492 research outputs found
A comparison of a class of earth-moon orbits with a class of rotating Kepler orbits
Comparison of class of orbits in Earth-Moon field and class of Kepler orbits in rotating coordinates by use of concurrent series of graph
The Affect of Writing on the Internet
This paper is a description of the development, objectives, implementation and results of an advanced composition course conducted on the Internet with IWE (International Writing Exchange) of the Helsinki University of Technology. The purpose of the course was to motivate students of English who were discouraged during the difficult IMF era in Korea in 1998. During the 90\u27s the majority of English Education majors at Pusan National University in Korea had studied and/or traveled overseas for extensive periods of time during their undergraduate career. But, in 1998 opportunities for overseas travel and study had been greatly curtailed due to IMF era-imposed austerity measures. Students were frustrated in their English study abroad plans, yet eager for overseas contact and direct communication with native English speakers. The first assumption of this course was that student motivation is increased through an international writing exchange on the internet. This enthusiasm results in a healthy quantity of work. In addition, the postings required by the program draw on a variety of rhetorical styles, thus providing students with practice in a number of modes. The second assumption was that internet English is the perfect scaffolding between spoken discourse and written discourse because it is more complex than spoken discourse, yet less complex than written discourse. Samples of student work are examined to illustrate these assumptions
In vitro production of bovine embryos derived from individual donors in the Corral® dish
Background: Since the identity of the embryo is of outmost importance during commercial in vitro embryo production, bovine oocytes and embryos have to be cultured strictly per donor. Due to the rather low yield of oocytes collected after ovum pick-up (OPU) per individual cow, oocyte maturation and embryo culture take place in small groups, which is often associated with inferior embryo development. The objective of this study was to improve embryonic development in small donor groups by using the Corral (R) dish. This commercial dish is designed for human embryo production. It contains two central wells that are divided into quadrants by a semi-permeable wall. In human embryo culture, one embryo is placed per quadrant, allowing individual follow-up while embryos are exposed to a common medium. In our study, small groups of oocytes and subsequently embryos of different bovine donors were placed in the Corral (R) dish, each donor group in a separate quadrant.
Results: In two experiments, the Corral (R) dish was evaluated during in vitro maturation (IVM) and/or in vitro culture (IVC) by grouping oocytes and embryos of individual bovine donors per quadrant. At day 7, a significantly higher blastocyst rate was noted in the Corral (R) dish used during IVM and IVC than when only used during IVM (12.9% +/- 2.10 versus 22.8% +/- 2.67) (P < 0.05). However, no significant differences in blastocyst yield were observed anymore between treatment groups at day 8 post insemination.
Conclusions: In the present study, the Corral (R) dish was used for in vitro embryo production (IVP) in cattle; allowing to allocate oocytes and/or embryos per donor. As fresh embryo transfers on day 7 have higher pregnancy outcomes, the Corral (R) dish offers an added value for commercial OPU/IVP, since a higher blastocyst development at day 7 is obtained when the Corral (R) dish is used during IVM and IVC
Plastin 3 is upregulated in iPSC-derived motoneurons from asymptomatic SMN1-deleted individuals
Spinal muscular atrophy (SMA) is a devastating motoneuron (MN) disorder caused by homozygous loss of SMN1. Rarely, SMN1-deleted individuals are fully asymptomatic despite carrying identical SMN2 copies as their SMA III-affected siblings suggesting protection by genetic modifiers other than SMN2. High plastin 3 (PLS3) expression has previously been found in lymphoblastoid cells but not in fibroblasts of asymptomatic compared to symptomatic siblings. To find out whether PLS3 is also upregulated in MNs of asymptomatic individuals and thus a convincing SMA protective modifier, we generated induced pluripotent stem cells (iPSCs) from fibroblasts of three asymptomatic and three SMA III-affected siblings from two families and compared these to iPSCs from a SMA I patient and control individuals. MNs were differentiated from iPSC-derived small molecule neural precursor cells (smNPCs). All four genotype classes showed similar capacity to differentiate into MNs at day 8. However, SMA I-derived MN survival was significantly decreased while SMA III- and asymptomatic-derived MN survival was moderately reduced compared to controls at day 27. SMN expression levels and concomitant gem
numbers broadly matched SMN2 copy number distribution; SMA I presented the lowest levels, whereas SMA III and asymptomatic showed similar levels. In contrast, PLS3 was significantly upregulated in mixed MN cultures from asymptomatic individuals pinpointing a tissue-specific regulation. Evidence for strong PLS3 accumulation in shaft and rim of growth cones in MN cultures from asymptomatic individuals implies an important role in neuromuscular synapse formation and maintenance. These findings provide strong evidence that PLS3 is a genuine SMA protective modifier
Genes and environmental factors that influence disease resistance to microbes in the female reproductive tract of dairy cattle
Identification and characterization of miRNAs expressed in the bovine ovary
<p>Abstract</p> <p>Background</p> <p>MicroRNAs are the major class of gene-regulating molecules playing diverse roles through sequence complementarity to target mRNAs at post-transcriptional level. Tightly regulated expression and interaction of a multitude of genes for ovarian folliculogenesis could be regulated by these miRNAs. Identification of them is the first step towards understanding miRNA-guided gene regulation in different biological functions. Despite increasing efforts in miRNAs identification across various species and diverse tissue types, little is known about bovine ovarian miRNAs. Here, we report the identification and characterization of miRNAs expressed in the bovine ovary through cloning, expression analysis and target prediction.</p> <p>Results</p> <p>The miRNA library (5'-independent ligation cloning method), which was constructed from bovine ovary in this study, revealed cloning of 50 known and 24 novel miRNAs. Among all identified miRNAs, 38 were found to be new for bovine and were derived from 43 distinct loci showing characteristic secondary structure. While 22 miRNAs precursor loci were found to be well conserved in more than one species, 16 were found to be bovine specific. Most of the miRNAs were cloned multiple times, in which let-7a, let-7b, let-7c, miR-21, miR-23b, miR-24, miR-27a, miR-126 and miR-143 were cloned 10, 28, 13, 4, 11, 7, 6, 4 and 11 times, respectively. Expression analysis of all new and some annotated miRNAs in different intra-ovarian structures and in other multiple tissues showed that some were present ubiquitously while others were differentially expressed among different tissue types. Bta-miR-29a was localized in the follicular cells at different developmental stages in the cyclic ovary. Bio-informatics prediction, screening and Gene Ontology analysis of miRNAs targets identified several biological processes and pathways underlying the ovarian function.</p> <p>Conclusion</p> <p>Results of this study suggest the presence of miRNAs in the bovine ovary, thereby elucidate their potential role in regulating diverse molecular and physiological pathways underlying the ovarian functionality. This information will give insights into bovine ovarian miRNAs, which can be further characterized for their role in follicular development and female fertility as well.</p
Extracellular vesicles from follicular and ampullary fluid isolated by density gradient ultracentrifugation improve bovine embryo development and quality
Extracellular vesicles (EVs) have been isolated from follicular (FF) and ampullary oviduct fluid (AOF), using different isolation methods. However, it is not clear whether different purification methods can affect the functionality of resulting EVs. Here, we compared two methods (OptiPrep (TM) density gradient ultracentrifugation (ODG UC) and single-step size exclusion chromatography (SEC) (qEV IZON (TM) single column)) for the isolation of EVs from bovine FF and AOF. Additionally, we evaluated whether the addition of EVs derived either by ODG UC or SEC from FF or AOF during oocyte maturation would yield extra benefits for embryo developmental competence. The characterization of EVs isolated using ODG UC or SEC from FF and AOF did not show any differences in terms of EV sizes (40-400 nm) and concentrations (2.4 +/- 0.2 x 10(12)-1.8 +/- 0.2 x 10(13) particles/mL). Blastocyst yield and quality was higher in groups supplemented with EVs isolated from FF and AOF by ODG UC, with higher total cell numbers and a lower apoptotic cell ratio compared with the other groups (p < 0.05). Supplementing in vitro maturation media with EVs derived by ODG UC from AOF was beneficial for bovine embryo development and quality
SMART Research: Toward Interdisciplinary River Science in Europe
Interdisciplinary science is rapidly advancing to address complex human-environment
interactions. River science aims to provide the methods and knowledge required to
sustainably manage some of the planet’s most important and vulnerable ecosystems;
and there is a clear need for river managers and scientists to be trained within an
interdisciplinary approach. However, despite the science community’s recognition of the
importance of interdisciplinary training, there are few studies examining interdisciplinary
graduate programs, especially in science and engineering. Here we assess and
reflect on the contribution of a 9-year European doctoral program in river science:
‘Science for MAnagement of Rivers and their Tidal Systems’ Erasmus Mundus Joint
Doctorate (SMART EMJD). The program trained a new generation of 36 early career
scientists under the supervision of 34 international experts from different disciplinary
and interdisciplinary research fields focusing on river systems, aiming to transcend
the boundaries between disciplines and between science and management. We
analyzed the three core facets of the SMART program, namely: (1) interdisciplinarity,
(2) internationalism, and (3) management-oriented science. We reviewed the contents
of doctoral theses and publications and synthesized the outcomes of two questionnaire
surveys conducted with doctoral candidates and supervisors. A high percentage of the
scientific outputs (80%) were interdisciplinary. There was evidence of active collaboration
between different teams of doctoral candidates and supervisors, in terms of joint
publications (5 papers out of the 69 analyzed) but this was understandably quite
limited given the other demands of the program. We found evidence to contradict
the perception that interdisciplinarity is a barrier to career success as employment
rates were high (97%) and achieved very soon after the defense, both in academia
(50%) and the private/public sector (50%) with a strong international dimension. Despite
management-oriented research being a limited (9%) portion of the ensemble of theses, employment in management was higher (22%). The SMART program also increased
the network of international collaborations for doctoral candidates and supervisors.
Reflections on doctoral training programs like SMART contribute to debates around
research training and the career opportunities of interdisciplinary scientists
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