Homework Help

Is there a rhyme or reason to the order we write molecular formulas (eg why do we write SiC instead of CSi)?

Can anybody help to find the fixed point of the statement? while x != y do (if x <y then y := y − x else x := x − y) (Denotational semantics)

I'm attempting to describe different aspects of variables in a paper. http://jama.jamanetwork.com/article.aspx?articleid=1360865 Association Between Urinary Bisphenol A Concentration and Obesity Prevalence in Children and Adolescents It listed different ranges of urinary bisphenol A, which I determined to be the independent variable. As such, I considered these different ranges, which there are four ranges described, to be four levels of the independent variable. I'm having trouble identifying the dependent variable. I would be quick to say it's body mass outcome, because the paper attempts to limit other things as confounding variables. The paper states that it…

Ok I don't even know where to begin with this problem A hairy-winged (h) Drosophila female is mated with a yellow bodied (y), white-eyed (w) male. The F1 flies are normal. The F1 progeny is then inter-bred. The F2 generation has the following phenotypic ratios- give the genotypes of its parents and the F1 (for each sex). List linkage relationship and calculate map distances. Can someone lead me through this?

Help, I am having a difficultly setting up this problem. A baseball is hit at a height H=1.00m and then caught at the same height. It travels alongside a wall, moving up past the top of a wall 1.00s after it is hit and then down past the top of the the wall 4 seconds later, at a distance D=50.0m farther along the wall. Find : (A) Horizontal distance traveled from hit to catch.

Hi all Why does the effective nuclear charge of a group on the periodic table remain constant. I tried to figure it out but i wasnt too sure. My teacher (BEST TEACHER EVA!!!) unfortunately didn't explain it to the class and i couldn't find it anywhere on the internet. so does any one know why this happens?

Hello, all. I'm reading through a recent research paper entitled: Association Between Urinary Bisphenol A Concentration and Obesity Prevalence in Children and Adolescents The article is from the Journal of the American Medical Association. (Attached) Page 2, the last paragraph is of importance, as is the information going to page 6 with table 3. I know it seems like a lot. The most important thing to me is understanding what kinds of statistical tests are being used, how, and how the p-values and prevalence values are being calculated. I'm having a major problem understanding how the authors computed their data and performed statistical tests on the data.…

Hi, As someone unscientific who knows nothing about genetics, I'm hoping to get some things cleared up for a writing assignment I have, and perhaps this is the place to get started? First off, I'm wondering if two people with the same ancestor, going back say five generations, compared a sample of eachother's DNA, would they be able to confirm they were from that same ancestor? Would they be able to identify the ancestor's genetic imprint for future comparisons with other people? And how much of the ancestor's genetic code would they be able to decipher? thanks

1) Asaturated water mixture enters a 1m x 1m channel at T1=70oC,and ν1=1.0m3/kg, the velocity has a profile of V(x) =100(x-x2) m/s in the x direction and is uniform in the y direction(Hint: velocity at x=0.5, is 25m/s, Section 4.2.3). The channel splits into twocircular channels, transporting the saturated vapor out of the system in onechannel, and the saturated liquid in the other. Determine the mass flow rate through each channel. Determine the exit area of each pipe if the averagevelocity is Ve,1=15m/s for the steam and Ve2 =0.1m/s forthe liquid respectively (Aliquid=0.137m2).

How are the periods numbered?

Hey guys, I'm having trouble determining the structure of a compound based on some NMR that I have been given. Here is what I've been given: Molecular Formula: C8H6O4 1H NMR: 1.57 (d, J=8.66 Hz, 1 H) 1.77 (d, J=8.66 Hz, 1 H) 3.51 (d, J=3.00 Hz, 1 H) 3.51 (d, J=3.00 Hz, 1 H) 3.60 (sc,J=7.56, 3.00 Hz, 1 H) 3.60 (sc, J=7.56, 3.00 Hz, 1 H) 6.31 (s, 2 H) 13C NMR: 46.10 (s, 1 C) 46.10 (s, 1 C) 47.20 (s, 1 C) 47.20 (s, 1 C) 52.80 (s, 1 C) 135.60 (s, 1 C) 135.60 (s, 1 C) 171.50 (s, 1 C) 171.50 (s, 1 C) So, here's what I've been able to figure out thus far: I decided to first find the degree of unsaturation in this molecule, which comes out as 6. From that, my fir…

Vertexes: A(5,6) B(-1,-2) C(unknown) Orthocenter: H(-1,2) I've though this: Find the line AB that crosses A and B -> Line HC that crosses H and C are perpendicular to it; use H to find its c (ax + by + c = 0) or q (y = mx + q) But still, i don't know how to find C, only a line that passes through it Help?:\

How do I solve this one? EDIT: I tried this, I don't think it's right.

Hi, I have just started my first Biochem course. I'm a bit confused about isoelectric focusing. So the ampholytes are added to the gel, and then the electric field is applied. If an ampholyte is singly positively charged, it moves toward the cathode...as if moves toward the cathode it will lose a proton, and because it is no longer charged it will be immobilized. Does that proton (or whatever solution is carrying the proton) move then toward the anode? Is this how the pH is established? I'm a bit confused as to how the ampholytes set up a pH when there is no proton gradient to start with.

Let's pretend that a particule with a relative speed V moves along a referential S (x; y and z) On that referential S, we measure this particule speed We then notice that particule has a speed on all 3 axes of that refrential S (x; y and z) Those speeds are then called Vx; Vy and Vz With those conditions, how would you write the lorentz transforms formula on the spatial (x;y and z) and temporal (T) coordinates?

I need ideas for biology science projects. Please help.

Hello! We are two freshmen from a high school in Arizona. In our physics class, we are participating in a bungee egg drop project. Although, we are having trouble thinking of ideas for a harness. Students will provide the elastic cord and harness to use for the drop. The teacher will provide a large raw Grade AA egg. Teams may bring a substance like sand to add to the harness to obtain a constant mass. At least two cm of the pointed end of the egg must be extending below the bottom of the attachment harness. This is where my friend and I are having problems. Does anyone have any ideas for a harness? It must be secure enough to hold this egg, must fit the size requi…

Imaginons qu'une particule douée d'une vitesse relativiste V se déplace le long d'un référentiel S (x;yet z) Sur le référentiel S on fait des mesures de vitesse de cette particule. On constate quelle posède une vitesse suivant les trois axes du référentiel S (x;y et z) Ces vitesses sont donc nommées arbitrairement Vx;Vy et Vz.

Hi I was going through my past exam paper and it doesn't provide answers for it... I wrote down the answers for every questions. Can you please check whether i am right or not please? Q1. Predict which one of the following people would initially produce the greatest urine volume? a.A person who is given some synthetic Vasopressin which acts in the same manner as the natural hormone b.A person who drinks 500mL of isotonic sports drink c.A person who drinks 500mL of water d.A person who eats salty chips and then drinks 500mL of isotonic sports drink e.A person who eats salty chips and then drinks 500mL of water For this question,…

"an underwater earthquake in the ocean generates a tsunami with a wavelength of 200 km and a height of 1.5 m. it travels in water that is uniformly deep (3 km) until it reaches an inlet, which is 4 m deep. when it is in the inlet, what will be its: a. speed © b. period (t) c. wavelength (L) d. height (h)" I understand tsunamis are treated as shallow water waves so the equation for speed is c= (gd)^1/2. (g = gravity = 9.8 m/s) and I'm assuming you just use the inlet depth of 4 m to get 6.26 m/second. what I don't know is the formulas for finding period and wavelength for shallow water waves. I know for deep waves you can use c=L/t where c=(g/2*pi)*t and L…

Hey Im having a bit of trouble with this homework. Can someone please help me with this. A vehicle makes a long journey. Before leaving, the driver checks the pressure of all the tyres using a tyre pressure gauge. The inner volume of each tyre is 30 litres and the indicator on the tyre pressure gauge reads 235kPa (about 34.1 psi). This is the safe operating pressure for these types of tyres. At the time of departure, the local weather forecast indicates the ambient temperature is at 25°C and the atmospheric pressure is 101.325kPa. At the end of the journey, the driver stops to inspect the tyres and finds the average temperature of the tyres is now at 50°C. …

figured it out.. how do i delete a topic?

Hello scientists, I have a question that's crucial to a project I'm working on: When I produce electricity with a magnet and a copper wire, I would like to conserve the energy I have produced instead of wasting in it on a lamp. Is there any way I can keep the energy I have produced into Batteries or something so I can use it later, if it's possible is there any way I can tell that the battery has been fully charged? like an LED lamp that changes colors. Thanks for reading this and I hope you will provide me some positive feedback. See you guys later.

Hello everyone, I prepare my first article (gas turbine modelling) in english language to register for PhD conferment procedure, and because I am not an englishman, I am sure the writing style is not too good. Some part is already "polished" by a friend of mine, but has no time to do the rest. I am kindly asking anybody who has some spare time to take a look at the following text and correct: Available catalogue gas turbine units data include following entities: frequency, electrical power, electrical efficiency, pressure ratio, exhaust gas mass flow rate and temperature after diffuser. These parameters are insufficient to carry out a simulation of turbine operati…

In a normal person, hyperkalemia causes decreased intracellular negativity which means depolarization happens more easily (resting potential is closer to threshold) and it also inhibits repolarization. Why is repolarization inhibited? Are depolarization and repolarization similarly affected by hyperkalemia in people who have channelopathies? I'm specifically working on Na+ channelopathies associated with hyperkalemia. I've read Na+ channels are unable to help regulate K+ potassium levels (because they stay open too long), so they cannot generate action potentials. But it seems if the person has hyperkalemia, it should be easier to generate an AP since depolarizat…