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Search Results: 1 - 10 of 1743 matches for " Susanne Velten "
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Improving the Dietary Protein Quality by Amino Acid Fortification with a High Inclusion Level of Micro Algae (Spirulina platensis) or Insect Meal (Hermetia illucens) in Meat Type Chicken Diets  [PDF]
Carmen Neumann, Susanne Velten, Frank Liebert
Open Journal of Animal Sciences (OJAS) , 2018, DOI: 10.4236/ojas.2018.81002
Abstract: The objective of this study was to measure protein quality parameters (PPV, NPU and NPUstd) of chicken diets with complete substitution of soybean meal (SBM) by Spirulina meal (SM) or partly defatted Hermetia meal (HM). N balance experiments were based on the quantitative excreta collection method, divided into starter period (10 - 20 d) and grower period (25 - 35 d). The study utilized 70 all male meat type chicken (Ross 308). Data assessment applied the exponential N utilization model of the “Goettingen approach”. The control diet was based on wheat, corn and SBM. In four experimental diets SBM was completely substituted by SM or HM, but fortified with feed amino acids (AA) both on a basic level of supplementation (Lys and Met added equal to the control diet) and on an extended level (Lys, Met, Thr, Arg, Val, Ile, His added). At a basic level of AA supplementation, complete replacement of SBM by SM or HM in chicken diets depressed dietary protein quality significantly (p < 0.05). However, the extended level of AA supplementation improved protein quality parameters of the diets with both of the alternative proteins significantly (p < 0.05), but still generally not on par with the control diet. The observed responses were accentuated when the well-known effect of N intake on protein utilization was eliminated through the standardization of N intake by application of the “Goettingen approach”.
The Graded Inclusion of Algae (Spirulina platensis) or Insect (Hermetia illucens) Meal as a Soybean Meal Substitute in Meat Type Chicken Diets Impacts on Growth, Nutrient Deposition and Dietary Protein Quality Depending on the Extent of Amino Acid Supplementation  [PDF]
Carmen Neumann, Susanne Velten, Frank Liebert
Open Journal of Animal Sciences (OJAS) , 2018, DOI: 10.4236/ojas.2018.82012
Abstract: Three consecutive growth experiments were conducted to evaluate growth performance, whole body analyses and protein quality parameters from chicken diets with 50%, 75% and 100% substitution of soybean meal (SBM) by Spirulina meal (SM) or partly defatted Hermetia meal (HM). Each of the experiments was divided into a starter period (1 - 21 d) and a grower period (22 - 34 d). One-day-old male growing chickens (Ross 308) were randomly allotted to 48 floor pens making use of 6 birds/pen (Exp.1) or 7 birds/pen (Exp. 2, 3), and the experiments included a control diet (n = 12) and four experimental diets (n = 9). Experiment 1 examined a 50 % replacement of SBM by the alternative proteins under study, both on a basic and an advanced level of amino acid (AA) fortification to meet the recommended ideal amino acid ratio (IAAR). In experiment 2, 75% (starter diet) and 50% (grower diet) replacement of SBM was investigated. Experiment 3 investigated the effects of complete SBM substitution by SM or HM in starter and grower diets. In the second and third experiment diets with both of the alternative proteins and the control diet were AA supplemented to meet the current IAAR. In a further step, the calculated first limiting AA (LAA) was reduced to 80% of its requirement recommendation to allow for further evaluation of the individual AA efficiency according to the Goettingen approach. Different levels (50%, 75%, or 100%) of replacing SBM by HM or SM in chicken diets depressed dietary protein quality (p <
Effects of the Partial Replacement of Soybean Meal by Insect or Algae Meal in Chicken Diets with Graded Amino Acid Supply on Parameters of Gut Microbiology and Dietary Protein Quality  [PDF]
Susanne Velten, Carmen Neumann, Jenny Sch?fer, Frank Liebert
Open Journal of Animal Sciences (OJAS) , 2018, DOI: 10.4236/ojas.2018.83020
Abstract: Insects or algae are considered future solutions to substitute imported feed proteins like soybean meal (SBM) in animal nutrition. The objective of this research, as part of the multidisciplinary project “Sustainability transitions”, focused on replacing 50% SBM by partly defatted larvae meal from black soldier flies (Hermetia illucens) or the blue-green algae Spirulina platensis in meat type chicken diets. The current study aimed to evaluate the effects on body composition, protein quality, apparent precaecal digestibility (apcD) and parameters of intestinal microbiota. In total, 288 one-day-old male growing chickens (Ross 308) from a commercial hatchery were randomly allotted to 48 pens (6 birds per pen) across five diets, which were fed at a free choice level. The control diet utilized SBM, wheat and corn as main ingredients, and experimental diets replaced 50% of SBM by the alternative proteins under study. Amino acid (AA) supplementation of the final diets was conducted both at a basic level (diets HM, SM; Lys and Met added equal to the control diet) and an extended level of AA fortification (diets HM+, SM+; extended supplementation of Lys, Met, Thr, Arg). After finishing the growth study, 4 individual birds per diet were slaughtered for whole body analyses to derive nutrient utilization and dietary protein quality parameters. Additionally, pooled chyme samples from 16 birds per diet (control, HM and SM) were analyzed to assess apcD and microbial parameters. Diets HM and SM with a basic level of AA fortification led to significant depressions in nutrient deposition and dietary protein quality. However, HM+ and SM+ diets with an extended level of AA supplementation led to significantly improved responses; however these were still generally not on par with the control diet. The HM+ diet provided superior CP deposition and dietary protein quality, as compared to the SM+ diet, but equal to the control diet. Results of gut microbiology yielded no significant effects due to feeding the alternative protein sources under study.
Effects of 50 Percent Substitution of Soybean Meal by Alternative Proteins from Hermetia illucens or Spirulina platensis in Meat-Type Chicken Diets with Graded Amino Acid Supply  [PDF]
Susanne Velten, Carmen Neumann, Martina Bleyer, Eva Gruber-Dujardin, Maria Hanuszewska, Barbara Przybylska-Gornowicz, Frank Liebert
Open Journal of Animal Sciences (OJAS) , 2018, DOI: 10.4236/ojas.2018.82009
Abstract: Alternative protein sources, such as insects or algae meals are in special focus of animal nutrition in order to replace soybean meal (SBM). As part of the multidisciplinary project “sustainability transitions” this study evaluated effects of replacing SBM by partly defatted larvae meal from the black soldier fly, Hermetia illucens or meal from the micro algae Spirulina platensis in broiler diets. The aim of the current study was to investigate the chickens growth performance and the intestinal morphology as well as the health status. 288 one-day-old male growing chickens (Ross 308) from a commercial hatchery were randomly allotted to 48 pens (6 birds per pen) for the growth study with five diets and feed supply on free choice level. The control diet was based on wheat, corn and SBM. The experimental diets replaced 50% of SBM by the alternative proteins under study, both on a basic level of amino acid (AA) supplementation (Lys and Met added equal to the control diet) (diet HM and SM) and an extended level of AA fortification (Lys, Met, Thr, Arg, Val added) (diet HM+ and SM+). Response of chickens was evaluated by zoo-technical parameters, which were under weekly control (e.g. growth, feed intake, feed conversion ratio, mortality). After finishing the growth study birds from control and the experimental diets at the basic level of AA supplementation were slaughtered after 12 hour fastening and utilized for gut morphometric analysis and histological evaluation of the health status. Diets at a basic level of AA fortification led to significant depression of growth, feed intake, feed conversion ratio, and protein conversion ratio, respectively. In addition, the acceptance of the Spirulina diet was lower (p 0.001) as compared to the Hermetia based diet.
Viscous Cold Dark Matter in agreement with observations
Hermano Velten
Physics , 2013,
Abstract: We discuss bulk viscous cosmological models. Since the bulk viscous pressure is negative, viable viscous cosmological scenarios with late time accelerated expansion can in principle be constructed. After discussing some alternative models based on bulk viscous effects we will focus on a model very similar to the standard $\Lambda$CDM. We argue that a $\Lambda${\rm v}CDM model, where we assign a very small (albeit perceptible) bulk viscosity to dark matter is in agreement with available cosmological observations. Hence, we work with the concept of viscous Cold Dark Matter ({\rm v}CDM). At the level of the perturbations, the growth of {\rm v}CDM structures is slightly suppressed when compared with the standard CDM ones. Having in mind that the small scale problems of the $\Lambda$CDM model are related to an excess of clustering, our proposal seems to indicate a possible direction for solving the serious drawbacks of the CDM paradigm within the standard cosmological model.
Albert Ellis (1913-2007)
Leonor Lega,Emmett Velten
Revista Latinoamericana de Psicología , 2008,
Abstract:
Power spectrum for the Bose-Einstein condensate dark matter
Hermano Velten,Etienne Wamba
Physics , 2011, DOI: 10.1016/j.physletb.2012.01.071
Abstract: We assume that dark matter is composed of scalar particles that form a Bose-Einstein condensate (BEC) at some point during the cosmic evolution. Afterwards, cold dark matter is in the form of a condensate and behaves slightly different from the standard dark matter component. We study the large scale perturbative dynamics of the BEC dark matter in a model where this component coexists with baryonic matter and cosmological constant. The perturbative dynamics is studied using neo- Newtonian cosmology (where the pressure is dynamically relevant for the homogeneous and isotropic background) which is assumed to be correct for small values of the sound speed. We show that BEC dark matter effects can be seen in the matter power spectrum if the mass of the condensate particle lies in the range 15meV < m < 700meV leading to a small, but perceptible, excess of power at large scales.
Exploring non-linear cosmological matter diffusion coefficients
Hermano Velten,Simone Calogero
Physics , 2014,
Abstract: Since microscopic velocity diffusion can be incorporated into general relativity in a consistent way, we study cosmological background solutions when the diffusion phenomena takes place in an expanding universe. Our focus here relies on the nature of the diffusion coefficient $\sigma$ which measures the magnitude of such transport phenomena. We test dynamics where $\sigma$ has a phenomenological dependence on the scale factor, the matter density, the dark energy and the expansion rate.
Cosmology with matter diffusion
Simone Calogero,Hermano Velten
Physics , 2013, DOI: 10.1088/1475-7516/2013/11/025
Abstract: We construct a viable cosmological model based on velocity diffusion of matter particles. In order to ensure the conservation of the total energy-momentum tensor in the presence of diffusion, we include a cosmological scalar field $\phi$ which we identify with the dark energy component of the Universe. The model is characterized by only one new degree of freedom, the diffusion parameter $\sigma$. The standard $\Lambda$CDM model can be recovered by setting $\sigma=0$. If diffusion takes place ($\sigma >0$) the dynamics of the matter and of the dark energy fields are coupled. We argue that the existence of a diffusion mechanism in the Universe can serve as a theoretical motivation for interacting models. We constrain the background dynamics of the diffusion model with Supernovae, H(z) and BAO data. We also perform a perturbative analysis of this model in order to understand structure formation in the Universe. We calculate the impact of diffusion both on the CMB spectrum, with particular attention to the integrated Sachs-Wolfe signal, and on the matter power spectrum $P(k)$. The latter analysis places strong constraints on the magnitude of the diffusion mechanism but does not rule out the model.
Semantic Jira - Semantic Expert Finder in the Bug Tracking Tool Jira
Velten Heyn,Adrian Paschke
Computer Science , 2013,
Abstract: The semantic expert recommender extension for the Jira bug tracking system semantically searches for similar tickets in Jira and recommends experts and links to existing organizational (Wiki) knowledge for each ticket. This helps to avoid redundant work and supports the search and collaboration with experts in the project management and maintenance phase based on semantically enriched tickets in Jira.
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