Amherst Pelham Regional School District

ABSTRACT Understanding of factors that regulate stream ecosystems is needed to guide effective management strategies. This study identified indicators effective in assessing spatial variation in stream trophic states by comparing a range of biochemical and physical properties with landscape features. Using monthly water samples collected from streams ranging from headwater tributaries to river outlets in lowland region of the Great Lakes Basin, we developed an analytical framework that integrates principal component analysis (PCA) to assess stream ecosystem services. The PCA analysis based on water properties explained ∼85% of the variance in annual mean trophic states, which increased to 91% with the inclusion of landscape features. Using principal components as variables, the linear regression model based on landscape features explained most of the variance in suspended chlorophyll a concentration (R² = 0.63), improving traditional models based on water properties (R² = 0.55). Despite ongoing challenges in applying estimates of benthic chlorophyll biomass, our linear models based on either water properties or landscape features showed comparable correlations with field measurements (R = 0.57 and R = 0.56, respectively). These findings highlight the strong predictive power of landscape features for assessing stream trophic states, offering a scalable approach for regional water quality assessments.

Cranberry phenolic compounds have been linked to many health benefits. A recent report suggested that cranberry bioactives inhibit adipogenesis in 3T3-L1 adipocytes. Thus, we investigated the effects and mechanisms of the cranberry product (CP) on lipid metabolism using the Caenorhabditis elegans (C. elegans) model. CP (0.016% and 0.08%) dose-dependently reduced overall fat accumulation in C. elegans (N2, wild type) by 43% and 74%, respectively, without affecting its pumping rates or locomotive activities. CP decreased fat accumulation in aak-2 (an ortholog of AMP-activated kinase α) and tub-1 (an ortholog of TUBBY) mutants significantly, but only minimal effects were observed in sbp-1 (an ortholog of sterol response element-binding protein-1) and nhr-49 (an ortholog of peroxisome proliferator-activated receptor-α) mutant strains. We further confirmed that CP downregulated sbp-1, cebp, and hosl-1 (an ortholog of hormone-sensitive lipase homolog) expression, while increasing the expression of nhr-49 in wild-type C. elegans. These results suggest that CP could effectively reduce fat accumulation in C. elegans dependent on sbp-1, cebp, and nhr-49, but not aak-2 and tub-1.

This unit begins with a pre-quiz to start students reflecting about why it is hard to increase or decrease the speed of an object.

These lessons, like previous lessons in this series, make use of analogies to teach difficult concepts. The instructional strategy is based on anchors introduced in earlier lessons. The unit also employs a variety of other techniques such as student voting, open discussions, collision demonstrations using students, and other laboratory experiments. This variety is built into the lessons to maintain student interest as the teacher carefully works to unpack their interwoven set of preconceptions.

ANSWERS TO EXERCISES: Unit 1 – Normal ForcesUnit 2 – Relative MotionUnit 3 – Surface Friction ForcesUnit 4 – Tension ForcesUnit 5 – Gravitational Force IUnit 6 – Gravitational Force IIUnit 7 – InertiaUnit 8 – Inertial and Gravitational ForceUnit 9 – Third Law in Dynamics

In spite of clear instruction to the contrary, many teachers will find that students retain the notion that the third law does not apply to gravitational forces between very different masses. This unit builds student understanding of the Law of Universal Gravitation starting with individual masslets. Building on the belief in the gravitational force between small objects established in the earlier Gravitational Force I unit, the argument is developed for equal and opposite gravitational forces. In order to ensure that students grasp the significance of the equal and opposite force pattern, we consider examples in the three domains of gravitational forces from Gravitational Force I.

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