Is the central-marginal hypothesis a general rule? Evidence from three distributions of an expanding mangrove species, Avicennia germinans (L.)

The central-marginal hypothesis (CMH) posits that range margins exhibit less genetic diversity 16 and greater inter-population genetic differentiation compared to range cores. CMH predictions 17 are based on long-held ‘abundant-centre’ assumptions of a decline in ecological conditions and 18 abundances towards range margins. Although much empirical research has confirmed CMH, 19 exceptions remain almost as common. We contend that mangroves provide a model system to 20 test CMH that alleviates common confounding factors and may help clarify this lack of 21 consensus. Here, we document changes in black mangrove (Avicennia germinans) population 22 genetics with 12 nuclear microsatellite loci along three replicate coastlines in the United States 23 (only 2 of 3 conform to underlying ‘abundant-centre’ assumptions). We then test an implicit 24 prediction of CMH (reduced genetic diversity may constrain adaptation at range margins) by 25 measuring functional traits of leaves associated with cold tolerance, the climatic factor that 26 controls these mangrove distributional limits. CMH predictions were confirmed only along the 27 coastlines that conform to ‘abundant-centre’ assumptions and, in contrast to theory, range margin 28 A. germinans exhibited functional traits consistent with greater cold tolerance compared to range 29 cores. These findings support previous accounts that CMH may not be a general rule across 30 species and that reduced neutral genetic diversity at range margins may not be a constraint to 31 shifts in functional trait variation along climatic gradients

Contrasting demographic history and gene flow patterns of two mangrove species on either side of the Central American Isthmus

Comparative phylogeography offers a unique opportunity to understand the interplay between past environmental events and life-history traits on diversification of unrelated but co-distributed species. Here, we examined the effects of the quaternary climate fluctuations and palaeomarine currents and present-day marine currents on the extant patterns of genetic diversity in the two most conspicuous mangrove species of the Neotropics. The black (Avicennia germinans, Avicenniaceae) and the red (Rhizophora mangle, Rhizophoraceae) mangroves have similar geographic ranges but are very distantly related and show striking differences on their life-history traits. We sampled 18 Atlantic and 26 Pacific locations for A.germinans (N=292) and R.mangle (N=422). We performed coalescence simulations using microsatellite diversity to test for evidence of population change associated with quaternary climate fluctuations. In addition, we examined whether patterns of genetic variation were consistent with the directions of major marine (historical and present day) currents in the region. Our demographic analysis was grounded within a phylogeographic framework provided by the sequence analysis of two chloroplasts and one flanking microsatellite region in a subsample of individuals. The two mangrove species shared similar biogeographic histories including: (1) strong genetic breaks between Atlantic and Pacific ocean basins associated with the final closure of the Central American Isthmus (CAI), (2) evidence for simultaneous population declines between the mid-Pleistocene and early Holocene, (3) asymmetric historical migration with higher gene flow from the Atlantic to the Pacific oceans following the direction of the palaeomarine current, and (4) contemporary gene flow between West Africa and South America following the major Atlantic Ocean currents. Despite the remarkable differences in life-history traits of mangrove species, which should have had a strong influence on seed dispersal capability and, thus, population connectivity, we found that vicariant events, climate fluctuations and marine currents have shaped the distribution of genetic diversity in strikingly similar ways

The Searsville Lake Site (California, USA) as a candidate Global Boundary Stratotype Section and Point for the Anthropocene Series

Cores from Searsville Lake within Stanford University’s Jasper Ridge Biological Preserve, California, USA, are examined to identify a potential GSSP for the Anthropocene: core JRBP2018-VC01B (944.5 cm-long) and tightly correlated JRBP2018-VC01A (852.5 cm-long). Spanning from 1900 CE ± 3 years to 2018 CE, a secure chronology resolved to the sub-annual level allows detailed exploration of the Holocene-Anthropocene transition. We identify the primary GSSP marker as first appearance of 239,240Pu (372–374 cm) in JRBP2018-VC01B and designate the GSSP depth as the distinct boundary between wet and dry season at 366 cm (6 cm above the first sample containing 239,240Pu) and corresponding to October-December 1948 CE. This is consistent with a lag of 1–2 years between ejection of 239,240Pu into the atmosphere and deposition. Auxiliary markers include: first appearance of 137Cs in 1958; late 20th-century decreases in δ15N; late 20th-century elevation in SCPs, Hg, Pb, and other heavy metals; and changes in abundance and presence of ostracod, algae, rotifer, and protozoan microfossils. Fossil pollen document anthropogenic landscape changes related to logging and agriculture. As part of a major university, the Searsville site has long been used for research and education, serves users locally to internationally, and is protected yet accessible for future studies and communication about the Anthropocene. PLAIN WORD SUMMARY: The Global Boundary Stratotype Section and Point (GSSP) for the proposed Anthropocene Series/Epoch is suggested to lie in sediments accumulated over the last ~120 years in Searsville Lake, Woodside, California, USA. The site fulfills all of the ideal criteria for defining and placing a GSSP. In addition, the Searsville site is particularly appropriate to mark the onset of the Anthropocene, because it was anthropogenic activities–the damming of a watershed–that created a geologic record that now preserves the very signals that can be used to recognize the Anthropocene worldwide

Argumentation in school science : Breaking the tradition of authoritative exposition through a pedagogy that promotes discussion and reasoning

The value of argumentation in science education has become internationally recognised and has been the subject of many research studies in recent years. Successful introduction of argumentation activities in learning contexts involves extending teaching goals beyond the understanding of facts and concepts, to include an emphasis on cognitive and metacognitive processes, epistemic criteria and reasoning. The authors focus on the difficulties inherent in shifting a tradition of teaching from one dominated by authoritative exposition to one that is more dialogic, involving small-group discussion based on tasks that stimulate argumentation. The paper builds on previous research on enhancing the quality of argument in school science, to focus on how argumentation activities have been designed, with appropriate strategies, resources and modelling, for pedagogical purposes. The paper analyses design frameworks, their contexts and lesson plans, to evaluate their potential for enhancing reasoning through foregrounding the processes of argumentation. Examples of classroom dialogue where teachers adopt the frameworks/plans are analysed to show how argumentation processes are scaffolded. The analysis shows that several layers of interpretation are needed and these layers need to be aligned for successful implementation. The analysis serves to highlight the potential and limitations of the design frameworks

Screening of DUB activity and specificity by MALDI-TOF mass spectrometry

Deubiquitylases (DUBs) are key regulators of the ubiquitin system which cleave ubiquitin moieties from proteins and polyubiquitin chains. Several DUBs have been implicated in various diseases and are attractive drug targets. We have developed a sensitive and fast assay to quantify in vitro DUB enzyme activity using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Unlike other current assays, this method uses unmodified substrates, such as diubiquitin topoisomers. By analyzing 42 human DUBs against all diubiquitin topoisomers we provide an extensive characterization of DUB activity and specificity. Our results confirm the high specificity of many members of the OTU and JAMM DUB families and highlight that all USPs tested display low linkage selectivity. We also demonstrate that this assay can be deployed to assess the potency and specificity of DUB inhibitors by profiling 11 compounds against a panel of 32 DUBs

1959: Abilene Christian College Bible Lectures - Full Text

UNTO ALL THE WORLD” Being the Abilene Christian College Annual Bible Lectures 1959 Price: $3.00 Published by FIRM FOUNDATION PUBLISHING HOUSE Box 77 Austin, Texa

Teaching Tolerance in a Globalized World: Final Remarks

Each of the five empirical studies presented in this report aimed to identify factors and conditions that help schools and teachers to promote tolerance in a globalized world. Each study acknowledged the complex, hierarchical layers of explanatory mechanisms, while focusing on what could be learned from in-depth analysis of data collected by the International Association for the Evaluation ofEducational Achievement’s International Civic and Citizenship Education Study 2009. In this chapter, key findings are summarized, while acknowledging limitations and caveats, and avenues for further research are identified. The report findings also flag some potential implications for policymakers

1957: Abilene Christian College Bible Lectures - Full Text

Featuring the Theme CHRIST IN YOU -THE HOPE OF GLORY PRICE: $3.00 FIRM FOUNDATION PUBLISHING HOUSE BOX 77 AUSTIN, TEXA

KIMA: Noise: A visual sound installation on urban noise

KIMA: Noise is a participatory art piece inviting audiences to explore impact of urban noises interactively. Using specific urban sound sources, the audience experiences noise as spatial soundscapes, responding to it, physically engaging and interacting with it. KIMA: Noise creates awareness for the phenomenon of noise pollution. The paper looks at preeminent research in the field, and draws conclusions of how sound affects us as individuals. The art project KIMA: Noise is introduced technically and conceptually