Urgent plea for global protection of springs Cantonati, Marco; Fensham, Roderick J.; Stevens, Lawrence E. ...
Conservation biology,
February 2021, 2021-02-00, 20210201, Letnik:
35, Številka:
1
Journal Article
We report THz transmission and reflection properties of an ultrafast optically excited highly resistive silicon wafer. Amplified Ti:Sapphire femtosecond laser pulses at 800 nm were used to create ...fluence-dependent carrier density on the front surface of the wafer which modifies the dielectric properties at the THz frequencies. Time-resolved experiments in the optical pump-THz probe configuration were conducted in which THz pulses reflected off from the surface at 0° and 45° angles of incidence make it possible to measure the pump-fluence dependent ultrafast evolution of the reflection and transmission coefficients in 0.5-6 THz range. An analytical model, where both the Drude contributions from the photo-excited electrons and holes account for the change of the dielectric constant of the photo-excited silicon, has been used to evaluate the THz reflection and transmission coefficients at steady state. Thus obtained results match well with the experimental results and demonstrate an all-optical means to convert a silicon wafer into an ultrafast, tunable and broadband neutral density filter or reflector in the THz frequency range.
Keel bone fractures and osteoporosis are prevalent and damaging skeletal issues in the laying hen industry. There is a large interest in improving bone quality parameters to reduce or eliminate these ...conditions, thus improving bird welfare. Both essential fatty acids (EFA) and vitamin D can play a role in bone metabolism. The hypothesis of this study was that birds supplemented with lower n-6:n-3 EFA ratio or vitamin D would have improved bone properties compared to a control diet. A total of 3,520 Lohmann Brown-Lite pullets were used in this study. Pullets were housed on the floor from 0 to 17 wk of age and then moved to an aviary (17–52 wk of age). Starting at 12 wk of age, birds were split into diet treatments—control, flax, fish, or vitamin D diets with n-6:n-3 ratios of 6.750, 0.534, 0.534, and 6.750, respectively. Diets were formulated to be isonitrogenous and isocaloric. Basal vitamin D3 levels were formulated to be 2,760 IU/kg across all diets; for the vitamin D diet, the vitamin D3 level was increased to 5,520 IU/kg. Hens on fish and vitamin D diets had greater bone density, keel bone volume, digital bone mineral content, and keel condition compared to flax and control hens. Additionally, birds fed the vitamin D diet had the heaviest body weights compared to birds fed fish or control diets. Birds fed the flax and vitamin D diets had improved feather coverage across multiple body regions. Feeding an n-3 EFA- or vitamin D-enriched diet decreased mortality by 1.6 to 3.3% compared to the control. The fish and vitamin D diets generated mixed production performance. Compared to the other treatments, the vitamin D diet generated higher case weights but lower hen day percentage throughout the study. When compared to the other treatments, the fish diet had the lowest case weights but had a greater hen day percentage after 36 wk of age. Results indicate that a fish-based EFA and vitamin D supplementation show promise in improving skeletal health but require further investigation.
Patterns of proliferation are templated by both gradients of mechanical stress as well as by gradients in membrane voltage (Vm), which is defined as the electric potential difference between the ...cytoplasm and the extracellular medium. Either gradient could regulate the emergence of the other, or they could arise independently and synergistically affect proliferation within a tissue. Here, we examined the relationship between endogenous patterns of mechanical stress and the generation of bioelectric gradients in mammary epithelial tissues. We observed that the mechanical stress gradients in the tissues presaged gradients in both proliferation and depolarization, consistent with previous reports correlating depolarization with proliferation. Furthermore, disrupting the Vm gradient blocked the emergence of patterned proliferation. We found that the bioelectric gradient formed downstream of mechanical stresses within the tissues and depended on connexin-43 (Cx43) hemichannels, which opened preferentially in cells located in regions of high mechanical stress. Activation of Cx43 hemichannels was necessary for nuclear localization of Yap/Taz and induction of proliferation. Together, these results suggest that mechanotransduction triggers the formation of bioelectric gradients across a tissue, which are further translated into transcriptional changes that template patterns of growth.
Many college students believe that typing lecture notes on computers produces better notes and higher achievement than handwritten lecture notes on paper. The few studies investigating computer ...versus longhand note taking yielded mixed note-taking and achievement findings. The present study investigated computer versus longhand note taking but permitted note takers to revise or recopy notes during pauses interspersed throughout the lecture. Moreover, the present study analyzed notes recorded while a lecture was ongoing and following revision pauses to determine if lecture ideas and images were recorded completely or partially. Findings did not support the belief that computers aid note taking and achievement and, instead, favored longhand note taking and revision. Computer and longhand note takers recorded a comparable number of complete and partial ideas in notes while the lecture was ongoing, but longhand note takers recorded more lecture images. Among note revisers, longhand note takers added three-times-as-many complete ideas to their notes during revision as computer note takers—an important finding because note completeness predicted achievement. Achievement results showed that longhand note takers who revised notes scored more than half a letter grade higher on a lecture posttest than computer note takers who revised notes. Present findings suggest that college instructors should provide students with revision pauses to improve note taking and achievement and encourage students to record and revise notes using the longhand method. Finally, regarding the computer versus longhand note-taking debate, the need to investigate further the interplay between note-taking medium and lesson material is discussed.
Abstract
Sustainable energy systems can only be achieved when reducing both carbon emissions and water use for energy generation. Although the water use for electricity generation has been well ...studied, integrated assessments of the water use by low-carbon heat systems are lacking. In this paper we present an analysis of the water use of scenarios for heat and electricity production for the year 2050 for the Netherlands and its capital, Amsterdam. The analysis shows that (i) the water withdrawal for heating can increase up to the same order of magnitude as the current water withdrawal of thermoelectric plants due to the use of aquifer thermal energy storage, (ii) the virtual water use for heating can become higher than the operational water consumption for heating, and (iii) the water use for electricity production becomes a relevant indicator for the virtual water use for heat generation because of the increase of power-to-heat applications.
Background
The Improving Access to Psychological Therapies (IAPT) service was established to address common mental health problems among the English population in a timely manner in order to counter ...the social and economic disadvantage accompanying such difficulties. Using the concept of candidacy, we examined how the legitimacy of claims by people with intellectual disabilities to use this service is facilitated or impeded.
Method
We used a sequential mixed methods design. We completed 21 interviews with a range of stakeholders, including people with intellectual disabilities and their carers. Themes from the interviews were used to design an online survey questionnaire that was returned by 452 staff from IAPT and specialist intellectual disability services.
Results
Using the candidacy framework, we noted that eligibility and access to IAPT were achieved through dynamic and iterative processes of negotiation involving people with intellectual disabilities and their supporters on one side and IAPT staff and service structures on the other. Barriers and facilitators were apparent throughout the seven dimensions of candidacy (identification, navigation, permeability of services, appearances, adjudications, offers and resistance and operating conditions) and were linked to discourses relating to the character and purpose of IAPT and specialist intellectual disability services.
Conclusions
Opportunities exist for some people with intellectual disabilities to assert their candidacy for IAPT input, although there are barriers at individual, professional, organisational and structural levels. More attention needs to be paid to how principles of inclusiveness are operationalised within IAPT teams and to the mental health facilitation role of specialist intellectual disability staff.
Antifreeze proteins (AFPs) protect certain cold-adapted organisms from freezing to death by selectively adsorbing to internal ice crystals and inhibiting ice propagation. The molecular details of AFP ...adsorption-inhibition is uncertain but is proposed to involve the Gibbs-Thomson effect. Here we show by using unbiased molecular dynamics simulations a protein structure-function mechanism for the spruce budworm Choristoneura fumiferana AFP, including stereo-specific binding and consequential melting and freezing inhibition. The protein binds indirectly to the prism ice face through a linear array of ordered water molecules that are structurally distinct from the ice. Mutation of the ice binding surface disrupts water-ordering and abolishes activity. The adsorption is virtually irreversible, and we confirm the ice growth inhibition is consistent with the Gibbs-Thomson law.
3D terahertz computed tomography has been performed using a monochromatic millimeter wave imaging system coupled with an infrared temperature sensor. Three different reconstruction methods (standard ...back-projection algorithm and two iterative analysis) have been compared in order to reconstruct large size 3D objects. The quality (intensity, contrast and geometric preservation) of reconstructed cross-sectional images has been discussed together with the optimization of the number of projections. Final demonstration to real-life 3D objects has been processed to illustrate the potential of the reconstruction methods for applied terahertz tomography.
Alginate lyase (AL) is a polysaccharide-degrading enzyme that can degrade alginate by hydrolyzing glycosidic bonds and produces unsaturated alginate oligosaccharides (AOSs). These AOSs have wide ...therapeutic and nutraceutical applications. However, to produce alginate oligosaccharides in a cost-effective manner is challenging due to the low availability and high cost of this degrading enzyme. Immobilization of the enzyme facilitates industrial applications owing to its stability, reusability, and cost-effectiveness. This study was focused on the enhancement of the properties of alginate lyase and improvement of the production of AOS. Alginate lyase was immobilized on magnetic nanoparticles (NPs) using glutaraldehyde as the crosslinker. The study showed that the maximum binding achieved between NPs and protein in the enzyme was 71% at a ratio of 1:150 NP:protein. As a result of immobilization, the optimum activity of free enzyme which was obtained at 37 °C and pH 7.4 changed to 45 °C and pH 9. Furthermore, the enzyme was thermostable at 45 °C for 3 h with up to 50% reusability for six consecutive cycles. Storage stability after 15 days showed ~67% relative hydrolysis of alginate. The free alginate lyase (25 IU) showed 76% raw biomass (seaweed) hydrolysis which is higher compared to 63% provided by the immobilized enzyme. As a result of efficient hydrolysis, AOSs with molecular weight profile of 370-1040 kDa were produced and detected using HPLC.
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