2,848 research outputs found
Strengthening the Nantucket Cultural District: Outreach and Data Collection
The Nantucket Cultural District (NCD) was officially designated in January 2016 with the goal to centralize, expand, and promote the island’s culture. This project’s goals were to assist the NCD by developing a community outreach plan and by creating a system to collect and evaluate metrics to measure the impacts of the district. To realize the first goal, we developed a website to centralize social and district media. To achieve our second goal, we utilized Google Forms and Google Sheets to develop a data collection and analysis tool. Finally, we made recommendations to the NCD to expand district membership, broaden web presence, increase metric tracking, and adopt a new sustainable financial model
Furfuryl Alcohol Emulsion Resins as Co-Binders for Urea-Formaldehyde Resin-Bonded Particleboards
An approach to using water-insoluble furfuryl alcohol (FA) resins as a co-binder for particleboard (PB) urea-formaldehyde (UF) resins was evaluated. Sprayable FA/UF mixed resins were made by emulsifying FA resins of varying advancements and mixing with various formaldehyde to urea (F/U) ratio UF resins in various proportions. The binder performance of the mixed FA/UF resins was then evaluated by bonding laboratory PBs using a weakly acidic ordinary UF resin curing catalyst at various hot pressing temperatures. The PBs were also heat-treated and were aged for two years at room temperature. The test results of bond strengths and formaldehyde emission levels of PBs showed promising improvements at about 30% FA resin additions, although the results were preliminary due to the variable performance nature of such binder systems
Spatial Patterns and Sequential Sampling Plans for Estimating Densities of Stink Bugs (Hemiptera: Pentatomidae) in Soybean in the North Central Region of the United States
Stink bugs are an emerging threat to soybean (Fabales: Fabaceae) in the North Central Region of the United States. Consequently, region-specific scouting recommendations for stink bugs are needed. The aim of this study was to characterize the spatial pattern and to develop sampling plans to estimate stink bug population density in soybean fields. In 2016 and 2017, 125 fields distributed across nine states were sampled using sweep nets. Regression analyses were used to determine the effects of stink bug species [Chinavia hilaris (Say) (Hemiptera: Pentatomidae) and Euschistus spp. (Hemiptera: Pentatomidae)], life stages (nymphs and adults), and field locations (edge and interior) on spatial pattern as represented by variance–mean relationships. Results showed that stink bugs were aggregated. Sequential sampling plans were developed for each combination of species, life stage, and location and for all the data combined. Results for required sample size showed that an average of 40–42 sample units (sets of 25 sweeps) would be necessary to achieve a precision of 0.25 for stink bug densities commonly encountered across the region. However, based on the observed geographic gradient of stink bug densities, more practical sample sizes (5–10 sample units) may be sufficient in states in the southeastern part of the region, whereas impractical sample sizes (\u3e100 sample units) may be required in the northwestern part of the region. Our findings provide research-based sampling recommendations for estimating densities of these emerging pests in soybean
Quantum Holographic Encoding in a Two-dimensional Electron Gas
The advent of bottom-up atomic manipulation heralded a new horizon for
attainable information density, as it allowed a bit of information to be
represented by a single atom. The discrete spacing between atoms in condensed
matter has thus set a rigid limit on the maximum possible information density.
While modern technologies are still far from this scale, all theoretical
downscaling of devices terminates at this spatial limit. Here, however, we
break this barrier with electronic quantum encoding scaled to subatomic
densities. We use atomic manipulation to first construct open
nanostructures--"molecular holograms"--which in turn concentrate information
into a medium free of lattice constraints: the quantum states of a
two-dimensional degenerate Fermi gas of electrons. The information embedded in
the holograms is transcoded at even smaller length scales into an atomically
uniform area of a copper surface, where it is densely projected into both two
spatial degrees of freedom and a third holographic dimension mapped to energy.
In analogy to optical volume holography, this requires precise amplitude and
phase engineering of electron wavefunctions to assemble pages of information
volumetrically. This data is read out by mapping the energy-resolved electron
density of states with a scanning tunnelling microscope. As the projection and
readout are both extremely near-field, and because we use native quantum states
rather than an external beam, we are not limited by lensing or collimation and
can create electronically projected objects with features as small as ~0.3 nm.
These techniques reach unprecedented densities exceeding 20 bits/nm2 and place
tens of bits into a single fermionic state.Comment: Published online 25 January 2009 in Nature Nanotechnology; 12 page
manuscript (including 4 figures) + 2 page supplement (including 1 figure);
supplementary movie available at http://mota.stanford.ed
Minimal nutrition intervention with high-protein/low-carbohydrate and low-fat, nutrient-dense food supplement improves body composition and exercise benefits in overweight adults: A randomized controlled trial
Background: Exercise and high-protein/reduced-carbohydrate and -fat diets have each been shown separately, or in combination with an energy-restricted diet to improve body composition and health in sedentary, overweight (BMI > 25) adults. The current study, instead, examined the physiological response to 10 weeks of combined aerobic and resistance exercise (EX) versus exercise + minimal nutrition intervention designed to alter the macronutrient profile, in the absence of energy restriction, using a commercially available high-protein/low-carbohydrate and low-fat, nutrient-dense food supplement (EXFS); versus control (CON). Methods: Thirty-eight previously sedentary, overweight subjects (female = 19; male = 19) were randomly assigned to either CON (n = 10), EX (n = 14) or EXFS (n = 14). EX and EXFS participated in supervised resistance and endurance training (2× and 3×/wk, respectively); EXFS consumed 1 shake/d (weeks 1 and 2) and 2 shakes/d (weeks 3–10). Results: EXFS significantly decreased total energy, carbohydrate and fat intake (-14.4%, -27.2% and -26.7%, respectively; p < 0.017), and increased protein and fiber intake (+52.1% and +21.2%, respectively; p < 0.017). EX and EXFS significantly decreased fat mass (-4.6% and -9.3%, respectively; p < 0.017), with a greater (p < 0.05) decrease in EXFS than EX and CON. Muscle mass increase only reached significance in EXFS (+2.3%; p < 0.017), which was greater (p < 0.05) than CON but not EX (+1.1%). Relative VO2max improved in both exercise groups (EX = +5.0% and EXFS = +7.9%; p < 0.017); however, only EXFS significantly improved absolute VO2max (+6.2%; p = 0.001). Time-to-exhaustion during treadmill testing increased in EX (+9.8%) but was significantly less (p < 0.05) than in EXFS (+21.2%). Total cholesterol and LDL decreased only in the EXFS (-12.0% and -13.3%, respectively; p < 0.017). Total cholesterol-to-HDL ratio, however, decreased significantly (p < 0.017) in both exercise groups. Conclusion: Absent energy restriction or other dietary controls, provision of a high-protein/low-carbohydrate and -fat, nutrient-dense food supplement significantly, 1) modified ad libitum macronutrient and energy intake (behavior effect), 2) improved physiological adaptations to exercise (metabolic advantage), and 3) reduced the variability of individual responses for fat mass, muscle mass and time-to-exhaustion – all three variables improving in 100% of EXFS subjects
Beta-alanine supplementation and high-intensity interval training augments metabolic adaptations and endurance performance in college-aged men
A randomized, double-blind, placebo-controlled study was conducted to evaluate the effects β-alanine supplementation and high-intensity interval training (HIIT) on endurance performance
Pre-workout consumption of Celsius® enhances the benefits of chronic exercise on body composition and cardiorespiratory fitness
The functional beverage Celsius®, has recently been shown, after acute and chronic (28 days) consumption, to increase resting metabolism and serum blood markers of lipolysis in healthy, college-aged men and women. The purpose of this study was to examine the combined effects of a 10-week exercise program while consuming Celsius® on body composition and cardiorespiratory fitness changes in sedentary men and women
Single-Atom Gating of Quantum State Superpositions
The ultimate miniaturization of electronic devices will likely require local
and coherent control of single electronic wavefunctions. Wavefunctions exist
within both physical real space and an abstract state space with a simple
geometric interpretation: this state space--or Hilbert space--is spanned by
mutually orthogonal state vectors corresponding to the quantized degrees of
freedom of the real-space system. Measurement of superpositions is akin to
accessing the direction of a vector in Hilbert space, determining an angle of
rotation equivalent to quantum phase. Here we show that an individual atom
inside a designed quantum corral can control this angle, producing arbitrary
coherent superpositions of spatial quantum states. Using scanning tunnelling
microscopy and nanostructures assembled atom-by-atom we demonstrate how single
spins and quantum mirages can be harnessed to image the superposition of two
electronic states. We also present a straightforward method to determine the
atom path enacting phase rotations between any desired state vectors. A single
atom thus becomes a real space handle for an abstract Hilbert space, providing
a simple technique for coherent quantum state manipulation at the spatial limit
of condensed matter.Comment: Published online 6 April 2008 in Nature Physics; 17 page manuscript
(including 4 figures) + 3 page supplement (including 2 figures);
supplementary movies available at http://mota.stanford.ed
Origin of high-velocity ejecta and early red excess emission in the infant Type Ia supernova 2021aefx
\object{SN 2021aefx} is a normal Type Ia Supernova (SN) with red excess
emission over the first 2 days. We present detailed analysis of this SN
using our high-cadence KMTNet multi-band photometry, spectroscopy, and publicly
available data. We provide the first measurements of its epochs of explosion
(MJD 59529.32 0.16) as well as ``first light'' (MJD 59529.85 0.55)
associated with the main ejecta distribution. This places our
first detection of SN 2021aefx at 0.5 hours since ``first light'',
indicating the presence of additional power sources. Our peak-spectrum confirms
its Type Ia sub-classification as intermediate between Core-Normal and
Broad-Line, and we estimate the ejecta mass to be 1.34 . The
pre-peak spectral evolution identifies fast-expanding material reaching
40,000 km s (the fastest ever observed in Type Ia SNe) and at least two
distinct homologously-expanding ejecta components: (1) a normal-velocity
(12,400 km s) component consistent with the typical photospheric
evolution of Chandrasekhar-mass ejecta; and (2) a high-velocity (23,500 km
s) component visible during the first 3.6 days post-explosion,
which locates the component within the outer 16\% of the ejecta mass.
Asymmetric, subsonic explosion processes producing a non-spherical photosphere
provide an explanation for the simultaneous presence of the two components, as
well as the red excess emission via a slight enrichment in the
outer 0.5\% of the ejecta mass. Our spectrum from 300 days post-peak
advances the constraint against non-degenerate companions and further supports
a near-Chandrasekhar-mass explosion origin. Off-center ignited
delayed-detonations of Chandrasekhar-mass white dwarfs may be responsible for
the observed features of SN 2021aefx in some normal Type Ia SNe.Comment: Submitted for publication in ApJ. 29 pages, 14 figures, 4 table
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