292 research outputs found
The Changing Financial Structure of the U.S. Farm Sector
Agricultural Finance,
Open access and open source in chemistry
Scientific data are being generated and shared at ever-increasing rates. Two new mechanisms for doing this have developed: open access publishing and open source research. We discuss both, with recent examples, highlighting the differences between the two, and the strengths of both
Cosmic Shear E/B-mode Estimation with Binned Correlation Function Data
In this work I study the problem of E/B-mode separation with binned cosmic
shear two-point correlation function data. Motivated by previous work on
E/B-mode separation with shear two-point correlation functions and the
practical considerations of data analysis, I consider E/B-mode estimators which
are linear combinations of the binned shear correlation function data points. I
demonstrate that these estimators mix E- and B-modes generally. I then show how
to define estimators which minimize this E/B-mode mixing and give practical
recipes for their construction and use. Using these optimal estimators, I
demonstrate that the vector space composed of the binned shear correlation
function data points can be decomposed into approximately ambiguous, E- and
B-mode subspaces. With simple Fisher information estimates, I show that a
non-trivial amount of information on typical cosmological parameters is
contained in the ambiguous mode subspace computed in this formalism. Next, I
give two examples which apply these practical estimators and recipes to generic
problems in cosmic shear data analysis: data compression and spatially locating
B-mode contamination. In particular, by using wavelet-like estimators with the
shear correlation functions directly, one can pinpoint B-mode contamination to
specific angular scales and extract information on its shape. Finally, I
discuss how these estimators can be used as part of blinded or closed-box
cosmic shear data analyses in order to assess and find B-mode contamination at
high-precision while avoiding observer biases.Comment: 15 pages, 5 figures, 3 appendices, MNRAS submitted, comments welcome
Overview of the Alberta Kidney Disease Network
<p>Abstract</p> <p>Background</p> <p>The Alberta Kidney Disease Network is a collaborative nephrology research organization based on a central repository of laboratory and administrative data from the Canadian province of Alberta.</p> <p>Description</p> <p>The laboratory data within the Alberta Kidney Disease Network can be used to define patient populations, such as individuals with chronic kidney disease (using serum creatinine measurements to estimate kidney function) or anemia (using hemoglobin measurements). The administrative data within the Alberta Kidney Disease Network can also be used to define cohorts with common medical conditions such as hypertension and diabetes. Linkage of data sources permits assessment of socio-demographic information, clinical variables including comorbidity, as well as ascertainment of relevant outcomes such as health service encounters and events, the occurrence of new specified clinical outcomes and mortality.</p> <p>Conclusion</p> <p>The unique ability to combine laboratory and administrative data for a large geographically defined population provides a rich data source not only for research purposes but for policy development and to guide the delivery of health care. This research model based on computerized laboratory data could serve as a prototype for the study of other chronic conditions.</p
Muscle-Specific Adaptations, Impaired Oxidative Capacity and Maintenance of Contractile Function Characterize Diet-Induced Obese Mouse Skeletal Muscle
BACKGROUND:The effects of diet-induced obesity on skeletal muscle function are largely unknown, particularly as it relates to changes in oxidative metabolism and morphology. PRINCIPAL FINDINGS:Compared to control fed mice, mice fed a high fat diet (HFD; 60% kcal: fat) for 8 weeks displayed increased body mass and insulin resistance without overt fasting hyperglycemia (i.e. pre-diabetic). Histological analysis revealed a greater oxidative potential in the HFD gastrocnemius/plantaris (increased IIA, reduced IIB fiber-type percentages) and soleus (increased I, IIA cross-sectional areas) muscles, but no change in fiber type percentages in tibialis anterior muscles compared to controls. Intramyocellular lipid levels were significantly increased relative to control in HFD gastrocnemius/plantaris, but were similar to control values in the HFD soleus. Using a novel, single muscle fiber approach, impairments in complete palmitate and glucose oxidation (72.8+/-6.6% and 61.8+/-9.1% of control, respectively; p<0.05) with HFD were detected. These reductions were consistent with measures made using intact extensor digitorum longus and soleus muscles. Compared to controls, no difference in succinate dehydrogenase or citrate synthase enzyme activities were observed between groups in any muscle studied, however, short-chain fatty acyl CoA dehydrogenase (SCHAD) activity was elevated in the HFD soleus, but not tibialis anterior muscles. Despite these morphological and metabolic alterations, no significant difference in peak tetanic force or low-frequency fatigue rates were observed between groups. CONCLUSIONS:These findings indicate that HFD induces early adaptive responses that occur in a muscle-specific pattern, but are insufficient to prevent impairments in oxidative metabolism with continued high-fat feeding. Moreover, the morphological and metabolic changes which occur with 8 weeks of HFD do not significantly impact muscle contractile properties
A protein functionalization platform based on selective reactions at methionine residues.
Nature has a remarkable ability to carry out site-selective post-translational modification of proteins, therefore enabling a marked increase in their functional diversity1. Inspired by this, chemical tools have been developed for the synthetic manipulation of protein structure and function, and have become essential to the continued advancement of chemical biology, molecular biology and medicine. However, the number of chemical transformations that are suitable for effective protein functionalization is limited, because the stringent demands inherent to biological systems preclude the applicability of many potential processes2. These chemical transformations often need to be selective at a single site on a protein, proceed with very fast reaction rates, operate under biologically ambient conditions and should provide homogeneous products with near-perfect conversion2-7. Although many bioconjugation methods exist at cysteine, lysine and tyrosine, a method targeting a less-explored amino acid would considerably expand the protein functionalization toolbox. Here we report the development of a multifaceted approach to protein functionalization based on chemoselective labelling at methionine residues. By exploiting the electrophilic reactivity of a bespoke hypervalent iodine reagent, the S-Me group in the side chain of methionine can be targeted. The bioconjugation reaction is fast, selective, operates at low-micromolar concentrations and is complementary to existing bioconjugation strategies. Moreover, it produces a protein conjugate that is itself a high-energy intermediate with reactive properties and can serve as a platform for the development of secondary, visible-light-mediated bioorthogonal protein functionalization processes. The merger of these approaches provides a versatile platform for the development of distinct transformations that deliver information-rich protein conjugates directly from the native biomacromolecules
Impaired Growth and Force Production in Skeletal Muscles of Young Partially Pancreatectomized Rats: A Model of Adolescent Type 1 Diabetic Myopathy?
This present study investigated the temporal effects of type 1 diabetes mellitus (T1DM) on adolescent skeletal muscle growth, morphology and contractile properties using a 90% partial pancreatecomy (Px) model of the disease. Four week-old male Sprague-Dawley rats were randomly assigned to Px (nβ=β25) or Sham (nβ=β24) surgery groups and euthanized at 4 or 8 weeks following an in situ assessment of muscle force production. Compared to Shams, Px were hyperglycemic (>15 mM) and displayed attenuated body mass gains by days 2 and 4, respectively (both P<0.05). Absolute maximal force production of the gastrocnemius plantaris soleus complex (GPS) was 30% and 50% lower in Px vs. Shams at 4 and 8 weeks, respectively (P<0.01). GP mass was 35% lower in Px vs Shams at 4 weeks (1.24Β±0.06 g vs. 1.93Β±0.03 g, P<0.05) and 45% lower at 8 weeks (1.57Β±0.12 vs. 2.80Β±0.06, P<0.05). GP fiber area was 15β20% lower in Px vs. Shams at 4 weeks in all fiber types. At 8 weeks, GP type I and II fiber areas were βΌ25% and 40% less, respectively, in Px vs. Shams (group by fiber type interactions, P<0.05). Phosphorylation states of 4E-BP1 and S6K1 following leucine gavage increased 2.0- and 3.5-fold, respectively, in Shams but not in Px. Px rats also had impaired rates of muscle protein synthesis in the basal state and in response to gavage. Taken together, these data indicate that exposure of growing skeletal muscle to uncontrolled T1DM significantly impairs muscle growth and function largely as a result of impaired protein synthesis in type II fibers
Neuromatch Academy: Teaching Computational Neuroscience with global accessibility
Neuromatch Academy designed and ran a fully online 3-week Computational
Neuroscience summer school for 1757 students with 191 teaching assistants
working in virtual inverted (or flipped) classrooms and on small group
projects. Fourteen languages, active community management, and low cost allowed
for an unprecedented level of inclusivity and universal accessibility.Comment: 10 pages, 3 figures. Equal contribution by the executive committee
members of Neuromatch Academy: Tara van Viegen, Athena Akrami, Kate Bonnen,
Eric DeWitt, Alexandre Hyafil, Helena Ledmyr, Grace W. Lindsay, Patrick
Mineault, John D. Murray, Xaq Pitkow, Aina Puce, Madineh Sedigh-Sarvestani,
Carsen Stringer. and equal contribution by the board of directors of
Neuromatch Academy: Gunnar Blohm, Konrad Kording, Paul Schrater, Brad Wyble,
Sean Escola, Megan A. K. Peter
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