The first record of Bergamina lineolata (Chydoridae; Aloninae) from Colombia

The Neotropical freshwater cladoceran Bergamina lineolata (Sars, 1901) was found in a small temporal pond in the Magdalena department. Hitherto, it has been reported in Brazil and El Salvador. It was originally described as Alonella lineolata by Sars, 1901 from Brazil and then placed to the genus Bergamina by Elmoor-Loureiro et al. (2013). This is the first record of this species in Colombia. B. lineolata can be identified by a unique combination of characters including: 1) a remarkably large and oblong postabdomen, with three denticles on distal corner; 2) basal spine of the claw very short, length less than the half claw diameter at base; 3) IDL with two setae shorter than ODL seta, armed with fine setules unilaterally in terminal half; 4) endite 1 of trunk limb I with a long smooth seta between endites 1 and 2.

Characteristics and possible mechanisms of formation of microinversions distinguishing human and chimpanzee genomes

Genomic inversions come in various sizes. While long inversions are relatively easy to identify by aligning high-quality genome sequences, unambiguous identification of microinversions is more problematic. Here, using a set of extra stringent criteria to distinguish microinversions from other mutational events, we describe microinversions that occurred after the divergence of humans and chimpanzees. In total, we found 59 definite microinversions that range from 17 to 33 nucleotides in length. In majority of them, human genome sequences matched exactly the reverse-complemented chimpanzee genome sequences, implying that the inverted DNA segment was copied precisely. All these microinversions were flanked by perfect or nearly perfect inverted repeats pointing to their key role in their formation. Template switching at inverted repeats during DNA replication was previously discussed as a possible mechanism for the microinversion formation. However, many of definite microinversions found by us cannot be easily explained via template switching owing to the combination of the short length and imperfect nature of their flanking inverted repeats. We propose a novel, alternative mechanism that involves repair of a double-stranded break within the inverting segment via microhomology-mediated break-induced replication, which can consistently explain all definite microinversion events.

Evaluation of the Radar Speed Cameras and Panels Indicating the Vehicles’ Speed as Traffic Calming Measures (TCM) in Short Length Urban Areas Located along Rural Roads

Traffic calming measures (TCMs) are implemented in urban areas to reduce vehicles’ speed and, generally speaking, results are obtained. However, speed is still a problem in rural roads crossing small villages without a bypass and with short-length urban areas, since drivers do not normally reduce their speed for that short segment. Hence, various TCM can be installed. It is necessary to maintain a calm area in these short segments to improve road safety, especially for pedestrian aiming to cross the road, and to save combustible by avoiding a constant increase-decrease of speed. Four villages were selected to evaluate the efficiency of radar speed cameras and panels indicating vehicle’s speed. Results showed that the presence of radar speed cameras reduces the speed in the direction they can fine, but with a lower effect in the non-fining direction. Additionally, a positive effect was observed in the fining direction in other points, such as pedestrian crossings. Nevertheless, the effect does not last long and speed cameras may be considered as punctual measures. If the TCMs are placed far from the start of the village they are not respected. Hence, it is recommended to place them near the real start of the build-up area. Lastly, it was verified that longer urban areas make overall speed decrease. However, when drivers feel that they are arriving to the end of the urban area, due to the inexistence of buildings, they start speeding up.

Fitting electron spectrum from AMS-02 by pulsar electrons

In this work, we aim to explain the latest data of cosmic-ray electrons from AMS-02 by an electron background model and pulsar electrons. We consider an electron background model which includes primary and secondary electrons. We assume that pulsars are major sources of the electron excess. Since electrons easily lose their energy through the interstellar radiation field and the magnetic field via inverse Compton scattering and synchrotron radiation, respectively, they propagate in a short length. We adopt nearby pulsar data in the distance of 1 kpc from the Australia Telescope National Facility (ATNF) pulsar catalogue. By using a Green’s function of an electron propagation model, we then fit pulsar parameters (i.e. the spectral index, the fraction of the total spin-down energy and the cutoff energy) for several cases of a single pulsar. With a combination of the electron background model, several cases of pulsar spectrum are able to explain the electron excess.

An experiment with two bottle tops

Two bottle tops are connected by a short length of string. What happens when one is given a short duration push in a direction at right angles to the string? Several answers are provided, plus a supplementary video.

A Mouse Model with Widespread Expression of the C9orf72-Linked Glycine-Arginine Dipeptide Displays Non-Lethal ALS/FTD-Like Phenotypes

Background: Translation of the hexanucleotide G4C2 expansion associated with C9orf72 Amyotrophic Lateral Sclerosis and Frontotemporal Dementia (ALS/FTD) produces five different dipeptide repeat protein (DPR) species that can confer toxicity. Yet, there is much to learn about the contribution of DPRs to disease pathogenesis, as not all DPRs function and localize within cells in the same manner, nor are they all the same repeat length. These phenomena create a heterogeneity that confounds the study of their toxic consequences. Methods: In vitro transfection of different lengths of the toxic DPR glycine-arginine (poly-GR) was used to determine a relevant pathogenic length for in vivo assessment. We then generated a novel transgenic mouse expressing poly-GR under a ubiquitous promoter for histological characterization and assessment of motor and cognitive behaviors. Results: We identify a short repeat length in vitro that, when expressed, correlates with a reduction in cell survival over an extended period. In vivo, we observe sex-specific chronic ALS/FTD-like phenotypes in our transgenic mice expressing the same short-length DPR, including mild motor neuron loss, but no TDP-43 mis-localization, as well as motor and cognitive impairments. Despite the chronic phenotype, survival of these animals is not affected over 12 months. Conclusions: We show that a short repeat length is sufficient for the DPR poly-GR to confer neurotoxicity in vitro, a phenomenon previously unobserved. This toxicity is reported in vivo in our novel knock-in mouse model characterized by widespread central nervous system (CNS) expression of the short-length poly-GR. We conclude that this short length poly-GR induces a chronic, but non-lethal phenotype in our mouse model and suggest that this model can serve as the foundation for phenotypic exacerbation through second-hit forms of stress.

Multistage closure of a congenital extrahepatic portosystemic shunt

Background Congenital extrahepatic portosystemic shunts (CEPS) are rare shunts connecting the extrahepatic portal system with the inferior vena cava. Shunt dimensions and the risk of portal hypertension determines the closure strategy. Endovascular treatment is indicated for single stage occlusion of longer length shunts, whereas the remaining shunt types are preferentially surgically occluded. Herein we describe the technical details of a novel endovascular treatment for short length CEPS. Case presentation A 15-years-old male with a short length CEPS complicated with multinodular liver disease was submitted to a multistage closure, as indicated by the high portal pressure values during shunt balloon occlusion venography. Initially a transjugular intrahepatic portosystemic shunt (TIPS) was created and the CEPS occluded with an atrial septal defect occluder. In a second procedure the TIPS was embolized with a flow reductor stent and an amplatzer vascular plug II. At a 1 year follow up the liver nodules size reduced, the patient remains asymptomatic, and the shunt adequately closed. Conclusion This paper outlines the potential use of a TIPS and an atrial septal defect occluder combination in complex CEPS, supporting its usage as an alternative to the standard surgical treatment. Level of Evidence: Level 4, Case report.

Algorithmic Structures for Realizing Short-Length Circular Convolutions with Reduced Complexity

A set of efficient algorithmic solutions suitable to the fully parallel hardware implementation of the short-length circular convolution cores is proposed. The advantage of the presented algorithms is that they require significantly fewer multiplications as compared to the naive method of implementing this operation. During the synthesis of the presented algorithms, the matrix notation of the cyclic convolution operation was used, which made it possible to represent this operation using the matrix–vector product. The fact that the matrix multiplicand is a circulant matrix allows its successful factorization, which leads to a decrease in the number of multiplications when calculating such a product. The proposed algorithms are oriented towards a completely parallel hardware implementation, but in comparison with a naive approach to a completely parallel hardware implementation, they require a significantly smaller number of hardwired multipliers. Since the wired multiplier occupies a much larger area on the VLSI and consumes more power than the wired adder, the proposed solutions are resource efficient and energy efficient in terms of their hardware implementation. We considered circular convolutions for sequences of lengths N= 2, 3, 4, 5, 6, 7, 8, and 9.

A Constructive Method for Generating Short Presentations for the Symmetric Groups Sm+n, S2m and Smn

A long-standing problem is how to create a short-length presentation for finite groups of degree n. This paper aimed at presenting a concrete method for generating presentations for the groups Sm+n, S2m and Smn for all m,nÎZ+ with fewer relations than the existing literature from the presentations of Sm and Sn. The aim is achieved by considering finite groups acting on sets and Cartesian product of groups which lead to the construction of multiple transformations as representatives of some finite groups.