Initial diversification of living amphibians predated the breakup of Pangaea

The origin and divergence of the three living orders of amphibians (Anura, Caudata, Gymnophiona) and their main lineages are one of the most hotly debated topics in vertebrate evolution. Here, we present a robust molecular phylogeny based on the nuclear RAG1 gene as well as results from a variety of alternative independent molecular clock calibrations. Our analyses suggest that the origin and early divergence of the three living amphibian orders dates back to the Palaeozoic or early Mesozoic, before the breakup of Pangaea, and soon after the divergence from lobe-finned fishes. The resulting new biogeographic scenario, age stimate, and the inferred rapid divergence of the three lissamphibian orders may account for the lack of fossils that represent plausible ancestors or immediate sister taxa of all three orders and the heretofore paradoxical distribution of some amphibian fossil taxa. Furthermore, the ancient and rapid radiation of the three lissamphibian orders likely explains why branch lengths connecting their early nodes are particularly short, thus rendering phylogenetic inference of implicated relationships especially difficult

Maximizing transcription of nucleic acids with efficient T7 promoters

In vitro transcription using T7 bacteriophage polymerase is widely used in molecular biology. Here, we use 5'RACE-Seq to screen a randomized initially transcribed region of the T7 promoter for cross-talk with transcriptional activity. We reveal that sequences from position +4 to +8 downstream of the transcription start site affect T7 promoter activity over a 5-fold range, and identify promoter variants with significantly enhanced transcriptional output that increase the yield of in vitro transcription reactions across a wide range of template concentrations. We furthermore introduce CEL-Seq(+) , which uses an optimized T7 promoter to amplify cDNA for single-cell RNA-Sequencing. CEL-Seq(+) facilitates scRNA-Seq library preparation, and substantially increases library complexity and the number of expressed genes detected per cell, highlighting a particular value of optimized T7 promoters in bioanalytical applications

The Ontogenetic Osteohistology of Tenontosaurus tilletti

Tenontosaurus tilletti is an ornithopod dinosaur known from the Early Cretaceous (Aptian-Albian) Cloverly and Antlers formations of the Western United States. It is represented by a large number of specimens spanning a number of ontogenetic stages, and these specimens have been collected across a wide geographic range (from central Montana to southern Oklahoma). Here I describe the long bone histology of T. tilletti and discuss histological variation at the individual, ontogenetic and geographic levels. The ontogenetic pattern of bone histology in T. tilletti is similar to that of other dinosaurs, reflecting extremely rapid growth early in life, and sustained rapid growth through sub-adult ontogeny. But unlike other iguanodontians, this dinosaur shows an extended multi-year period of slow growth as skeletal maturity approached. Evidence of termination of growth (e.g., an external fundamental system) is observed in only the largest individuals, although other histological signals in only slightly smaller specimens suggest a substantial slowing of growth later in life. Histological differences in the amount of remodeling and the number of lines of arrested growth varied among elements within individuals, but bone histology was conservative across sampled individuals of the species, despite known paleoenvironmental differences between the Antlers and Cloverly formations. The bone histology of T. tilletti indicates a much slower growth trajectory than observed for other iguanodontians (e.g., hadrosaurids), suggesting that those taxa reached much larger sizes than Tenontosaurus in a shorter time

Profile and Work Immersion Performance of Accountancy, Business, and Man-agement (ABM) Students of Selected Implementing Schools in Subic District, Zambales, Philippines

Work immersion is a key subject under the Senior High School (SHS) curriculum that is conducted in different ways and time frame as needed by SHS learners. This study was conducted to find out the work immersion performance of the Grade 12 students at San Isidro High School and Subic National High School, Zambales, Philippines. The IV-DV model of this research involved the profile of the student respondents and their work immersion performances in the schools’ partner companies. This study utilized the descriptive method of research which adapted the DepEd Schools Division of Bulacan’s checklist for work immersion performance. Data revealed that student-trainees performed very satisfactorily on their work immersion showing good work ethics and personality suitable of a future employee in any company they want to apply in. Male and female ABM students have the same level in job skills which implied that the profile variables of the trainees have no influence on the work immersion performance. From the findings and conclusion of this study, the implementing schools may need to improve the academic performance of ABM students to reach an excellent level and may allow them to join trainings and seminars given to regular employees about improving work ethics and personality development

Efectos del riego deficitario controlado sobre la fisiología y la calidad de fruto en albaricoquero

The effects of regulated deficit irrigation (RDI) were studied on 9 year-old apricot-trees (Prunus armeniaca L. cv. ‘Búlida’) grafted on ‘Real Fino’ rootstock. Two irrigation treatments were established. The first, a control treatment, was irrigated to fully satisfy the crop water requirements (100% ETc) and the second, a RDI treatment, was subject to water shortage during the non-critical periods of crop development, by reducing the amount of applied irrigation water to: a) 40% of ETc from flowering until the end of the first stage of fruit growth; b) 60% of ETc during the second stage of fruit growth and c) 50% and 25% of ETc during the late postharvest period (that starts 60 days after harvesting), for the first 30 days and until the end of tree defoliation, respectively. The results indicated that the apricot tree is an appropriate species to apply RDI thanks to the clear separation between their vegetative and reproductive growths and its ability to recover the fruit diameter reduction suffered during RDI application. Furthermore, some qualitative characteristics such as the level of soluble solids, fruit taste and the colour of the fruit are enhanced. These two reasons, together with irrigation water savings of 39%, emphasize the RDI strategies as a possible solution in areas with water shortages, like the south-eastern region of Spain.Se estudiaron los efectos de estrategias de riego deficitario controlado(RDC) sobre albaricoqueros de 9 años de edad (Prunus armeniaca L. cv. ‘Búlida’) injertados sobre patrón franco de ‘Real Fino’. Para ello, se establecieron 2 tratamientos de riego, uno de riego control, que se regó satisfaciendo los requerimientos hídricos del cultivo (100% ETc) y un tratamiento de RDC, que consistió en reducir los aportes de agua con respecto a la ETc en los períodos no críticos en este cultivo: a) 40% de la ETc desde floración hasta el final de la primera fase de crecimiento del fruto; b) 60% de la ETc durante la segunda fase de crecimiento del fruto y c) 50% y 25% durante la post-cosecha final (60 días después de recolección), diferenciando 2 períodos de 30 días, el primero al 50% de la ETc, y otro hasta la caída de hojas al 25% de la ETc. Los resultados obtenidos indican que el albaricoquero es una especie adecuada para realizar estrategias de RDC, debido principalmente a la clara separación entre el crecimiento vegetativo y reproductivo y, también al efecto de crecimientos compensatorios que se producen en los frutos que han estado bajo RDC, lo cual hace que finalmente no se produzcan mermas significativas de calibre. Además, ciertas características cualitativas, como el nivel en sólidos solubles, sabor y coloración de la fruta, se ven incrementadas. Estas dos razones, junto con ahorros de agua vía riego, del 39%, conducen a que estrategias de RDC puedan suponer una clara alternativa en zonas con infradotación hídrica, como es el sureste español