Implantable devices were designed in silico. Drug and PLA were placed into the extruder to produce a 5% blend at 1.75-mm diameter. Material characterization included differential scanning calorimetry, thermogravimetric analysis plus inverse GC-surface energy analyzer. Results: Implantable constructs from the PLA feedstock were acquired. The extrusion processes had a detrimental effect on the active pharmaceutical ingredient-base blend. differential scanning calorimetry and thermogravimetric analysis analysis indicated drug–base interactions. Thermal history was found to influence inverse GC probe interaction. Conclusion: Drug-base incompatibilities must be considered during 3D printing
Releasing the CRaQAn (Coreference Resolution in Question-Answering): An open-source dataset and dataset creation methodology using instruction-following models
Instruction-following language models demand robust methodologies for
information retrieval to augment instructions for question-answering
applications. A primary challenge is the resolution of coreferences in the
context of chunking strategies for long documents. The critical barrier to
experimentation of handling coreferences is a lack of open source datasets,
specifically in question-answering tasks that require coreference resolution.
In this work we present our Coreference Resolution in Question-Answering
(CRaQAn) dataset, an open-source dataset that caters to the nuanced information
retrieval requirements of coreference resolution in question-answering tasks by
providing over 250 question-answer pairs containing coreferences. To develop
this dataset, we developed a novel approach for creating high-quality datasets
using an instruction-following model (GPT-4) and a Recursive Criticism and
Improvement Loop.Comment: NeurIPS 2023 Workshop on Instruction Tuning and Instruction Followin
ChIP-on-chip significance analysis reveals large-scale binding and regulation by human transcription factor oncogenes
ChIP-on-chip has emerged as a powerful tool to dissect the complex network of regulatory interactions between transcription factors and their targets. However, most ChIP-on-chip analysis methods use conservative approaches aimed to minimize false-positive transcription factor targets. We present a model with improved sensitivity in detecting binding events from ChIP-on-chip data. Biochemically validated analysis in human T-cells reveals that three transcription factor oncogenes, NOTCH1, MYC, and HES1, bind one order of magnitude more promoters than previously thought. Gene expression profiling upon NOTCH1 inhibition shows broad-scale functional regulation across the entire range of predicted target genes, establishing a closer link between occupancy and regulation. Finally, the resolution of a more complete map of transcriptional targets reveals that MYC binds nearly all promoters bound by NOTCH1. Overall, these results suggest an unappreciated complexity of transcriptional regulatory networks and highlight the fundamental importance of genome-scale analysis to represent transcriptional programs
Entropy of Kaluza-Klein Black Hole from Kerr/CFT Correspondence
We extend the recently proposed Kerr/CFT correspondence to examine the dual
conformal field theory of Kaluza-Klein black hole. For the extremal
Kaluza-Klein black hole, the central charge and temperature of the dual
conformal field are calculated, and the microscopic entropy calculated by using
Cardy formula agrees with the Bekenstein-Hawking entropy of extremal
Kaluza-Klein black hole. For the non-extremal case, we investigate the hidden
conformal symmetry of Kaluza-Klein black hole by studying the near-region wave
equation of a neutral massless scalar field, and find the left and right
temperatures of dual conformal field theory. Furthermore, the entropy of
non-extremal Kaluza-Klein black hole is reproduced by using Cardy formula.Comment: 13pages, no figure, published versio
Ultra-High Yield Growth of Vertical Single-Walled Carbon Nanotubes: Hidden Roles of Hydrogen and Oxygen
An oxygen assisted hydrocarbon chemical vapor deposition (CVD) method is
developed to afford large-scale highly reproducible ultra high-yield growth of
vertical single-walled carbon nanotubes (SWNT). It is revealed that reactive
hydrogen (H)-species, inevitable in hydrocarbon-based growth, are damaging to
the formation of sp2-like SWNTs. The addition of oxygen scavenges H-species and
provides a powerful control over the C/H ratio to favor SWNT growth. The
revelation of the roles played by hydrogen and oxygen leads to a unified and
universal optimum growth condition for SWNTs. Further, a versatile method is
developed to form vertical SWNT films on any substrate, lifting a major
substrate-type limitation for aligned SWNTs.Comment: 14 pages of text and 6 figure
Brane-Antibrane Inflation in Orbifold and Orientifold Models
We analyse the cosmological implications of brane-antibrane systems in
string-theoretic orbifold and orientifold models. In a class of realistic
models, consistency conditions require branes and antibranes to be stuck at
different fixed points, and so their mutual attraction generates a potential
for one of the radii of the underlying torus or the 4D string dilaton. Assuming
that all other moduli have been fixed by string effects, we find that this
potential leads naturally to a period of cosmic inflation with the radion or
dilaton field as the inflaton. The slow-roll conditions are satisfied more
generically than if the branes were free to move within the space. The
appearance of tachyon fields at certain points in moduli space indicates the
onset of phase transitions to different non-BPS brane systems, providing ways
of ending inflation and reheating the corresponding observable brane universe.
In each case we find relations between the inflationary parameters and the
string scale to get the correct spectrum of density perturbations. In some
examples the small numbers required as inputs are no smaller than 0.01, and are
the same small quantities which are required to explain the gauge hierarchy.Comment: 30 pages, 2 figures. Substantial changes on version 1. New
cosmological scenarios proposed including the dilaton as the inflaton. Main
conclusions unchange
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