Walking Before and During a Sea Voyage

In this article More Share Options Abstract Stationary and moving surfaces impose different constraints on walking. In this study we investigated within-participants differences between walking on a ship before (at the dock) and during (at sea) a sea voyage. Four individuals participated in the study. While on the ship they wore a tri-axial accelerometer (ActiGraph GT3X+; ActiGraph LLC, Pensacola, FL) on their waists. Activity data were sampled at 30 Hz. Data were collected on the day before the voyage began and on several days at sea. The number of steps per day was greater at the dock than at sea. The net resultant force per day also was greater at the dock than at sea. However, resultant force per step was greater at sea (79.97 ± 8.50 vector magnitude counts/step) than on land (62.94 ± 10.03 vector magnitude counts/step). In addition, we observed variations in resultant force per step across days at sea. Ship motion decreased overall activity but increased the force per step

Sources and Structures of Mitotic Crossovers That Arise When BLM Helicase Is Absent in Drosophila

The Bloom syndrome helicase, BLM, has numerous functions that prevent mitotic crossovers. We used unique features of Drosophila melanogaster to investigate origins and properties of mitotic crossovers that occur when BLM is absent. Induction of lesions that block replication forks increased crossover frequencies, consistent with functions for BLM in responding to fork blockage. In contrast, treatment with hydroxyurea, which stalls forks, did not elevate crossovers, even though mutants lacking BLM are sensitive to killing by this agent. To learn about sources of spontaneous recombination, we mapped mitotic crossovers in mutants lacking BLM. In the male germline, irradiation-induced crossovers were distributed randomly across the euchromatin, but spontaneous crossovers were nonrandom. We suggest that regions of the genome with a high frequency of mitotic crossovers may be analogous to common fragile sites in the human genome. Interestingly, in the male germline there is a paucity of crossovers in the interval that spans the pericentric heterochromatin, but in the female germline this interval is more prone to crossing over. Finally, our system allowed us to recover pairs of reciprocal crossover chromosomes. Sequencing of these revealed the existence of gene conversion tracts and did not provide any evidence for mutations associated with crossovers. These findings provide important new insights into sources and structures of mitotic crossovers and functions of BLM helicase

Lack of the DNA Repair Protein Blm During Drosophila Embryonic Development Impacts Metabolic Function

Blm DNA helicase is essential during early development in Drosophila. Most embryos from Blm mutant mothers do not survive due to a lack of maternally provided Blm products. We hypothesize that the small number of progeny that do survive this Blm-deficiency during early development will have experienced DNA damage that impacts long-term metabolic function. This will be assessed by measuring adult body weight and triglyceride levels in progeny that develop with or without maternal Blm

Lack of Blm Protein During Early Embryonic Development in \u3cem\u3eDrosophila\u3c/em\u3e Impacts the Lifespan of Surviving Progeny

During the early stages of Drosophila embryogenesis, maternally loaded Blm DNA helicase is essential for proper DNA replication; embryos from Blm mutant females, who fail to provision Blm to their eggs, accumulate DNA damage and most do not survive this early developmental period. Despite this severe maternal effect lethality, a small percentage of embryos do survive in the absence of Blm. However, survivors of this Blm-null embryonic environment may experience sub-lethal DNA damage that poses long-term biological consequences, such as decreased lifespan. We found that flies that developed without Blm had a reduced lifespan compared to those that developed with Blm. Due to the role Blm plays in ensuring proper replication through repetitive DNA sequences, we hypothesize that Y chromosomes containing more repetitive DNA might further reduce lifespan in a Blm deficient background

Identifying Socio-Cultural Factors That Impact the Use of Open Educational Resources in Local Public Administrations

The goal of this paper is to define relevant barriers to the exchange of Open Educational Resources in local public administrations. Building upon a cultural model, eleven experts were interviewed and asked to evaluate several factors, such as openness in discourse, learning at the workplace, and superior support, among others. The result is a set of socio-cultural factors that shape the use of Open Educational Resources in public administrations. Significant factors are, in this respect, the independent choice of learning resources, the spirit of the platform, the range of available formats and access to technologies. Practitioners use these factors to elaborate on the readiness of public administrations towards the use of open e-Learning systems. To academic debates on culture in e-Learning, the results provide an alternative model that is contextualized to meet the demands of public sector contexts. Overall, the paper contributes to the lack of research about open e-Learning systems in the public sector, as well as regarding culture in the management of learning and knowledge exchange

Identifying Socio-Cultural Factors That Impact the Use of Open Educational Resources in Local Public Administrations

The goal of this paper is to define relevant barriers to the exchange of Open Educational Resources in local public administrations. Building upon a cultural model, eleven experts were interviewed and asked to evaluate several factors, such as openness in discourse, learning at the workplace, and superior support, among others. The result is a set of socio-cultural factors that shape the use of Open Educational Resources in public administrations. Significant factors are, in this respect, the independent choice of learning resources, the spirit of the platform, the range of available formats and access to technologies. Practitioners use these factors to elaborate on the readiness of public administrations towards the use of open e-Learning systems. To academic debates on culture in e-Learning, the results provide an alternative model that is contextualized to meet the demands of public sector contexts. Overall, the paper contributes to the lack of research about open e-Learning systems in the public sector, as well as regarding culture in the management of learning and knowledge exchange

Asynchronous replication, mono-allelic expression, and long range Cis-effects of ASAR6.

Mammalian chromosomes initiate DNA replication at multiple sites along their length during each S phase following a temporal replication program. The majority of genes on homologous chromosomes replicate synchronously. However, mono-allelically expressed genes such as imprinted genes, allelically excluded genes, and genes on female X chromosomes replicate asynchronously. We have identified a cis-acting locus on human chromosome 6 that controls this replication-timing program. This locus encodes a large intergenic non-coding RNA gene named Asynchronous replication and Autosomal RNA on chromosome 6, or ASAR6. Disruption of ASAR6 results in delayed replication, delayed mitotic chromosome condensation, and activation of the previously silent alleles of mono-allelic genes on chromosome 6. The ASAR6 gene resides within an ∼1.2 megabase domain of asynchronously replicating DNA that is coordinated with other random asynchronously replicating loci along chromosome 6. In contrast to other nearby mono-allelic genes, ASAR6 RNA is expressed from the later-replicating allele. ASAR6 RNA is synthesized by RNA Polymerase II, is not polyadenlyated, is restricted to the nucleus, and is subject to random mono-allelic expression. Disruption of ASAR6 leads to the formation of bridged chromosomes, micronuclei, and structural instability of chromosome 6. Finally, ectopic integration of cloned genomic DNA containing ASAR6 causes delayed replication of entire mouse chromosomes

Long-Term Biological Consequences of Blm-Deficiency During Early Embryonic Development in \u3cem\u3eDrosophila Melanogaster\u3c/em\u3e

During the early stages of Drosophila embryogenesis, maternally loaded Blm DNA helicase is essential for proper DNA replication; embryos from Blm mutant females, who fail to provision Blm to their eggs, accumulate DNA damage and most do not survive this early developmental period. Despite this severe maternal effect lethality, a small percentage of embryos do survive in the absence of Blm. However, we hypothesize that survivors of this Blm-null embryonic environment experience sub-lethal DNA damage that may pose long-term biological consequences, such as reductions in size, locomotor activity, fertility, and lifespan. To test these hypotheses, adult flies that developed with or without Blm during early stages of development will be compared. We have determined that flies that develop without Blm have a reduced lifespan compared to those that develop with Blm. This data implicates Blm in preventing lasting biological impacts which may be caused by DNA damage accumulation during early development

Delineation of the critical region required for DRT on chromosome 6.

<p>Cells containing either an ∼47 kb deletion (ΔAAV-1d) or an ∼76 kb deletion (Δ175-23a) at the <i>ASAR6</i> locus (see <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003423#pgen-1003423-g007" target="_blank">Figure 7A</a> and <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003423#pgen.1003423.s005" target="_blank">S5A</a>) were incubated with BrdU for 4.5 hours, harvested, and processed for FISH using a chromosome 6 paint (red) as probe and for BrdU incorporation using an antibody against BrdU (green). The DNA was stained with DAPI (blue). A) An example of this analysis from the ΔAAV-1d (∼47 kb deletion). The two chromosome 6 s are indicated with arrows, and arbitrarily assigned i or ii. B) The two chromosome 6 s from panel A, were cut out and aligned with each color displayed separately or in combination. C) Pixel intensity profiles of the BrdU incorporation (green), and DAPI (blue) staining along the two chromosome 6 s from panel A. D) Quantification of the BrdU incorporation in chromosome 6 s. The red and blue bars represent the two chromosomes identified by the chromosome 6 paint in six different cells. E) An example of this analysis from the Δ175-23a cells (∼76 kb deletion). The two chromosome 6 s are indicated with arrows, and arbitrarily assigned i or ii. F) The two chromosome 6 s from panel E, were cut out and aligned with each color displayed separately. G) Pixel intensity profiles of the BrdU incorporation (green), and DAPI (blue) staining along the two chromosome 6 s from panel E. H) Quantification of the BrdU incorporation in chromosome 6 s. The red and blue bars represent the two chromosomes identified by the chromosome 6 paint in six different cells, the late replicating chromosome contains a deletion of ∼76 kb <a href="http://www.plosgenetics.org/article/info:doi/10.1371/journal.pgen.1003423#pgen.1003423-Stoffregen1" target="_blank">[9]</a>.</p