98 research outputs found
Results of Millikan Library Forced Vibration Testing
This report documents an investigation into the dynamic properties of Millikan Library under forced excitation. On July 10, 2002, we performed frequency sweeps from 1 Hz to 9.7 Hz in both the East-West (E-W) and North-South (N-S) directions using a roof level vibration generator. Natural frequencies were identified at 1.14 Hz (E-W fundamental mode), 1.67 Hz (N-S fundamental mode), 2.38 Hz (Torsional fundamental mode), 4.93 Hz (1st E-Wovertone), 6.57 Hz (1st Torsional overtone), 7.22 Hz (1st N-S overtone), and at 7.83 Hz (2nd E-Wovertone). The damping was estimated at 2.28% for the fundamental E-W mode and 2.39% for the N-S fundamental mode. On August 28, 2002, a modal analysis of each natural frequency was performed using the dense instrumentation network located in the building. For both the E-W and N-S fundamental modes, we observe a nearly linear increase in displacement with height, except at the ground floor which appears to act as a hinge. We observed little basement movement for the E-W mode, while in the N-S mode 30% of the roof displacement was due to basement rocking and translation. Both the E-W and N-S fundamental modes are best modeled by the first mode of a theoretical bending beam. The higher modes are more complex and not well represented by a simple structural system
Personality Profiles of Iditasport Ultra-marathon Participants
Each February, competitors convene in Big Lake, Alaska, to participate in the “Iditasport Human Powered Ultra-Marathon”. Who would attempt this challenging race? Personality might be one factor predicting participation. Iditasport represents a unique athletic event with a distinctive social and psychological climate that might be reflected in the personalities of the participants in many ways. This study was designed to identify the personality profile of Iditasport athletes when compared to normative populations and to explore differences between athletes competing in different race divisions
Hyponatremia in a Cold Weather Ultraendurance Race
We assessed the incidence and etiology of hyponatremia in the 100-mile (161 km) Iditasport ultramarathon. Subjects (8 cyclists, 8 runners) were weighed and serum sodium was measured pre- and post-race. Race diets were analyzed to determine fluid and sodium consumption. Subjects were split by post-race serum sodium concentration into hyponatremic and normonatremic groups for statistical analyses. Seven of 16 subjects (44%) were hyponatremic. The hyponatremic group exhibited a significant decrease in serum sodium concentration (137.0 to 132.9 mmol/L, and the normonatremic group experienced a significant decrease in weight (82.1 to 80.2 kg) pre- to post-race. The hypornatremic group drank more friud per hour (0.5 versus 0.4 L/h) and consumed less sodium per hour (235 versus 298 mg/h) compared to the normonatremic group. In conclusion, hyponatremia is common in an ultraendurance race held in the extreme cold, and may be caused by excessive fluid consumption and/or inadequate sodium intake
Bostonia: The Boston University Alumni Magazine. Volume 32
Founded in 1900, Bostonia magazine is Boston University's main alumni publication, which covers alumni and student life, as well as university activities, events, and programs
A life in progress: motion and emotion in the autobiography of Robert M. La Follette
This article is a study of a La Follette’s Autobiography, the autobiography of the leading Wisconsin progressive Robert M. La Follette, which was published serially in 1911 and, in book form, in 1913. Rather than focusing, as have other historians, on which parts of La Follette’s account are accurate and can therefore be trusted, it explains instead why and how this major autobiography was conceived and written. The article shows that the autobiography was the product of a sustained, complex, and often fraught series of collaborations among La Follette’s family, friends, and political allies, and in the process illuminates the importance of affective ties as well as political ambition and commitment in bringing the project to fruition. In the world of progressive reform, it argues, personal and political experiences were inseparable
Parker Solar Probe Observations of High Plasma Beta Solar Wind from Streamer Belt
In general, slow solar wind from the streamer belt forms a high plasma beta
equatorial plasma sheet around the heliospheric current sheet (HCS) crossing,
namely the heliospheric plasma sheet (HPS). Current Parker Solar Probe (PSP)
observations show that the HCS crossings near the Sun could be full or partial
current sheet crossing (PCS), and they share some common features but also have
different properties. In this work, using the PSP observations from encounters
4 to 10, we identify streamer belt solar wind from enhancements in plasma beta,
and we further use electron pitch angle distributions to separate it into HPS
solar wind that around the full HCS crossings and PCS solar wind that in the
vicinity of PCS crossings. Based on our analysis, we find that the PCS solar
wind has different characteristics as compared with HPS solar wind: a) PCS
solar wind could be non-pressure-balanced structures rather than magnetic
holes, and the total pressure enhancement mainly results from the less reduced
magnetic pressure; b) some of the PCS solar wind are mirror unstable; c) PCS
solar wind is dominated by very low helium abundance but varied alpha-proton
differential speed. We suggest the PCS solar wind could originate from coronal
loops deep inside the streamer belt, and it is pristine solar wind that still
actively interacts with ambient solar wind, thus it is valuable for further
investigations on the heating and acceleration of slow solar wind
Status report on emerging photovoltaics
\ua9 2023 Society of Photo-Optical Instrumentation Engineers (SPIE).This report provides a snapshot of emerging photovoltaic (PV) technologies. It consists of concise contributions from experts in a wide range of fields including silicon, thin film, III-V, perovskite, organic, and dye-sensitized PVs. Strategies for exceeding the detailed balance limit and for light managing are presented, followed by a section detailing key applications and commercialization pathways. A section on sustainability then discusses the need for minimization of the environmental footprint in PV manufacturing and recycling. The report concludes with a perspective based on broad survey questions presented to the contributing authors regarding the needs and future evolution of PV
Predicting Positive p53 Cancer Rescue Regions Using Most Informative Positive (MIP) Active Learning
Many protein engineering problems involve finding mutations that produce proteins
with a particular function. Computational active learning is an attractive
approach to discover desired biological activities. Traditional active learning
techniques have been optimized to iteratively improve classifier accuracy, not
to quickly discover biologically significant results. We report here a novel
active learning technique, Most Informative Positive (MIP), which is tailored to
biological problems because it seeks novel and informative positive results. MIP
active learning differs from traditional active learning methods in two ways:
(1) it preferentially seeks Positive (functionally active) examples; and (2) it
may be effectively extended to select gene regions suitable for high throughput
combinatorial mutagenesis. We applied MIP to discover mutations in the tumor
suppressor protein p53 that reactivate mutated p53 found in human cancers. This
is an important biomedical goal because p53 mutants have been
implicated in half of all human cancers, and restoring active p53 in tumors
leads to tumor regression. MIP found Positive (cancer rescue) p53 mutants
in silico using 33% fewer experiments than
traditional non-MIP active learning, with only a minor decrease in classifier
accuracy. Applying MIP to in vivo experimentation yielded
immediate Positive results. Ten different p53 mutations found in human cancers
were paired in silico with all possible single amino acid
rescue mutations, from which MIP was used to select a Positive Region predicted
to be enriched for p53 cancer rescue mutants. In vivo assays
showed that the predicted Positive Region: (1) had significantly more
(p<0.01) new strong cancer rescue mutants than control regions (Negative,
and non-MIP active learning); (2) had slightly more new strong cancer rescue
mutants than an Expert region selected for purely biological considerations; and
(3) rescued for the first time the previously unrescuable p53 cancer mutant
P152L
Structural analyses of 2015-updated drug-resistant mutations in HIV-1 protease: an implication of protease inhibitor cross-resistance
Roadmap on Photovoltaic Absorber Materials for Sustainable Energy Conversion
Photovoltaics (PVs) are a critical technology for curbing growing levels of
anthropogenic greenhouse gas emissions, and meeting increases in future demand
for low-carbon electricity. In order to fulfil ambitions for net-zero carbon
dioxide equivalent (CO2eq) emissions worldwide, the global
cumulative capacity of solar PVs must increase by an order of magnitude from
0.9 TWp in 2021 to 8.5 TWp by 2050 according to the International Renewable
Energy Agency, which is considered to be a highly conservative estimate. In
2020, the Henry Royce Institute brought together the UK PV community to discuss
the critical technological and infrastructure challenges that need to be
overcome to address the vast challenges in accelerating PV deployment. Herein,
we examine the key developments in the global community, especially the
progress made in the field since this earlier roadmap, bringing together
experts primarily from the UK across the breadth of the photovoltaics
community. The focus is both on the challenges in improving the efficiency,
stability and levelized cost of electricity of current technologies for
utility-scale PVs, as well as the fundamental questions in novel technologies
that can have a significant impact on emerging markets, such as indoor PVs,
space PVs, and agrivoltaics. We discuss challenges in advanced metrology and
computational tools, as well as the growing synergies between PVs and solar
fuels, and offer a perspective on the environmental sustainability of the PV
industry. Through this roadmap, we emphasize promising pathways forward in both
the short- and long-term, and for communities working on technologies across a
range of maturity levels to learn from each other.Comment: 160 pages, 21 figure
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