Pennsylvania Folklife Vol. 33, No. 4

• I Remember Well: Thirty-Five Years of the Kutztown Folk Festival • Furniture Graining • Old Fashioned Clear Toy Candy • Metal Etching • Stenciling • Baskets and Basket Weavers • Apple Butter: Then and Now • Festival Focus • Festival Programs • 20th Annual Quilting Contest • Quilts and Quilt Marking • The Art of the Pennsylvania Dutch • Music on the Main Stage • Scratchboard • Pennsylvania Dutch Folk Art in Wood • The Windsor Chair • Hex Signshttps://digitalcommons.ursinus.edu/pafolklifemag/1104/thumbnail.jp

Photoacclimation of natural phytoplankton communities

ABSTRACT: Phytoplankton regulate internal pigment concentrations in response to light and nutrient availability. Chlorophyll a to phytoplankton carbon ratios (chl:C phyto) are commonly reported as a function of growth irradiance (Eg) for evaluating the photoacclimation response of phytoplankton. In contrast to most culture experiments, natural phytoplankton communities experience fluctuating environmental conditions, making it difficult to compare field and lab observations. Observing and understanding photoacclimation in nature is important for deciphering changes in chl:C phyto resulting from environmental forcings and for accurately estimating net primary production (NPP) in models which rely on a parameterized description of photoacclimation. Here we employ direct analytical measurements of C phyto and parallel high-resolution biomass estimates from particulate backscattering (bbp) and flow cytometry to investigate chl:C phyto in natural phytoplankton communities. Chl:C phyto observed over a wide range of Eg in the field was consistent with photoacclimation responses inferred from satellite observations. Field-based photoacclimation observations for a mixed natural community contrast with laboratory results for single species grown in continuous light and nutrient-replete conditions. Applying a carbon-based NPP model to our field data for a north-south transect in the Atlantic Ocean results in estimates that closely match 14C depth-integrated NPP for the same cruise and with historical records for the distinct biogeographic regions of the Atlantic Ocean. Our results are consistent with previous satellite and model observations of cells growing in natural or fluctuating light and showcase how direct measurements of Cphyto can be applied to explore phytoplankton photophysiology, growth rates, and production at high spatial resolution in situ.KEY WORDS: Phytoplankton carbon · Chlorophyll · Growth irradiance · Photoacclimation · Growth rate · Primary production · Nutrient

Analytical phytoplankton carbon measurements spanning diverse ecosystems

The measurement of phytoplankton carbon (C[subscript]phyto) in the field has been a long-sought but elusive goal in oceanography. Proxy measurements of C[subscript]phyto have been employed in the past, but are subject to many confounding influences that undermine their accuracy. Here we report the first directly measured C[subscript]phyto values from the open ocean. The C[subscript]phyto samples were collected from a diversity of environments, ranging from Pacific and Atlantic oligotrophic gyres to equatorial upwelling systems to temperate spring conditions. When compared to earlier proxies, direct measurements of C[subscript]phyto exhibit the strongest relationship with particulate backscattering coefficients (b[subscript]bp) (R²=0.69). Chlorophyll concentration and total particulate organic carbon (POC) concentration accounted for ~ 20% less variability in C[subscript]phyto than b[subscript]bp. Ratios of C[subscript]phyto to Chl a span an order of magnitude moving across and within distinct ecosystems. Similarly, C[subscript]phyto:POC ratios were variable with the lowest values coming from productive temperate waters and the highest from oligotrophic gyres. A strong relationship between C[subscript]phyto and b[subscript]bp is particularly significant because b[subscript]bp is a property retrievable from satellite ocean color measurements. Our results, therefore, are highly encouraging for the global monitoring of phytoplankton biomass from space. The continued application of our C[subscript]phyto measurement approach will enable validation of satellite retrievals and contribute to an improved understanding of environmental controls on phytoplankton biomass and physiology

Curriculum in early childhood education: critical questions about content, coherence, and control

A continuing struggle over curriculum in early childhood education is evident in contemporary research and debate at national and international levels. This reflects the dominant influence of developmental psychology in international discourses, and in policy frameworks that determine approaches to curriculum, pedagogy, and assessment. Focusing on early childhood education, we argue that this struggle generates critical questions about three significant themes within curriculum theory: content, coherence, and control. We outline two positions from which these themes can be understood: Developmental and Educational Psychology and contemporary policy frameworks. We argue that within and between these positions, curriculum content, coherence, and control are viewed in different and sometimes oppositional ways. Following this analysis, we propose that a focus on ‘working theories’ as a third position offers possibilities for addressing some of these continuing struggles, by exploring different implications for how content, coherence, and control might be understood. We conclude that asking critical questions of curriculum in early childhood education is a necessary endeavour to develop alternative theoretical frameworks for understanding the ways in which curriculum can be considered alongside pedagogy, assessment, play, and learning

Factors associated with dental visit and barriers to utilisation of oral health care services in a sample of antenatal mothers in Hospital Universiti Sains Malaysia

<p>Abstract</p> <p>Background</p> <p>The aims of this study were to determine factors associated with dental visit and to describe barriers to utilisation of oral health care services among antenatal mothers attending the Obstetric and Gynaecology Specialist clinic in Hospital Universiti Sains Malaysia.</p> <p>Methods</p> <p>A structured, self-administered questionnaire was used obtain information on the variables of interest pertaining to the current pregnancy from 124 antenatal mothers.</p> <p>Results</p> <p>The majority of the mothers claimed that their oral health status was good (67.0%) or very good (2.4%). On the contrary, most of them admitted of having had at least one oral health problem (59.7%) including cavitated (43.5%) and painful teeth (15.3%), bleeding gum (21.0%), and bad breath (10.5%). However, only 29% of the mothers visited dentist during the current pregnancy. Factors associated with the mothers' dental visit were exposure to oral health education before the pregnancy and awareness of relationship between poor maternal oral health and adverse pregnancy outcomes with odds ratio of 4.06 (95% CI: 1.67-9.78) and 3.57 (95% CI: 1.30-9.77) respectively. Common excuses given by most mothers include perceptions of not having any oral health problems (65.9%), long waiting time at the clinic (71.6%), and no immediate treatment given by the dentist (64.8%).</p> <p>Conclusions</p> <p>Utilisation of oral health care services among antenatal mothers was low. Mothers who reported dental visit were more likely to be those who had received oral health education before the current pregnancy and knew of the association between poor maternal oral health and adverse pregnancy outcomes. Dissatisfaction with the services rendered and perceptions of not having any oral health problems were the main barriers.</p

Potential controls of isoprene in the surface ocean

Isoprene surface ocean concentrations and vertical distribution, atmospheric mixing ratios, and calculated sea-to-air fluxes spanning approximately 125° of latitude (80°N–45°S) over the Arctic and Atlantic Oceans are reported. Oceanic isoprene concentrations were associated with a number of concurrently monitored biological variables including chlorophyll a (Chl a), photoprotective pigments, integrated primary production (intPP), and cyanobacterial cell counts, with higher isoprene concentrations relative to all respective variables found at sea surface temperatures greater than 20°C. The correlation between isoprene and the sum of photoprotective carotenoids, which is reported here for the first time, was the most consistent across all cruises. Parameterizations based on linear regression analyses of these relationships perform well for Arctic and Atlantic data, producing a better fit to observations than an existing Chl a-based parameterization. Global extrapolation of isoprene surface water concentrations using satellite-derived Chl a and intPP reproduced general trends in the in situ data and absolute values within a factor of 2 between 60% and 85%, depending on the data set and algorithm used

Archaeal and Bacterial Communities Respond Differently to Environmental Gradients in Anoxic Sediments of a California Hypersaline Lake, the Salton Sea ▿

Sulfidic, anoxic sediments of the moderately hypersaline Salton Sea contain gradients in salinity and carbon that potentially structure the sedimentary microbial community. We investigated the abundance, community structure, and diversity of Bacteria and Archaea along these gradients to further distinguish the ecologies of these domains outside their established physiological range. Quantitative PCR was used to enumerate 16S rRNA gene abundances of Bacteria, Archaea, and Crenarchaeota. Community structure and diversity were evaluated by terminal restriction fragment length polymorphism (T-RFLP), quantitative analysis of gene (16S rRNA) frequencies of dominant microorganisms, and cloning and sequencing of 16S rRNA. Archaea were numerically dominant at all depths and exhibited a lesser response to environmental gradients than that of Bacteria. The relative abundance of Crenarchaeota was low (0.4 to 22%) at all depths but increased with decreased carbon content and increased salinity. Salinity structured the bacterial community but exerted no significant control on archaeal community structure, which was weakly correlated with total carbon. Partial sequencing of archaeal 16S rRNA genes retrieved from three sediment depths revealed diverse communities of Euryarchaeota and Crenarchaeota, many of which were affiliated with groups previously described from marine sediments. The abundance of these groups across all depths suggests that many putative marine archaeal groups can tolerate elevated salinity (5.0 to 11.8% [wt/vol]) and persist under the anaerobic conditions present in Salton Sea sediments. The differential response of archaeal and bacterial communities to salinity and carbon patterns is consistent with the hypothesis that adaptations to energy stress and availability distinguish the ecologies of these domains