Stacked crop rotations and cultural practices for canola and flax yield and quality

Canola (Brassica napus L.) and flax (Linum usitatissimum L.) are important oilseed crops, but improved management practices to enhance their yields and quality are needed. We studied the effect of stacked versus alternate‐year crop rotations and traditional versus improved cultural practices on canola and flax growth, seed yield, oil concentration, and N‐use efficiency from 2006 to 2011 in the northern Great Plains, USA. Stacked rotations were durum (Triticum turgidum L.)‐durum‐canola‐pea (Pisum sativum L.) (DDCP) and durum‐durum‐flax‐pea (DDFP). Alternate‐year rotations were durum‐canola‐durum‐pea (DCDP) and durum‐flax‐durum‐pea (DFDP). The traditional cultural practice included a combination of conventional tillage, recommended seed rate, broadcast N fertilization, and reduced stubble height. The improved cultural practice included a combination of no‐tillage, increased seed rate, banded N fertilization, and increased stubble height. Canola stand count was 36–123% greater with the improved than the traditional cultural practice in 2006, 2009, 2010, and 2011. Canola pod number and oil concentration were 3–36% greater in the improved than the traditional practice in 2007 and 2010, but trends reversed by 5–19% in 2008. Flax stand count was 28% greater with DFDP than DDFP in 2007 and 56% greater in the improved than the traditional practice in 2010. Flax pod number, seed weight, seed yield, N content, N‐use efficiency, and N‐removal index varied with crop rotations, cultural practices, and years. Canola growth and oil concentration increased with the improved cultural practice as well as flax growth, yield, and quality enhanced with alternate‐year crop rotation and the improved cultural practice in wet years

Rough Fibrils Provide a Toughening Mechanism in Biological Fibers

Spider silk is a fascinating natural composite material. Its combination of strength and toughness is unrivalled in nature, and as a result, it has gained considerable interest from the medical, physics, and materials communities. Most of this attention has focused on the one to tens of nanometer scale: predominantly the primary (peptide sequences) and secondary (β sheets, helices, and amorphous domains) structure, with some insights into tertiary structure (the arrangement of these secondary structures) to describe the origins of the mechanical and biological performance. Starting with spider silk, and relating our findings to collagen fibrils, we describe toughening mechanisms at the hundreds of nanometer scale, namely, the fibril morphology and its consequences for mechanical behavior and the dissipation of energy. Under normal conditions, this morphology creates a nonslip fibril kinematics, restricting shearing between fibrils, yet allowing controlled local slipping under high shear stress, dissipating energy without bulk fracturing. This mechanism provides a relatively simple target for biomimicry and, thus, can potentially be used to increase fracture resistance in synthetic materials

Polymorphisms in the selectin gene cluster are associated with fertility and survival time in a population of Holstein Friesian cows

Selectins are adhesion molecules, which mediate attachment between leucocytes and endothelium. They aid extravasation of leucocytes from blood into inflamed tissue during the mammary gland’s response to infection. Selectins are also involved in attachment of the conceptus to the endometrium and subsequent placental development. Poor fertility and udder health are major causes for culling dairy cows. The three identified bovine selectin genes SELP, SELL and SELE are located in a gene cluster. SELP is the most polymorphic of these genes. Several SNP in SELP and SELE are associated with human vascular disease, while SELP SNP rs6127 has been associated with recurrent pregnancy loss in women. This study describes the results of a gene association study for SNP in SELP (n = 5), SELL (n = 2) and SELE (n = 1) with fertility, milk production and longevity traits in a population of 337 Holstein Friesian dairy cows. Blood samples for PCR-RFLP were collected at 6 months of age and animals were monitored until either culling or 2,340 days from birth. Three SNP in SELPEx4-6 formed a haplotype block containing a Glu/Ala substitution at rs42312260. This region was associated with poor fertility and reduced survival times. SELPEx8 (rs378218397) coded for a Val475Met variant locus in the linking region between consensus repeats 4 and 5, which may influence glycosylation. The synonymous SNP rs110045112 in SELEEx14 deviated from Hardy Weinberg equilibrium. For both this SNP and rs378218397 there were too few AA homozygotes present in the population and AG heterozygotes had significantly worse fertility than GG homozygotes. Small changes in milk production associated with some SNP could not account for the reduced fertility and only SELPEx6 showed any association with somatic cell count. These results suggest that polymorphisms in SELP and SELE are associated with the likelihood of successful pregnancy, potentially through compromised implantation and placental development

G-quadruplex structures mark human regulatory chromatin

G-quadruplex (G4) structural motifs have been linked to transcription, replication and genome instability and are implicated in cancer and other diseases. However, it is crucial to demonstrate the bona fide formation of G4 structures within an endogenous chromatin context. Herein we address this through the development of G4 ChIP-seq, an antibody-based G4 chromatin immunoprecipitation and high-throughput sequencing approach. We find ∼10,000 G4 structures in human chromatin, predominantly in regulatory, nucleosome-depleted regions. G4 structures are enriched in the promoters and 5' UTRs of highly transcribed genes, particularly in genes related to cancer and in somatic copy number amplifications, such as $\textit{MYC}$. Strikingly, $\textit{de novo}$ and enhanced G4 formation are associated with increased transcriptional activity, as shown by HDAC inhibitor-induced chromatin relaxation and observed in immortalized as compared to normal cellular states. Our findings show that regulatory, nucleosome-depleted chromatin and elevated transcription shape the endogenous human G4 DNA landscape.European Molecular Biology Organization (EMBO Long-Term Fellowship), University of Cambridge, Cancer Research UK (Grant ID: C14303/A17197), Wellcome Trust (Grant ID: 099232/z/12/z

The classroom observation protocol for socioscientific issue-based instruction: development and implementation of a new research tool

Background: For the past decade, science educators have been exploring the use of Socio-scientific Issues (SSI) as contexts for science teaching and learning, and research indicates that doing so can support significant learning gains. However, research related to how teachers take up the practice of SSI-based instruction is far more limited, due in part to a lack of tools for use in this kind of research. Purpose: The focus of this research is development and testing of a new classroom observation protocol specifically designed for SSI-based instructional contexts. Design and methods: Development of this SSI-Observation Protocol (SSI-OP) took place in four distinct phases: review of existing protocols and SSI-based instruction frameworks, writing and revision of protocol items, initial testing of the draft protocol, and soliciting feedback from SSI experts. Sample: Following the four stages of SSI-OP development, we progressed to a series of field tests. The field tests were conducted with three different samples. The first sample was an experienced (10 + years) high school biology teacher and one of her honors biology classes. The second sample consisted of seven Turkish Pre-service Science Teachers (PST) participating in a science methods course. The third sample included two Thai PST from a field experience course embedded within a teacher education program. Results: The final version of the protocol addressed five dimensions of SSI-based instructional activities: focus of instruction, teaching moves, role of teacher, role of students, and classroom environment. Conclusions: The SSI-OP could be used in a variety of ways for research including documentation of current practices, impacts of professional development and/or curricula on teaching practices, and changes in teaching over time. We offer the SSI-OP as a new tool with the potential to contribute to science teacher education and research that may advance the teaching and learning of science through SSI. © 2017, © 2017 Informa UK Limited, trading as Taylor & Francis Group.Kementerian Pendidikan Nasional 2016-09-04-KAP01SSI-based instruction has been presented as a powerful strategy for the development of science learning and scientific literacy (Zeidler 2014). Empirical studies suggest that when classroom instruction is centered around contentious societal issues that connect to science, students are able to learn science content (Klosterman and Sadler 2010) and scientific practices such as argumentation (Dawson and Venville 2013) while also building reasoning competencies (Zeidler et al. 2009). Consistent with the growing body of research that confirms effectiveness of SSI-based instruction, many countries (e.g. Australia, England, Thailand, and Turkey) have adopted SSI-based instruction as a pedagogical approach in their elementary through high school science curricula (21st Century Science Project Team 2003; Australian Curriculum, Assessment and Reporting Authority [ACARA] 2015; Ministry of National Education of Turkey [MONE] 2013; Office of the National Education Commission of Thailand [ONEC] 2003).This article is based upon work supported by the Yıldız Technical University Scientific Research Projects Office under Award Number 2016-09-04-KAP01