67 research outputs found
Self-Alignment with Instruction Backtranslation
We present a scalable method to build a high quality instruction following
language model by automatically labelling human-written text with corresponding
instructions. Our approach, named instruction backtranslation, starts with a
language model finetuned on a small amount of seed data, and a given web
corpus. The seed model is used to construct training examples by generating
instruction prompts for web documents (self-augmentation), and then selecting
high quality examples from among these candidates (self-curation). This data is
then used to finetune a stronger model. Finetuning LLaMa on two iterations of
our approach yields a model that outperforms all other LLaMa-based models on
the Alpaca leaderboard not relying on distillation data, demonstrating highly
effective self-alignment
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Comparison of Surface Texture from Various Surface Morphology Techniques for Evaluating As-Built Ti6Al4V Laser Powder Bed Fusion
Additive manufacturing (AM) is capable of creating unique and complex geometries that
conventional methods cannot achieve. The applications for AM have been rapidly increasing
across a variety of sectors, particularly for biomedical and aerospace components, the relatively
low production volumes and high demand for customizability in both sectors are especially
amiable to AM. However, without post-processing, AM components contain a variety of flaws,
such as surface roughness and porosity, that can partially be mitigated by process parameters like
scan speed and laser power. Surface roughness is a flaw present for every as-built AM surface
that serves as an array of sites for every mode of material failure to occur. Common surface
roughness measurements involve the use of optical and contact stylus profilometry. However, xray Computed Tomography (xCT) is already the most widely used method of analyzing AM
parts for porosity, inclusions, and various other flaws. In terms of resolution, xCT should be fully
capable of analyzing surface roughness and is the only method of the three investigated that can
inspect interior geometries. Therefore, evaluating xCT as a fully inclusive analysis method for
AM parts is advantageous. In this study, we compared three surface characterization
technologies, xCT, optical profilometry, and contact stylus profilometry. The comparison of
these technologies is being done on as-built Laser Powder Bed Fusion (L-BPF) Ti6AI4V fourpoint bending fatigue samples. Further understanding the difference among each of the
technologies will aid ongoing research on developing a standard for xCT surface characterization
while also providing more knowledge and insight into each technique and what can be expected.
Each of the samples was produced by varying scanning speed and laser power, resulting in
different surface textures. Preliminary results show deviations of Sa _%, Sz _%, Sv _%, and Sku
_% between the xCT and optical microscopy methods are comparable between these two
methods.Mechanical Engineerin
A Prospective Program to Reduce the Clinical Incidence of Clostridium Difficile Colitis Infection after Cystectomy
Purpose
The development of Clostridium difficile infection after cystectomy is associated with significant morbidity and mortality. We implemented a prospective screening program to identify asymptomatic carriers of Clostridium difficile and assessed its impact on clinical Clostridium difficile infection rates compared to historical matched controls.
Materials and Methods
Prospective Clostridium Difficile screening prior to cystectomy began in March 2015. The 380 consecutive patients undergoing cystectomy prior to initiation of screening (control cohort) were matched based on 5 clinical factors with the 386 patients who underwent cystectomy from March 2015 to December 2017 (trial cohort). Screened positive patients were placed in contact isolation and treated prophylactically with Metronidazole. Multivariable models were built on an intention-to-screen and an effectiveness of screening basis to determine if screening reduced the rates of symptomatic Clostridium Difficile infections postoperatively.
Results
With the implementation of the screening protocol, Clostridium difficile infections rates declined from 9.4 to 5.5% (OR 0.52, p=0.0268) on an intention-to-screen protocol and from 9.2 to 4.9% on an effectiveness of screening protocol (OR 0.46, p=0.0174).
Conclusions
Clostridium difficile screening prior to cystectomy is associated with a significant decrease in rates of clinically symptomatic infections postoperatively. These results should be confirmed in a randomized controlled trial
The Primordial Inflation Polarization Explorer (PIPER)
The Primordial Inflation Polarization Explorer (PIPER) is a balloon-borne
cosmic microwave background (CMB) polarimeter designed to search for evidence
of inflation by measuring the large-angular scale CMB polarization signal.
BICEP2 recently reported a detection of B-mode power corresponding to the
tensor-to-scalar ratio r = 0.2 on ~2 degree scales. If the BICEP2 signal is
caused by inflationary gravitational waves (IGWs), then there should be a
corresponding increase in B-mode power on angular scales larger than 18
degrees. PIPER is currently the only suborbital instrument capable of fully
testing and extending the BICEP2 results by measuring the B-mode power spectrum
on angular scales = ~0.6 deg to 90 deg, covering both the reionization
bump and recombination peak, with sensitivity to measure the tensor-to-scalar
ratio down to r = 0.007, and four frequency bands to distinguish foregrounds.
PIPER will accomplish this by mapping 85% of the sky in four frequency bands
(200, 270, 350, 600 GHz) over a series of 8 conventional balloon flights from
the northern and southern hemispheres. The instrument has background-limited
sensitivity provided by fully cryogenic (1.5 K) optics focusing the sky signal
onto four 32x40-pixel arrays of time-domain multiplexed Transition-Edge Sensor
(TES) bolometers held at 140 mK. Polarization sensitivity and systematic
control are provided by front-end Variable-delay Polarization Modulators
(VPMs), which rapidly modulate only the polarized sky signal at 3 Hz and allow
PIPER to instantaneously measure the full Stokes vector (I, Q, U, V) for each
pointing. We describe the PIPER instrument and progress towards its first
flight.Comment: 11 pages, 7 figures. To be published in Proceedings of SPIE Volume
9153. Presented at SPIE Astronomical Telescopes + Instrumentation 2014,
conference 915
High fidelity: extra-pair fertilisations in eight Charadrius plover species are not associated with parental relatedness or social mating system
Extra-pair paternity is a common reproductive strategy in many bird species. However, it remains unclear why extra-pair paternity occurs and why it varies among species and populations. Plovers (Charadrius spp.) exhibit considerable variation in reproductive behaviour and ecology, making them excellent models to investigate the evolution of social and genetic mating systems. We investigated inter- and intra-specific patterns of extra-pair parentage and evaluated three major hypotheses explaining extra-pair paternity using a comparative approach based on the microsatellite genotypes of 2049 individuals from 510 plover families sampled from twelve populations that constituted eight species. Extra-pair paternity rates were very low (0 to 4.1% of chicks per population). No evidence was found in support of the sexual conflict or genetic compatibility hypotheses, and there was no seasonal pattern of extra-pair paternity (EPP). The low prevalence of EPP is consistent with a number of alternative hypotheses, including the parental investment hypothesis, which suggests that high contribution to care by males restricts female plovers from engaging in extra-pair copulations. Further studies are needed to critically test the importance of this hypothesis for mate choice in plovers
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A review of high impact weather for aviation meteorology
This review paper summarizes current knowledge available for aviation operations related to meteorology and provides suggestions for necessary improvements in the measurement and prediction of weather-related parameters, new physical methods for numerical weather predictions (NWP), and next-generation integrated systems. Severe weather can disrupt aviation operations on the ground or in-flight. The most important parameters related to aviation meteorology are wind and turbulence, fog visibility, aerosol/ash loading, ceiling, rain and snow amount and rates, icing, ice microphysical parameters, convection and precipitation intensity, microbursts, hail, and lightning. Measurements of these parameters are functions of sensor response times and measurement thresholds in extreme weather conditions. In addition to these, airport environments can also play an important role leading to intensification of extreme weather conditions or high impact weather events, e.g., anthropogenic ice fog. To observe meteorological parameters, new remote sensing platforms, namely wind LIDAR, sodars, radars, and geostationary satellites, and in situ instruments at the surface and in the atmosphere, as well as aircraft and Unmanned Aerial Vehicles mounted sensors, are becoming more common. At smaller time and space scales (e.g., < 1 km), meteorological forecasts from NWP models need to be continuously improved for accurate physical parameterizations. Aviation weather forecasts also need to be developed to provide detailed information that represents both deterministic and statistical approaches. In this review, we present available resources and issues for aviation meteorology and evaluate them for required improvements related to measurements, nowcasting, forecasting, and climate change, and emphasize future challenges
Electronic spectra of positively charged carbon clusters - C2n+ (n=6-14)
Electronic spectra are measured for mass-selected C+2( = 6–14) clusters over the visible and near-infrared spectral range through resonance enhanced photodissociation of clusters tagged with N2 molecules in a cryogenic ion trap. The carbon cluster cations are generated through laser ablation of a graphite disk and can be selected according to their collision cross section with He buffer gas and their mass prior to being trapped and spectroscopically probed. The data suggest that the C+2( = 6–14) clusters have monocyclic structures with bicyclic structures becoming more prevalent for C+22 and larger clusters. The C+2 electronic spectra are dominated by an origin transition that shifts linearly to a longer wavelength with the number of carbon atoms and associated progressions involving excitation of ring deformation vibrational modes. Bands for C+12, C+16, C+20, C+24, and C+28 are relatively broad, possibly due to rapid non-radiative decay from the excited state, whereas bands for C+14, C+18, C+22, and C+26 are narrower, consistent with slower non-radiative deactivation
Why Has Personality Psychology Played an Outsized Role in the Credibility Revolution?
21 pages. Published at PsychOpen: 10.5964/ps.6001Personality is not the most popular subfield of psychology. But, in one way or another, personality psychologists have played an outsized role in the ongoing “credibility revolution” in psychology. Not only have individual personality psychologists taken on visible roles in the movement, but our field’s practices and norms have now become models for other fields to emulate (or, for those who share Baumeister’s (2016, https://doi.org/10.1016/j.jesp.2016.02.003) skeptical view of the consequences of increasing rigor, a model for what to avoid). In this article we discuss some unique features of our field that may have placed us in an ideal position to be leaders in this movement. We do so from a subjective perspective, describing our impressions and opinions about possible explanations for personality psychology’s disproportionate role in the credibility revolution. We also discuss some ways in which personality psychology remains less-than-optimal, and how we can address these flaws
Expanding the diversity of mycobacteriophages: insights into genome architecture and evolution.
Mycobacteriophages are viruses that infect mycobacterial hosts such as Mycobacterium smegmatis and Mycobacterium tuberculosis. All mycobacteriophages characterized to date are dsDNA tailed phages, and have either siphoviral or myoviral morphotypes. However, their genetic diversity is considerable, and although sixty-two genomes have been sequenced and comparatively analyzed, these likely represent only a small portion of the diversity of the mycobacteriophage population at large. Here we report the isolation, sequencing and comparative genomic analysis of 18 new mycobacteriophages isolated from geographically distinct locations within the United States. Although no clear correlation between location and genome type can be discerned, these genomes expand our knowledge of mycobacteriophage diversity and enhance our understanding of the roles of mobile elements in viral evolution. Expansion of the number of mycobacteriophages grouped within Cluster A provides insights into the basis of immune specificity in these temperate phages, and we also describe a novel example of apparent immunity theft. The isolation and genomic analysis of bacteriophages by freshman college students provides an example of an authentic research experience for novice scientists
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