Preservice teachers’ pictorial strategies for a multistep multiplicative fraction problem

Previous research has documented that preservice teachers (PSTs) struggle with under- standing fraction concepts and operations, and misconceptions often stem from their understanding of the referent whole. This study expands research on PSTs’ understanding of wholes by investigating pictorial strategies that 85 PSTs constructed for a multistep fraction task in a multiplicative context. The results show that many PSTs were able to construct valid pictorial strategies, and the strategies were widely diverse with respect to how they made sense of an unknown referent whole of a fraction in multiple steps, how they represented the wholes in their drawings, in which order they did multiple steps, and which type of model they used (area or set). Based on their wide range of pictorial strategies, we discuss potential benefits of PSTs’ construction of their own representations for a word problem in developing problem solving skills

Re-analysis of the Levanluhta skeletal material : Sex and stature estimation of individuals in an Iron Age water burial in Finland

Levanluhta, an Iron Age water burial site in Finland, and its material consisting of commingled skeletal remains and artifacts, has been studied by several researchers over the past 100 years, resulting in multiple interpretations of the people and the site. Previous skeletal analyses have concluded that the majority of the individuals represented in the remains were females and children and were of relatively short stature, so possibly nutritionally deprived. This study re-analyzed the commingled adult human remains with updated methods. The methods applied in this study to estimate sex and stature were based on more representative European reference samples than the previously applied methods. The methods included morphology, osteometrics, and computed tomography (CT) scans. Our results indicated that depending on the reference data, the majority of the individual adult bones including os coxae (73%, n = 45) and long bones (humerus 83%-89%, n = 52; radius 72%-89%, n = 47; ulna 50%-65%, n = 58; femur 92%-100%, n = 25; tibia 77%-85%, n = 26) were classified as females based on their size and morphology. The cross-sectional bone properties of humerii, femora, and tibiae visualized using CT scanning also supported these findings. However, the cranial morphology did not show as clear female-biased sex ratio as other methods (42% females, 33% males, 24% undetermined, n = 33). In females, the mean stature based on the tibia (155.3 cm, n = 10) was within the range of the coeval European females and did not necessarily indicate nutritional deprivation, which is in line with previously published stable isotope findings from the site. The mean stature based on the tibia suggested that the Levanluhta males were short (164.0 cm, n = 3), but final interpretations were limited due to the small number of male individuals. The current study affirmed that the Levanluhta skeletal assemblage was female biased and gave new insights into interpretation of the stature.Peer reviewe

Professional–Collector Collaboration: Moving beyond Debate to Best Practice

This article introduces the first of what will ultimately be two collections of case studies in archaeologist–responsible/responsive artifact collector collaboration. Focused on the United States, the articles in this issue of Advances in Archaeological Practice share the thoughts and experiences of archaeologists representing diverse employment sectors (compliance, agency, museum, and university), artifact collectors, and members of descendant communities. Research areas extend from California to Virginia and from Ohio to the Texas/Mexico border. The breadth of the writers' backgrounds and their focal regions reinforce the wide applicability of collaborative best practices. Every author explicitly treats two subjects: (1) the intersection of their work with the Society for American Archaeology's (SAA) recently published guidelines for ethical professional–collector collaboration, and (2) their own practical suggestions for establishing and nurturing those relationships. This introductory article provides an overview of each of the other contributions, notes how the contributions articulate with the SAA guidelines, and offers its own, mostly philosophical suggestions for prospective members of professional–collector collaborations. Este artículo introduce la primera de las que eventualmente serán dos colecciones de casos prácticos en colaboración responsable / receptiva entre arqueólogos y coleccionistas de artefactos. Centrados en los Estados Unidos, los artículos de esta edición de Advances in Archaeological Practice comparten los pensamientos y experiencias de arqueólogos que representan diversos sectores laborales (cumplimiento regulatorio, agencia, museo y universidad); coleccionistas de artefactos; y miembros de comunidades descendientes. Las áreas de investigación se extienden desde California hasta Virginia y desde Ohio hasta la frontera entre Texas y México. La amplitud del historial los escritores y sus regiones focales refuerza la amplia aplicabilidad de las mejores prácticas colaborativas. Cada autor versa explícitamente dos temas: la intersección de su trabajo con las directrices publicadas recientemente por la Sociedad para la Arqueología Americana (SAA) para la colaboración ética entre profesionales y coleccionistas; y sus propias sugerencias prácticas para establecer y nutrir esas relaciones. Este artículo introductorio resume cada trabajo, señala cómo cumple con las pautas de la SAA y ofrece sus propias sugerencias, principalmente filosóficas, para futuros miembros sobre las colaboraciones entre coleccionistas y profesionales.Ye

Previous antibiotic exposure increases risk of infection with extended-spectrum-β-lactamase- and AmpC-producing Escherichia coli and Klebsiella pneumoniae in pediatric patients

The objective of this study was to determine whether antibiotic exposure is associated with extended-spectrum-beta-lactamase- or AmpC-producing Escherichia coli or Klebsiella pneumoniae infections in children. We collected extended-spectrum-beta-lactamase- or AmpC-producing E. coli or K. pneumoniae isolates and same-species susceptible controls from normally sterile sites of patients aged ≤21 years, along with associated clinical data, at four free-standing pediatric centers. After controlling for potential confounders, the relative risk of having an extended-spectrum-beta-lactamase-producing isolate rather than a susceptible isolate was 2.2 times higher (95% confidence interval [CI], 1.49 to 3.35) among those with antibiotic exposure in the 30 days prior to infection than in those with no antibiotic exposure. The results were similar when analyses were limited to exposure to third-generation cephalosporins, other broad-spectrum beta-lactams, or trimethoprim-sulfamethoxazole. Conversely, the relative risk of having an AmpC-producing versus a susceptible isolate was not significantly elevated with any antibiotic exposure in the 30 days prior to infection (adjusted relative risk ratio, 1.12; 95% CI, 0.65 to 1.91). However, when examining subgroups of antibiotics, the relative risk of having an AmpC-producing isolate was higher for patients with exposure to third-generation cephalosporins (adjusted relative risk ratio, 4.48; 95% CI, 1.75 to 11.43). Dose-response relationships between antibiotic exposure and extended-spectrum-beta-lactamase-producing or AmpC-producing isolates were not demonstrated. These results reinforce the need to study and implement pediatric antimicrobial stewardship strategies, and they indicate that epidemiological studies of third-generation cephalosporin-resistant E. coli and K. pneumoniae isolates should include resistance mechanisms when possible

Ploidy in bone marrow cells from healthy donors: a MAC (morphology antibody chromosomes) study

The ploidy of human bone marrow cells belonging to the megakaryocytic, granulocytic-monocytic and erythrocytic lineages was studied by in situ hybridization using the biotin-labelled Y chromosome-specific DNA probe pY431 and the chromosome 1-specific probe pUC1.77 on cells identified morphologically and immunologically by the MAC procedure. Cells of the granulocytic-monocytic and erythrocytic lineages were seen to be 2N in ploidy, whereas the ploidy of the megakaryocytic lineage ranged from 2N to 32N, with the ploidy classes 4N and 8N being predominant. The frequency of megakaryocytes with 2N chromosomes was also high.Facultad de Ciencias Naturales y Muse

Free energy barrier for melittin reorientation from a membrane-bound state to a transmembrane state

An important step in a phospholipid membrane pore formation by melittin antimicrobial peptide is a reorientation of the peptide from a surface into a transmembrane conformation. In this work we perform umbrella sampling simulations to calculate the potential of mean force (PMF) for the reorientation of melittin from a surface-bound state to a transmembrane state and provide a molecular level insight into understanding peptide and lipid properties that influence the existence of the free energy barrier. The PMFs were calculated for a peptide to lipid (P/L) ratio of 1/128 and 4/128. We observe that the free energy barrier is reduced when the P/L ratio increased. In addition, we study the cooperative effect; specifically we investigate if the barrier is smaller for a second melittin reorientation, given that another neighboring melittin was already in the transmembrane state. We observe that indeed the barrier of the PMF curve is reduced in this case, thus confirming the presence of a cooperative effect

Nuorten avomuotoinen OPI-mielenterveyskuntoutus : Koettu hyöty ja vaikuttavuus sekä kuntoutusmallin soveltuvuus

OPI-hankkeen tarkoituksena oli kehittää avomuotoista kuntoutusmallia ammatillisessa koulutuksessa oleville 16–25-vuotiaille opiskelijoille, joilla oli diagnosoitu masennus- ja/tai ahdistuneisuushäiriö. Kuntoutusmallilla pyrittiin tukemaan nuoria elämänhallinnassa ja opiskelussa, vahvistamaan nuoren toimintakykyä ja hyvinvointia sekä vähentämään mielenterveysongelmiin liittyviä haittoja. Vuosina 2011–2013 toteutettiin yhteensä kahdeksan avomuotoista ryhmäkuntoutuskurssia, joihin kuului myös yksilökäyntejä sekä verkostotapaamisia. Kurssit kestivät seurantoineen noin 1,5 vuotta ja ne toteutettiin lukukausien aikana. OPI-hankkeen yhteydessä toteutettiin arviointitutkimus, jonka tavoite oli selvittää kuntoutusmallin koettua hyötyä ja vaikuttavuutta, sidosryhmäyhteistyötä sekä kuntoutusmallin soveltuvuutta vakiintuneeksi toiminnaksi. Tutkimukseen osallistui 70 kuntoutujaa. Aineistoa kerättiin kyselylomakkeilla sekä eri tahojen haastatteluilla (kuntoutujat, projektiryhmät). Kuntoutuksen ja opiskelujen yhteen nivominen onnistui enimmäkseen hyvin. Ryhmässä saatu vertaistuki koettiin kuntoutuksen suurimmaksi anniksi. Seuranta-aikana nuorten masennusoireet vähenivät, elämänlaatu, itse arvioitu terveydentila sekä opiskelukyky ja kognitiivinen toimintakyky kohentuivat. Nuoret olisivat kuitenkin tarvinneet kuntoutusta jo varhaisemmassa vaiheessa. Noin kolme nuorta neljästä arvioi, että oli saavuttanut kuntoutukselle asettamansa tavoitteet vähintään melko hyvin. Tavoitteiden saavuttaminen ja kuntoutuksen koettu vaikuttavuus olivat yhteydessä kuntoutuksen oikea-aikaisuuteen, yhteistyöhön hoitavan tahon sekä opiskeluterveydenhuollon kanssa sekä vuorovaikutuksen onnistumiseen ohjaajan ja nuoren välillä. Tutkimuksen tulokset antavat varsin rohkaisevan kuvan oppilaitoksen kanssa yhteistyössä toimivan ja opintojen kanssa yhteen sovitetun kuntoutuksen mahdollisuuksista nuorten syrjäytymisen ehkäisemisessä

Evaluating drug targets through human loss-of-function genetic variation

Naturally occurring human genetic variants that are predicted to inactivate protein-coding genes provide an in vivo model of human gene inactivation that complements knockout studies in cells and model organisms. Here we report three key findings regarding the assessment of candidate drug targets using human loss-of-function variants. First, even essential genes, in which loss-of-function variants are not tolerated, can be highly successful as targets of inhibitory drugs. Second, in most genes, loss-of-function variants are sufficiently rare that genotype-based ascertainment of homozygous or compound heterozygous 'knockout' humans will await sample sizes that are approximately 1,000 times those presently available, unless recruitment focuses on consanguineous individuals. Third, automated variant annotation and filtering are powerful, but manual curation remains crucial for removing artefacts, and is a prerequisite for recall-by-genotype efforts. Our results provide a roadmap for human knockout studies and should guide the interpretation of loss-of-function variants in drug development.Peer reviewe

Transcript expression-aware annotation improves rare variant interpretation

The acceleration of DNA sequencing in samples from patients and population studies has resulted in extensive catalogues of human genetic variation, but the interpretation of rare genetic variants remains problematic. A notable example of this challenge is the existence of disruptive variants in dosage-sensitive disease genes, even in apparently healthy individuals. Here, by manual curation of putative loss-of-function (pLoF) variants in haploinsufficient disease genes in the Genome Aggregation Database (gnomAD)(1), we show that one explanation for this paradox involves alternative splicing of mRNA, which allows exons of a gene to be expressed at varying levels across different cell types. Currently, no existing annotation tool systematically incorporates information about exon expression into the interpretation of variants. We develop a transcript-level annotation metric known as the 'proportion expressed across transcripts', which quantifies isoform expression for variants. We calculate this metric using 11,706 tissue samples from the Genotype Tissue Expression (GTEx) project(2) and show that it can differentiate between weakly and highly evolutionarily conserved exons, a proxy for functional importance. We demonstrate that expression-based annotation selectively filters 22.8% of falsely annotated pLoF variants found in haploinsufficient disease genes in gnomAD, while removing less than 4% of high-confidence pathogenic variants in the same genes. Finally, we apply our expression filter to the analysis of de novo variants in patients with autism spectrum disorder and intellectual disability or developmental disorders to show that pLoF variants in weakly expressed regions have similar effect sizes to those of synonymous variants, whereas pLoF variants in highly expressed exons are most strongly enriched among cases. Our annotation is fast, flexible and generalizable, making it possible for any variant file to be annotated with any isoform expression dataset, and will be valuable for the genetic diagnosis of rare diseases, the analysis of rare variant burden in complex disorders, and the curation and prioritization of variants in recall-by-genotype studies.Peer reviewe