Effect of culture in simulated microgravity on the development of mouse embryonic testes

BACKGROUND All known organisms develop and evolve in the presence of gravitational force, and it is evident that gravity has a significant influence on organism physiology and development. Microgravity is known to affect gene expression, enzyme activity, cytoskeleton organization, mitotic proliferation and intracellular signaling. OBJECTIVES: The aim of the present study was to study some aspects of the development in vitro of mouse embryonic testes in simulated microgravity. MATERIAL AND METHODS: Testes from mouse embryos (12.5-16.5 days post coitum, d.p.c.) were cultured in simulated microgravity and standard static culture conditions. The microgravity condition was provided by a Rotary Cell Culture System (RWV) bioreactor, an apparatus designated for 3D tissue and small organ cultures. After 48 h of the culture in the RWV, testis morphology and size was evaluated. RESULTS: The first observation was that the culture in the RWV bioreactor had a beneficial effect on the testis growth and on the survival of germ cells in comparison to static 2D culture methods. Moreover, we found, that RWV culture caused disorganization the gonadal tissues, namely of the testis cords. CONCLUSIONS: The results suggest that the maintenance of testis cord could be sensitive to microgravity. We hypothesize that while the effect on testis growth is due to a better nutrient and oxygen supply, the testis cord's disorganization might depend on the microgravity conditions simulated by the bioreactor. Considering the complexity of the processes involved in the formation of the testis cords and their dynamic changes during the embryo fetal period, further studies are needed to identify the causes of such effect

Automated seismic waveform location using multichannel coherency migration (MCM)–I: theory

With the proliferation of dense seismic networks sampling the full seismic wavefield, recorded seismic data volumes are getting bigger and automated analysis tools to locate seismic events are essential. Here, we propose a novel Multichannel Coherency Migration (MCM) method to locate earthquakes in continuous seismic data and reveal the location and origin time of seismic events directly from recorded waveforms. By continuously calculating the coherency between waveforms from different receiver pairs, MCM greatly expands the available information which can be used for event location. MCM does not require phase picking or phase identification, which allows fully automated waveform analysis. By migrating the coherency between waveforms, MCM leads to improved source energy focusing. We have tested and compared MCM to other migration-based methods in noise-free and noisy synthetic data. The tests and analysis show that MCM is noise resistant and can achieve more accurate results compared with other migration-based methods. MCM is able to suppress strong interference from other seismic sources occurring at a similar time and location. It can be used with arbitrary 3D velocity models and is able to obtain reasonable location results with smooth but inaccurate velocity models. MCM exhibits excellent location performance and can be easily parallelized giving it large potential to be developed as a real-time location method for very large datasets

Hidden breakpoints in genome alignments

During the course of evolution, an organism's genome can undergo changes that affect the large-scale structure of the genome. These changes include gene gain, loss, duplication, chromosome fusion, fission, and rearrangement. When gene gain and loss occurs in addition to other types of rearrangement, breakpoints of rearrangement can exist that are only detectable by comparison of three or more genomes. An arbitrarily large number of these "hidden" breakpoints can exist among genomes that exhibit no rearrangements in pairwise comparisons. We present an extension of the multichromosomal breakpoint median problem to genomes that have undergone gene gain and loss. We then demonstrate that the median distance among three genomes can be used to calculate a lower bound on the number of hidden breakpoints present. We provide an implementation of this calculation including the median distance, along with some practical improvements on the time complexity of the underlying algorithm. We apply our approach to measure the abundance of hidden breakpoints in simulated data sets under a wide range of evolutionary scenarios. We demonstrate that in simulations the hidden breakpoint counts depend strongly on relative rates of inversion and gene gain/loss. Finally we apply current multiple genome aligners to the simulated genomes, and show that all aligners introduce a high degree of error in hidden breakpoint counts, and that this error grows with evolutionary distance in the simulation. Our results suggest that hidden breakpoint error may be pervasive in genome alignments.Comment: 13 pages, 4 figure

Ground-State Electromagnetic Moments of Calcium Isotopes

High-resolution bunched-beam collinear laser spectroscopy was used to measure the optical hyperfine spectra of the $^{43-51}$Ca isotopes. The ground state magnetic moments of $^{49,51}$Ca and quadrupole moments of $^{47,49,51}$Ca were measured for the first time, and the $^{51}$Ca ground state spin $I=3/2$ was determined in a model-independent way. Our results provide a critical test of modern nuclear theories based on shell-model calculations using phenomenological as well as microscopic interactions. The results for the neutron-rich isotopes are in excellent agreement with predictions using interactions derived from chiral effective field theory including three-nucleon forces, while lighter isotopes illustrate the presence of particle-hole excitations of the $^{40}$Ca core in their ground state.Comment: Accepted as a Rapid Communication in Physical Review

Shells and Shapes in the N=28 isotones

International audienceNew experimental results on 43S and 44S reveal that these nuclei are located in a transitional region of shape coexistence between the spherical 48Ca and the oblate 42Si. The origin of the deformation is discussed in terms of the evolution of the single particle energy levels leading to the compression of the energy difference of the orbitals in the sd and pf shells for protons and neutrons, respectively. Therefore, due to quadrupole excitations across the Z = 14 and N = 28 gaps, the intruder configuration in the neutron rich S isotopes became the ground state

Quantification of storm-induced bathymetric change in a back-barrier estuary

© The Author(s), 2016. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Estuaries and Coasts 40 (2017): 22-36, doi:10.1007/s12237-016-0138-5.Geomorphology is a fundamental control on ecological and economic function of estuaries. However, relative to open coasts, there has been little quantification of storm-induced bathymetric change in back-barrier estuaries. Vessel-based and airborne bathymetric mapping can cover large areas quickly, but change detection is difficult because measurement errors can be larger than the actual changes over the storm timescale. We quantified storm-induced bathymetric changes at several locations in Chincoteague Bay, Maryland/Virginia, over the August 2014 to July 2015 period using fixed, downward-looking altimeters and numerical modeling. At sand-dominated shoal sites, measurements showed storm-induced changes on the order of 5 cm, with variability related to stress magnitude and wind direction. Numerical modeling indicates that the predominantly northeasterly wind direction in the fall and winter promotes southwest-directed sediment transport, causing erosion of the northern face of sandy shoals; southwesterly winds in the spring and summer lead to the opposite trend. Our results suggest that storm-induced estuarine bathymetric change magnitudes are often smaller than those detectable with methods such as LiDAR. More precise fixed-sensor methods have the ability to elucidate the geomorphic processes responsible for modulating estuarine bathymetry on the event and seasonal timescale, but are limited spatially. Numerical modeling enables interpretation of broad-scale geomorphic processes and can be used to infer the long-term trajectory of estuarine bathymetric change due to episodic events, when informed by fixed-sensor methods

A gauge theoretic approach to elasticity with microrotations

We formulate elasticity theory with microrotations using the framework of gauge theories, which has been developed and successfully applied in various areas of gravitation and cosmology. Following this approach, we demonstrate the existence of particle-like solutions. Mathematically this is due to the fact that our equations of motion are of Sine-Gordon type and thus have soliton type solutions. Similar to Skyrmions and Kinks in classical field theory, we can show explicitly that these solutions have a topological origin.Comment: 15 pages, 1 figure; revised and extended version, one extra page; revised and extended versio

Energy efficiency parametric design tool in the framework of holistic ship design optimization

Recent International Maritime Organization (IMO) decisions with respect to measures to reduce the emissions from maritime greenhouse gases (GHGs) suggest that the collaboration of all major stakeholders of shipbuilding and ship operations is required to address this complex techno-economical and highly political problem efficiently. This calls eventually for the development of proper design, operational knowledge, and assessment tools for the energy-efficient design and operation of ships, as suggested by the Second IMO GHG Study (2009). This type of coordination of the efforts of many maritime stakeholders, with often conflicting professional interests but ultimately commonly aiming at optimal ship design and operation solutions, has been addressed within a methodology developed in the EU-funded Logistics-Based (LOGBASED) Design Project (2004–2007). Based on the knowledge base developed within this project, a new parametric design software tool (PDT) has been developed by the National Technical University of Athens, Ship Design Laboratory (NTUA-SDL), for implementing an energy efficiency design and management procedure. The PDT is an integral part of an earlier developed holistic ship design optimization approach by NTUA-SDL that addresses the multi-objective ship design optimization problem. It provides Pareto-optimum solutions and a complete mapping of the design space in a comprehensive way for the final assessment and decision by all the involved stakeholders. The application of the tool to the design of a large oil tanker and alternatively to container ships is elaborated in the presented paper

Unveiling the intruder deformed 02+^+_2 state in 34^{34}Si

The 0$^+_2$ state in $^{34}$Si has been populated at the {\sc Ganil/Lise3} facility through the $\beta$-decay of a newly discovered 1$^+$ isomer in $^{34}$Al of 26(1) ms half-life. The simultaneous detection of $e^+e^-$ pairs allowed the determination of the excitation energy E(0$^+_2$)=2719(3) keV and the half-life T$_{1/2}$=19.4(7) ns, from which an electric monopole strength of $\rho^2$(E0)=13.0(0.9)$\times10^{-3}$ was deduced. The 2$^+_1$ state is observed to decay both to the 0$^+_1$ ground state and to the newly observed 0$^+_2$ state (via a 607(2) keV transition) with a ratio R(2$^+_1$$\rightarrow0^+_1/2^+_1$$\rightarrow0^+_2$)=1380(717). Gathering all information, a weak mixing with the 0$^+_1$ and a large deformation parameter of $\beta$=0.29(4) are found for the 0$^+_2$ state, in good agreement with shell model calculations using a new {\sc sdpf-u-mix} interaction allowing \textit{np-nh} excitations across the N=20 shell gap.Comment: 5 pages, 3 figures, accepted for publication in Physical Review Letter