A Novel Combined System of Direction Estimation and Sound Zooming of Multiple Speakers

This article presents a new system for estimation the direction of multiple speakers and zooming the sound of one of them at a time. The proposed system is a combination of two levels; namely, sound source direction estimation, and acoustic zooming. The sound source direction estimation uses so-called the energetic analysis method for estimation the direction of multiple speakers, whereas the acoustic zooming is based on modifying the parameters of the directional audio coding (DirAC) in order to zoom the sound of a selected speaker among the others. Both listening tests and objective assessments are performed to evaluate this system using different time-frequency transforms

Spin fluctuations in the 0.7-anomaly in quantum point contacts

It has been argued that the 0.7 anomaly in quantum point contacts (QPCs) is due to an enhanced density of states at the top of the QPC-barrier (van Hove ridge), which strongly enhances the effects of interactions. Here, we analyze their effect on dynamical quantities. We find that they pin the van Hove ridge to the chemical potential when the QPC is subopen; cause a temperature dependence for the linear conductance that qualitatively agrees with experiment; strongly enhance the magnitude of the dynamical spin susceptibility; and significantly lengthen the QPC traversal time. We conclude that electrons traverse the QPC via a slowly fluctuating spin structure of finite spatial extent

Laser-assisted zona pellucida thinning does not facilitate hatching and may disrupt the in vitro hatching process: a morphokinetic study in the mouse

STUDY QUESTION: Does laser-assisted zona thinning of cleavage stage mouse embryos facilitate hatching in vitro? SUMMARY ANSWER: No, unlike laser zona opening, zona thinning does not facilitate embryo hatching. WHAT IS KNOWN ALREADY: Artificial opening of the zona pellucida facilitates hatching of mouse and human embryos. Laser-assisted zona thinning has also been used for the purpose of assisted hatching of human embryos but it has not been properly investigated in an animal model; thinning methods have produced inconsistent clinical results. STUDY DESIGN, SIZE, DURATION: Time-lapse microscopy was used to study the hatching process in the mouse after zona opening and zona thinning; a control group of embryos was not zona-manipulated but exposed to the same laser energy. PARTICIPANTS/MATERIALS, SETTING, METHODS: Eight-cell CB6F1/J mouse embryos were pooled and allocated to three groups (n = 56 per group): A control group of embryos that were exposed to a dose of laser energy focused outside the zona pellucida (zona intact); one experimental group of embryos in which the zona pellucida was opened by complete ablation using the same total number of pulses as the control group; a second experimental group of embryos in which the zona pellucida was thinned to establish a smooth lased area using the same number of pulses as used in the other two groups. The width of the zona opening was 25 mum and width of the thinned area was 35 mum. Development was monitored by time-lapse microscopy. Overall treatment differences for continuous variables were analyzed by analysis of variance and pairwise comparisons using the Student t-test allowing for unequal variances, while for categorical data, a standard chi-squared test was utilized for all pairwise comparisons. MAIN RESULTS AND THE ROLE OF CHANCE: The frequency of complete hatching was 33.9% in the control group, 94.4% after zona opening, and 39.3% after zona thinning (overall group comparison, P \u3c 0.0001). Overall, 60.7% of the zona-thinned embryos did not complete the hatching process and remained trapped within the zona; when they did hatch, they did not necessarily hatch from the zona-thinned area. Hatching in about one-third of the zona-intact embryos began with breaches at multiple sites by small groups of cells. Likewise, 53.6% of zona-thinned embryos had multiple breaches, always involving an area outside the thinned zone. Zona opening decreased multiple breaching and led to blastocyst escape an average of 14 h earlier than zona-thinned embryos and 5.5 h before control embryos (P = 0.0003). LIMITATIONS, REASONS FOR CAUTION: The experiments presented here were limited to in vitro experiments performed in the mouse. Whether human embryos would behave the same way under similar circumstances is unknown. We postulate that zona thinning is not beneficial in human embryos. WIDER IMPLICATIONS OF THE FINDINGS: The experiments demonstrate that zona thinning is not equivalent to zona opening for assisted hatching. The study provides reason for systematic reviews of assisted hatching trials to take the method of assisted hatching into consideration and not combine the results of zona thinning and zona opening procedures. STUDY FUNDING/COMPETING INTERESTS: Institutional funds were used for the study. No competing interests are declared

De Koninklijke Nederlandse Bosbouw Vereniging en het imago bij haar leden

Het bestuur van de Koninklijke Nederlandse Bosbouw Vereniging besloot in 2000 om door middel van een intern onderzoek onder de leden bouwstenen te vinden voor een nieuw verenigingsbeleid. Dit is gebeurd door middel van een enquête onder alle leden. De analyse van de antwoorden had betrekking op 44% van de leden, zijnde de respons. De functie van de KNBV wordt thans nog vooral gezien als een kennis- en informatieplatform, maar in de toekomst zou de KNBV meer als belangenorganisatie mogen fungeren. Leeftijd speelt een rol bij de mate van betrokkenheid bij en tevredenheid over de KNBV. Deze zijn groter naarmate men ouder is. Desondanks is meer aandacht voor de wensen en ideeën van de jongere leden noodzakelijk voor de ‘verjonging’ en het voortbestaan van de vereniging, zeker als 80% van de respondenten aangeeft het jammer te vinden als de KNBV zou worden opgeheven

Mistranslation and its control by tRNA synthetases

Aminoacyl tRNA synthetases are ancient proteins that interpret the genetic material in all life forms. They are thought to have appeared during the transition from the RNA world to the theatre of proteins. During translation, they establish the rules of the genetic code, whereby each amino acid is attached to a tRNA that is cognate to the amino acid. Mistranslation occurs when an amino acid is attached to the wrong tRNA and subsequently is misplaced in a nascent protein. Mistranslation can be toxic to bacteria and mammalian cells, and can lead to heritable mutations. The great challenge for nature appears to be serine-for-alanine mistranslation, where even small amounts of this mistranslation cause severe neuropathologies in the mouse. To minimize serine-for-alanine mistranslation, powerful selective pressures developed to prevent mistranslation through a special editing activity imbedded within alanyl-tRNA synthetases (AlaRSs). However, serine-for-alanine mistranslation is so challenging that a separate, genome-encoded fragment of the editing domain of AlaRS is distributed throughout the Tree of Life to redundantly prevent serine-to-alanine mistranslation. Detailed X-ray structural and functional analysis shed light on why serine-for-alanine mistranslation is a universal problem, and on the selective pressures that engendered the appearance of AlaXps at the base of the Tree of Life