A
bstract
We examine current collider constraints on some simple
Z
′
models that fit neutral current
B
-anomalies, including constraints coming from measurements of Standard Model (SM) signatures at ...the LHC. The ‘MDM’ simplified model is not constrained by the SM measurements but
is
strongly constrained by a 139 fb
−1
13 TeV ATLAS di-muon search. Constraints upon the ‘MUM’ simplified model are much weaker. A combination of the current
B
s
mixing constraint and ATLAS’
Z
′
search implies
M
Z
′
>
1.2
TeV in the Third Family Hypercharge Model example case. LHC SM measurements rule out a portion of the parameter space of the model for
M
Z
′
>
1.5
TeV.
Direct carbon dioxide flux measurements using eddy covariance from an icebreaker in the high‐latitude Southern Ocean and Antarctic marginal ice zone are reported. Fluxes were combined with the ...measured water‐air carbon dioxide partial pressure difference (ΔpCO2) to compute the air‐sea gas transfer velocity (k, normalized to Schmidt number 660). The open water data showed a quadratic relationship between k (cm h−1) and the neutral 10 m wind speed (U10n, m s−1), kopen = 0.245 U10n2 + 1.3, in close agreement with decades old tracer‐based results and much lower than cubic relationships inferred from previous open ocean eddy covariance studies. In the marginal ice zone, the effective gas transfer velocity decreased in proportion to sea ice cover, in contrast with predictions of enhanced gas exchange in the presence of sea ice. The combined open water and marginal ice zone results affect the calculated magnitude and spatial distribution of Southern Ocean carbon flux.
Key Points
First unattended eddy covariance CO2 fluxes in Southern Ocean and Antarctic marginal ice zone
Quadratic dependence of open ocean gas transfer velocity on wind speed
Gas exchange in marginal ice zone proportional to fraction of open water
Polysaccharides derived from plant foods are major components of the human diet, with limited contributions of related components from fungal and algal sources. In particular, starch and other ...storage carbohydrates are the major sources of energy in all diets, while cell wall polysaccharides are the major components of dietary fiber. We review the role of these components in the human diet, including their structure and distribution, their modification during food processing and effects on functional properties, their behavior in the gastrointestinal tract, and their contribution to healthy diets.
► Starch digestibility data can usually be fitted to a first-order rate equation. ► Guggenheim and/or log of slope (LOS) plots do not need end-point values. ► LOS plots provide end point ...concentrations (i.e., the maximum available starch) directly. ► If both are present, RDS and SDS fractions result in discontinuities in LOS plots. ► Examples of Guggenheim and LOS plots fits for starch are shown and merits discussed.
Investigators often study product release from starches during prolonged incubations with α-amylase in vitro. The reaction time courses usually fit to a linear form of a first order rate equation, i.e., ln(C∞−Ct)/C∞=−kt. This equation calls for an accurate estimate of C∞, i.e., the concentration of product at the end of the reaction. Estimates of C∞ from digestibility curves can be unreliable. The Guggenheim method does not require prior knowledge of C∞ but seems not to have been applied to starch hydrolysis data. An alternative method is also available in which the logarithm of the slope (LOS) of a digestibility curve at various time points is plotted against time. This allows estimations of both k and C∞ and can also reveal whether changes occur in digestion rate from rapid to slow as digestion proceeds. We describe the Guggenheim and LOS methods and provide examples of their application to starch digestibility data.
Starch is a principal dietary source of digestible carbohydrate and energy. Glycaemic and insulinaemic responses to foods containing starch vary considerably and glucose responses to starchy foods ...are often described by the glycaemic index (GI) and/or glycaemic load (GL). Low GI/GL foods are beneficial in the management of cardiometabolic disorders (e.g., type 2 diabetes, cardiovascular disease). Differences in rates and extents of digestion of starch-containing foods will affect postprandial glycaemia.
Amylolysis kinetics are influenced by structural properties of the food matrix and of starch itself. Native (raw) semi-crystalline starch is digested slowly but hydrothermal processing (cooking) gelatinises the starch and greatly increases its digestibility. In plants, starch granules are contained within cells and intact cell walls can limit accessibility of water and digestive enzymes hindering gelatinisation and digestibility. In vitro studies of starch digestion by α-amylase model early stages in digestion and can suggest likely rates of digestion in vivo and expected glycaemic responses. Reports that metabolic responses to dietary starch are influenced by α-amylase gene copy number, heightens interest in amylolysis.
This review shows how enzyme kinetic strategies can provide explanations for differences in digestion rate of different starchy foods. Michaelis-Menten and Log of Slope analyses provide kinetic parameters (e.g., Km and kcat/Km) for evaluating catalytic efficiency and ease of digestibility of starch by α-amylase. Suitable kinetic methods maximise the information that can be obtained from in vitro work for predictions of starch digestion and glycaemic responses in vivo.
Display omitted
•Michaelis-Menten kinetics determines catalytic efficiency of amylase action on starch.•Kinetic parameters Km and kcat/Km are useful for estimating ease of digestibility.•Log of slope analysis can quantify starch fractions digested at different rates.•Categorisation of Resistant Starch can be based on types of interaction with amylase.•Enzyme kinetic studies of amylolysis are useful for predicting postprandial glycaemia.
A
bstract
The large and growing library of measurements from the Large Hadron Collider has significant power to constrain extensions of the Standard Model. We consider such constraints on a ...well-motivated model involving a gauged and spontaneously-broken
B
−
L
symmetry, within the C
ontur
framework. The model contains an extra Higgs boson, a gauge boson, and right-handed neutrinos with Majorana masses. This new particle content implies a varied phenomenology highly dependent on the parameters of the model, very well-suited to a general study of this kind. We find that existing LHC measurements significantly constrain the model in interesting regions of parameter space. Other regions remain open, some of which are within reach of future LHC data.
We examine current Large Hadron Collider constraints on some simple
Z
′
models that significantly improve on Standard Model fits to
b
→
s
μ
+
μ
-
transition data. The models that we consider are the ...‘third family baryon number minus second family lepton number’ (
B
3
-
L
2
) model and the ‘third family hypercharge’ model and variants. The constraints are applied on parameter regions of each model that fit the
b
→
s
μ
+
μ
-
transition data and come from high-mass Drell–Yan di-muons and measurements of Standard Model processes. This latter set of observables place particularly strong bounds upon the parameter space of the
B
3
-
L
2
model when the mass of the
Z
′
boson is less than 300 GeV.
ABSTRACT
We explore deep rest-frame UV to FIR data in the COSMOS field to measure the individual spectral energy distributions (SED) of the ∼4000 SC4K (Sobral et al.) Lyman α (Ly α) emitters (LAEs) ...at z ∼ 2–6. We find typical stellar masses of 109.3 ± 0.6 M⊙ and star formation rates (SFR) of SFR$_{\rm SED}=4.4^{+10.5}_{-2.4}$ M⊙ yr−1 and SFR$_{\rm Ly\,\alpha }=5.9^{+6.3}_{-2.6}$ M⊙ yr−1, combined with very blue UV slopes of $\beta =-2.1^{+0.5}_{-0.4}$, but with significant variations within the population. MUV and β are correlated in a similar way to UV-selected sources, but LAEs are consistently bluer. This suggests that LAEs are the youngest and/or most dust-poor subset of the UV-selected population. We also study the Ly α rest-frame equivalent width (EW0) and find 45 ‘extreme’ LAEs with EW0 > 240 Å (3σ), implying a low number density of (7 ± 1) × 10−7 Mpc−3. Overall, we measure little to no evolution of the Ly α EW0 and scale length parameter (w0), which are consistently high (EW$_0=140^{+280}_{-70}$ Å, $w_0=129^{+11}_{-11}$ Å) from z ∼ 6 to z ∼ 2 and below. However, w0 is anticorrelated with MUV and stellar mass. Our results imply that sources selected as LAEs have a high Ly α escape fraction (fesc,Ly α) irrespective of cosmic time, but fesc,Ly α is still higher for UV-fainter and lower mass LAEs. The least massive LAEs (<109.5 M⊙) are typically located above the star formation ‘main sequence’ (MS), but the offset from the MS decreases towards z ∼ 6 and towards 1010 M⊙. Our results imply a lack of evolution in the properties of LAEs across time and reveals the increasing overlap in properties of LAEs and UV-continuum selected galaxies as typical star-forming galaxies at high redshift effectively become LAEs.
Communication requires both the encoding of information and its effective transmission, but little is known about display traits that primarily serve to enhance efficacy. Here we examined the visual ...courtships of Lispe cana, a cursorial fly that lives and mates in heterogeneous foreshores, and tested the prediction that males should seek to enhance signal salience and consequent fitness through the flexible choice of display locations. We show that courting males access the field of view of females by straddling them and holding their wings closed before moving ahead to present their structurally colored faces in ritualized dances. Males preferentially present these UV-white signals against darker backgrounds and the magnitude of contrast predicts female attention, which in turn predicts mating success. Our results demonstrate a striking interplay between the physical and attentional manipulation of receivers and reveal novel routes to the enhancement of signal efficacy in noisy environments.
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