The Power of Pythons String Templates

Python is an interpreted, object-oriented, high-level programming language. It is easy to learn because its syntax emphasizes readability, which reduces the expense of program maintenance. Many programmers love working with Python because—without the compilation step—testing and debugging go quickly.​ Python Web Templating Templating, especially web templating, represents data in forms usually intended to be readable by  a viewer. The simplest form of a templating engine substitutes values into the template to produce the output.   Aside from the string constants and the deprecated string functions, which moved to string methods, Pythons string module also includes string templates. The template itself is a class that receives a string as its argument. The object instantiated from that class is called a template string object. Template strings were first introduced in Python 2.4. Where string formatting operators used the percentage sign for substitutions, the template object uses dollar signs. $$ is an escape sequence; it is replaced with a single $.$identifier names a substitution placeholder matching a mapping key of identifier. By default, identifier must spell a Python identifier. The first non-identifier character after the $ character terminates this placeholder specification.${identifier} is equivalent to $identifier. It is required when valid identifier characters follow the placeholder but are not part of the placeholder, such as ${noun}ification. Outside of these uses of the dollar sign, any appearance of $ causes a ValueError to be raised. The methods available through template strings are as follows: Class string. Template(template): The constructor takes a single argument, which is the template string.Substitute(mapping, **keywords): Method that substitutes the string values (mapping) for the template string values. Mapping is a dictionary-like object, and its values may be accessed as a dictionary. If the keywords argument is used, it represents placeholders. Where both mapping and keywords are used, the latter takes precedence. If a placeholder is missing from mapping or keywords, a KeyError is thrown.Safe_substitute(mapping, **keywords): Functions similarly to substitute(). However, if a placeholder is missing from mapping or keywords, the original placeholder is used by default, thus avoiding the KeyError. Also, any occurrence of $ returns a dollar sign. Template objects also have one publicly available attribute: Template is the object passed to the constructors template argument. While read-only access is not enforced, it is best not to change this attribute in your program. The sample shell session below serves to illustrate template string objects. from string import Template s Template($when, $who $action $what.) s.substitute(whenIn the summer, whoJohn, actiondrinks, whaticed tea) In the summer, John drinks iced tea. s.substitute(whenAt night, whoJean, actioneats, whatpopcorn) At night, Jean eats popcorn. s.template $when, $who $action $what. d dict(whenin the summer) Template($who $action $what $when).safe_substitute(d) $who $action $what in the summer

Essay about Symbolism in “The Story of an Hour” - 671 Words

The symbols and imagery used by Kate Chopins in â€Å"The Story of an Hour† give the reader a sense of Mrs. Mallard’s new life appearing before her through her view of an â€Å"open window† (para. 4). Louise Mallard experiences what most individuals long for throughout their lives; freedom and happiness. By spending an hour in a â€Å"comfortable, roomy armchair† (para.4) in front of an open window, she undergoes a transformation that makes her understand the importance of her freedom. The authors use of Spring time imagery also creates a sense of renewal that captures the authors idea that Mrs. Mallard was set free after the news of her husbands death. Right from the moment Louise Mallard hears of her husbands death, Kate Chopin dives into a her†¦show more content†¦Immediately after the news of her husbands death, Mrs. Mallard races upstairs into her room where she settles into â€Å"a comfortable, roomy armchair† (para.4). The armchair symbolizes the rest from the oppressive life she had and freedom from societys expectations. Since it was tradition for women to be married by a certain age, Louise Mallard must have obligated to marry Brently. Sitting in the armchair, she gazes out of the window and starts indulges in deep thought, which establishes her as an intelligent individual. The open window from which Louise gazes is symbolic for her freedom and the good fortune that she is now presented with. Her attention to the blue sky, fluffy clouds, tree tops and the delicious breath of rain denote her newly found inner well-being. The writers use of language is well-chosen as it explicitly portrays Mrs. Mallards true feelings. By capturing all the senses, the imagery created represents Louises new life and establishes her as a round character. The open window provides a clear and bright view into the distance of Louise’s own bright future, which was obstructed by the demands of her husband. As Mrs. Mallard left the room, there was a feverish triumph in her eyes, and she carried herself unwittingly like a goddess of Victory (para.19). â€Å"The goddess of victory† (para.19) embodies Louises triumph over repression, over the â€Å"powerful will bending hers in that blind persistence...right to impose a privateShow MoreRelatedSymbolism in The Story of an Hour758 Words   |  4 PagesSymbolism in the â€Å"Story of an Hour† by Kate Chopin For this lesson I read The Story of an Hour by Kate Chopin. Although there are many literary devices used in The Story of an Hour, I have decided to write my essay on the use of symbolism. The literary device symbolism is a technique used to represent ideas and events by using significant or important things that stand out in the story. A few things that stood out most in the story would be the comfortable chair, and Mrs. Mallards heartRead MoreThe Story Of An Hour Symbolism Essay1089 Words   |  5 Pages The Story of an Hour, by Kate Chopin, is a wonderful short story filled with many different peculiar twists and turns. Written in 1894, the author tells a tale of a woman who learns of her husband’s death, but comes to find joy in it. Many of the things Kate Chopin writes about in this story symbolize something more than just the surface meaning. Through this short story, told in less than one thousand one hundred words, Kate Chopin illustrates deeper meanings through many different forms of symbolismRead MoreSymbolism In Kate Chopins The Story Of An Hour1013 Words   |  5 PagesWhile most of Kate Chopin’s short stories were well received, â€Å"The Story of an Hour† was originally rejected by publishers until 1894 when Vogue decided to publish the short story. However after her death most of Chopin’s work was forgotten, that was until the 1950s when her work again was recognized as insightful and moving, setting into motion a Kate Chopin revival which was both successful and remarkable (Biography). â€Å"The Story of an Hour† focuses on the liberation and new found freedom of a newlyRead MoreSymbolism Of The Story Of An Hour By Kate Chopin945 Words   |  4 PagesSymbolism in â€Å"The Story of an Hour† In her piece â€Å"The Story of an Hour,† Kate Chopin uses several symbols to bring Louise Mallard’s dramatic hour to life, as well as the themes of freedom and disillusionment that come with marriage and life. Chopin used Mrs. Mallard’s heart trouble, the open window and spring life, and her final descent down the stairs that led to her death to show that Louise’s marriage to Brently was suffocating her free spirit and decreasing her quality of life. These main symbolsRead MoreSymbolism as Found in Kate Chopins Story of an Hour Essay1532 Words   |  7 PagesSymbolism as found in Kate Chopin’s â€Å"Story of an Hour† In Kate Chopin’s â€Å"Story of an Hour† the protagonist, Louise Mallard, is going through a life-changing event that is brought on by the news of the death of her husband, Brently Mallard. During this hour, she is told of her husband’s death, grieves for a short time, discovers that she will now be able to â€Å"live for herself† (16) and is finally able to free herself of the restrictive marriage she has been living in. The end of her last hour comesRead MoreThe Use of Symbolism to Foreshadow the Future in Kate Chopins The Story of an Hour and Toni Cade Bambaras The Lesson1673 Words   |  7 PagesThe Use of Symbolism to Foreshadow the Future in Kate Chopins The Story of an Hour and Toni Cade Bambaras The Lesson Often authors use signs to foreshadow events that will happen in the future in their stories. For example an author might write As he was walking down the dark eerie path dark skies began to form . Here the writer uses a usually negative sign to foreshadow a negative future. This is the most common way for authors to foreshadow in a story, but it isnt the only way. In someRead MoreEssay about Comp and Lit Comparison of Blue+Yellow/Story of an Hour1296 Words   |  6 Pagesthe short story â€Å"the Story of an Hour† by Kate Chopin and the short story â€Å"blue + yellow† by Chris Killen compare in many ways. These two stories use the same literary device strongly such as imagery. Imagery is a literary device in which the author uses words and phrases to paint a picture in the readers head throughout the story. These two short stories are written with very descriptive language to help paint a picture of the occurrences in the story and describe a scene. These two st ories also contrastRead MoreThe Story Of An Hour By Kate Chopin855 Words   |  4 PagesThe Story of an Hour In the â€Å"Story of an Hour† by Kate Chopin, is about pleasure of freedom and the oppression of marriage. Just like in Kate Chopin’s story, inside most marriages, even the ones that seem to be the happiest, one can be oppressed. Even though, one might seem to be happy deep inside they miss the pleasure of freedom and living life to the fullest. Just like, in this story Mrs. Mallard feels trapped and when she hears about her husband’s death she first feels distraught, but ultimatelyRead More The Story of an Hour and The Hand Essay1161 Words   |  5 PagesThe â€Å"Story of an Hour† by Kate Chopin and ‘†The Hand† by Sidonie-Gabrielle Colette are similar in theme and setting. Sidonie-Gabrielle Colette and Kate Chopin create the theme of obligatory love and the unhappiness it entails. Both stories illustrate the concealed emotions many women feel in their marriage yet fail to express them. The two stories take place in a sacred room o f the house and both transpire in a brief amount of time. The differences between the two stories are seen through theRead MoreThe Theme Of Loneliness1549 Words   |  7 PagesBrill by Katherine Mansfield what they both have in common is the literary device theme loneliness. Theme is the general idea or insight revealed in a narrative. These two stories are also different from the style of writing these two authors wrote how to tell their stories. Loneliness is introduced in the beginning of the short story â€Å"A Clean, Well-Lighted Place† by Hemingway. The deaf old man, with no wife and only a niece to care for him, is noticeably lonely. The younger waiter, upset that the old

Ap Biology - Modern Genetics free essay sample

DNA is the template (3’ to 5’) ! 3. RNA Polymerase Binds to promoters, separates strands of DNA and ! hook together RNA nucleotides (only add to 3’ end) ! a. TATA Box Where RNA polymerase H binds (eukaryotes) ! ! b. Transcription Factors Aid polymerase in locating promoters ! ! such as the TATA Box ! ! c. Reads in sets of 3 called codons. ! 4. Termination site on DNA indicates end in prokaryotes ! 5. Eukaryotes Pre-mRNA separates from DNA at the polyadenylation ! signal, but RNA polymerase continues to transcribe until it falls off the ! DNA. C. Pre-mRNA processing in eukaryotes ! 1. Heterogenous nuclear RNA (hnRNA) contains introns and exons. ! ! a. Introns not used (stay IN nucleus) ! ! b. Exons used (EXIT nucleus) ! 2. Small nuclear ribonucleic proteins (snRNP’s/snurps) help excise introns ! and fuse exons. ! 3. Splicosomes Snurps and proteins working together ! 4. Poly A tail is added to 3’ end which a 5’ cap is added to the 5’ end. ! ! a. Prevent damage to mRNA as it leaves nucleus ! ! b. Helps mRNA leave nucleus ! ! c. Helps mRNA attach to ribosome. D. rRNA Formed in nucleoli, makes up part of ribosome. ! 1. Ribosomes Binding site for rRNA. E. Translation ! 1. Initiation Brings mRNA and tRNA together by means of factors (start ! codon is AUG) ! 2. Elongation Amino acids are added with aide of elongation factors. ! ! a. Codon Recognition mRNA codon on A site forms H bonds with ! ! anticodon of incoming tRNA. ! ! b. Aminoacyl tRNA synthetase matches amino acid with correct ! ! tRNA ! ! c. Peptidyl transferase catalyzes the formation of a peptide bond ! ! between polypeptide at P site and amino acids at A site. ! ! d. Wobble Effect Exact base pairing is not always necessary. ! 3. Translocation ! ! a. A site on ribosome holds tRNA carrying the next amino acid to be ! ! added. ! ! b. P site on ribosome holds tRNA carrying the growing polypeptide ! ! chain. ! ! c. E site is where it exits. F. Termination Indicated by termination codons (UAA, UAG, UGA) ! . Release Factor Protein which binds to termination codon on A site ! causing hydrolysis reaction and freeing the polypeptide. ! 2. Posttranslational modi? cations now take place Protein goes into ! secondary, and tertiary structure. AP Bio Modern Genetics IV. Mutations ! A. Point Mutations Chemical changes in one or a few nucleotides. ! ! 1. Base Pair Substitutions Replacement of one nucleotide and its partner ! ! from a complementary DNA strand with another pair of nucleotides. ! ! ! a. Missense Mutations Altered codons still code from amino acids ! ! ! but don’t always make sense. ! ! b. Nonsense Mutations Change amino acids codon to a stop ! ! ! signal (most result in nonfunctional codons) ! ! 2. Insertions and Deletions Additions or losses of one or more nucleotide ! ! pairs in a gene. ! ! ! a. Frameshift Mutation Alters reading from (usually nonfunctional) ! B. Mutagenesis Creation of mutations ! ! 1. Hermann Muller discovered that genetic changes occurred when fruit ! ! ? ies were exposed to X-Rays. ! ! 2. Spontaneous mutations result from errors in DNA replication, repair, or ! ! recombination. ! ! 3. Mutagens Physical and chemical agent which cause mutations. Chapter 18 The Genetics of Viruses and Bacteria I. Viruses ! A. Wendell Stanley (American-1935) crystallized particle, now called tobacco ! mosaic virus (TMV) ! B. Genomes May be double or single stranded DNA or RNA. ! C. Capsid Protein shell enclosing genome, built from capsomere ! D. Phages Virus which infects bacteria. ! E. Lack enzymes for metabolism and have no ribosomes, nonliving ! F. Vaccine Harmless variation which stimulates immune response (? rst made ! from cowpox) ! G. Viroids Tiny molecules of naked RNA, upset metabolism of plants ! H. Prions Infectious proteins ! ! 1. Often cause brain diseases like mad cow and scrapie in sheep ! ! 2. Not killed by heat, long incubation period II. Sources of New Viruses ! A. Mutations of current viruses ! B. Spread between species typically due to new exposure. ! C. Spread within species between a small population and the rest of the world. III. Replication and Infection ! A. Obligate intracellular parasites ! B. Basic Infection ! ! 1. Some recognize host by a â€Å"lock and key† ? t, and only infect certain cells ! ! of the body. ! ! 2. Genome Enters Cell Method varies (leaving ghost behind-empty ! ! capsid) AP Bio Modern Genetics ! ! ! ! ! ! ! ! ! ! ! ! ! 3. Genome reprograms cell to copy viral genes and manufacture capsid ! proteins. ! ! a. DNA viruses use DNA polymerases of host cell ! ! b. RNA viruses contain their own enzymes to initiate replication. ! 4. Self Assembly Assembly of capsids and nucleic acid molecules into ! viruses. ! 5. Viruses leave host cell C. Bacteriophages Virus which infect b acteria ! 1. Lytic Cycle Reproductive cycle which ends with death of host cell ! 2. Lysogenic Cycle Reproduces viral genome without destroying host ! ! a. Viral DNA is incorporated into bacterial DNA (prophage) ! b. Prophage is replicated every time bacteria devices ! ! c. Eventually goes into lytic cycle. IV. Animal Viruses ! A. Viruses with Envelopes ! ! 1. Envelopes fuse with host membrane, inserting information ! ! 2. Enzymes remove capsid, genome replicates ! ! 3. Viral offspring are wrapped in a membrane and released ! ! 4. Provirus Some viruses become integrated into cell’s genome (infection ! ! tends to reoccur throughout life, HIV, herpes) ! B. RNA Viruses ! ! 1. Retroviruses Most complicated life cycle (HIV) ! ! ! a. Reverse Transcriptase Transcribes DNA from RNA template ! ! ! b. Newly formed DNA integrates as a provirus into a chromosome ! ! ! within the nucleus of the host cell. ! C. Viral Diseases ! ! 1. Vaccine Harmless variants or derivatives of pathogenic microbes ! ! which stimulate an immune response. V. Plant Viruses ! A. Horizontal Transmission Plant infected from external source ! B. Vertical Transmission Plant inherits infection from parent VI. Bacteria ! A. Single stranded, circular DNA, found in nucleoid region ! B. Plasmids Smaller circles of DNA, used in genetic engineering ! C. Replication of chromosome is followed by binary ? ssion (copying of DNA ! occurs in both directions) VII. Genetic Recombination of Bacteria ! A. Transformation Alteration of a bacterial cell’s genotype by the uptake of ! naked, foreign DNA from environment. ! B. Transduction Transfer of bacteria by means of a virus ! C. Conjugation Direct transfer of genetic material between two bacterial cells ! ! 1. Donor is â€Å"male† (requires F plasmid, F+), receiver is â€Å"female† (F-) AP Bio Modern Genetics ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! ! 2. Plasmid Not required for survival or reproduction, but can be ! advantageous in stressful environments. ! ! a. Episomes Can replicate as a free molecule in cytoplasm or as ! part of the main bacterial chromosome. ! 3. R Plasmids cause bacteria to be resistant to antibiotics D. Transposons Pieces of DNA which can move from one location to another in a cell’s genome (jumping genes) discovered by Barbara McClintock. ! 1. Conservative Transposition Genes are not replicated, number of ! copies is conserved (cut and paste) ! 2. Replicative Transposition Transposon replicates at original site and a ! copy inserts at another location (copy and paste) E. Insertion Sequences Simplest transposons, consist of only the DNA necessary for act of transposition itself. F. Barbara McClintock (1940’s-50’s) worked with Indian corn, based on observations, she believed there were mobile elements. VII. Operons Unit of genetic function common in bacteria and phages and consisting of regulated clusters of genes with related function. ! A. Jacob and Monod Discovered operon model in 1961 ! B. Operon is made of an operator, promoter and the genes they control ! C. Operator Switch which gets turned on ! D. Oppressor Segment of DNA, functions as an on/off switch for an operon ! E. Repressor Protein which turns off the operon (operator speci? c) ! F. Corepressor Metabolite that cooperates with a repressor protein to switch an ! operon off ! G. E coli Operons ! ! 1. Lac Operon ! ! ! a. Regulatory Gene gt; Repressor gt; Binds to Operator ! ! ! b. RNA Polymerase cannot transcribe structural genes needed to ! ! ! make enzymes break down lactose ! ! ! c. When lactose is present, some of the lactose attaches to the ! ! ! repressor and shuts it down allowing RNA polymerase to transcribe ! ! ! (example of an inducible operon Usually off but can be induced. ) ! ! 2. Trp Operon (Tryptophan is an amino acid) ! ! ! a. Regulatory Gene gt; Inactive repressor that doesn’t attach to the ! ! ! operator so RNA polymerase can transcribe. ! ! ! b. Increased levels of trp combine with repressor to make it active ! ! ! and the RNA polymerase can’t transcribe (example of corepressor) ! ! ! c. Repressible Operon Transcription usually on but can be ! ! ! repressed Chapter 19 Eukaryotic Genomes: Organization, Regulation, and Evolution I. Key Terms ! A. Cellular Differentiation Process of cells becoming specialized and therefore ! only parts of genes expressed. AP Bio Modern Genetics ! ! ! ! ! ! ! ! ! B. Histones Positively charged proteins which bind to negative DNA and â€Å"package it together† C. Nucleosome Basic unit of DNA packaging in eukaryotes, consisting of DNA around a protein core (2 copies of each of the 4 types of histones) D. Multigene Families Collections of identical or similar genes (hemoglobin alpha and beta are expressed at different times) E. Pseudogenes Similar to functioning genes but are lacking some essential part. F. Heterochromatin, euchromatin, telomere. II. Gene Control Eukaryotes ! A. Transcriptional Control Factor which tell where to start and stop ! B. Posttranscriptional Splicing, cap and tail ! C. mRNA Degradation ! ! 1. Prokaryotic mRNA are usually broken down within minutes of use ! ! 2. Eukaryotic mRNA can live hours to weeks before being broken down by ! ! enzymes. ! D. Chromosomes Puffs In insects, regions of intense transcription, chemicals ! signal when they should form. ! E. Steroids in Humans ! ! 1. Steroid diffuses through cell (lipid soluble) into cytoplasm and binds to ! ! receptor. ! ! 2. Binding to an enhancer then occurs and activates transcription. ! ! 3. Steroid acts as a signal to turn on speci? c gene. ! F. Hormones bind to outside of cell (not lipid soluble) and operate with the help of ! receptor protein on the outside of the cell. ! G. Gene Ampli? cation Selective replication of certain genes. ! H. Immunoglobulin Proteins which speci? cally recognize and help ? ght viruses, ! bacteria and invaders. ! ! 1. Made by B lymphocytes ! ! 2. Antibody variation results from different combinations of variable and ! ! constant regions of immunoglobulin polypep tides. ! I. DNA Methylation III. Abnormal Expression of Genes ! A. Oncogenes Cancer causing genes found in RNA viruses ! B. Proto-Oncogenes Found in human cells, normal genes which may become ! oncogenes. ! ! 1. Increased activity may cause change ! 2. Gene Ampli? cation ! ! 3-5. Translocation, Gene Transposition, and Point Mutation ! C. Tumor Suppressor Genes Normally prevent cell division and may produce ! proteins which repair damaged DNA. ! D. The more mutations throughout life, the greater the chance of cancer. AP Bio Modern Genetics Chapter 20 DNA Technology I. Gene Manipulation ! A. Restriction Enzymes Bacterial enzymes which cut up foreign DNA forming ! sticky ends. ! ! 1. Sticky ends can be used to join DNA pieces originating from different ! ! sources. ! ! 2. Restriction fragments can be separated by gel electrophoresis ! ! ! a. Brief electric pulse is applied to a solution of DNA to separate ! ! ! DNA. ! ! ! b. DNA is negative and moves towards positive end ! ! ! c. Can be used to compare DNA of different species. ! B. Gene Cloning in a Plasmid ! ! 1. Isolate bacterial plasmid and eukaryotic DNA with gene desired ! ! 2. Both are treated with same restriction enzyme ! ! ! a. Plasmid DNA Cut at restriction site ! ! ! b. Eukaryotic DNA Generates thousands of fragments ! ! 3. Two types of DNA are mixed Sticky ends of each pair up ! ! 4. DNA ligase joins molecules (called recombinant DNA) ! ! 5. Recombinant DNA is introduced into a bacterial cell ! 6. Gene Cloning Production of multiple copies of desired gene ! C. Inserting DNA into Cells ! ! 1. Cloning Vectors Carriers for moving recombinant DNA (plasmids, ! ! phages-transformation) ! D. Sources of Genes for Cloning ! ! 1. DNA isolated directly from organism ! ! 2. Complementary DNA (cDNA) made in a lab from mRNA templates. ! E. Probes Nucleic molecules w hich will hydrogen bond speci? cally to a desired ! gene, location traced by labeling ! F. Sanger Method of Sequencing ! ! 1. Synthesizing in vitro DNA strands complementary to one of the strands ! ! being sequenced. ! G. Amplifying DNA ! ! 1. Polymerase chain reaction (PCR) technique by which any piece of DNA ! ! can be quickly ampli? ed in vitro ! ! ! a. DNA is incubated with DNA polymerase and primers. II. Applications ! A. Human Genome Project Mapping of entire human genome ! B. Analyzing genomes of other species ! C. Human Gene Therapy Correct Disorders ! D. Vaccines ! E. Mammalian Hormones and Proteins Growth hormones, clotting factor, insulin ! F. Treating Farm Animal with vaccines, antibodies and growth hormones ! G. Transgenic Organisms Contain genes from another species ! H. Manipulating Plant Genes Herbicide resistance, better foods

Sexually Transmitted Diseases Essays (2574 words) -

Sexually Transmitted Diseases Sexually transmitted diseases are infectious diseases that can be spread by sexual contact. Some can also be transmitted by non-sexual ways, but these make up a minority of the total number of cases. An estimated ten to twelve million Americans have sexually transmitted diseases. Sexually transmitted diseases in the United States affect both sexes, all races, and every economic stature. STD's come from different sources. Some are epidemic like gonorrhea, infections of the urethra, genital herpes, and genital warts. Some diseases are caused by a bacterium such as Chlamydia, and others are from protozoan or yeast. Many of these infections are transmitted largely by sexual contact with an infected person. The practice of anal and oral sex also lead to cases of anal and oral infections. Gonorrhea, syphilis, and chlamydial infections can also be transmitted from a pregnant woman to her infant, either in the uterus or during birth. Sexually transmitted diseases are very hard to control. Some public officials attribute the increase in many of these diseases to increasing sexual activity. Others say the replacement of the condom with birth control pills and diaphragms might also increase the risk of STD's. "Many STD's are transmitted more efficiently from men to women than the reverse, perhaps because the vagina serves as a reservoir that prolongs exposure to infectious secretion (Handsfield 2)" The physical examination of patients with STD or at risk is a simple procedure. All patients require inspection of the entire skin surface. At a minimum they carefully inspect all skin surfaces that are uncovered or exposed during genital examination. This includes the face, head, hands, lower arms, lower trunk, pubic area, thighs, mouth and throat. Also checked in men are the genitals and the pubic and inguinal regions, the penis, urethra, urethral bulb, and the scrotum are checked for tenderness and other abnormalities. "For homosexually active men, the anus and perineum are carefully inspected. The examination of women includes inspection of the pubis area, the external genitals, perineum and anus, speculum examination of the vaginal mucosa and cervix, and a bimanual pelvic examination (Handsfield 4)." A way to avoid STD's and unwanted pregnancies is to use a condom. "A condom is a sheath worn over the penis during oral, anal, and vaginal sexual contact (Virginia Tech Health Services)." Condoms can be made of latex rubber or animal membrane. Animal membrane condoms prevent pregnancy but have large enough pores for tiny HIV viruses to pass through. Latex condoms are much better in forming a barrier against HIV. Polyurethane condoms haven't been fully tested, so people should avoid using them. Do not use novelty condoms like the ones that glow in the dark, these are not FDA approved. Always check the expiration date. Never use a condom after the date stamped on the wrapper or on the seal. Do not use a condom that has been in a wallet for more than a month. Heat and pressure can damage it. Also, stay away from oil-based lubricants, like Vaseline, which can eat through the latex. And finally, do not open the packet with scissors or your teeth, the condom could rip. Nudge the condom away from the edge and gently tear the packet open. Next to abstinence, which is having no sexual relations at all, condoms are the best protection against STD's. When a condom is used correctly, they are about 90 percent effective in preventing pregnancy, and 95 percent effective when used with spermicide. Spermicide, also called Nonoxynol 9, has been found to be effective in killing the HIV virus in laboratory experiments when used at 5 percent strength. Spermicide immobilizes and kills sperm. It comes in jellies, creams, foams, suppositories, film, and as a coating on condoms. STD's can also be avoided by remaining monogamous. This means only having sex with one person whom only has sex with you. If you know that you are clean of all STD's and that your partner is also clean, then you both can avoid STD's by only being with each other. Chlamydia is a STD caused by the bacterium Chlamydia trachomatis. The bacterium is found in infected body fluids from the penis or vagina and it spreads through direct sexual contact and from mother to baby. Chlamydia is the most prevalent bacterial STD, about four million people will become infected with Chlamydia this year. Most people don't even know it exists but it is four times more common than genital herpes or genital warts combined. Up to 70 percent of women and 30 percent of men who are infected