Rediscovery of the holotype of Characidium sanctjohanni Dahl 1960 (Characiformes: Crenuchidae) from the Colombian Pacific slope

We report the rediscovery of the holotype of Characidium sanctjohanni Dahl, previously considered as lost in the ICN collections. We present counts, measurements and photographs, also offering a comparison between the holotype and the original description.Presentamos el redescubrimiento de la especie Characidium sanctjohanni descrita por Dahl (1960), lote que se encontraba perdido en el ICN. Tomamos conteos, medidas y fotografías para comparar los datos del holotipo con la descripción original

The VLT-FLAMES Tarantula Survey X: Evidence for a bimodal distribution of rotational velocities for the single early B-type stars

Aims: Projected rotational velocities (\vsini) have been estimated for 334 targets in the VLT-FLAMES Tarantula survey that do not manifest significant radial velocity variations and are not supergiants. They have spectral types from approximately O9.5 to B3. The estimates have been analysed to infer the underlying rotational velocity distribution, which is critical for understanding the evolution of massive stars. Methods: Projected rotational velocities were deduced from the Fourier transforms of spectral lines, with upper limits also being obtained from profile fitting. For the narrower lined stars, metal and non-diffuse helium lines were adopted, and for the broader lined stars, both non-diffuse and diffuse helium lines; the estimates obtained using the different sets of lines are in good agreement. The uncertainty in the mean estimates is typically 4% for most targets. The iterative deconvolution procedure of Lucy has been used to deduce the probability density distribution of the rotational velocities. Results: Projected rotational velocities range up to approximately 450 \kms and show a bi-modal structure. This is also present in the inferred rotational velocity distribution with 25% of the sample having $0\leq$\ve$\leq$100\,\kms and the high velocity component having \ve$\sim 250$\,\kms. There is no evidence from the spatial and radial velocity distributions of the two components that they represent either field and cluster populations or different episodes of star formation. Be-type stars have also been identified. Conclusions: The bi-modal rotational velocity distribution in our sample resembles that found for late-B and early-A type stars. While magnetic braking appears to be a possible mechanism for producing the low-velocity component, we can not rule out alternative explanations.Comment: to be publisged in A&

The VLT-FLAMES Tarantula Survey XXI. Stellar spin rates of O-type spectroscopic binaries

The initial distribution of spin rates of massive stars is a fingerprint of their elusive formation process. It also sets a key initial condition for stellar evolution and is thus an important ingredient in stellar population synthesis. So far, most studies have focused on single stars. Most O stars are however found in multiple systems. By establishing the spin-rate distribution of a sizeable sample of O-type spectroscopic binaries and by comparing the distributions of binary sub-populations with one another as well as with that of presumed single stars in the same region, we aim to constrain the initial spin distribution of O stars in binaries, and to identify signatures of the physical mechanisms that affect the evolution of the massive stars spin rates. We use ground-based optical spectroscopy obtained in the framework of the VLT-FLAMES Tarantula Survey (VFTS) to establish the projected equatorial rotational velocities (\vrot) for components of 114 spectroscopic binaries in 30 Doradus. The \vrot\ values are derived from the full-width at half-maximum (FWHM) of a set of spectral lines, using a FWHM vs. \vrot\ calibration that we derive based on previous line analysis methods applied to single O-type stars in the VFTS sample. The overall \vrot\ distribution of the primary stars resembles that of single O-type stars in the VFTS, featuring a low-velocity peak (at \vrot < 200 kms) and a shoulder at intermediate velocities (200 < \vrot < 300 kms). The distributions of binaries and single stars however differ in two ways. First, the main peak at \vrot \sim100 kms is broader and slightly shifted toward higher spin rates in the binary distribution compared to that of the presumed-single stars. Second, the \vrot distribution of primaries lacks a significant population of stars spinning faster than 300 kms while such a population is clearly present in the single star sample.Comment: 16 pages, 16 figures, paper accepted in Astronomy & Astrophysic

Rotational properties of the O-type star population in the Tarantula region

The 30 Doradus (30\,Dor) region in the Large Magellanic Cloud (also known as the Tarantula Nebula) is the nearest massive starburst region, containing the richest sample of massive stars in the Local Group. It is the best possible laboratory to investigate aspects of the formation and evolution of massive stars. Here, we focus on rotation which is a key parameter in the evolution of these objects. We establish the projected rotational velocity, $v_{e}\sin i$, distribution of an unprecedented sample of 216 radial velocity constant ($\rm{\Delta RV\, \leq\, 20 \,km s^{-1}}$) O-type stars in 30\,Dor observed in the framework of the VLT-FLAMES Tarantula Survey (VFTS). The distribution of $v_{e}\sin i$ shows a two-component structure: a peak around 80 $\rm{km s^{-1}}$ and a high-velocity tail extending up to $\sim$600 $\rm{km s^{-1}}$. Around 75% of the sample has 0 $\leq\, v_{e}\sin i \leq$ 200 $\rm{km s^{-1}}$ with the other 25% distributed in the high-velocity tail. The presence of the low-velocity peak is consistent with that found in other studies of late-O and early-B stars. The high-velocity tail is compatible with expectations from binary interaction synthesis models and may be predominantly populated by post-binary interaction, spun-up, objects and mergers. This may have important implications for the nature of progenitors of long-duration gamma ray bursts.Comment: 4 pages, 1 figure. Conference proceedings article: Massive stars: from alpha to Omega, 10-14 June 2013, Rhodes, Greec

An Introduction and High Yield Summary of Female Contraceptive Methods

Globally, contraceptive studies and their use are major challenges in the realm of public health. The ideal goal is to obtain a contraceptive method that is highly effective at minimizing unplanned pregnancies and nullifying the chance of contracting a sexually transmitted disease. Abstinence is currently the only way to attain such a dualistic goal, and while effective, it may not be suitable for sexually active individuals. While there is an abundance of methodspecific information regarding the use of any one female contraceptive device, there is a paucity of resources that compare and contrast the advantages and disadvantages of such methods and enable an individual to optimize family planning. This paper attempts to address many of these topics by reviewing a multitude of U.S. Food and Drug Administration (FDA) approved contraceptive methods. This work is intentionally written towards educating medical students, educators and teachers at all levels of training with foundational knowledge regarding female contraception

Rotational velocities of single and binary O-type stars in the Tarantula Nebula

Rotation is a key parameter in the evolution of massive stars, affecting their evolution, chemical yields, ionizing photon budget, and final fate. We determined the projected rotational velocity, $v_e\sin i$, of $\sim$330 O-type objects, i.e. $\sim$210 spectroscopic single stars and $\sim$110 primaries in binary systems, in the Tarantula nebula or 30 Doradus (30\,Dor) region. The observations were taken using VLT/FLAMES and constitute the largest homogeneous dataset of multi-epoch spectroscopy of O-type stars currently available. The most distinctive feature of the $v_e\sin i$ distributions of the presumed-single stars and primaries in 30 Dor is a low-velocity peak at around 100\,$\rm{km s^{-1}}$. Stellar winds are not expected to have spun-down the bulk of the stars significantly since their arrival on the main sequence and therefore the peak in the single star sample is likely to represent the outcome of the formation process. Whereas the spin distribution of presumed-single stars shows a well developed tail of stars rotating more rapidly than 300\,$\rm{km s^{-1}}$, the sample of primaries does not feature such a high-velocity tail. The tail of the presumed-single star distribution is attributed for the most part -- and could potentially be completely due -- to spun-up binary products that appear as single stars or that have merged. This would be consistent with the lack of such post-interaction products in the binary sample, that is expected to be dominated by pre-interaction systems. The peak in this distribution is broader and is shifted toward somewhat higher spin rates compared to the distribution of presumed-single stars. Systems displaying large radial velocity variations, typical for short period systems, appear mostly responsible for these differences.Comment: 6 pages, 3 figures, Proceedings IAU Symposium No. 307, 2014, 'New windows on massive stars: asteroseismology, interferometry, and spectropolarimetry

Effects of discontinued endurance methods on VO2max in judokas

Este estudio tuvo como objetivo investigar el efecto de dos diferentes planes de entrenamiento de resistencia basados en la metodología discontinua (intermitente e interválica), sobre el VO2Máx de atletas Antioqueños de Judo de rendimiento. Para ello, 21 Judokas de la Selección Antioqueña pertenecientes a la categoría Senior (20,43±4,18 años), fueron distribuidos aleatoriamente en tres grupos, dos grupos experimentales y un grupo control. Ambos grupos experimentales entrenaron la resistencia durante 4 semanas con 4 estímulos por semana, uno de los grupos experimentales basó su entrenamiento en el método interválico y el otro en el intermitente. Por su parte, el grupo control no realizó ningún tipo de entrenamiento de la resistencia. No se hallaron diferencias significativas entre pretest y postest de ninguno de los grupos ni experimentales ni el de grupo control (p>0,05). Se concluyó que el entrenamiento de la resistencia basado en métodos discontinuos no produjo diferencias significativas en el VO2Máx

Caracterización clínica del síndrome nefrótico en infantes de Neiva

Nephrotic Syndrome is a chronic glomerular disease more commonly found in children. The United States has an annual incidence of 2.0 to 2.7 cases per 100,000 children and an accumulated prevalence of 16 per 100,000. The department of Huila, Colombia lacks up-to-date information that would allow the establishment and standardisation of clear objectives in the diagnosis and treatment of this disease in the paediatric population. Equipment and Methods.&nbsp;A descriptive, cross-sectional study was carried out of the clinical and epidemiological characteristics of Nephrotic Syndrome in children treated at Neiva's Hospital Universitario between March 2011 and December 2013. The information was collected by reviewing clinical records. 67 patients with a confirmed diagnosis were included. Results.&nbsp;The average age of onset was 46 months (0-175 months) and patients were mainly male (53.7%). 19% showed cortical resistance, the most common disease was focal segmental glomerulosclerosis (FSGS) (60%). High blood pressure at the beginning, or during follow-up, haematuria, hypocomplementemia and persistent dyslipidaemia are associated with cortical resistance (P &lt; 0.01). Changes in the anthropometric measurements of height and weight were analysed in the patients at the beginning and at the end of the follow-up (P &lt; 0.01). Conclusion.&nbsp;Nephrotic Syndrome is a common disease in the region of Neiva and the presence of cortical resistance and the progression to chronic kidney disease and death is also seen. Therefore, early diagnosis, treatment and timely follow-up is imperative in order to avoid complications in the future.El Síndrome Nefrótico es la enfermedad glomerular crónica más prevalente en pediatría, en los Estados Unidos presenta una incidencia anual de 2,0 a 2,7 casos por 100.000 niños, y una prevalencia acumulada de 16 por 100.000 (1). El departamento del Huila, carece de información actualizada que permita establecer y unificar objetivos claros en el diagnóstico y tratamiento de esta patología en la población pediátrica. Materiales y Métodos.&nbsp;Se realizó un estudio descriptivo tipo corte transversal de las características clínicas y epidemiológicas del Síndrome Nefrótico en niños atendidos en el Hospital Universitario de Neiva, entre marzo de 2011 y diciembre de 2013; la información se recolectó mediante revisión de historias clínicas. Se incluyeron 67 pacientes con diagnóstico confirmado. Resultados.&nbsp;la edad promedio de debut fue 46 meses (0-175 meses), en su mayoría de género masculino (53,7%). El 19% presentaron corticoresistencia, la patología más frecuente fue la glomeruloesclerosis focal y segmentaria (GEFS) (60%). La presencia de hipertensión arterial al debut o durante el seguimiento, hematuria, hipocomplementemia y dislipidemia persistente se asoció con cortico-resistencia (P &lt; 0,01). Se observó cambios en las medidas antropométricas de talla y peso en los pacientes al inicio y final del seguimiento (P &lt; 0,01). Conclusión.&nbsp;El Síndrome Nefrótico en esta región es una patología prevalente, con presencia de cortico-resistencia y progresión a enfermedad renal crónica y muerte, por lo tanto es imperativo su diagnóstico temprano, tratamiento y seguimiento oportuno para evitar complicaciones a futuro

Simulación de propiedades mecánicas demulticapas de Zr/ZrN y TiN/ZrNempleando el método de elementos finitos

This paper presents the study of mechanical properties of multilayers of Zr / ZrN and TiN / ZrN by varying the number of bilayers in 1, 2, 5 and 10, that is, periods of 2, 1, 0.4 and 0.2 μm, with a constant thickness of 2 μm in a ratio of 1: 1 and 1: 3. For this simulation, the ANSYS software was used, which is based on the finite element method. Effort curves were obtained - Deformation, hardness and Young's modulus depending on the number of bilayers. According to the analysis performed, the TiN / ZrN bilayers with a 1: 3 ratio have greater hardness (31 ± 1 GPa) in relation to the other systems and a Young's modulus of approximately 460 GPa. The results of the simulations of the mechanical properties of Ti and Zr-based materials, using methods such as finite elements, are promising in the field of new materials to predict their performance in technological and industrial applications such as hard coatings on different tools and pieces of machinery and thus reduce production costs. In addition, the simulations presented in this work can be extended to systems composed of other useful materials.En este trabajo se presenta el estudio de propiedades mecánicas de multicapas de Zr/ZrN y TiN/ZrN variando el número de bicapas en 1, 2, 5 y 10, es decir, períodos de 2, 1, 0,4 y 0,2 μm, con espesor constante de 2 μm en una relación de 1:1 y 1:3. Para esta simulación se empleó el software ANSYS, el cual se basa en el método de elementos finitos. Se obtuvieron curvas de Esfuerzo– Deformación, dureza y módulo de Young en función del número de bicapas. De acuerdo al análisis realizado, las bicapas de TiN/ZrN con relación 1:3 presentan mayor dureza (31±1 GPa) en relación a los demás sistemas y un módulo de Young de aproximadamente 460 GPa. Los resultados de las simulaciones de las propiedades mecánicas de materiales basados en Ti y Zr, empleando métodos como el de elementos finitos, son prometedores en el campo de los nuevos materiales para predecir su desempeño en aplicaciones tecnológicas e industriales como recubrimientos duros sobre diferentes herramientas y piezas de maquinaria y así disminuir costos de producción. Además, las simulaciones presentadas en este trabajo pueden extenderse a sistemas compuestos de otros materiales de gran utilidad