1,400 research outputs found
Long walk to genomics : history and current approaches to genome sequencing and assembly
Genomes represent the starting point of genetic studies. Since the discovery of DNA structure, scientists have devoted great efforts to determine their sequence in an exact way. In this review we provide a comprehensive historical background of the improvements in DNA sequencing technologies that have accompanied the major milestones in genome sequencing and assembly, ranging from early sequencing methods to Next-Generation Sequencing platforms. We then focus on the advantages and challenges of the current technologies and approaches, collectively known as Third Generation Sequencing. As these technical advancements have been accompanied by progress in analytical methods, we also review the bioinformatic tools currently employed in de novo genome assembly, as well as some applications of Third Generation Sequencing technologies and high-quality reference genomes
Circuit training during physical education classes to prepare cadets for military academies tests: Analysis of an educational project
Background: The aim of this study was to test the efficacy of an eight-week physical education program based on circuit training to better improve the overall physical and military-specific performance compared to a conventional physical education program in military high school students. Methods: Sixty-four students were enrolled in this study and randomly assigned to an experimental (EG, circuit training) or a control group (CG, traditional physical education program). Immediately before and after the eight-week training period, participants were tested on strength and endurance performance, circuit training tests, and military tests. Moreover, the acquisition of the educational objectives and the pleasantness of the experimental intervention were tested using a qualitative approach. Results: Despite the higher workload in EG than CG during the training period, the effect of the experimental intervention compared to the control was only possibly to likely positive for a few strength and endurance performances and circuit training tests, respectively. A trivial effect was shown in the military tests. On the contrary, the high percentage of motivation (76%), understanding (78%) and collaboration (86%) showed by the students suggests the achievement of acquisition of the educational objectives and a fair pleasantness of the lessons. Conclusions: A lack of clear and marked effect of the experimental intervention could be ascribed to an insufficient exposure time to the training and a high subjective overall workload encountered in military high school students
How surface properties influence mineral dust emissions in the Sahelian region ? A modelling case study during AMMA
Tropical mesoscale convective systems (MCSs) are a prominent feature of the African meteorology. A continuous monitoring of the aeolian activity in an experimental site located in Niger shows that such events are responsible for the major part of the annual local wind erosion, i.e. for most of the Sahelian dust emissions [Rajot, 2001]. However, the net effect of these MCSs on mineral dust budget has to be estimated: on the one hand, these systems produce extremely high surface wind velocities leading to intense dust uptake, but on the other hand, rainfalls associated with these systems can efficiently remove the emitted dust from the atmosphere. High resolution modelling appears as a relevant approach to correctly reproduce the surface meteorology associated with such meteorological systems [Bouet et al., submitted]. The question now arising concerns the reliability of surface characteristics available for the Sahelian region, especially soil texture and surface roughness, which are critical parameters for dust emissions. Contrary to arid regions, which are now well documented, data is still missing to correctly characterize semi-arid regions like the Sahel. This is in particular due to the well pronounced annual cycles of precipitations and vegetation in these regions and to the impact of land-use on surface properties. This study focuses on a case study of dust emission associated with the passage of a MCS observed during one of the Special Observing Periods of the international African Monsoon Multidisciplinary Analysis (AMMA – SOPs 1-2) program. The simulations were made using the Regional Atmospheric Modeling System (RAMS, Cotton et al. [2003]) coupled online with the dust production model developed by Marticorena and Bergametti [1995] and recently improved by Laurent et al. [2008] for Africa. The sensitivity of dust emission associated with the passage of the MCS to surface features is investigated using different data sets of surface properties (Harmonized World Soil Database, HWSD) and land-use (GLOBCOVER). In-situ measurements of dust concentrations (both ground-based and airborne), and of dust emission flux are used to validate the simulations
Feulgen-DNA Content and C-Banding of Robertsonian Transformed Karyotypes in Dugesia Lugubris
SUMMARYIn the planarian species, Dugesia lugubris, two biotypes are found: E (2n = 8, n = 4) and F (2n = 6, n = 3); on the basis of karyometric studies it has been hypothesized that the second was derived from the first through a Robert-sonian mechanism of centric fusion. The quantitative cytochemical data reported here confirm the hypothesis of karyotype evolution, since there are no significant differences between the DNA content of the nucleus in the two biotypes. The regenerative blastemas of both biotypes contain a number of cellular populations with a variable Feulgen-DNA content; these correspond to successive doublings of the 2C diploid content. In addition, metaphase plates with multistranded chromosomes have been found. A difference between the chromosome C-banding in the two biotypes has also been observed
Bilateral asymmetry of skin temperature is not related to bilateral asymmetry of crank torque during an incremental cycling exercise to exhaustion
© 2018 Trecroci et al. Although moderate relationships (|r|~0:5) were reported between skin temperature and performance-related variables (e.g., kinetic), it remains unclear whether skin temperature asymmetry reflects muscle force imbalance in cycling. Therefore, the aim of this study was to assess whether a relationship exists between kinetic and thermal asymmetry during a fatiguing exercise. Ten elite cyclists were enrolled and tested on a maximal incremental cycling test. Peak crank torques of both legs were obtained at the initial and final workload. Likewise, bilateral skin temperatures were recorded before and after exercise. Asymmetric indexes were also calculated for kinetic (AIK) and skin temperature (AIT) outcomes. The bilateral peak crank torques showed a larger difference at the final compared to the initial workload (p0:05). Additionally, trivial relationships were reported between AIK and AIT (-0:3<r<0:2) at the initial and final workload. The obtained results showed that changes in bilateral kinetic values did not reflect concurrent changes in bilateral skin temperatures. This finding emphasizes the difficulty of associating the asymmetry of skin temperature with those of muscle effort in elite cyclists. Lastly, our study also provided further insights on thermal skin responses during exhaustive cycling exercise in very highly-trained athletes
Conservation Laws in Cellular Automata
If X is a discrete abelian group and B a finite set, then a cellular
automaton (CA) is a continuous map F:B^X-->B^X that commutes with all X-shifts.
If g is a real-valued function on B, then, for any b in B^X, we define G(b) to
be the sum over all x in X of g(b_x) (if finite). We say g is `conserved' by F
if G is constant under the action of F. We characterize such `conservation
laws' in several ways, deriving both theoretical consequences and practical
tests, and provide a method for constructing all one-dimensional CA exhibiting
a given conservation law.Comment: 19 pages, LaTeX 2E with one (1) Encapsulated PostScript figure. To
appear in Nonlinearity. (v2) minor changes/corrections; new references added
to bibliograph
Change of direction asymmetry across different age categories in youth soccer
Background
In youth, the development of change of direction (COD) and sprint performance is a key component for successfully competing in soccer across age. During a COD, the presence of directional asymmetries may be detrimental due to the unpredictable nature of the sport. Therefore, the aims of the study were to investigate asymmetries in COD ability and to examine the differences in COD and sprint performance across age in young soccer players.
Methods
Sixty-eight sub-elite soccer players of different age categories (U18, U17, U16, U15) were tested on a 10-m linear sprint test and 90°COD (5-m entry and exit) test in both directions. Asymmetric index (AI) of COD deficit was obtained for dominant (fastest) and non-dominant directions (slowest).
Results
The results showed that U16 were more asymmetrical than U18, U17, and U15 from large to moderate effects. The sprint time improved linearly across age with U18 and U15 displaying the fastest and slowest 10-m sprint performance (p 0.05).
Conclusion
Given the results of this study, practitioners are encouraged to assess asymmetries between dominant and non-dominant directions rather than solely players’ COD ability in young soccer players
Atmospheric aerosols at the Pierre Auger Observatory and environmental implications
The Pierre Auger Observatory detects the highest energy cosmic rays.
Calorimetric measurements of extensive air showers induced by cosmic rays are
performed with a fluorescence detector. Thus, one of the main challenges is the
atmospheric monitoring, especially for aerosols in suspension in the
atmosphere. Several methods are described which have been developed to measure
the aerosol optical depth profile and aerosol phase function, using lasers and
other light sources as recorded by the fluorescence detector. The origin of
atmospheric aerosols traveling through the Auger site is also presented,
highlighting the effect of surrounding areas to atmospheric properties. In the
aim to extend the Pierre Auger Observatory to an atmospheric research platform,
a discussion about a collaborative project is presented.Comment: Regular Article, 16 pages, 12 figure
Study of a New Trigger on Multiplicity and Primary Interaction Vertex using the ALICE Silicon Pixel Detector
New trigger inputs for the ALICE Central Trigger Processor (CTP) are proposed. They are based on the use of Fast Multiplicity (FM) output signals generated by the ALICE Silicon Pixel Detector (SPD). These can be used for a multiplicity based centrality trigger and for a fast on-line computation of the primary vertex. A simple algorithm for primary vertex location at the trigger level is proposed. The precision that can be achieved with this method on centrality selection and primary vertex location, is discussed for interactions with different pseudo-rapidity density level. The feasibility of background rejection is also considered
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