Positive Terms
Positive Terms - Related Videos
09:58
C. elegans Positive Butanone Learning, Short-term, and Long-term Associative Memory Assays
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Cited by 92 •
2011
Here we describe methods to test C. elegans associative learning and short- and long-term associative memory. These population assays employ the worms abilities to chemotax toward volatile odorants, and form positive associations upon pairing food with the chemoattractant butanone. Increasing the number of conditioning periods induces long-term memory.
06:41
Isolation Method for Long-Term and Short-Term Hematopoietic Stem Cells
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2023
We present a step-by-step protocol for the isolation of long-term hematopoietic stem cells (LT-HSCs) and short-term HSCs (ST-HSCs) using the Hoxb5 reporter system.
01:05
Long-term Depression
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2019
Long-term depression, or LTD, is one of the ways by which synaptic plasticity—changes in the strength of chemical synapses—can occur in the brain. LTD is the process of synaptic weakening that occurs over time between pre and postsynaptic neuronal connections. The synaptic weakening of LTD works in opposition to synaptic strengthening by long-term potentiation (LTP) and together are the main mechanisms that underlie learning and memory. Calcium Ion Concentration Mechanism If over time, all...
02:32
Position-effect Variegation
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2020
In 1928, a German botanist Emil Heitz observed the moss nuclei with a DNA binding dye. He observed that while some chromatin regions decondense and spread out in the interphase nucleus, others do not. He termed them euchromatin and heterochromatin, respectively. He proposed that the heterochromatin regions reflect a functionally inactive state of the genome. It was later confirmed that heterochromatin is transcriptionally repressed, and euchromatin is transcriptionally active chromatin.
03:41
In Vitro Calcium Imaging in Short-Term and Long-Term Rat Hippocampal Cultures
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2025
Source: Calvo-Rodríguez, et al. Fluorescence and Bioluminescence Imaging of Subcellular Ca2+ in Aged Hippocampal Neurons. J. Vis. Exp. (2015). This video demonstrates the use of fluorescence imaging to measure cytosolic calcium levels in short-term and long-term rat hippocampal cultures. By comparing young and aged neurons, it highlights how increased L-type voltage-gated calcium channel density and prolonged activation in aged neurons result in calcium overloading, a hallmark of neuronal aging.
FAQs
The sign of a term affects the total independently of the signs of neighboring terms. For example, a positive term may increase an expression even when a larger negative term makes the final value negative. This distinction separates two tasks: identifying each contribution and determining the sign of the completed expression after all terms have been combined.
A positive coefficient does not by itself determine the final numerical value of a term when variables later receive values. During symbolic work, the coefficient records the term's sign; during evaluation, substituted values also affect the result. Keeping these stages separate prevents a sign identified in an expression from being confused with the expression's evaluated total.
When collecting like terms, preserve each term's sign while combining coefficients attached to the same variable part. Thus, 5x + 2x produces 7x, whereas 5x - 2x produces 3x. The operation changes the coefficients, not the variable structure, so sign awareness is essential for simplifying polynomials without changing their meaning.
First separate the expression into terms at its addition and subtraction signs. Next, record the sign attached to each term, including a positive sign that may be understood rather than written. Finally, group like terms and combine their coefficients, checking that subtraction has not been treated as addition. This workflow supports reliable simplification and evaluation.
In an equation, a positive term can be handled by applying the inverse operation to both sides. For instance, isolating a variable in x + 4 = 9 requires subtracting 4 from both sides, leaving x = 5. Tracking the positive constant before and after that operation helps preserve equality and reduces sign errors during solution.
Positive terms provide a way to represent gains, increases, and other quantities added to a mathematical model. In an inequality, their signs help describe how contributions affect a comparison, while in a polynomial they show which parts add directly to the total. Interpreting these terms connects symbolic manipulation with changes or outcomes represented by the model.