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Effects of Cryogenic Aging on a Rapid Prototyped (RP) Polymer
Little research has been done on the post-processing (aging) of rapid prototyped (RP)
polymers at temperatures below 123K (–238˚F). Test specimens of RP thermosetting resin
(DSM-Somos 8110) were fabricated and cryogenically aged from 10-25 hours. The tensile
strength and impact toughness were measured. This work will study the effect of cryogenic
aging on yield strength of Somos 8110. This paper will also discuss our interpretation of the data
based on fractography.The work was funded by an NSF Grant under Research Experiences for Undergraduates
(REU).Mechanical Engineerin
Detection of the pairwise kinematic Sunyaev-Zel'dovich effect with BOSS DR11 and the Atacama Cosmology Telescope
We present a new measurement of the kinematic Sunyaev-Zeldovich effect using
data from the Atacama Cosmology Telescope (ACT) and the Baryon Oscillation
Spectroscopic Survey (BOSS). Using 600 square degrees of overlapping sky area,
we evaluate the mean pairwise baryon momentum associated with the positions of
50,000 bright galaxies in the BOSS DR11 Large Scale Structure catalog. A
non-zero signal arises from the large-scale motions of halos containing the
sample galaxies. The data fits an analytical signal model well, with the
optical depth to microwave photon scattering as a free parameter determining
the overall signal amplitude. We estimate the covariance matrix of the mean
pairwise momentum as a function of galaxy separation, using microwave sky
simulations, jackknife evaluation, and bootstrap estimates. The most
conservative simulation-based errors give signal-to-noise estimates between 3.6
and 4.1 for varying galaxy luminosity cuts. We discuss how the other error
determinations can lead to higher signal-to-noise values, and consider the
impact of several possible systematic errors. Estimates of the optical depth
from the average thermal Sunyaev-Zeldovich signal at the sample galaxy
positions are broadly consistent with those obtained from the mean pairwise
momentum signal.Comment: 15 pages, 8 figures, 2 table
Results from the Atacama B-mode Search (ABS) Experiment
The Atacama B-mode Search (ABS) is an experiment designed to measure cosmic
microwave background (CMB) polarization at large angular scales (). It
operated from the ACT site at 5190~m elevation in northern Chile at 145 GHz
with a net sensitivity (NEQ) of 41 K. It employed an
ambient-temperature sapphire half-wave plate rotating at 2.55 Hz to modulate
the incident polarization signal and reduce systematic effects. We report here
on the analysis of data from a 2400 deg patch of sky centered at
declination and right ascension . We perform a blind
analysis. After unblinding, we find agreement with the Planck TE and EE
measurements on the same region of sky. We marginally detect polarized dust
emission and give an upper limit on the tensor-to-scalar ratio of (95%
cl) with the equivalent of 100 on-sky days of observation. We also present a
new measurement of the polarization of Tau A and introduce new methods
associated with HWP-based observations.Comment: 38 pages, 11 figure
Changes in pathways and vectors of biological invasions in Northwest Europe
We assessed how establishment patterns of non-native freshwater, marine and terrestrial species into Northwest Europe (using Great Britain, France, Belgium and the Netherlands as the study countries) have changed over time, and identified the prevalent pathways and vectors of recent arrivals. Data were extracted from 33 sources on (a) presence/absence and (b) first year of observation in the wild in each country, and (c) continent(s) of origin, (d) invasion pathway(s), (e) invasion vector(s) and (f) environment(s) for 359 species, comprising all non-native Mollusca, Osteichthyes (bony fish), Anseriformes (wildfowl) and Mammalia, and non-native invasive Angiospermae present in the area. Molluscs, fish and wildfowl, particularly those originating from South America, arrived more recently into Northwest Europe than other groups, particularly mammals, invasive plants and species originating from North America. Non-deliberate introductions, those of aquatic species and those from elsewhere in Europe and/or Asia increased strongly in importance after the year 2000 and were responsible for 69, 83 and 89 % of new introductions between 2001 and 2015, respectively. Non-deliberate introductions and those from Asia and North America contributed significantly more to introductions of invasive species in comparison to other non-native species. From the 1960s, ornamental trade has increased in importance relative to other vectors and was responsible for all deliberate introductions of study groups since 2001. Non-deliberate introductions of freshwater and marine species originating from Southeast Europe and Asia represent an increasingly important ecological and economic threat to Northwest Europe. Invertebrates such as molluscs may be particularly dangerous due to their small size and difficulties in detection. Prevention of future invasions in this respect will require intensive screening of stowaways on boats and raising of public awareness.Research leading to this study was funded by the European Regional Development Fund through the EU co-funded Interreg 2Seas project RINSE (reducing the impact of non-native species in Europe; www.rinse-europe.eu), which seeks to improve awareness of the threats posed by INNS, and the methods to address them. AZ and BG received financial support from RINSE. AZ is supported by a Postdoctoral Research Fellowship of the University of Nottingham, Malaysia Campus. BG holds a Postdoctoral Research Fellowship from the Spanish Ministry of Economy and Competitiveness (JCI-2012-11908)
Subtidal macrozoobenthos communities from northern Chile during and post El Niño 1997–1998
Despite a large amount of climatic and oceanographic information dealing with the recurring climate phenomenon El Niño (EN) and its well known impact on diversity of marine benthic communities, most published data are rather descriptive and consequently our understanding of the underlying mechanisms and processes that drive community structure during EN are still very scarce. In this study, we address two questions on the effects of EN on macrozoobenthic communities: (1) how does EN affect species diversity of the communities in northern Chile? and (2) is EN a phenomenon that restarts community assembling processes by affecting species interactions in northern Chile? To answer these questions, we compared species diversity and co-occurrence patterns of soft-bottoms macrozoobenthos communities from the continental shelf off northern Chile during (March 1998) and after (September 1998) the strong EN event 1997–1998. The methods used varied from species diversity and species co-occurrence analyses to multivariate ordination methods.
Our results indicate that EN positively affects diversity of macrozoobenthos communities in the study area, increasing the species richness and diversity and decreasing the species dominance. EN represents a strong disturbance that affects species interactions that rule the species assembling processes in shallow-water, sea-bottom environments
Author correction : a global database for metacommunity ecology, integrating species, traits, environment and space
Correction to: Scientific Data https://doi.org/10.1038/s41597-019-0344-7, published online 08 January 202
Author correction : a global database for metacommunity ecology, integrating species, traits, environment and space
Correction to: Scientific Data https://doi.org/10.1038/s41597-019-0344-7, published online 08 January 202
The Atacama Cosmology Telescope: Two-Season ACTPol Spectra and Parameters
We present the temperature and polarization angular power spectra measured by
the Atacama Cosmology Telescope Polarimeter (ACTPol). We analyze night-time
data collected during 2013-14 using two detector arrays at 149 GHz, from 548
deg of sky on the celestial equator. We use these spectra, and the spectra
measured with the MBAC camera on ACT from 2008-10, in combination with Planck
and WMAP data to estimate cosmological parameters from the temperature,
polarization, and temperature-polarization cross-correlations. We find the new
ACTPol data to be consistent with the LCDM model. The ACTPol
temperature-polarization cross-spectrum now provides stronger constraints on
multiple parameters than the ACTPol temperature spectrum, including the baryon
density, the acoustic peak angular scale, and the derived Hubble constant.
Adding the new data to planck temperature data tightens the limits on damping
tail parameters, for example reducing the joint uncertainty on the number of
neutrino species and the primordial helium fraction by 20%.Comment: 23 pages, 25 figure
The Atacama Cosmology Telescope: Cosmological parameters from three seasons of data
We present constraints on cosmological and astrophysical parameters from
high-resolution microwave background maps at 148 GHz and 218 GHz made by the
Atacama Cosmology Telescope (ACT) in three seasons of observations from 2008 to
2010. A model of primary cosmological and secondary foreground parameters is
fit to the map power spectra and lensing deflection power spectrum, including
contributions from both the thermal Sunyaev-Zeldovich (tSZ) effect and the
kinematic Sunyaev-Zeldovich (kSZ) effect, Poisson and correlated anisotropy
from unresolved infrared sources, radio sources, and the correlation between
the tSZ effect and infrared sources. The power ell^2 C_ell/2pi of the thermal
SZ power spectrum at 148 GHz is measured to be 3.4 +\- 1.4 muK^2 at ell=3000,
while the corresponding amplitude of the kinematic SZ power spectrum has a 95%
confidence level upper limit of 8.6 muK^2. Combining ACT power spectra with the
WMAP 7-year temperature and polarization power spectra, we find excellent
consistency with the LCDM model. We constrain the number of effective
relativistic degrees of freedom in the early universe to be Neff=2.79 +\- 0.56,
in agreement with the canonical value of Neff=3.046 for three massless
neutrinos. We constrain the sum of the neutrino masses to be Sigma m_nu < 0.39
eV at 95% confidence when combining ACT and WMAP 7-year data with BAO and
Hubble constant measurements. We constrain the amount of primordial helium to
be Yp = 0.225 +\- 0.034, and measure no variation in the fine structure
constant alpha since recombination, with alpha/alpha0 = 1.004 +/- 0.005. We
also find no evidence for any running of the scalar spectral index, dns/dlnk =
-0.004 +\- 0.012.Comment: 26 pages, 22 figures. This paper is a companion to Das et al. (2013)
and Dunkley et al. (2013). Matches published JCAP versio
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