OALib Journal期刊

ISSN: 2333-9721



匹配條件: “Ulrich Sinsch” ,找到相關結果約3579條。
Rapid assessment of montane anuran communities in the Albertine Rift: Hyperolius castaneus Ahl, 1931 as an umbrella species for conservation
Ulrich Sinsch
African Zoology , 2012,
Abstract: The species richness of seven montane anuran communities of the Albertine Rift was assessed with visual and acoustic transects. A total of 28 anuran species were detected. The highland anuran communities at (2 000 – 2 800 m) were dominated by up to nine Albertine Rift endemic species considered threatened by IUCN Red List criteria, whereas the community at lower elevation included mainly wide–ranging, least–concern species. Cluster analyses of the presence/absence data on the overall array of species indicated that Ahl′s reed frog (Hyperolius castaneus) is a suitable umbrella species for the highland Albertine Rift endemics. Hyperolius castaneus was always among the first species collected at each site, either by visual detection or by acoustic detection based on the characteristic advertisement and aggression calls which were emitted during the day and at night. The ease of its detection in the field makes this species an ideal candidate for rapid assessments of priority sites for conservation measures.
Acoustic niche partitioning in an anuran community inhabiting an afromontane wetland (Butare, Rwanda)
Ulrich Sinsch,Katrin Lümkemann,Katharina Rosar,K. Schwarz
African Zoology , 2012,
Abstract: The species richness and calling activity of an anuran community inhabiting an agricultural wetland area at 1 645 m asl near Butare, Rwanda, was assessed with visual and acoustic transects. The community included 15 species which were readily distinguishable using morphological, bioacoustic and molecular features. Eight species (Xenopus victorianus, Amietophrynus regularis, Ptychadena anchietae, P. porosissima, Kassina senegalensis, Afrixalus quadrivittatus, Hyperolius kivuensis, H. lateralis) were taxonomically identified. The remaining seven species (3 species of Hyperolius, 2 Phrynobatrachus, 1 Amietia, 1 Ptychadena) represent undescribed or currently unrecognized taxa suggesting a significant magnitude of overlooked amphibian diversity in afromontane communities. Acoustic niche analysis of the 14 species producing airborne advertisement calls integrated the spatial dimension, i.e. the microhabitat used for calling, the temporal dimension, i.e. the daytime at which calling takes place, and the call structure dimension, i.e. the physical features of the advertisement call. Average standardized acoustic niche breadth was narrow (measured: 0.08, predicted: 0.07) and showed low variability (0.04 - 0.16) among species, which means that empiric data are in full agreement with the predictions of stochastic niche theory for species-saturated communities. Niche segregation was mainly based on advertisement call features, whereas spatial and temporal niche dimension contributed less. Measured average niche overlap (0.30) was intermediate between random overlap (0.51) and minimum possible overlap (0.11) indicating significant acoustic resource partitioning. The only taxon group with widely overlapping acoustic niches were Ptychadena spp. which might indicate a recent invasion of the community by one or two of the three species.
Mathematical Rotordynamic Model Regarding Excitation Due to Elliptical Shaft Journals in Electrical Motors Considering the Gyroscopic Effect  [PDF]
Ulrich Werner
Applied Mathematics (AM) , 2013, DOI: 10.4236/am.2013.48A009

The paper presents a mathematical rotordynamic model regarding excitation due to elliptical shaft journals in sleeve bearings of electrical motors also considering the gyroscopic effect. For this kind of excitation, a mathematical rotordynamic model was developed considering the influence of the oil film stiffness and damping of the sleeve bearings, the stiffness of the end-shields and bearing housings, the stiffness of the rotor, the electromagnetic stiffness in the air gap of the electrical motor and the mass moment of inertia of the rotor and therefore also considering the gyroscopic effect. The solution of the linear differential equation system leads to the mathematical description of the absolute orbits of the shaft centre, the shaft journals and the bearing housings and to the relative orbits between the shaft journals and the bearing housings. Additionally, the bearing housing velocities can also be derived with this mathematical rotordynamic model.

Mathematical Multibody Model of a Soft Mounted Induction Motor Regarding Forced Vibrations Due to Dynamic Rotor Eccentricities Considering Electromagnetic Field Damping  [PDF]
Ulrich Werner
Journal of Applied Mathematics and Physics (JAMP) , 2017, DOI: 10.4236/jamp.2017.52032
Abstract: The paper presents a mathematical multibody model of a soft mounted induction motor with sleeve bearings regarding forced vibrations caused by dynamic rotor eccentricities considering electromagnetic field damping. The multibody model contains the mass of the stator, rotor, shaft journals and bearing housings, the electromagnetic forces with respect of electromagnetic field damping, stiffness and internal (rotating) damping of the rotor, different kinds of dynamic rotor eccentricity, stiffness and damping of the bearing housings and end shields, stiffness and damping of the oil film of the sleeve bearings and stiffness and damping of the foundation. With this multibody model, the bearing housing vibrations and the relative shaft vibrations in the sleeve bearings can be derived.
Influence of the Foundation on the Threshold of Stability for Rotating Machines with Roller Bearings—A Theoretical Analysis  [PDF]
Ulrich Werner
Journal of Applied Mathematics and Physics (JAMP) , 2017, DOI: 10.4236/jamp.2017.56114
Abstract: The paper presents a mathematical model for analyzing the threshold of stability for rotating machines, where the rotor is linked to the stator by roller bearings, bearing housings and end-shields and where the stator feet are mounted on a soft foundation. The internal (rotating) damping of the rotor is the only source of instability, which is considered in the paper. After the mathematical coherences of the multibody model are described, a procedure is presented for deriving the threshold of stability. Additionally, a numerical example is shown, where the threshold of stability is calculated for different boundary conditions. It could be demonstrated, that the stiffness of the foundation—even if the foundation stiffness is isotropic—can help stabilizing this kind of vibration system in the same way as orthotropic bearing stiffness or orthotropic bearing housing and end-shield stiffness for a rigid foundation.
Analysis of Different Vibration Control Strategies for Soft Mounted Induction Motors with Sleeve Bearings Using Active Motor Foot Mounts  [PDF]
Ulrich Werner
Journal of Applied Mathematics and Physics (JAMP) , 2019, DOI: 10.4236/jamp.2019.73045
Abstract: The paper presents a theoretical analysis of different vibration control strategies of soft mounted induction motors with sleeve bearings, using active motor foot mounts. After the vibration model is presented, different controllers in combination with different feedback strategies are mathematically investigated. The focus is here on the forced vibrations, caused by dynamic rotor eccentricityrotor mass eccentricity, magnetic eccentricity and bent rotor deflection. After the mathematically coherences are described, a numerical example is shown, where the forced vibrations caused by bent rotor deflection are investigated, for different control strategies, where the mass matrix, the stiffness matrix and the damping matrix are influenced by different control parameters. The aim of the paper is to show the mathematically coherences and the possibility to influence the vibration behaviour, by different control strategies to optimize the vibration behaviour of soft mounted induction motors.
Dirac Hamiltonian with Imaginary Mass and Induced Helicity—Dependence by Indefinite Metric  [PDF]
Ulrich D. Jentschura
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.39116
Abstract: It is of general theoretical interest to investigate the properties of superluminal matter wave equations for spin one-half particles. One can either enforce superluminal propagation by an explicit substitution of the real mass term for an imaginary mass, or one can use a matrix representation of the imaginary unit that multiplies the mass term. The latter leads to the tachyonic Dirac equation, while the equation obtained by the substitution m im in the Dirac equation is naturally referred to as the imaginary-mass Dirac equation. Both the tachyonic as well as the imaginary-mass Dirac Hamiltonians commute with the helicity operator. Both Hamiltonians are pseudo-Hermitian and also possess additional modified pseudo-Hermitian properties, leading to constraints on the resonance eigenvalues. Here, by an explicit calculation, we show that specific sum rules over the The spectrum is found to consist of well-defined real energy eigenvalues and complex resonance and anti-resonance energies. In the quantized imaginary-mass Dirac field, one-particle states of right-handed helicity acquire a negative norm (“indefinite metric”) and can be excluded from the physical spectrum by a Gupta-Bleuler type condition.
Non-peptide ligands in the characterization of peptide receptors at the interface between neuroendocrine and mental diseases  [PDF]
Margit Pissarek, Ulrich Disko
World Journal of Neuroscience (WJNS) , 2013, DOI: 10.4236/wjns.2013.32014

Hypothalamic receptors for neuropeptide Y, melaninconcentrating hormone, melanocortins and orexins/ hypocretins as well as for the downstream signaling corticotrophic factor have been discussed broadly for their influence on food intake and reward but also on several psychiatric disorders. For the development of non-peptide ligands for the in vivo detection of alterations in density and affinity of such G-protein coupled (GPCRs) peptide receptors the requirements to affinity and pharmacokinetics have been shifted to thresholds markedly distict from classical GPCRs to dissociation constants < 0.5 nM, partition coefficients log P < 3.5 and transcellular transport ratios, e.g. for the permeability glycoprotein transporter, below 3. Nevertheless, a multitude of compounds has been reported originally as potential therapeutics in the treatment of obesity among which some are suitable candidates for labeling as PET or SPECT-tracers providing receptor affinities even below 0.1 nM. These could be unique tools not only for better understanding of the mechanism of obesity but also for investigations of extrahypothalamic role of “feeding receptors” at the interface between neuroendocrine and mental diseases.

Age of grassy strips influences biodiversity of ground beetles in organic agro-ecosystems  [PDF]
Mazhar Ranjha, Ulrich Irmler
Agricultural Sciences (AS) , 2013, DOI: 10.4236/as.2013.45030

The following investigations were conducted to evaluate grassy strips of different age for organic arable fields. From September 2009 to October 2010, adult ground beetles were sampled by pitfall traps in three grassy strips (2, 4, and 9 years old), their adjacent cropping areas, their field edges, and a control field (age 0) in Schleswig-Holstein, northern Germany. Carabid assemblages were similar among the fields, strips and edges. Grassy strips and edges had higher species richness and lower activity density than the control field. Activity density increased with increasing distance from the field edge in grassy strips and in the adjacent fields. In cropping areas, species richness andShannon’s H increased with increasing age of strips, whereas evenness and activity density decreased with increasing distance from the field edges. Compared to carnivorous and phytophagous carbides, omnivorous species were affected less by age of strips and distance from field margins. In the strips, species richness of the dominant species increased with age and decreased with distance, but the effect of strip age on species richness was still found in more than150 mfrom the margin. A positive effect of the age of grassy strips on species richness was found for cropping fields, grassy strips and field edges. Old grassy strips also exerted greater influence on the species richness and biodiversity of the adjacent arable fields than the younger strips.

Pregnancy and Loneliness: The Therapeutic Value of 3D/4D Ultrasound  [PDF]
Ulrich Honemeyer, Asim Kurjak
Psychology (PSYCH) , 2014, DOI: 10.4236/psych.2014.57085

The fetal sensual and motoric equipment and its successful development within the maternal organism on the one hand, and the harmonic psycho-physic transformation and maturation of the woman into a mother on the other hand, are linked in dialectic inter-dependence. We describe situations in which the harmony of this process is disturbed. Visualization of the fetus in 3D and real time 3D (4D) can influence parental phantasies of the unborn, improve compromised bonding, or create bonding between fetus and (foster)-parents, and support understanding and even acceptance of fetal pathology.


Copyright ? 2008-2017 Open Access Library. All rights reserved.