Specialist and more-able mathematics students: understanding their engagement with mathematics support

<p>Along with a growing body of evidence of the challenges experienced by specialist and more-able mathematics students during their undergraduate studies, there now exists evidence that these students are increasingly accessing mathematics support centres as a means of enhancing their mathematical learning experience. Here, we report on a survey of 47 specialist mathematics students, studying within the mathematics department of a large, UK research-intensive university. Our findings show that whilst such students have high levels of engagement with core teaching components, additional, and optional, opportunities for personalized support and dialogue provided by the mathematics department to support their studies are less well used and valued. Friends provide an important source of additional support along with visits to the mathematics support centre. Our data show that users of mathematics support from later years are not necessarily returners, but instead are new to the centre. Whilst many students use the centre only occasionally and as the need arises, there is evidence that others are more regular users and are using the centre as a core part of their mathematical learning experience. The reasons given for their usage are linked to the convenient availability of support, its personalized nature with friendly tutors of a similar-age and subject profile, the ability to use the centre as a group study space to work with friends, and as an opportunity to engage in dialogue about their mathematical learning.</p

Are North Atlantic Alaria esculenta and A. grandifolia (Alariaceae, Phaeophyceae) conspecific?

Alaria (Alariaceae, Phaeophyceae) is a common genus of kelps in the northern hemisphere. Fourteen species are currently recognized, of which three, Alaria esculenta (L.) Greville, A. pylaii (Bory de Saint-Vincent) Greville and A. grandifolia J. Agardh, are reported for the cold-temperate North Atlantic Ocean. Alaria esculenta, the type species described originally from the North Atlantic, exhibits a range of biogeographically correlated morphotypes suggesting the possibility of multiple species, subspecies or hybrids. In Ireland we discovered an A. esculenta population with unusually long stipes resembling the type specimen of A. grandifolia described from Spitsbergen by J. Agardh in 1872. These and other plants of A. esculenta h om Ireland were compared with plants from Spitsbergen fitting the description of A. grandifolia, using sexual hybridization relative growth rate measurements and DNA sequence comparisons. Complete interfertility was observed between the different isolates. Three nucleotide substitutions (0.37%) were found in the rbcL and RuBisCo spacer of A. grandifolia, and two in the partial 18S rRNA gene and ITS1 sequences. The relative growth rate at 10 OC of an Irish self-cross was significantly lower than those of all the other crosses. Comparison of RuBisCo spacer sequences of the Spitsbergen A. grandifolia and six A. esculenta isolates showed that A. grandifolia was identical to A. esculenta from Halifax, Canada. The partial 18S rRNA gene and ITS1 sequence of A. grandifolia was identical to that of A. praelonga from Japan and differed by a single substitution from A. esculenta from Scotland and by two nucleotide substitutions from the isolate from Ireland. The intraspecific differences in A. esculenta, together with the hybridization and morphometric results, suggest that A. grandifolia is to be considered conspecific with A. esculenta, and that A. grandifolia is most probably a large deep-water morphological variant subspecies or ecotype of A. esculenta

Biogeographic population structure of chimeric blades of porphyra in the northeast atlantic reveals southern rich gene pools, introgression and cryptic plasticity

The genus Porphyra sensu lato (Bangiaceae, Rhodophyta), an important seaweed grown in aquaculture, is the most genetically diverse group of the Class Bangiophyceae, but has poorly understood genetic variability linked to complex evolutionary processes. Genetic studies in the last decades have largely focused on resolving gene phylogenies; however, there is little information on historical population biogeography, structure and gene flow in the Bangiaceae, probably due to their cryptic nature, chimerism and polyploidy, which render analyses challenging. This study aims to understand biogeographic population structure in the two abundant Porphyra species in the Northeast Atlantic: Porphyra dioica (a dioecious annual) and Porphyra linearis (protandrous hermaphroditic winter annual), occupying distinct niches (seasonality and position on the shore). Here, we present a large-scale biogeographic genetic analysis across their distribution in the Northeast Atlantic, using 10 microsatellites and cpDNA as genetic markers and integrating chimerism and polyploidy, including simulations considering alleles derived from different ploidy levels and/or from different genotypes within the chimeric blade. For P. linearis, both markers revealed strong genetic differentiation of north-central eastern Atlantic populations (from Iceland to the Basque region of Northeast Iberia) vs. southern populations (Galicia in Northwest Iberia, and Portugal), with higher genetic diversity in the south vs. a northern homogenous low diversity. For. P. dioica, microsatellite analyses also revealed two genetic regions, but with weaker differentiation, and cpDNA revealed little structure with all the haplotypes mixed across its distribution. The southern cluster in P. linearis also included introgressed individuals with cpDNA from P. dioica and a winter form of P. dioica occurred spatially intermixed with P. linearis. This third entity had a similar morphology and seasonality as P. linearis but genomes (either nuclear or chloroplast) from P. dioica. We hypothesize a northward colonization from southern Europe (where the ancestral populations reside and host most of the gene pool of these species). In P. linearis recently established populations colonized the north resulting in homogeneous low diversity, whereas for P. dioica the signature of this colonization is not as obvious due to hypothetical higher gene flow among populations, possibly linked to its reproductive biology and annual life history.info:eu-repo/semantics/publishedVersio

Marine forests of the Mediterranean-Atlantic Cystoseira tamariscifolia complex show a southern Iberian genetic hotspot and no reproductive isolation in parapatry

Climate-driven range-shifts create evolutionary opportunities for allopatric divergence and subsequent contact, leading to genetic structuration and hybrid zones. We investigate how these processes influenced the evolution of a complex of three closely related Cystoseira spp., which are a key component of the Mediterranean-Atlantic seaweed forests that are undergoing population declines. The C. tamariscifolia complex, composed of C. tamariscifolia s.s., C. amentacea and C. mediterranea, have indistinct boundaries and natural hybridization is suspected. Our aims are to (1) infer the genetic structure and diversity of these species throughout their distribution ranges using microsatellite markers to identify ancient versus recent geographical populations, contact zones and reproductive barriers, and (2) hindcast past distributions using niche models to investigate the influence of past range shifts on genetic divergence at multiple spatial scales. Results supported a single, morphologically plastic species the genetic structure of which was incongruent with a priori species assignments. The low diversity and low singularity in northern European populations suggest recent colonization after the LGM. The southern Iberian genetic hotspot most likely results from the role of this area as a climatic refugium or a secondary contact zone between differentiated populations or both. We hypothesize that life-history traits (selfing, low dispersal) and prior colonization effects, rather than reproductive barriers, might explain the observed genetic discontinuities.Pew Charitable Trusts (USA); MARINERA, Spain [CTM2008-04183-E/MAR]; FCT (Portugal) [FCT-BIODIVERSA/004/2015, CCMAR/Multi/04326/2013, SFRH/BPD/107878/2015, SFRH/BPD/85040/2012]; FPU fellowship of the Spanish Ministry of Education; European Community ASSEMBLE visiting grant [00399/2012]; University of Cadi

Cosmopolitan geographic distribution of Phaeosaccion multiseriatum (Phaeosacciaceae, Phaeosacciophyceae), and description of P. westermeieri sp. nov. from Chile

Author Contributions: Conceptualization, A.F.P.; methodology, A.F.P.; software, A.F.P., N.J. and L.A.M.; validation, A.F.P.; formal analysis, L.A.M., A.F.P.; investigation, A.F.P., G.Y.C., A.R. and N.J.; resources, A.F.P, G.Y.C. and F.C.K.; data curation, A.F.P.; writing—original draft preparation, A.F.P.; writing—review and editing, A.F.P., M.D.G and all co-authors; visualization, A.F.P.; supervision, A.F.P.; project administration, A.F.P.; funding acquisition, A.F.P, G.Y.C. and F.C.K. The authors have accepted responsibility for the entire content of this manuscript and approved its submission. Persons: We appreciated assistance in the field by A. Montecinos, M.-L. Guillemin, S. Faugeron, E. Kytinou, Steve Cartwright and K.J. Yoon, and in the laboratory by H. Weitz.Peer reviewe

The CCAP knowledgebase:Linking protistan and cyanobacterial biological resources with taxonomic and molecular data

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