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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.

Draft #4, week 5, Hofmann Ch. 13 notes

Submitted by vvikhrev on Thu, 02/22/2018 - 17:26

This chapter was on posters. Design the poster based on your research question, include images/visuals, and focus only on the main points from each section. It is important to remember that just like with many other visual representations (ex: advertisements, movie posters, powerpoints, etc), the poster is supposed to grab the readers attention, keep them interested and most importantly, provide a concise overview of your work in your absence. Think about all the posters hanging in the Morrill building! A poster has the same sequence format as your research paper but it doesn't include the discussion. And word count is less. They focus on the most important main parts and attempts to present them visually. When you present, you can expand further on your research and state your conclusion clearly.
"Aim for 20% text, 40% graphics and 40% blank space" (pg. 194). The abstract and conclusion are considered the most important sections of the poster therefore they shoud be placed in the correct spaces, top left and bottom right corners, respectively. It could help the audience if you number each panel, arrange the materials in columns, and maintain a consistent style. It is best to use a white or very light background and nothing too extravagant because that could be overbearing and distractive for your audience. Page 196 provides a guideline of how big (or small) our font should be on the poster. Your main objective is to edit the text youre preparing to a very concise language. As always, the title should grab your readers attention, the abstract should be short (50-100 words in this case), and omit unnecessary details in your introduction. Beacuse posters are displayed for a while after your presentation, the introduction (ad the rest of the sections on your poster) should be self-explanatory.

Draft #3, week 5, Bio class notes

Submitted by vvikhrev on Thu, 02/22/2018 - 17:07

what is renin, it enters blood stream and cleaves the angiotenisin from the liver, to produce Ang2
ANG2 increases efferent arterioles, increases resistant to outflow of blood in the glomerulus a dn decrease resistance in afferent?
it also goes to the brain and causes you to be thirsty
ANG2 causes production of aldosterone in adrenal gland
decrease in volume = decrease in pressure = stimulation of cells in macule densa = increases enzyme that cleaves ANG to make ANG1 that goes to the lungs = ACE in the lungs converts ANG1 to ANG2 = acts on juxtaglomelular apparatus and acts on adrenal cortex to stimulate aldosterone release = act on nuclear receptors that controls expressure of Na+/K+ ATPase in these cells (pumping Na+ out of the filtrate and K+ enters)
get more hypotonic filtrate in the DCT
brings tonicity of filtrate to 50
they are the 2 hormones that work in combination to conserve water
pressure active transport of solutes, selective water permeability = how does this system work on its own
aldosterone controls pumps
vasopressin controls water permeability at the right spot at the right time

Draft #2, week 5, notes on the auditory system

Submitted by vvikhrev on Wed, 02/21/2018 - 13:42

Something interesting about tonotopic mapping is that it is similar to the concept of somatosensory mapping (something we go over in every biology class probably). One difference is that the mapping doesn't start on the surface on any of our ear structures but rather it is the neurons that are mapped tonotopically from hair cell afferent neurons to the neurons in the cochlear nucleus to higher levels in teh cortex. Also, I believe that every frequency signal has the same amount of space on the cochlear nuclei. However in a somatosensory map, some things such as the fingers, are over-represented because of the immense amount of neuronal pathways leading from there to the cortex in the brain compared to our toes for example.

What does an Audiograph tell us? (ex: tells sensitivity decreases as you go lower than 20Hz)
What are tuning curves?
- info that goes to the brain by the auditory nerve (type 1 AP spikes) must be extracted and processed to form a perception of the stimulus
- info = which fibers are responding, rate, time patterns of the spikes in each fiber
- response area for a fiber is plotted sound pressure level vs. frequency = tuning curve
CF: the frequency that evokes a response at the lowest sound pressure level , at CF, auditory nerve fibers can respond to sound levels as low as 0dB in the most sensitive range of hearing
- likely generated by active motility of the OHCs
- narrow at low sounds b/c the fiber responds only a narrow band of frequencies near CF
- wider at higher sounds, this reflects the passive mechanical characteristics of basilar membrane motion w/ little contribution
from OHCs
- fibers w/ low CFs innervate the apex of the cochlea and high CFs = more basal places (as expected from the pattern of BM vibration)
Tonotopic Mapping: the precise mapping of frequency to position
- it is preserved as the auditory nerve projects into the cochlear nucleus
- this suggest that the frequency is coded via a place code, w/ neurons at different places coding for different frequencies
- spontaneous APs = no sound stimulation, what causes these?
- 20% voltage-gated channels are open at rest and Na+ is entering, APs are “smaller”
- hair cells RMP = (-55mV)
- but if you get a stronger signal (NT) then you would fire more frequent spikes, more “prominent” AP
- represents how this neuron responds to different frequences, the most sensitive response is @CF
- sharp-tuning, afferent neuron can separate frequencies very well b/c everything happens before the auditory fiber

Draft #1, week 5, notes on the Kidneys

Submitted by vvikhrev on Tue, 02/20/2018 - 20:56

- 2 functions of the kidneys: get rid of waste material that are ingested or produced by metabolism and control volume and electrolyte composition of the body fluids
- what is the regulatory function of the kidneys: balance b/w intake (due to ingestion and metabolic production) and output (due to excretion and metabolic consumption) = maintains stable environment (homeostasis)
- filter plasma and filtrate by excreting them into the urine
- some products of metabolism that are eliminated as waste by the kidney: creatine, urea, uric acid, end products of hemoglobin breakdown and metabolites of various hormones
- also eliminate most toxins such as pesticides, drugs and food additives!
- excretion of water and electrolytes must match intake, intake depends on person's diet
- EX: response to daily rapid jump of sodium intake = kidneys have to later sodium excretion, in many people sodium intake can be increased 10x normal w/ relatively small changes in the ECF volume or plasma sodium concentration (otherwise sodium will accummulate and raise the ECF beyond normal causing hormonal changes and other responses to signal kidneys to increase sodium excretion)
- regulate arterial pressure, acid-base balance, erthroyte production, D3 production, and glucose synthesis
- blood flow to the 2 kidney is about 22% of cardiac output
- renal circulation has 2 capillary beds = glomerular and peritubular, arranged in series, separated by the efferent arterioles
- efferent arterioles lead from the glomerulus to the peritubular capillaries that surround the renal tubules (afferent arterioles lead to the the glomerulus)
- these arterioles help regulate the hydrostatic pressure in both sets of capillaries
- high hydrostatic pressure in the glomerular capillaries causes rapid fluid filtration
- a much lower hydrostatic in the peritubular capillaries permits rapid fluid reabsorption


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