Historically, marine survival estimates for salmon have been confounded with freshwater seaward migration (outmigration) survival. Telemetry studies have revealed low and variable survival during ...outmigration, suggesting marine mortality may not be the primary source of variability in cohort size as previously believed. Using a novel combination of tagging technologies, survival during these two life stages was decoupled over 5 years for Sacramento River Chinook salmon (Oncorhynchus tshawytscha). Outmigration survival ranged from 2.6% to 17%, and marine survival ranged from 4.2% to 22.8%. Influential environmental drivers in both life stages were also compared with smolt-to-adult ratios (SAR) for three Chinook salmon populations over 20 years. Streamflow during outmigration had higher correlation with SAR (r
2
> 0.34) than two marine productivity indices (r
2
< 0.08). The few SAR estimates that were poorly predicted by flow occurred during years with the lowest marine productivity, suggesting most interannual SAR fluctuations are explained by outmigration survival, but abnormally poor marine conditions also reduce SAR. The outsized influence of flow on SAR provides managers with a powerful mitigation tool in a watershed where flow is tightly regulated.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Falls are a major public health issue not only for older adults but also young adults, with fall-related injuries occurring more frequently in adult females than males. However, the sex differences ...in the frequency and circumstances of falls in young adults are understudied. This research quantified the frequency and circumstances of falls as a function of sex, physical activity, and prescription medications in young adults. For 16 weeks, young adult participants (N = 325; 89 males; 19.9±1.1 years) responded to a daily email asking if they had slipped, tripped, or fallen in the past 24 hours. Falls and fall-related injuries were not uncommon in young adults: 48% fell at least once, 25% fell more than once, and 10% reported an injury. The most common activities at the time of the fall for females were walking (44%) and sports (33%), and for males, sports (49%) and walking (37%). A zero-inflated Poisson model revealed that higher number of falls were associated with the following: higher levels of physical activity (p = 0.025), higher numbers of medications (p<0.0001), and being male (p = 0.008). Regarding circumstances of falling, females were more likely to be talking to a friend at the time of the fall (OR (95% CI): 0.35 (0.14-0.73); p = 0.01). For slips and trips without a fall, males and females reported the same number of slips (OR (95% CI): 0.885 (0.638-1.227) p = 0.46), but females reported more trips (OR (95% CI): 0.45 (0.30-0.67); p<0.01). Only females reported serious injuries such as concussion and fracture. In conclusion, the rate of falls in young adults was affected by physical activity levels, number of medications, and sex. Quantifying and understanding these differences leads to increased knowledge of falls across the lifespan and is instrumental in developing interventions to prevent falls.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Positron emission tomography (PET) allows detecting molecular brain changes in vivo. However, the accuracy of PET is limited by partial volume effects (PVE) that affects quantitative analysis and ...visual interpretation of the images. Although PVE-correction methods have been shown to effectively increase the correspondence of the measured signal with the true regional tracer uptake, these procedures are still not commonly applied, neither in clinical nor in research settings. Here, we present an implementation of well validated PVE-correction procedures as a SPM toolbox, PETPVE12, for automated processing. We demonstrate its utility by a comprehensive analysis of the effects of PVE-correction on amyloid-sensitive AV45-PET data from 85 patients with Alzheimer's disease (AD) and 179 cognitively normal (CN) elderly. Effects of PVE-correction on global cortical standard uptake value ratios (SUVR) and the power of diagnostic group separation were assessed for the region-wise geometric transfer matrix method (PVEc-GTM), as well as for the 3-compartmental voxel-wise “Müller-Gärtner” method (PVEc-MG). Both PVE-correction methods resulted in decreased global cortical SUVRs in the low to middle range of SUVR values, and in increased global cortical SUVRs at the high values. As a consequence, average SUVR of the CN group was reduced, whereas average SUVR of the AD group was increased by PVE-correction. These effects were also reflected in increased accuracies of group discrimination after PVEc-GTM (AUC=0.86) and PVEc-MG (AUC=0.89) compared to standard non-corrected SUVR (AUC=0.84). Voxel-wise analyses of PVEc-MG corrected data also demonstrated improved detection of regionally increased AV45 SUVR values in AD patients. These findings complement the growing evidence for a beneficial effect of PVE-correction in quantitative analysis of amyloid-sensitive PET data. The novel PETPVE12 toolbox significantly facilitates the application of PVE-correction, particularly within SPM-based processing pipelines. This is expected to foster the use of PVE-correction in brain PET for more widespread use. The toolbox is freely available at http://www.fil.ion.ucl.ac.uk/spm/ext/#PETPVE12.
•Partial volume effects (PVE) introduce significant bias in PET imaging studies.•PETPVE12 is a user-friendly toolbox for PVE correction within SPM software.•We evaluate the toolbox on AV45 PET images from AD patients and controls.•PVE correction improves diagnostic group separation based on AV45 PET scans.•Results underline the benefit of PVEc for quantitative amyloid PET analysis.
Any solution to rising levels of CO2 depends on human behavior. One common approach to changing human behavior is rewarding desired behavior. Because financial incentives often have side effects that ...diminish efficacy, we predict that social rewards are more effective, because they invoke adherence to descriptive and injunctive social norms. We investigated this by measuring electricity use for 13weeks at a Dutch firm. Each week, employees were rewarded for conserving energy. They either received monetary rewards (€0–€5) or social rewards (grade points with a descriptive comment). Rewards were either private or public. In both the short and long term, public rewards outperformed private rewards, and social rewards outperformed monetary rewards. This suggests that private monetary rewards, although popular, may be ineffective. Instead, public social rewards may be a more promising approach to stimulating energy conservation. We argue that this approach should be considered more frequently by policy-makers.
► We experimentally manipulated incentives for energy conservation in a company. ► We show that private financial incentives are ineffective for changing behavior. ► We show that using public social rewards is a more promising approach. ► We show this using actual individual energy conservation data over a 13week period. ► Public social rewards offer a cheap and effective policy alternative.
In the human brain, ≈30% of the energy is spent on synaptic transmission. Disappearance of synaptic activity is the earliest consequence of cerebral ischemia. The changes of synaptic function are ...generally assumed to be reversible and persistent damage is associated with membrane failure and neuronal death. However, there is overwhelming experimental evidence of isolated, but persistent, synaptic failure resulting from mild or moderate cerebral ischemia. Early failure results from presynaptic damage with impaired transmitter release. Proposed mechanisms include dysfunction of adenosine triphosphate-dependent calcium channels and a disturbed docking of glutamate-containing vesicles resulting from impaired phosphorylation. We review energy distribution among neuronal functions, focusing on energy usage of synaptic transmission. We summarize the effect of ischemia on neurotransmission and the evidence of long-lasting synaptic failure as a cause of persistent symptoms in patients with cerebral ischemia. Finally, we discuss the implications of synaptic failure in the diagnosis of cerebral ischemia, including the limited sensitivity of diffusion-weighted MRI in those cases in which damage is presumably limited to the synapses.
Radiation-Balanced Silica Fiber Amplifier Knall, Jennifer M.; Engholm, Magnus; Boilard, Tommy ...
Physical review letters,
07/2021, Letnik:
127, Številka:
1
Journal Article
Recenzirano
Odprti dostop
We report what we believe to be the first radiation-balanced fiber amplifier-a device that provides optical gain while experiencing no temperature rise. The gain medium is a silica fiber with a 21 − ...μ m -diameter core highly doped with Yb3+ (2.52 wt. %) and codoped with 2.00 wt. % Al to reduce concentration quenching. The amplifier is core pumped with 1040-nm light to create anti-Stokes fluorescence cooling and gain in the core at 1064 nm. Using a custom slow-light fiber Bragg grating sensor with mK resolution, temperature measurements are performed at multiple locations along the amplifier fiber. A 4.35-m fiber pumped with 2.62 W produced 17 dB of gain, while the average fiber temperature remained slightly below room temperature. This advancement is a fundamental step toward the creation of ultrastable lasers necessary to many applications, especially low-noise sensing and high-precision metrology.
The radiative effects of biomass‐burning aerosols on regional and global scales can be substantial. Accurate modeling of the radiative effects of smoke aerosols requires wavelength‐dependent ...measurements and parameterizations of their optical properties in the UV and visible spectral ranges along with improved description of their chemical composition. To address this issue, we used a recently developed approach to retrieve the time‐ and spectral‐dependent optical properties of ambient biomass‐burning aerosols from 300 to 650 nm wavelengths during a regional nighttime bonfire festival in Israel. During the biomass burning event, the overall absorption at 400 nm increased by about 2 orders of magnitude, changing the single scattering albedo from a background level of 0.95 to 0.7. Based on the new retrieval method, we provide parameterizations of the wavelength‐dependent effective complex refractive index from 350 to 650 nm for freshly emitted and slightly aged biomass‐burning aerosols. In addition, PM2.5 filter samples were collected for detailed offline chemical analysis of the water‐soluble organics that contribute to light absorption. Nitroaromatics were identified as major organic species responsible for the increased absorption at 400 to 500 nm. Typical chromophores include 4‐nitrocatechol, 4‐nitrophenol, nitrosyringol, and nitroguaiacol; oxidation‐nitration products of methoxyphenols; and known products of lignin pyrolysis. Our findings emphasize the importance of both primary and secondary organic aerosols from biomass burning in absorption of solar radiation and in effective radiative forcing.
Plain Language Summary
The radiative effects of biomass‐burning aerosols on regional and global scales are substantial. Accurate modeling of the radiative effects of smoke aerosols requires wavelength‐dependent measurements and parameterizations of their optical properties in the UV and visible spectral ranges along with improved description of their chemical composition. To address this issue we used a recently developed approach to retrieve the time‐ and spectral‐dependent optical properties of the ambient aerosol from 300 to 650 nm wavelengths and a high‐resolution mass spectrometry analysis of fine particulate matter. We found a significant increase in aerosol light absorption in the UV‐Vis spectral range which is correlated to high levels of nitroaromatic compounds identified in the water‐soluble extracts of the filter samples. Additionally, for further applications of our results in radiative transfer models, we provide parameterizations of the wavelength‐dependent effective complex refractive index from 350 to 650 nm for freshly emitted and aged biomass‐burning aerosols.
Key Points
Evolution of the time‐ and UV‐Vis spectral‐dependent optical properties of ambient aerosols during a biomass‐burning event
Parameterizations of wavelength‐dependent effective complex refractive index of biomass‐burning aerosols
Nitration products of syringol and guaiacol identified as major brown carbon light absorbing compounds with significant absorption above 350 nm
See Gratwicke and Foltynie (doi:10.1093/brain/awx333) for a scientific commentary on this article.
Cognitive impairments in Parkinson's disease show variable onset, severity and progression. Ray et ...al. demonstrate that the future cognitive status of newly diagnosed patients can be predicted from the volume of the nucleus basalis of Meynert, with implications for the development of interventions for cognitive decline in Parkinson's disease dementia.
Abstract
See Gratwicke and Foltynie (doi:10.1093/brain/awx333) for a scientific commentary on this article.
Cognitive impairments are a prevalent and disabling non-motor complication of Parkinson's disease, but with variable expression and progression. The onset of serious cognitive decline occurs alongside substantial cholinergic denervation, but imprecision of previously available techniques for in vivo measurement of cholinergic degeneration limit their use as predictive cognitive biomarkers. However, recent developments in stereotactic mapping of the cholinergic basal forebrain have been found useful for predicting cognitive decline in prodromal stages of Alzheimer's disease. These methods have not yet been applied to longitudinal Parkinson's disease data. In a large sample of people with de novo Parkinson's disease (n = 168), retrieved from the Parkinson's Progressive Markers Initiative database, we measured cholinergic basal forebrain volumes, using morphometric analysis of T1-weighted images in combination with a detailed stereotactic atlas of the cholinergic basal forebrain nuclei. Using a binary classification procedure, we defined patients with reduced basal forebrain volumes (relative to age) at baseline, based on volumes measured in a normative sample (n = 76). Additionally, relationships between the basal forebrain volumes at baseline, risk of later cognitive decline, and scores on up to 5 years of annual cognitive assessments were assessed with regression, survival analysis and linear mixed modelling. In patients, smaller volumes in a region corresponding to the nucleus basalis of Meynert were associated with greater change in global cognitive, but not motor scores after 2 years. Using the binary classification procedure, patients classified as having smaller than expected volumes of the nucleus basalis of Meynert had ∼3.5-fold greater risk of being categorized as mildly cognitively impaired over a period of up to 5 years of follow-up (hazard ratio = 3.51). Finally, linear mixed modelling analysis of domain-specific cognitive scores revealed that patients classified as having smaller than expected nucleus basalis volumes showed more severe and rapid decline over up to 5 years on tests of memory and semantic fluency, but not on tests of executive function. Thus, we provide the first evidence that volumetric measurement of the nucleus basalis of Meynert can predict early cognitive decline. Our methods therefore provide the opportunity for multiple-modality biomarker models to include a cholinergic biomarker, which is currently lacking for the prediction of cognitive deterioration in Parkinson's disease. Additionally, finding dissociated relationships between nucleus basalis status and domain-specific cognitive decline has implications for understanding the neural basis of heterogeneity of Parkinson's disease-related cognitive decline.
Accidental ground state degeneracies-those not a consequence of global symmetries of the Hamiltonian-are inevitably lifted by fluctuations, often leading to long-range order, a phenomenon known as ..."order-by-disorder" (ObD). The detection and characterization of ObD in real materials currently lacks clear, qualitative signatures that distinguish ObD from conventional energetic selection. We show that for order by thermal disorder (ObTD) such a signature exists: a characteristic temperature dependence of the fluctuation-induced pseudo-Goldstone gap. We demonstrate this in a minimal two-dimensional model that exhibits ObTD, the ferromagnetic Heisenberg-compass model on a square lattice. Using spin-dynamics simulations and self-consistent mean-field calculations, we determine the pseudo-Goldstone gap, Δ, and show that at low temperatures it scales as the square root of temperature, sqrtT. We establish that a power-law temperature dependence of the gap is a general consequence of ObTD, showing that all key features of this physics can be captured in a simple model of a particle moving in an effective potential generated by the fluctuation-induced free energy.
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