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Search Results: 1 - 10 of 5582 matches for " Henning Meyer "
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Eggspot Number and Sexual Selection in the Cichlid Fish Astatotilapia burtoni
Frederico Henning,Axel Meyer
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0043695
Abstract: Sexual selection on male coloration is one of the main mechanisms proposed to explain the explosive speciation rates in East African cichlid fish. True eggspots are color patterns characteristic of the most species-rich lineage of cichlids, the Haplochromini, and have been suggested to be causally related to the speciation processes. Eggspots are thought to have originated by sensory exploitation and subsequently gained several roles in sexual advertisement. However, for most of these functions the evidence is equivocal. In addition, the genetic architecture of this trait still is largely unknown. We conducted bidirectional selective breeding experiments for eggspot numbers in the model cichlid, Astatotilapia burtoni. After two generations, low lines responded significantly, whereas the high lines did not. Body size was both phenotypically and genotypically correlated with eggspot number and showed correlated response to selection. Males with higher numbers of eggspots were found to sire larger offspring. Despite the potential to act as honest indicators of fitness, the behavioral experiments showed no evidence of a role in either intra- or inter-sexual selection. Visual-based female preference was instead explained by courtship intensity. The evolution of this trait has been interpreted in light of adaptive theories of sexual selection, however the present and published results suggest the influence of non-adaptive factors such as sensory exploitation, environmental constraints and sexual antagonism.
The nearby population of M dwarfs with WISE: A search for warm circumstellar dust
Henning Avenhaus,Hans Martin Schmid,Michael R. Meyer
Physics , 2012, DOI: 10.1051/0004-6361/201219783
Abstract: Circumstellar debris disks are important because of their connection to planetary systems. An efficient way to identify these systems is through their infrared excess. Most studies so far concentrated on early-type or solar-type stars, but less effort has gone into investigating M dwarfs. We characterize the mid-infrared photometric behavior of M dwarfs and search for infrared excess in nearby M dwarfs taken from the volume-limited RECONS sample using data from the WISE satellite and the 2MASS catalog. Our sample consists of 85 sources encompassing 103 M dwarfs. We derive empirical infrared colors from these data and discuss their errors. Based on this, we check the stars for infrared excess and discuss the minimum excess we would be able to detect. Other than the M8.5 dwarf SCR 1845-6357 A, where the excess is produced by a known T6 companion, we detect no excesses in any of our sample stars. The limits we derive for the 22um excess are slightly higher than the usual detection limit of 10-15% for Spitzer studies, but including the [12]-[22] color in our analysis allows us to derive tight constraints on the fractional dust luminosity L_dust/L_star. We show that this result is consistent with M dwarf excesses in the mid-inrared being as frequent as excesses around earlier-type stars. The low detection rate could be an age effect. We also present a tentative excess detection at 22um around the known cold debris disk M dwarf AU Mic, which is not part of our statistical sample. There is still no clear detection of a mid-infrared excess around any old (>30 Myr) main-sequence M dwarf. It is unclear whether this is due to a different dust evolution around M dwarfs or whether this is an age effect combined with the diffculties involved in searching M dwarfs for infrared excesses. A significantly larger sample of well-studied M dwarfs is required to solve this question.
Untangling Phase and Time in Monophonic Sounds  [PDF]
Henning Thielemann
Journal of Signal and Information Processing (JSIP) , 2010, DOI: 10.4236/jsip.2010.11001
Abstract: We are looking for a mathematical model of monophonic sounds with independent time and phase dimensions. With such a model we can resynthesise a sound with arbitrarily modulated frequency and progress of the timbre. We propose such a model and show that it exactly fulfils some natural properties, like a kind of timeinvariance, robustness against non-harmonic frequencies, envelope preservation, and inclusion of plain resampling as a special case. The resulting algorithm is efficient and allows to process data in a streaming manner with phase and shape modulation at sample rate, what we demonstrate with an implementation in the functional language Haskell. It allows a wide range of applications, namely pitch shifting and time scaling, creative FM synthesis effects, compression of monophonic sounds, generating loops for sampled sounds, synthesise sounds similar to wavetable synthesis, or making ultrasound audible.
Diagnostic procedures and classification of antisocial behavior in Norwegian inmates in preventive detention  [PDF]
Henning Vaeroy
Open Journal of Psychiatry (OJPsych) , 2012, DOI: 10.4236/ojpsych.2012.23027
Abstract: In official Norwegian government reports’ prison statistics, it is claimed that the prevalence of Dissocial Personality Disorder (DPD) or Antisocial Personality Disorder (APD) among inmates in preventive detention is approximately 50%. Furthermore, previous findings have described a practice in which forensic examiners use the DSM SCID axis II for APD to confirm an ICD 10 diagnosis of DPD. Clinical investigation supported by the use of SCID Axis II for quality assurance was performed on almost half the population of inmates (46.4%) in preventive detention at a high security prison. The inmates had all committed severe violent acts including murder. All the information obtained by applying the DSM IV-TR criteria was tested against the ICD-10 Research Criteria (ICD-10-RC) for Dissocial Personality Disorder (ICD-10, DPD). It was found that all inmates met the ICD-10-RC for (DPD) and the DSM-IV-TR definition for Adult Antisocial Behavior (AAB). On the other hand, none met the DSM-IV-TR criteria for (APD). The SCID Axis II failed to identify inmates with APD because the DSM-IV-TR C-criteria, referring to symptoms of childhood Conduct Disorder (CD), were not met. These findings raise important questions since the choice of diagnostic system may influence whether a person’s clinically described antisocial behaviour should be classified as a personality disorder or not. For the inmates, a diagnosis of APD or DPD may compromise their legal rights and affect decisions on prolongation of the preventive detention. Studies have shown that combining the DSM and the ICD diagnostic systems may have consequences for the reliability of the diagnosis.
HG-LG Mode Conversion with Stressed 3-Mode Fibers under Polarization  [PDF]
Henning Soller
Open Journal of Applied Sciences (OJAppS) , 2012, DOI: 10.4236/ojapps.2012.24033
Abstract: We have coupled an upright HG mode into a fiber-optic waveguide and used the application of stress to generate a Laguerre-Gaussian laser mode. We have generalized previous results by McGloin et al. by using a polarized input beam, a true 3-mode fiber and by applying the stress on a stripped piece of the optical waveguide. These generalizations are necessary in order to perform quantum information experiments and obtain reliable information on the stress imposed on the optical fiber.
Balanced Min Cost Flow on Skew Symmetric Networks with Convex Costs  [PDF]
Henning Soller
Open Journal of Discrete Mathematics (OJDM) , 2013, DOI: 10.4236/ojdm.2013.33028
Abstract:

We consider the solution of matching problems with a convex cost function via a network flow algorithm. We review the general mapping between matching problems and flow problems on skew symmetric networks and revisit several results on optimality of network flows. We use these results to derive a balanced capacity scaling algorithm for matching problems with a linear cost function. The latter is later generalized to a balanced capacity scaling algorithm also for a convex cost function. We prove the correctness and discuss the complexity of our solution.

Proximity Effect in Normal-Superconductor Hybrids at the Nanoscale  [PDF]
Henning Soller
Journal of Applied Mathematics and Physics (JAMP) , 2014, DOI: 10.4236/jamp.2014.28082
Abstract:

We analyse the proximity effect in hybrid nanoscale junctions involving superconducting leads. We develop a general framework for the analysis of the proximity effect using the same theoretical methods typically employed for the analysis of conductance properties. We apply our method to a normal-superconductor tunnel contact and compare our results to previous results.

Exciton Condensates and Superconductors-Technical Differences and Physical Similarities  [PDF]
Henning Soller
Journal of Applied Mathematics and Physics (JAMP) , 2015, DOI: 10.4236/jamp.2015.39149
Abstract: We review several recent theoretical and experimental results in the study of exciton condensates. This includes the present experimental advances in the study of exciton condensates both using layers and coupled bilayers. We will shortly illustrate the different phases of exciton condensates. We focus especially on the Bardeen-Cooper-Schrieffer-like phase and illustrate the similarities to superconductors. Afterwards, we want to illustrate several recent advances and proposals for measuring the different phases of superconductors. In the remainder of this short review, we will provide an outlook for the possibilities and complications for future technical applications of exciton condensates.
Dissipative Quantum Computing with Majorana Fermions  [PDF]
Henning Soller
Journal of Applied Mathematics and Physics (JAMP) , 2016, DOI: 10.4236/jamp.2016.42030
Abstract: We describe a scheme for universal quantum computation with Majorana fermions. We investigate two possible dissipative couplings of Majorana fermions to external systems, including metallic leads and local phonons. While the dissipation when coupling to metallic leads to uninteresting states for the Majorana fermions, we show that coupling the Majorana fermions to local phonons allows to generate arbitrary dissipations and therefore universal quantum operations on a single QuBit that can be enhanced by additional two-QuBit operations.
Superconductor Hybrids-Electronic Paths to Quantum Computing  [PDF]
Henning Soller
Journal of Applied Mathematics and Physics (JAMP) , 2017, DOI: 10.4236/jamp.2017.53052
Abstract: We review several recent theoretical and experimental results in the study of superconductor hybrids. This includes the recent experimental advances in the study of superconducting beamsplitters as well as more advanced superconductor hybrid systems including ferromagnets or Majorana fermions. In the same manner, theoretical studies have revealed that such superconductor hybrid systems pave the way towards electronic generation and detection of entanglement as well as possible use cases in quantum computing. We will review the aspects in detail and illustrate the possible next steps to be taken.
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