What is the Liskov principle and how does it relate to polymorphism?
553253
http://en.wikipedia.org/wiki/Liskov_substitution_principle click the link to know in detail.
323326
The "L" in L-Dopa refers to "levorotatory", meaning that the molecule rotates plane polarized light counterclockwise. The "L" is sometimes written as (-). The opposite is dextrorotatory ("D" or "+"), which rotates plane polarized light clockwise.\n\nYou cannot use "L" to predict whether the molecule is an "S" or an "R" enationmer. They are seperate things.\n\nThe "R" and "S" refer to the arrangement of the atoms around the chiral center. The "L" and "D" refer to the direction that the molecule rotates plane polarized light. All chiral carbons will therefore carry an "R/S" and a "D/L" distiction, but both indicate different things.\n\nYou did the correct thing in determining the R/S configuration by assigning priorities to the 4 groups connected to the chiral carbon and so on and so forth. The L/D distinction can only be determined experimentally.
315846
Specifically, I do not know.  However the principal of a slide rule is that it utilizes natural logs of numbers.  Specifically, the natural log of the product of two numbers is the inverse log of the sum of the two logs... or, in normal terms...\n\nln(a*b) = exp( ln(a) + ln(b) );\n\nSo the way to do this on a slide rule is to add the two natural logs together and then calculate the inverse..
124889
I have a copy of the second edition. Is that good enough?\n\nIs there something in particular you need, or do you want the outline of the whole book?\n\n1. Set theory\nIntroduction\nFunctions\nUnions, Intersections, and complements\nAlgebra of sets\nThe axiom of chice and infinite direct product\nCountable sets\nRelations and equivalences\nPartial orderings and the maximal principle\nWell ordering and the countable ordinal\n\nPart One -- Theory of Functions of a Real Variable\n\n2. The Real Number System\n\nAxioms for the real numbers\nThe natural and rational numbers as subsets of R\nThe extended real numbers\nSequences of real numbers\nOpen and closed sets of real numbers\nContinuous functions\nBorel sets\n\n3. Lebesgue Measure\nIntroduction\nOuter measure\nMeasurable sets and Lebesgue measure\nA nonmeasurable set\nMeasurable functions\nLittlwood's three principles\n\n4. The Lebesgue Integral\nThe Riemann integral\nThe Lebesgue integral of a bounded function over a set of finite measure\nThe integral of a nonnegative function\nThe general Lebesque integral\nConvergence in measure\n\n5. Differentiation and Integration\nDifferentiation of a monotone function\nFunction of bounded variation\nDifferentiation of an integral\nAbsolute continuity\nConvex functions\n\n6. The Classical Banach Spaces\nThe Lp spaces\nThe Holder Minkowski inequalities\nConvergence and completeneww\nBounded linear functionsals on the Lp spaces\n\n\nPart Two -- Abstract Spaces\n\n7. Metric Spaces\nIntroduction\nOpen and closed sets\nContinuous function and homeomorphisms\nConvergence and completeness\nUniform continuity and uniformity\nSubspaces\nBaire category\n\n8. Topological Spaces\nFundamental notions\nBases and countability\nThe separation axioms and continuous real-valued functions\nProduct spaces\nConnectedness\nAbsolute (G delta)\nNets\n\n9. Compact Spaces\nBasic properties\nCountable compactness and the Bolzano-Weierstrass property\nCompact metric spaces\nProducts of compact spaces\nLocally compact spaces\nThe Stone-Cech compactification\nThe Stone-Weierstrass theorem\nThe Ascoli theorem\n\n10. Banach Spaces\nIntroduction\nLinear Operators\nLinear Functionals and the Hahn-Banach theorem\nThe closed graph theorem\nTopological vector spaces\nWeak topologies\nConvexity\nHilbert space\n\nPart Three -- General Measure and Integration Theory\n\n11. Measure and Integration\nMeasure spaces\nMeasurable functions\nIntegration\nGeneral convergence theorems\nSigned measures\nThe Radon-Nikodym theorem\nThe Lp spaces\n\n12. Measure and Outer Measure\nOuter measure and measurability\nThe extension theorem\nThe Lebesgue-Stieltjes integral\nProduct measures\nInner measure\nExtension by sets of measure zero\nCaratheodory outer measure\n\n13. The Daniell Integral\nIntroduction\nThe extension theorem\nUniqueness\nMeasureability and measure\n\n14. Measure and Topology\nBaire sets and Borel sets\nPositive linear functionals and Baire measure\nBounded linear fuctionals on C(X)\nThe Borel extension of a measure\n\n15. Mappings of Measure Spaces\nPoint mappings and set mappings\nMeasure algebras\nBorel equivalences\nSet mappings and point mappings ofn complete metric spaces\nThe isometries of Lp
55798
do u mean the Le Chatelier's principle for chemical equilibrium? This principle states that: \n\nIf a chemical system at equilibrium experiences a change in concentration, temperature or total pressure the equilibrium will shift in order to minimize that change.\n\nThis is often used by chemists to increase yield of products. For example, in the reaction \n\n                   CO + 2H2 ↔ CH3OH\n\nIf we increase the amount of carbon monoxide, according to the principle, methanol yield will increase so as to decrease CO concentration.
403310
This is a classic Le Chatelier's Principle question.  Le Chatelier's Principle states that when you apply a stress to a chemical reaction system, the system shifts to relieve that stress.  \n\na. If you increase the pressure by decreasing the volume, the system wants to relieve the increase in pressure by going to a condition of lower pressure.  The system can do that by going to less moles of gas.  The less moles of gas you have, the lower the pressure (and lower pressure will counter-act the increase in pressure that is being applied).  That means that the equilibrium will shift to the left, the reactants side, because there is only one mole of gas on that side but two moles of gas on the other side.  \n\nb. When NO2 is added, the system wants to relieve stress by counteracting the increase in NO2, so the system will shift left to use up some of the NO2 that was added in.  \n\nc. Because N2O2 is not involved in this reaction, adding some does nothing to the equilibrium.  \n\nHowever, if N2O4 is added, the equilibrium will shift right to consume some of the N2O4 that was added.
341242
Encapsulation; polymorphism and inheritance.\n\nEncapsulation lets you contain your data in objects that somewhat mirror 'real' objects.\nCustomer1 = new Customer (you would then populate your customer with public and private fields; perhaps everyone can see the public field that is the name of your customer; but the Customer object could also contain private fields; containing perhaps passwords and what that customer bought.) Encapsulation allows for data hiding; only other classes that have the correct permissions may access appropriate data. For example; another class that sends bills to your customers would also need to see the private data from the customer class. The data and methods that act on that data being enclosed in the methods allow you to change your class with little concern to the other classes that use the class you want to change. As long as you provide the same methods; the other classes will still be able to use the new class. The methods can also be either public or private; perhaps you want any class to be able to change the customer's phone number; but you would want to be more careful perhaps about changing the amount they owe. \n\nPolymorphism allows you to change your classes as required by using different input and output data; different types of data can use the same class. For example, a class could be written to print something; and can act differently if it is passed a string or a number. This allows you to use a class to do similar things with different types of data. It allows for the calling classes to be less concerned about what type of data you have; and more with what you want to do with that data.\n\nInheritance allows you to create new classes from existing classes. You could extend your Customer class by making a new HighSpendingCustomer. This new class would provide the same basic data and methods as your regular customer; but you could also add some new functionality to be more appropriately deal with the high-value customers. The new class would inherit the same functionality. This is often seen called 'is a' relationship. As in HighSpendingCustomer "is a" Customer; meaning that HighSpendingCustomer inherits from Customer.\n\nThe advantages of these are that they typically allow for easier code reuse (your customer class could be moved to a new application with little or no modification); easier to maintain (if you have a problem with a class; you can just change that class rather than dig through a huge program trying to find all occurances of a problem). As well; the classes tend to be smaller bits of code; it makes it easier to read and understand.\n\nThat's the 2 minute intro; hope it provides some value.
199797
The tradeoffs are always the same when implementing types or subtypes when creating anything..logical or not, schema or not.....it's all a means to an end that is an effect based on cause...
1075511
what Mendel gave us was the "Law of Independent Assortment" and the "Law of Random Segregation".  Basically, that chromosomes behave in an independent manner when segregating from each other. (ie-when chromosomes are segregated to your gametes, the chromosomes your father gave you will not all go together, they will act independently of each other.)\nIn short, he gave us a way to predict what ratios of progeny to expect from parental generations. \n\nFor example, a dihybrid cross between PPSS and ppss will result in all F1 progeny PpSs, and if intercrossed, those F1 progeny will produce F2 progeny in a 9:3:3:1 ratio....\nso on and so forth.\n\nOf course these principles don't really apply with more complex human genetics...
204094
ok, i think i have an idea for this one. \nSketch of a proof:\nSuppose that a is an element of order k. Also suppose that f is an isomorphism. Then we know that f(a*a*a...k times)=f(a)*f(a)*f(a)*...k times (homomorphism definition). We know that f(a)^k is the identity because isomorphisms take the identity to the identity. Now see that k must be the first number with the quality f(a)^k=e. This comes as a result of the isomorphism having a kernel with one element. If we suppose for the sake of contradiction that f(a)^m=e with m<k, then we would have f(a*a*a*a...m times)=e, so that means that f(a^m)=e at the same time as f(a^k)=e with a^m not equal a^k, this is a contradiction.\n\nQED...ish
1000473
Microevolution is a change in a population's alleles over a period of time.\n\nIt is very difficult to detect changes that occur on the microscopic level. These changes must manifest themselves in the organisms phenotype. Since individuals do not evolve, one must keep a close eye on the individuals population to detect any change in genotypic modification. Biologists have a way to help them detect such changes; it is called the Hardy -Weinberg theorem.   This idea was developed to determine if a population was evolving. The authors of the theorem set up a series of parameters, which do not exist in nature, to be followed when determining the allele frequencies of any population. These guide lines are as follows:\nThe population must be very large in size.\nIt must be isolated from other populations. ( no gene flow)\nNo mutations.\nRandom mating.\nNo natural selection.\nAs one can see, these characteristics cannot be eliminated from nature. \n\nThere are 5 basic causes of microevolution:\n1. Genetic Drift: This represents random changes in small gene pools due to sampling errors in propagation of alleles. The bottleneck effect and founder effect are prime examples of genetic drift. In either case the number of individuals in a population is drastically reduced distorting the original allelic frequencies.\n2. Gene Flow: The movement of alleles into and out of a gene pool. Migration of an organism into different areas can cause the allelic frequencies of that population to increase. Most populations are not isolated, which is contrary to the Hardy-Weinberg Theorem.\n3. Mutations: These changes in the genome of an organism are an important source of natural selection.\n4. Nonrandom mating: Inbreeding is a popular form of nonrandom mating. Individuals will mate more frequently with close individuals than more distant ones. Assortive mating, is another form of nonrandom mating. Here the individuals will mate with partners that closely resemble themselves in certain characteristics.\n5. Natural Selection: Populations vary in the types of individuals and their reproductive success. Those individuals who leave more offspring behind than others, pass on more of their alleles and have a better success rate in dominating the population.\n\nMacroevolution can be defined simply as evolution above the species level, and its subject matter includes the origins and fates of major novelties such as tetrapod limbs and insect wings, the waxing and waning of multi-species lineages over long time-scales, and the impact of continental drift and other physical processes on the evolutionary process. \nFossils: any preserved remnant or impression left by organisms that lived in the past.\nThese remnants of the past are only meaningful in the context of macroevolution only if their vintages relative to other fossils can be determined by methods we shall now discuss.\n \nGeological Time Scale:\n \nRelative dating: Superimposition of sedimentary rocks tells the relative age of fossils. The fossils in each layer are a local sampling of the organisms that existed when that sediment was deposited. Younger strata are superimposed on the top of older ones , and the succession of fossil species is a story of macroevolution that can be read by paleobiologists.\n \nAbsolute dating: This does not mean errorless dating. The age is given in years and not in relative terms such as early , before , and after. Radioactive dating is the method often used to determine the age of the fossils and rocks . Fossils contain isotopes of elements accumulated in the organism when they were alive. Because each radioactive isotope has a fixed rate of decay, half-life, it can be used to date the species. Half-life is unaffected by pressure, temperature, or other environmental variables.\n \nExamples of half-life:\n\nPotassium 40 -- 1.3 x 109\nRubidium 87 -- 4.9 x 1010\nUranium 238 -- 4.5 x 109\nCarbon 14 -- 5.7 x 103\n \nAnother form of dating is called the "clock". Am
230841
Hi. First off, its "deScent with modification".\nThat was Darwin's term for what is now known as genetic variability in a population, and a stage of his proposed evolutionary mechanism, natural selection.\nHe did not have the genetic background to explain the variations that he saw generation after generation (Mendel's works had been ignored at the time), but he noticed that in every new generation, the individuals showed varied characteristics: some traits where similar to their parents, but others were novel or maybe similar to those of older ancestors. \nThese variations occur because of 1) spontaneous mutations in the parental gametes; 2) recombination between homologous chromosomes during gamete formation (crossing over); 3) the combination of the parents' genotypes to form the genotype of the offspring (this is not strictly new material, only a new combination of preexisting ones).\n\nOnce there is a new generation of individuals that are growing and living together, some of those characteristics may result in better adjustment to the environment. The individuals with those "adaptively advantageous" traits will have higher probabilities of growing, maturing and reproducing more, with respect to other individuals. \nIf those advantageous characteristics are heritable, that is, if they are determined by the individual's combination of alleles (=the two versions of the same gene in each of us), when the individual is able to "pass them on" to more descendants those alleles will spread in the population, and eventually be present in most individuals. This, in a nutshell, is natural selection. NS leads to gradual adjustment of the population with respect to its environment.\nFrom a population genetics perspective, evolution is defined as _the change in allele frequencies_; thus, "descent with modification", coupled with evolutionary factors, leads to evolution of the population. \nIn addition to mutation and natural selection, this change in allele frequencies may be occasioned by migration (genetic flux among different populations), genetic drift (a random process) and selective mating (which strictly speaking only alters the proportion of combinations, but does not produce new material).\n\nSorry for the lengthy answer, but evolutionary processes need a little context to be understood. Good luck with your explanation!
760977
Try this website for information on and comparisons of the theories of Maslow and Alderfer:\n\nhttp://chiron.valdosta.edu/whuitt/col/regsys/maslow.html
466194
Consider K_3,3, which is the graph obtained when you draw all lines between 3 points {a,b,c} and three other points {x,y,z}. So there is a line between a and x, but not one between a and b.\n\nAn automorphism, f, will take a to one of the six points. There are two possibilities: either f(a) is in {a,b,c} or f(a) is in {x,y,z}. In the first case, {f(a), f(b), f(c)} is a permutation of {a,b,c} and {f(x),f(y),f(z)} is a permutation of {x,y,z}. In the second case, it goes the other way around. Furthermore, any two permutations in both sets will lead to an automorphism of your graph.\n\nThus, the order of the automorphism group will be 6*6*2=72.\nThere is a subgroup isomorphic to S_3 cross S_3 of index 2. Just checking commutativity tells us that the reflection between {a,b,c} and {x,y,z} is not in the center, and in fact, conjugation by the reflection reverses the order of elements in S_3xS_3. Thus, the automorphism group is the semi-direct product of S_3 cross S_3 with Z_2 where Z_2 reverses the order of the cross product.\n\nI hope this helps!
943195
It has been many years since I even cracked the book on crystal field theory, but I refreshed myself a bit here:\n\nhttp://www.unine.ch/chim/chw/Chapter%204.html\n\nBasically, the difference in splitting (delta value) decreases as you go down a group and increases by about 50% as you add positive charge on a metal cation. Other factors are covered on that page as well. Thanks for the reminder that I took a graduate inorganic chemistry class once back in the early 90's! I assure you that, at one time, I actually understood it, but I haven't used it in so long...well, you get the picture!\n\nP.S. (I had forgotten that it replaced VB theory, which I was supposed to teach my students but ran out of time!)
964100
object-oriented programming, a virtual function or virtual method is a function whose behavior, by virtue of being declared "virtual", is determined by the definition of a function with the same signature furthest in the inheritance lineage of the instantiated object on which it is called. This concept is a very important part of the polymorphism portion of object-oriented programming (OOP).\n\n\nThe concept of the virtual function solves the following problem:\n\nIn OOP when a derived class inherits from a base class, an object of the derived class may be referred to (or cast) as either being the base class type or the derived class type. If there are base class functions overridden by the derived class, a problem then arises when a derived object has been cast as the base class type. When a derived object is referred to as being of the base's type, the desired function call behavior is ambiguous.\n\nThe distinction between virtual and not virtual is provided to solve this issue. If the function in question is designated "virtual" then the derived class's function would be called (if it exists). If it is not virtual, the base class's function would be called.
214785
There are LOTS. Pauli Exclusion Principle. Newton's Laws. Kepler's Laws. Galileo had some principles that might be called laws. Thermodynamic laws. Heisenberg Uncertainty Principle. Refraction Law. Ideal Gas Law. Boyle's Law. Charles Law. Biot-Savart Law. And so on and so forth. Hookie's law. \n\nStart researching.