691 research outputs found

    Energy efficiency (EE) and cost-effective means to increase EE and to mitigate the climate change of pork and broiler meat production in five European countries

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    Production of pork and broiler meat in the European Union (EU) has increased by 7.8 and 16.1%, respectively, in the period of 2001 – 2011. At that time pork and broiler meat produced, amounted together to over four times the cattle meat. Meat is an important protein source in human diet, but on the other hand, livestock uses globally 30% of ice-free terrestrial land and produces 18% of global greenhouse gas (GHG) emissions. This exceeds the global emissions of the transport sector. Furthermore, energy ratio (output/input) for meat production is less than 1.0 in general and it is much lower than that of plant production. This paper presents cost-effectiveness of EE measures in pork and broiler meat production and it is based on the results of the Agriculture and Energy Efficiency Project (www.AGREE.aua.gr). The structure of the energy input appeared to be very similar in pork and broiler meat production. Feed was found to be the major indirect energy input. Its contribution to the total energy demand varied from 51% to 82% in pork production and from 55% to 94% in broiler meat production. The percentage of feed was the lowest in the Northern European countries and the highest in the south. This difference was mainly attributable to the demand for heating of animal houses during the winter period. Differences could also be found in the absolute energy input of feed. It indicated that there may be possibilities to improve feeding strategies or feed conversation rate of animals. In pork production, the energy input of feed was 12.5 GJ t-1 (live weight) in average and 8.6 GJ t-1 (live weight) in broiler production. The difference between pork and broiler meat is a consequence of the higher feed conversation rate of broilers in contrast to pigs. The category “Other energy use” was the second highest energy input and it consisted of energy input for ventilation, illumination, feeding, and heating of animal houses. In pork production, the input of this category was 4.7 GJ t-1 (live weight) in average (25% from the total energy input) and 2.4 GJ t-1 (live weight) in broiler meat production (22% from the total energy input). The specific energy input in pork production was the lowest in The Netherlands ( 14.5 GJ t-1) and that of broiler meat production in Germany (9.8 GJ t-1). Case studies analysed in five participating countries demonstrated EE measures capable to reduce costs, to increase EE, and to cut GHG emissions at the same time. Proposed EE measures were related to ventilation, heating, feeding, animal bedding, energy generation from manure, and feed production. As an example, an airtight grain storage met all three goals at the same time. Investment costs were lower than those for a grain dryer, no energy was needed for drying, and no GHG emissions were generated because no gas or oil was needed for drying. All suggested EE measures were not as successful. They might appear negative for costs but positive for EE and GHG reduction, resulting in a trade-off situation. An approach like this helps to rank potential EE measures in terms of their cost-effectiveness and capability to cut GHG emissions

    Fiber-optic probe for noninvasive real-time determination of tissue optical properties at multiple wavelengths

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    We present a compact, fast, and versatile fiber-optic probe system for real-time determination of tissue optical properties from spatially resolved continuous-wave diffuse reflectance measurements. The system collects one set of reflectance data from six source-detector distances at four arbitrary wavelengths with a maximum overall sampling rate of 100 Hz. Multivariate calibration techniques based on two-dimensional polynomial fitting are employed to extract and display the absorption and reduced scattering coefficients in real-time mode. The four wavelengths of the current configuration are 660, 785, 805, and 974 nm, respectively. Cross-validation tests on a 6 x 7 calibration matrix of Intralipid-dye phantoms showed that the mean prediction error at, e.g., 785 nm was 2.8% for the absorption coefficient and 1.3% for the reduced scattering coefficient. The errors are relative to the range of the optical properties of the phantoms at 785 nm, which were 0-0.3/cm for the absorption coefficient and 6-16/cm for the reduced scattering coefficient. Finally, we also present and discuss results from preliminary skin tissue measurements. (C) 2001 Optical Society of Americ

    Monopolin subunit Csm1 associates with MIND complex to establish monopolar attachment of sister kinetochores at meiosis I

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    Sexually reproducing organisms halve their cellular ploidy during gametogenesis by undergoing a specialized form of cell division known as meiosis. During meiosis, a single round of DNA replication is followed by two rounds of nuclear divisions (referred to as meiosis I and II). While sister kinetochores bind to microtubules emanating from opposite spindle poles during mitosis, they bind to microtubules originating from the same spindle pole during meiosis I. This phenomenon is referred to as mono-orientation and is essential for setting up the reductional mode of chromosome segregation during meiosis I. In budding yeast, mono-orientation depends on a four component protein complex referred to as monopolin which consists of two nucleolar proteins Csm1 and Lrs4, meiosis-specific protein Mam1 of unknown function and casein kinase Hrr25. Monopolin complex binds to kinetochores during meiosis I and prevents bipolar attachments. Although monopolin associates with kinetochores during meiosis I, its binding site(s) on the kinetochore is not known and its mechanism of action has not been established. By carrying out an imaging-based screen we have found that the MIND complex, a component of the central kinetochore, is required for monopolin association with kinetochores during meiosis. Furthermore, we demonstrate that interaction of monopolin subunit Csm1 with the N-terminal domain of MIND complex subunit Dsn1, is essential for both the association of monopolin with kinetochores and for monopolar attachment of sister kinetochores during meiosis I. As such this provides the first functional evidence for a monopolin-binding site at the kinetochore

    Review of biorthogonal coupled cluster representations for electronic excitation

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    Single reference coupled-cluster (CC) methods for electronic excitation are based on a biorthogonal representation (bCC) of the (shifted) Hamiltonian in terms of excited CC states, also referred to as correlated excited (CE) states, and an associated set of states biorthogonal to the CE states, the latter being essentially configuration interaction (CI) configurations. The bCC representation generates a non-hermitian secular matrix, the eigenvalues representing excitation energies, while the corresponding spectral intensities are to be derived from both the left and right eigenvectors. Using the perspective of the bCC representation, a systematic and comprehensive analysis of the excited-state CC methods is given, extending and generalizing previous such studies. Here, the essential topics are the truncation error characteristics and the separability properties, the latter being crucial for designing size-consistent approximation schemes. Based on the general order relations for the bCC secular matrix and the (left and right) eigenvector matrices, formulas for the perturbation-theoretical (PT) order of the truncation errors (TEO) are derived for energies, transition moments, and property matrix elements of arbitrary excitation classes and truncation levels. In the analysis of the separability properties of the transition moments, the decisive role of the so-called dual ground state is revealed. Due to the use of CE states the bCC approach can be compared to so-called intermediate state representation (ISR) methods based exclusively on suitably orthonormalized CE states. As the present analysis shows, the bCC approach has decisive advantages over the conventional CI treatment, but also distinctly weaker TEO and separability properties in comparison with a full (and hermitian) ISR method

    Gradient microfluidics enables rapid bacterial growth inhibition testing

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    Bacterial growth inhibition tests have become a standard measure of the adverse effects of inhibitors for a wide range of applications, such as toxicity testing in the medical and environmental sciences. However, conventional well-plate formats for these tests are laborious and provide limited information (often being restricted to an end-point assay). In this study, we have developed a microfluidic system that enables fast quantification of the effect of an inhibitor on bacteria growth and survival, within a single experiment. This format offers a unique combination of advantages, including long-term continuous flow culture, generation of concentration gradients, and single cell morphology tracking. Using Escherichia coli and the inhibitor amoxicillin as one model system, we show excellent agreement between an on-chip single cell-based assay and conventional methods to obtain quantitative measures of antibiotic inhibition (for example, minimum inhibition concentration). Furthermore, we show that our methods can provide additional information, over and above that of the standard well-plate assay, including kinetic information on growth inhibition and measurements of bacterial morphological dynamics over a wide range of inhibitor concentrations. Finally, using a second model system, we show that this chip-based systems does not require the bacteria to be labeled and is well suited for the study of naturally occurring species. We illustrate this using Nitrosomonas europaea, an environmentally important bacteria, and show that the chip system can lead to a significant reduction in the period required for growth and inhibition measurements (<4 days, compared to weeks in a culture flask)

    Reproductive Trade-Offs May Moderate the Impact of Gyrodactylus salaris in Warmer Climates

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    Gyrodactylus salaris is a notifiable freshwater ectoparasite of salmonids. Its primary host is Atlantic salmon (Salmo salar), upon which infections can cause death, and have led to massive declines in salmon numbers in Norway, where the parasite is widespread. Different strains of S. salar vary in their susceptibility, with Atlantic strains (such as those found in Norway) exhibiting no resistance to the parasite, and Baltic strains demonstrating an innate resistance sufficient to regulate parasite numbers on the host causing it to either die out or persist at a low level. In this study, Leslie matrix and compartmental models were used to generate data that demonstrated the population growth of G. salaris on an individual host is dependent on the total number of offspring per parasite, its longevity and the timing of its births. The data demonstrated that the key factor determining the rate of G. salaris population growth is the time at which the parasite first gives birth, with rapid birth rate giving rise to large population size. Furthermore, it was shown that though the parasite can give birth up to four times, only two births are required for the population to persist as long as the first birth occurs before a parasite is three days old. As temperature is known to influence the timing of the parasite's first birth, greater impact may be predicted if introduced to countries with warmer climates than Norway, such as the UK and Ireland which are currently recognised to be free of G. salaris. However, the outputs from the models developed in this study suggest that temperature induced trade-offs between the total number of offspring the parasite gives birth to and the first birth timing may prevent increased population growth rates over those observed in Norway

    Sensory, microbiological and chemical changes in vacuum-packaged Blue Spotted Emperor (Lethrinus sp), Saddletail Snapper (Lutjanus malabaricus), Crimson Snapper (Lutjanus erythropterus), Barramundi (Lates calcarifer) and Atlantic Salmon (Salmo salar) fillets stored at 4°C

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    Quality assessment of finfish fillets during storage is important to be able to predict the shelf life of the fresh product during distribution. Microbial, chemical (pH, TMA, and TVB‐N), and sensory (Quality index assessment QIA, Torry scheme) changes in vacuum‐packaged blue‐spotted emperor (Lethrinus sp), saddletail (Lutjanus malabaricus), crimson snapper (Lutjanus erythropterus), barramundi (Lates calcarifer), and Atlantic salmon (Salmo salar) fillets stored at 4°C were evaluated for 5 days. Microbiological study included evaluation of TVC (total viable counts), total psychrotrophic organisms, and H2S‐producing bacteria. Numbers increased during storage time and reached an average of 8.5, 8.5, and 9.2 log10 cfu/g, respectively, for the five different fish species. These levels were above accepted microbiological limits for fish fillets. Although the sensory analyses showed a decrease in quality, none of the finfish fillets were considered unacceptable at the end of the storage trial. Chemically, there was a slight pH increase, but trimethylamine (TMA) levels remained low. However, total volatile basic nitrogen (TVB‐N) levels increased over time, reaching levels above 35 mg/100 g for blue spotted emperor, saddletail snapper, and crimson snapper by the end of the storage period. Results show that the deterioration of finfish fillet quality is a complex event of biochemical, sensory, and microbial factors, and multiple analyses may be required to define acceptability
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