4,008 research outputs found
Leptospirosis presenting in a woman with fulminant hepatic failure from Wilson's disease: a case report
An Assessment of the Hydration Status of Recreational Endurance Athletes during Mountain Marathon Events.
Changes in hydration status have been shown to have deleterious effects on physiological functioning, physical performance, mental decision making, and subjective sensation of effort. This exploratory study assessed the hydration status of athletes taking part in mountain marathon events and the implications on performance, cognition and well-being markers. Twenty-nine male recreational athletes from the Original Mountain Marathon (OMM) and nineteen from the Longmynd Hike (LH) provided urine samples before, at mid-point (in the OMM) and after the events. Body mass; reaction time tests; and subjective ratings of well-being and effort were also collected/performed at these time points. Post-urine specific gravity (Usg) values [(OMM: 1.023 (range: 1.008 – 1.038) g/ml; LH: 1.024 (range: 1.014 – 1.035) g/ml] were significantly higher than pre-values [(OMM: 1.013 (range: 1.002 – 1.026) g/ml; LH: 1.013 (range: 1.002 – 1.026) g/ml] in both events (p 0.05). There was no association between hydration status and overall performance in the LH, whilst change in Usg from pre- to mid-event was positively associated with performance in the OMM (r = .561, p = 0.004). Whilst no associations were observed between hydration status and reaction time, rate of perceived exertion and subjective ratings of nausea showed positive associations with Usg. These findings suggest that although changes in hydration status of this level may not significantly affect performance, they can impact on participant sensations of effort and well-being
Macronutrient Consumption Prior to, and During, Mountain Marathon Events
Participation in ultra-endurance events such as mountain marathons is increasing, yet analysis of the nutritional intake and requirements of this group of athletes have received relatively little attention. This field study examined athletes’ food intake prior to, and during a mountain marathon event to assess compliance with recommendations and to identify associations with performance. Nineteen male athletes competing in the Longmynd Hike (LH) completed a 7-day food diary in the week prior to the event and a weighed food inventory of all items consumed during the event. Despite reported intentions to increase carbohydrate (CHO) consumption in the week prior to the event, there was no significant change in consumption across the week. The mean daily CHO intake of 4.5 g/kg/d was below that recommended to effectively enhance glycogen stores. CHO and energy consumption prior to the event were positively associated with performance [energy (kJ/kg/d): r = .56, p = 0.03; CHO (g/kg/d): r = .54, p = 0.04]. Energy and CHO consumption during the event were also positively correlated with performance [energy (kJ/kg/h): r = .80, p < 0.001; CHO (g/kg/h): r = .75, p = 0.001)], despite most participants again failing to meet recommendations for intake. Further research is needed to determine reasons for non-compliance with nutritional guidelines and to investigate to what extent type and timing of macronutrient intake during such events impacts on performance
Supersymmetric geometries of IIA supergravity I
IIA supergravity backgrounds preserving one supersymmetry locally admit four
types of Killing spinors distinguished by the orbits of on the
space of spinors. We solve the Killing spinor equations of IIA supergravity
with and without cosmological constant for Killing spinors representing two of
these orbits, with isotropy groups and .
In both cases, we identify the geometry of spacetime and express the fluxes in
terms of the geometry. We find that the geometric constraints of backgrounds
with a invariant Killing spinor are identical to
those found for heterotic backgrounds preserving one supersymmetry.Comment: 21 page
A Novel Flowchart for Model Validation: Is it conceivable to validate without new measurements?
Long-term trends in diatom diversity and palaeoproductivity: a 16 000-year multidecadal record from Lake Baikal, southern Siberia
Biological diversity is inextricably linked to community stability and
ecosystem functioning, but our understanding of these relationships in
freshwater ecosystems is largely based on short-term observational,
experimental, and modelling approaches. Using a multidecadal diatom record
for the past ca. 16 000 years from Lake Baikal, we investigate how diversity
and palaeoproductivity have responded to climate change during periods of
both rapid climate fluctuation and relative climate stability. We show
dynamic changes in diatom communities during the past 16 000 years, with
decadal shifts in species dominance punctuating millennial-scale seasonal
trends. We describe for the first time in Lake Baikal a gradual shift from
spring to autumnal diatom communities that started during the Younger Dryas
and peaked during the Late Holocene, which likely represents orbitally driven
ecosystem responses to long-term changes in seasonality. Using a
multivariate classification tree, we show that trends in planktonic and
tychoplanktonic diatoms broadly reflect both long-term climatic changes
associated with the demise of Northern Hemisphere ice sheets and abrupt
climatic changes associated with, for example, the Younger Dryas stadial.
Indeed, diatom communities are most different before and after the boundary
between the Early and Middle Holocene periods of ca. 8.2 cal kyr BP, associated
with the presence and demise of Northern Hemisphere ice sheets respectively.
Diatom richness and diversity, estimated using Hill's species numbers, are
also shown to be very responsive to periods characterized by abrupt climate
change, and using knowledge of diatom autecologies in Lake Baikal, diversity
trends are interpreted in terms of resource availability. Using diatom
biovolume accumulation rates (BVARs; µm3 cm−2 yr−1), we
show that spring diatom crops dominate palaeoproductivity for nearly all of
our record, apart from a short period during the Late Holocene, when
autumnal productivity dominated between 1.8–1.4 cal kyr BP.
Palaeoproductivity was especially unstable during the Younger Dryas,
reaching peak rates of 18.3 × 103 µm3 cm−2 yr−1 at
ca. 12.3 cal kyr BP. Generalized additive models (GAMs), which explore
productivity–diversity relationships (PDRs) during pre-defined climate
periods, reveal complex relationships. The strongest statistical evidence for
GAMs were found during the Younger Dryas, the Early Holocene, and the Late
Holocene, i.e. periods of rapid climate change. We account for these
differences in terms of climate-mediated resource availability, and the
ability of endemic diatom species in Lake Baikal to adapt to extreme forms
of living in this unique ecosystem. Our analyses offer insight into how
productivity–diversity relationships may develop in the future under a
warming climate
Investigating interfacial electron transfer in dye-sensitized NiO using vibrational spectroscopy
Understanding what influences the formation and lifetime of charge-separated states is key to developing photoelectrochemical devices. This paper describes the use of time-resolved infrared absorption spectroscopy (TRIR) to determine the structure and lifetime of the intermediates formed on photoexcitation of two organic donor-π-acceptor dyes adsorbed to the surface of NiO. The donor and π-linker of both dyes is triphenylamine and thiophene but the acceptors differ, maleonitrile (1) and bodipy (2). Despite their structural similarities, dye 1 outperforms 2 significantly in devices. Strong transient bands in the fingerprint region (1 and 2) and nitrile region (2300-2000 cm–1) for 1 enabled us to monitor the structure of the excited states in solution or adsorbed on NiO (in the absence and presence of electrolyte) and the corresponding kinetics, which on a ps-ns timescale. The results are consistent with rapid (<1 ps) charge-transfer from NiO to the excited dye (1) to give exclusively the charge-separated state on the timescale of our measurements. Conversely, the TRIR experiments revealed that multiple species are present shortly after excitation of the bodipy chromophore in 2, which is electronically decoupled from the thiophene linker. In solution, excitation first populates the bodipy singlet excited state, followed by charge transfer from the triphenylamine to the bodipy. The presence and short lifetime (τ ≈ 30 ps) of the charge-transfer excited state when 2 is adsorbed on NiO (2|NiO) suggests that charge separation is slower and/or less efficient in 2|NiO than in 1|NiO. This is consistent with the difference in performance between the two dyes in dye-sensitized solar cells and photoelectrochemical water splitting devices. Compared to n-type materials such as TiO2, less is understood regarding electron transfer between dyes and p-type metal oxides such as NiO, but it is evident that fast charge-recombination presents a limit to the performance of photocathodes. This is also a major challenge to photocatalytic systems based on a “Z-scheme”, where the catalysis takes place on a μs-s timescale
Serum C-reactive protein is associated with earlier mortality across different interstitial lung diseases
Background and Objective: The acute-phase protein C-reactive protein (CRP) is known to be associated with poor outcomes in cancer and cardiovascular disease, but there is limited evidence of its prognostic implications in interstitial lung diseases (ILDs). We therefore set out to test whether baseline serum CRP levels are associated with mortality in four different ILDs. Methods: In this retrospective study, clinically measured CRP levels, as well as baseline demographics and lung function measures, were collected for ILD patients first presenting to the Royal Brompton Hospital between January 2010 and December 2019. Cox regression analysis was used to determine the relationship with 5-year mortality. Results: Patients included in the study were: idiopathic pulmonary fibrosis (IPF) n = 422, fibrotic hypersensitivity pneumonitis (fHP) n = 233, rheumatoid arthritis associated ILD (RA-ILD) n = 111 and Systemic Sclerosis associated ILD (SSc-ILD) n = 86. Patients with a recent history of infection were excluded. Higher CRP levels were associated with shorter 5-year survival in all four disease groups on both univariable analyses, and after adjusting for age, gender, smoking history, immunosuppressive therapy and baseline disease severity (IPF: HR (95% CI): 1.3 (1.1–1.5), p = 0.003, fHP: 1.5 (1.2–1.9), p = 0.001, RA-ILD: 1.4 (1.1–1.84), p = 0.01 and SSc-ILD: 2.7 (1.6–4.5), p < 0.001). Conclusion: Higher CRP levels are independently associated with reduced 5-year survival in IPF, fHP, RA-ILD and SSc-ILD
Deep Learning for Cardiologist-level Myocardial Infarction Detection in Electrocardiograms
Myocardial infarction is the leading cause of death worldwide. In this paper,
we design domain-inspired neural network models to detect myocardial
infarction. First, we study the contribution of various leads. This systematic
analysis, first of its kind in the literature, indicates that out of 15 ECG
leads, data from the v6, vz, and ii leads are critical to correctly identify
myocardial infarction. Second, we use this finding and adapt the ConvNetQuake
neural network model--originally designed to identify earthquakes--to attain
state-of-the-art classification results for myocardial infarction, achieving
classification accuracy on a record-wise split, and
classification accuracy on a patient-wise split. These two results represent
cardiologist-level performance level for myocardial infarction detection after
feeding only 10 seconds of raw ECG data into our model. Third, we show that our
multi-ECG-channel neural network achieves cardiologist-level performance
without the need of any kind of manual feature extraction or data
pre-processing.Comment: Accepted to the European Medical and Biological Engineering
Conference (EMBEC) 202
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