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Week 7, Perfect Paragraph

Submitted by vvikhrev on Fri, 03/09/2018 - 13:22

In response to this week's assignment, I took an introductory to statistics course during the Spring of 2015. It was set-up as a team-based learning class therefore towards the end of the semester my team had to complete a large research writing project. This project encompassed all of the concepts we learned throughout the semester. Other than that, basic statistical concepts that I do remember learning were mean, median and mode. I also learned a lot of survey-taking approaches and then how to incorporate the survey raw data into some type of graph. I remember learning about possible graphical skews and biases that might not be noticed at first glance. It was a great learning experience overall, considering how bad I was at AP Statistics in high school. This type of knowledge became very useful in my science classes.

Draft #6, week 7, different sensory theories

Submitted by vvikhrev on Fri, 03/09/2018 - 13:14

just to review for my upcoming exam, hear are some notes:
There are 2 theories as to how our brain perceives sound. (the brain detects pitch!!!)
1.) Frequency theory: the frequency of auditory neural impulses corresponds to frequency of tone. lower notes vibrate at slower speeds and higher notes vibrate at higher speeds, as pitch increases, nerve impulses of the same frequency are sent to the auditory nerve
EX: a tone with a frequency of 700 Hz will produce 700 nerve impulses per second
- it is speed that determines pitch!
2.) place theory: we can hear different pitches due to sound frequencies on specific parts of the cochlear basiliar membrane, different parts of the cochlea are activated by different frequencies
EX: a sound that is 6000Hz would stimulate the spot along the membrane that passeses a characteristic frequency of 6000 Hz
- the brain detects pitch based on the position of hair cells that transmitted the neural signal

There are 2 theories as to how a "taste is encoded" by taste receptor cells
1.) Labelled-line model: each single TRC can sense all 5 tastes but it will only respond to one, they are innervated by individually tuned nerve fibers
2.) Across-fiber model: has two parts: individual taste receptor cells are tuned to multiple tastes and the same afferent fiber carries info for more than one taste OR that TRCs are tuned to single taste qualities but the same afferent fiber carries info for more than one taste

There are 3 theories/models to the mechanical gating of touch
1.) Indirect/Direct tether model
2.) membrane model
3.) secondary-messenger model

Draft #5, week 7, feature detection neurons image

Submitted by vvikhrev on Thu, 03/08/2018 - 18:33

Since Chapter 5 was on data presenting, I thought it would be interesting to share this image. This is a great and appealing visual display of their  data. I don't think there could have been a better way to display it!

This is a link to how intrinsic our hand is. There are so many nerves in our hands, with different sizes of receptive fields and cortical representations. Here is an interpretation of the figure: 

     EX: motion sensitive neuron responds to stroking the skin in all directions

     EX: direction sensitive neuron responds strongly to motions towards the ulnar side of the palm but fails to respond to motion along the same               path in the opposite direction

     EX: an orientation sensitive neuron responds better to motion across a finger (ulnar-radial) than to motion along the finger (distal-proximal)                 but doesn’t distinguish from radial nor proximal from distal directions


Draft #4, week 7, what I need to know for my Bio exam

Submitted by vvikhrev on Thu, 03/08/2018 - 18:15

displacement of hair bundle to taller SC inc. # of open channels, producing an increase of inward resting current deploarizing voltage change = receptor potential inc. permeability to (+) dep more NTs released
at high tone bursts, rate decreases b/c fiber is adapted and less likely to respond
How can the auditory nerve signal the large range in level of audible sound from 0-100 dB? (b/c when theres masking fiber can’t signal changes in tone burst)
1.) as the level of tone increases more and more fibers that are tuned to other CF begin to respond, b/c tuning ccurves become broader at higher sound levels
2.) auditory nerve fibers vary in sensitivity to sound and as sound level is incresaed, the less sensitive fibers begin to respond

Phase-Locking: when neurons only fire at a preferred phase of the sound wave at each cycle, usually at peak amplitude
- phase-locking in nerve fibers results from the phasic release of NT as dictated by the ac receptor potential
- @ low frequencies, neurons can fire APs at every cycle, easy to determine frequency of sound b/c it’s the same as the frequency of the neurons APs
- @ higher frequencies (1kHz-4kHz), neurons can’t fire AP w/ every cycle, b/c firing rate is limited by refractory periods
- the only code for sound frequency at high frequencies is the place code
- intensity of stimulus is encoded by the # of fibers that are active other than frequency of firing

The relationship between degree of bundle deflection and receptor potential magnitude is neither linear nor symmetric
I.E. – displacement of bundles in the depolarizing direction produces larger response than equal displacements in the other direction = sigmoidal input and output (not sine)
Thus, symmetrical sinusoidal deflections of the bundle (as might occur with acoustic stimuli) will produce both (ac) and (dc) changes in membrane potential.
dc Component = superimposed depolarizing steady-state
ac Component = sinusoidal
- as you increase F, there is less of this but dc component will remain unperturbed (this is called rectification)
OHC: function to amplify the signal so there is a high sensitivity to hearing
- decrease in resting length by a factor of 4 from the apical to the basal ends, responds by altering its length
- there is a driving force to hyper- and de-polarize the cell depending on K+ and Ca2+ channels
- depends on ratios of ion channels and capacitance of the membrane, there are also big and small hair cells, EX: bigger hair cells respond better to lower F

Draft #3, week 7, statistics

Submitted by vvikhrev on Wed, 03/07/2018 - 19:23

I took an introductory to statistics course in Spring of 2015. I was a freshman at the time therefore I don't remember quite a lot except for the big group project we had to do. Basic statistical concepts that I do remember learning were mean, median and mode. I also learned a lot of survey-taking and then incorporating that raw data into some type of graph. I remember learning about skews and bias that might not be noticed at first glance of the graph. Since this was a team-based learning course, towards the end of the semester the big group project we had to do wrapped up all the concepts we learned in class. There was a scientific work with a large collection of data from which we selected two-three variables (such as smoking, stroke, and exercise). Then, formed a hypothesis, and used all the equations we learned in class to "test" or "prove" our hypothesis without actually doing any type of experiment. We displayed the data in circle graphs, bar graphs and other forms of tables. It was a great learning experience overall considering how bad I was at AP statistics in high school. This type of knowledge became very useful in my science classes because it is easy to spot some bias and skewing of data in some research. For instance, the values on the x-axis may go from 0.1-0.2-0.3, etc and the line on the graph may appear to be at a very steep slope but the x-values are so small that there appears to be no correlation at all.

Draft #2, week 7, Hoffman Ch. 5 notes part 2

Submitted by vvikhrev on Wed, 03/07/2018 - 19:03

- you can present your data in a photograph, draing, diagram or graph (most common)
- line graphs are the most common types of graphs used in science
- don't make it too compact and don't leave too much white space either
- 3-4 curves should be the max, especially if the curves cross each other
- when lines do cross, it would be best to distinguish each line by thickness or different patterns
- bar graphs are different lengths to display comparative values
- use vertical rather than horizontal bars
- use bar graphs instead of line graphs for discrete data or when findings can be divided and compared in different ways
- scatter plots are similar to line graphs except the dots are not connected by lines
- instead a best-fit line is drawn to show how the two variables are related to each other, can be curved or linear
- data points can overlap which is fine because you are mostly looking for the relationship/correlation between the 2 variables
- place the independent variable on the x-axis and the dependent variable on the y-axis
- if you are req'd to write a title for your paper, the best thing to do is describe what is graphed in terms of y axis versus x axis
- the figure legend should be a description of the figure content
- the legend should contain: title, description of contents and explanations of symbols and abbreviations( (pg. 70)
- figures w/ only figure titles don't usually appear in scientific writing except for on posters and slides

Draft #1, week 7, Hoffman Ch. 5 notes part 1

Submitted by vvikhrev on Wed, 03/07/2018 - 18:19

- decide how you want to present your data, in the text or in an illustration
- if your data is listed in words then its best to present it in a couple of sentences in your results section
- present data in graphs when you want to reveal some kind of trend or correlation
- if you want to give precise numbers then its important to prepare tables rather than graphs
- look for patterns in order to create the most useful table
- usually independent values go on the right and depend values go on the left
- it is best to use a graph when you want to stress the importance of standard error or deviation
- tables present data more precisely than a graph but don't usually clearly show trends within your data
- tables are a good way to present facts
- for a graph, it is trend that is more important than exact numbers
- design figures and tables by keeping the reader in mind in order to have a strong impact
- figures and tables must be able to stand on their own
- not all data needs to be described in the text, just emphasize your key findings and use tables and figures to back up conclusions you've made
- figures and legends need to be independent of the text, meaning the reader must be able to understand what is being portrayed by reading the title and the legend without searching the text for an explanation
- place info where you would want/expect the reader to find it

Week 5, Perfect Paragraph

Submitted by vvikhrev on Fri, 02/23/2018 - 10:52

Hofmann’s chapter 13 provides some advice and guidelines to follow when creating and presenting a scientific poster. The poster is a short visual version of a long research paper therefore, it should include the most important ideas of each section and be more “visually appealing” to the audience. The poster should be self-explanatory so that a reader can understand it without the author’s presence. The experimental approach should be summarized very briefly and preferrably displayed as a flowchart or schematic to create a visual appeal. The results section of the poster should be considered as the most important section. The results should be presented in the form of figures and tables in a consistent order between what is written in the conclusion section. Conclusions are usually brief, and would provide more appeal if displayed as short bullet points. It is acceptable to highlight or draw arrows on the areas of the figures that need to be emphasized. When presenting, a 5-10 min talk should be prepared that can be practiced beforehand in front of peers or professors. Most importantly, the well-designed poster serves as a visual aid and not something to read off.

Draft #6, week 5, Hofmann Chapter 13 cont.

Submitted by vvikhrev on Fri, 02/23/2018 - 10:35

- summarize experimental approach very briefly on your poster, you can talk more about it when you present
- maybe you could use a flowchart or schematic to display the experimental approach instead to make it more "visual" and easier to grasp than describing the approach in words
- the results section is the most important part of the poster
- most if not all of your findings should be presented in the form of figures and tables in a consistent order b/w your results and conclusion
- conclusions are usually brief, mention only 2-4 main points here
- if written as bullet points, these findings will be more visually pleasing than a whole paragraph of text!
- because all the figures and tables should be self-explanatory as well, make sure to include a legend and a title
- if possible, use graphics instead of tables
- if you need to emphasize things, use highlighting, circles, arrows, etc
- if you are going to present at a conference, you usually need to send in an abstract first that would be reviewed by a committee
- if your abstract is accepted, review THEIR poster guidelines before beginning the poster
- don't use the abstract that you sent them on your poster too, because the abstract that goes on your poster is much shorter
than the one you sent them
- when presenting, prepare a 5-10 minute talk, always be present at your poster, if you want, you can practice in front of other peers or professors
- use poster as a visual aid and not something to read off of!!!!!
- pg. 202 provides a sample poster that is well-designed and a checklist to follow on pg. 203

Draft #5, week 5, analysis of review article

Submitted by vvikhrev on Fri, 02/23/2018 - 10:20

This article comes from a book called "Forty Studies that Changed Psychology" and is found in chapter 1, reading 4. The article reviews a study done by E. J. Gibson (et al.) on depth perception and avoidance in very young children. It begins with an introduction that provides some background information. This essay isn't critiquing the research, instead, it is providing a summary of the purpose, methods, results, a conclusion, and some real-world applications. I believe that it has done a decent job of doing so. However, it would have been helpful to include some visuals from the research paper itself. This isn't a review article because it doesn't evaluate the "primary source" and doesn't include other sources to support their opinion. Instead, it's purpose is to convey a single piece of information that is most important for the reader and their context. For instance, if someone is trying to learn more about how humans understand depth perception, they would read a summary article such as this instead of the entire research paper. The reader should not cite this article if they were to write a review article, instead they should find the primary source and use that instead. This is because, the author of this article has summarized what they think is most important. I think this goes along with the reason why you would cite a research poster if you were to write a review article because it just provides an orverview of what the author thinks you should know the most.


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