180 research outputs found
Evaluation of a commercial in situ fluorometer probe for water quality monitoring programs
Benthic Algae is often used in water quality monitoring; however, traditional methods of benthic algae assessment are relatively expensive and time consuming. The Benthotorch® is a portable fluorimeter probe used to measure in situ benthic chlorophyll-a (µg/cm2) and relative abundance of cyanobacteria, green algae and diatoms (cells/cm2) in about 20 seconds. During the summer of 2014, at 42 locations across Oklahoma, 119 benthic algae samples were measured with the Benthotorch®, extracted for chlorophyll a and a taxonomic assessment conducted. Medians for each method were statistically similar based on Mann Whitney tests. Regression analyses resulted in significant and positive correlations between BenthoTorch® chlorophyll a estimates and extracted chlorophyll a, although BenthoTorch® estimates underestimated extracted chlorophyll a. The most likely causes of discrepancies between the extracted chlorophyll a and the BenthoTorch® were self-shading of the algae, high biomass concentrations and sediments present in the samples. The BenthoTorch® measured an area of 1.0 cm2 while the field samples were collected from an area of 13.1 cm2, which is another error source. To test this, benthic algae was grown under controlled conditions in a laboratory. After a period of growth, the benthic algae was measured in situ, ex situ/in vivo with the BenthoTorch® and compared to extracted chlorophyll a measured with a spectrophotometer. The results were improved over field tests with an R2 of 0.64 and a slope of 0.86 for the in situ and R2 of 0.79 and a slope of 0.81 for the modified method. Tests for variance of sampler size concluded that the larger sampler area improved characterizing the algal variability. BenthoTorch® estimates of relative abundance were evaluated, were statistically different based on Mann Whitney tests, and were not significantly correlated in regression analyses
Understanding precision nitrogen stress to optimize the growth and lipid content tradeoff in oleaginous green microalgae
Nitrogen deficiency promotes lipid formation in many microalgae, but also limits growth and lipid productivity. In spite of numerous studies, there is poor understanding of the interactions of growth and lipid content, the time course of lipid accumulation and the magnitude of nitrogen deficiency required to stimulate lipid formation. These relationships were investigated in six species of oleaginous green algae, comparing high and low levels of deficiency. Nitrogen stress typically had disproportionate effects on growth and lipid content, with profound differences among species. Optimally balancing the tradeoffs required a wide range in nitrogen supply rate among species. Some species grew first and then accumulated lipids, while other species grew and accumulated lipids concurrently which resulted in increased lipid productivity. Accumulation of high lipid content generally resulted from a response to minimal stress. The data highlight the tremendous biodiversity that may be exploited to optimally produce lipids with precision nitrogen stress
Ordering of timescales predicts applicability of quasi-linear theory in unstable flows
We discuss the applicability of quasilinear-type approximations for a
turbulent system with a large range of spatial and temporal scales. We consider
a paradigm fluid system of rotating convection with a vertical and horizontal
temperature gradients. In particular, the interaction of rotating with the
horizontal temperature gradient drives a ``thermal wind'' shear flow whose
strength is controlled by a horizontal temperature gradient. Varying the
parameters systematically alters the ordering of the shearing timescale, the
convective timescale, and the correlation timescale. We demonstrate that
quasilinear-type approximations work well when the shearing timescale or the
correlation timescale is sufficiently short. In all cases, the Generalised
Quasilinear approximation (GQL) systematically outperforms the Quasilinear
approximation (QL). We discuss the consequences for statistical theories of
turbulence interacting with mean gradients. We conclude with comments about the
general applicability of these ideas across a wide variety of non-linear
physical systems.Comment: 5 pages, 3 figure
Potential Polygamous Breeding Behavior in Northern Bobwhite
Breeding behavior ofradio-tagged northern bobwhite (Colinus uirginianus) was observed at Fort Bragg Military Reservation (n = 19), North Carolina, in 1985-88, and Tall Timbers Research Station (n = 27), Florida, during 1984-86. We observed apparent polygamous breeding behavior in 95% (18 of 19) of the radio-tagged northern bobwhite at Fort Bragg, and 93% (25 of 27) of the birds at Tall Timbers. We documented 5 cases of double-clutching by radio-tagged females. Twenty-seven percent of Fort Bragg clutches (n = 30), and 20% of Tall Timbers clutches (n = 56) were incubated by radio-tagged males. Northern bobwhite exhibited characteristics of both rapid multiclutch and am bisexual polygamous mating systems. Northern bobwhite are capable of uniparental care, have long breeding seasons, live in an environment with fluctuating resources, suffer high predation pressure during the nesting season, and raise precocial young; all traits that are similar to other bird species which have evolved polygamous mating systems
Challenges associated with insulin therapy progression among patients with type 2 diabetes: Latin American MOSAIc study baseline data
Background: Poor glycemic control in patients with type 2 diabetes is commonly recorded worldwide; Latin America (LA) is not an exception. Barriers to intensifying insulin therapy and which barriers are most likely to negatively impact outcomes are not completely known. The objective was to identify barriers to insulin progression in individuals with type 2 diabetes mellitus (T2DM) in LA countries (Mexico, Brazil, and Argentina). Methods: MOSAIc is a multinational, non-interventional, prospective, observational study aiming to identify the patient-, physician-, and healthcare-based factors affecting insulin intensification. Eligible patients were ≥18 years, had T2DM, and were treated with insulin for ≥3 months with/without oral antidiabetic drugs (OADs). Demographic, clinical, and psychosocial data were collected at baseline and regular intervals during the 24-month follow-up period. This paper however, focuses on baseline data analysis. The association between glycated hemoglobin (HbA1c) and selected covariates was assessed. Results: A trend toward a higher level of HbA1c was observed in the LA versus non-LA population (8.40 ± 2.79 versus 8.18 ± 2.28; p ≤ 0.069). Significant differences were observed in clinical parameters, treatment patterns, and patient-reported outcomes in LA compared with the rest of the cohorts and between Mexico, Brazil, and Argentina. Higher number of insulin injections and lower number of OADs were used, whereas a lower level of knowledge and a higher level of diabetes-related distress were reported in LA. Covariates associated with HbA1c levels included age (-0.0129; p < 0.0001), number of OADs (0.0835; p = 0.0264), higher education level (-0.2261; p = 0.0101), healthy diet (-0.0555; p = 0.0083), self-monitoring blood glucose (-0.0512; p = 0.0033), hurried communication style in the process of care (0.1295; p = 0.0208), number of insulin injections (0.1616; p = 0.0088), adherence (-0.1939; p ≤ 0.0104), and not filling insulin prescription due to associated cost (0.2651; p = 0.0198). Conclusion: MOSAIc baseline data showed that insulin intensification in LA is not optimal and identified several conditions that significantly affect attaining appropriate HbA1c values. Tailored public health strategies, including education, should be developed to overcome such barriers.Centro de Endocrinología Experimental y Aplicad
Probabilistic reaction norm reveals family-related variation in the association between size, condition and sexual maturation onset in Atlantic salmon (Salmo salar)
This study investigated the relationship between the size, condition, year class, family, and sexual maturity of Atlantic salmon (Salmo salar) using data collected in an aquaculture selective breeding programme. Males that were sexually mature at 2 years of age (maiden spawn) have, on average, greater fork length and condition factor (K) at 1 year of age than their immature counterparts. For every 10-mm increase in fork length or 0.1 increase in K at 1 year of age, the odds of sexual maturity at 2 years of age increased by 1.48 or 1.22 times, respectively. Females that were sexually mature at 3 years of age (maiden spawn) have, on average, greater fork length and K at 2 years of age than their immature counterparts. For every 10-mm increase in fork length or 0.1 increase in K at 2 years of age, the odds of sexual maturity at 3 years of age increased by 1.06 or 1.44 times, respectively. The family explained 34.93% of the variation in sexual maturity among 2-year-old males that was not attributable to the average effects of fork length and K at 1 year of age and year class. The proportion of variation in sexual maturity among 3-year-old females explained by the family could not be investigated. These findings suggest that the onset of sexual maturation in Atlantic salmon is conditional on performance (with respect to energy availability) surpassing a threshold, the magnitude of which can vary between families and is determined by a genetic component. This could support the application of genetic selection to promote or inhibit the onset of sexual maturation in farmed stocks.</p
Measuring nickel masses in Type Ia supernovae using cobalt emission in nebular phase spectra
The light curves of Type Ia supernovae (SNe Ia) are powered by the
radioactive decay of Ni to Co at early times, and the decay of
Co to Fe from ~60 days after explosion. We examine the evolution
of the [Co III] 5892 A emission complex during the nebular phase for SNe Ia
with multiple nebular spectra and show that the line flux follows the square of
the mass of Co as a function of time. This result indicates both
efficient local energy deposition from positrons produced in Co decay,
and long-term stability of the ionization state of the nebula. We compile 77
nebular spectra of 25 SN Ia from the literature and present 17 new nebular
spectra of 7 SNe Ia, including SN2014J. From these we measure the flux in the
[Co III] 5892 A line and remove its well-behaved time dependence to infer the
initial mass of Ni () produced in the explosion. We then examine
Ni yields for different SN Ia ejected masses ( - calculated
using the relation between light curve width and ejected mass) and find the
Ni masses of SNe Ia fall into two regimes: for narrow light curves (low
stretch s~0.7-0.9), is clustered near ~ 0.4 and
shows a shallow increase as increases from ~1-1.4; at high
stretch, clusters at the Chandrasekhar mass (1.4) while
spans a broad range from 0.6-1.2. This could constitute
evidence for two distinct SN Ia explosion mechanisms.Comment: 16 pages, 12 figures (main text), plus data tables in appendix.
Spectra released on WISeREP. Submitted to MNRAS, comments welcom
KELT-10b: The First Transiting Exoplanet from the KELT-South Survey -- A Hot Sub-Jupiter Transiting a V = 10.7 Early G-Star
We report the discovery of KELT-10b, the first transiting exoplanet
discovered using the KELT-South telescope. KELT-10b is a highly inflated
sub-Jupiter mass planet transiting a relatively bright star (TYC
8378-64-1), with T = K, =
and [Fe/H] = , an inferred mass
M = M and radius R =
R. The planet has a radius R =
R and mass M =
M. The planet has an eccentricity consistent with zero and a semi-major
axis = AU. The best fitting linear
ephemeris is = 2457066.720450.00027 BJD and P =
4.16627390.0000063 days. This planet joins a group of highly inflated
transiting exoplanets with a radius much larger and a mass much less than those
of Jupiter. The planet, which boasts deep transits of 1.4%, has a relatively
high equilibrium temperature of T = K, assuming zero
albedo and perfect heat redistribution. KELT-10b receives an estimated
insolation of 10 erg s cm,
which places it far above the insolation threshold above which hot Jupiters
exhibit increasing amounts of radius inflation. Evolutionary analysis of the
host star suggests that KELT-10b is unlikely to survive beyond the current
subgiant phase, due to a concomitant in-spiral of the planet over the next
1 Gyr. The planet transits a relatively bright star and exhibits the
third largest transit depth of all transiting exoplanets with V 11 in the
southern hemisphere, making it a promising candidate for future atmospheric
characterization studies.Comment: 20 pages, 13 figures, 7 tables, accepted for publication in MNRA
Challenges associated with insulin therapy progression among patients with type 2 diabetes: Latin American MOSAIc study baseline data
Background: Poor glycemic control in patients with type 2 diabetes is commonly recorded worldwide; Latin America (LA) is not an exception. Barriers to intensifying insulin therapy and which barriers are most likely to negatively impact outcomes are not completely known. The objective was to identify barriers to insulin progression in individuals with type 2 diabetes mellitus (T2DM) in LA countries (Mexico, Brazil, and Argentina). Methods: MOSAIc is a multinational, non-interventional, prospective, observational study aiming to identify the patient-, physician-, and healthcare-based factors affecting insulin intensification. Eligible patients were ≥18 years, had T2DM, and were treated with insulin for ≥3 months with/without oral antidiabetic drugs (OADs). Demographic, clinical, and psychosocial data were collected at baseline and regular intervals during the 24-month follow-up period. This paper however, focuses on baseline data analysis. The association between glycated hemoglobin (HbA1c) and selected covariates was assessed. Results: A trend toward a higher level of HbA1c was observed in the LA versus non-LA population (8.40 ± 2.79 versus 8.18 ± 2.28; p ≤ 0.069). Significant differences were observed in clinical parameters, treatment patterns, and patient-reported outcomes in LA compared with the rest of the cohorts and between Mexico, Brazil, and Argentina. Higher number of insulin injections and lower number of OADs were used, whereas a lower level of knowledge and a higher level of diabetes-related distress were reported in LA. Covariates associated with HbA1c levels included age (-0.0129; p < 0.0001), number of OADs (0.0835; p = 0.0264), higher education level (-0.2261; p = 0.0101), healthy diet (-0.0555; p = 0.0083), self-monitoring blood glucose (-0.0512; p = 0.0033), hurried communication style in the process of care (0.1295; p = 0.0208), number of insulin injections (0.1616; p = 0.0088), adherence (-0.1939; p ≤ 0.0104), and not filling insulin prescription due to associated cost (0.2651; p = 0.0198). Conclusion: MOSAIc baseline data showed that insulin intensification in LA is not optimal and identified several conditions that significantly affect attaining appropriate HbA1c values. Tailored public health strategies, including education, should be developed to overcome such barriers.Centro de Endocrinología Experimental y Aplicad
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