Between paracentric inversion and pericentric inversion in the mutation process, which is more lethal?

In genetics, a mutation is any form of change which occurs in genetic material. An inversion mutation is a form of genetic mutation which occurs when a section of DNA breaks off and then reattaches in a reversed order to the chromosome.

When the break occurs in only one arm of the chromosome and the inverted segment does not include the area where the arms of the chromosome are attached to each other, referred to as the centromere, the inversion is said to be paracentric.

When the break happens between two arms of a chromosome and the inverted segment includes the area where the arms of the chromosome are attached to each other (the centromere), the inversion is said to be pericentric.

Not all inversion mutations result in abnormalities, provided the rearrangement is balanced and there is no extra or missing DNA. Some might even reorganise genetic code in a beneficial evolutionary way, but the pericentric inversion is more likely to lead to genetic abnormalities or lethal consequences.

What criteria would have been used to exonerate Nella Larsen from the plagiarism scandal regarding her story "Sanctuary"? Why didn't she ever...

Nella Larsen’s short story “Sanctuary,” unfortunately, was almost certainly adapted from British author Sheila Kaye-Smith’s story “Mrs. Adis.” While Larsen’s version reflected her own unique history and the culture in which she was raised and lived as an adult, the similarities between the two stories were such that charges of plagiarism were valid. Even Larsen biographer George Hutchinson states in an endnote accompanying his book In Search of Nella Larsen: A Biography of the Color Line that the charge of plagiarism leveled against Larsen was “probably valid.” What made Larsen’s case particularly tragic, and one of the reasons she was unable to continue her career as a writer, was that, being of mixed-race with noticeably dark skin, she was unlikely to receive either the benefit of the doubt in early-20th century America or credit for being a legitimately-talented writer whose “crime” was minor, if that, and little different than what has occurred in the arts for centuries. The only writer, painter, or musician who was not influenced by at least one predecessor had to have existed in biblical times—specifically, within the timeframe of the Old Testament. Adapting a theme to one’s own circumstances, in fact, is very common, whether it was George Harrison’s “plagiarism” of Ronnie Mack’s “She’s so Fine” when he wrote his hit single “My Sweet Lord,” or the openly-acknowledged adaptation of Joseph Conrad’s Heart of Darkness by film director Francis Ford Coppola and screenwriter John Milius for their surrealistic Vietnam War movie Apocalypse Now. Each generation of artist influences those that follow, and it may have been accurate to accuse Larsen of plagiarism, but it probably was not fair. The fact that Larsen had been seriously and unambiguously influenced by Edith Wharton, however, lent additional credence to the accusation.

In any event, the plagiarism case wounded Larsen’s literary career, but might not have ended it had not her marriage dissolved among accusations of infidelity on the part of her husband, Elmer Imes, a prominent African American physicist. The humiliation of the revelations of Imes’ infidelity and their subsequent divorce is believed to have so adversely affected Larsen that she was never able to recover emotionally or professionally from these two developments.

As to what criteria would have been used to exonerate Larsen or any other individual accused of plagiarism, that would depend upon certain facts in the individual case. Plagiarism is easy to detect in its most obvious form: the verbatim copying of another author’s words. Exonerating somebody from a charge of plagiarism when one or more passages of this person’s work was clearly taken from another source is more than a little difficult. Exonerating somebody whose work was thematically influenced by another writer, however, is another matter. As noted above, it is the very rare writer or artist who hasn’t been influenced during the course of his or her intellectual development by earlier generations of writers or artists. That is why jazz aficionados so enjoy linking disparate jazz musicians to each other; they have all been influenced to greater or lesser degrees by those who came before them, or to contemporaries they admire. Judgements regarding accusations of plagiarism, therefore, can be very subjective. It is this subjectivity that allowed for Larsen’s exoneration. As with political mud-throwing, however, once the charge is made and publicized, protecting one’s reputation is extraordinarily difficult, even if found innocent.

What is the most likely end for a star that formed from an extremely large nebula?

A star that formed from an extremely large nebulae may ultimately end up as a black hole. Here the assumption is that the mass of the star formed from the extremely large nebula would be more than 10 times the mass of our sun.

During the main sequence of its life cycle, a star obtains its energy from the nuclear fusion of hydrogen to helium. Over time, the hydrogen runs out in the core, while the fusion continues in the outer envelope. This causes an expansion of the outer envelope and the star becomes a massive red giant. The contraction of the core will cause fusion of helium to carbon and further fusion reactions will ultimately result in the formation of iron. At this stage, this massive star will undergo a brilliant explosion, known as a supernova. This will provide enough light to brighten the part of galaxy for some time. After this reaction, only the core remains and it becomes so dense that its gravity is high enough to capture light. When this happens, even the light is unable to reflect back from the core and we have a black hole--a celestial body of extremely high density and gravity.

Note that for stars with average mass, like our sun, the last stage of the life cycle is white dwarf, while the more massive stars become neutron stars. Only the most massive stars end up as black holes.

Hope this helps.

How does drug use affect pregnancy?

Drug Use During Pregnancy

For the years 2012 and 2013, 5.4 percent of pregnant girls and women age fifteen to forty-four years, including 8.6 percent of women age eighteen to twenty-five years, admitted to some kind of current illicit drug use, according to the Substance Abuse and Mental Health Services Administration.

Certain factors in the life of a drug-abusing woman contribute to her reluctance to seek help, obtain prenatal care, or to stop using drugs during pregnancy. Many women who exhibit a pattern of drug use have mental, social, and financial problems. These situations contribute to an overall unhealthy routine that may include smoking, poor diet, stress, violence, and unpredictable living conditions, resulting in adverse pregnancy outcomes.

Drug-addicted women frequently are much more likely to smoke cigarettes and to use intravenous drugs during pregnancy, potentially exposing themselves to blood-borne infections. The high rates of mental illness in women who abuse drugs and illnesses that include anxiety, depression, and personality disorders contribute to a high rate of relapse among women who attempt to discontinue drug use while pregnant.

Women who abuse drugs may fail to obtain prenatal care for several reasons. For example, amenorrhea is a common side effect of drug abuse, so a woman may not realize she is pregnant. Drug use can be particularly risky to the fetus during the first eight weeks of pregnancy, a critical period of fetal development. Drug addiction also may lead to forgotten or missed appointments or to a lack of concern regarding the health of the fetus. Women who abuse drugs also endanger their own health through unhealthy lifestyles and relationships that may involve physical abuse, which also risks harm to the fetus.

Cocaine

The 1980s witnessed a significant increase in the use of cocaine
and crack cocaine in the United States. Cocaine remains a serious public health issue in the United States, with the majority of cocaine-using women in their childbearing years.

It has been determined that when a pregnant woman uses cocaine, the drug crosses the blood-brain barrier and the placenta, becoming readily available to the developing fetus. Animal models have shown that cocaine interferes with fetal brain development because it interacts with neurotransmitters and affects gene expression, but the mechanisms for this are unknown. Children exposed to cocaine prenatally have demonstrated deficits in attention span and impulse control, which may be attributed to the effects of cocaine on areas of the brain regulating these functions.

Cocaine is known to be a vasoconstrictor and may contribute to spontaneous abortion and low birth weight from a lack of blood flow to the fetus. Cocaine use during pregnancy, especially crack cocaine, has been linked to deformed arms, legs, and internal organs because of this vasoconstriction effect during fetal development. Lack of blood flow across the placenta also prevents the transport of oxygen and nutrients to the fetus. Infants born to cocaine-addicted women also are more likely to be hospitalized in a neonatal intensive care unit.

Infants are also affected indirectly by their mother’s cocaine use through the effects that use has on the area of the brain that controls maternal behavior. Cocaine disrupts the pathways in the brain that control maternal-infant bonding behavior and disrupts the production of oxytocin, a hormone that is key to triggering response behaviors in mothers.

Other Substances

In addition to cocaine, other frequently misused substances, such as methamphetamine, marijuana, hallucinogens, and opiates, have demonstrated increased risk of premature labor and low birth-weight infants. Methamphetamine
use has grown substantially in the United States, particularly in the western half of the country. Thus far, however, there have been few studies of the effect of methamphetamine use on the developing fetus.

It is known that methamphetamine interacts with biochemical transporters in the brain and is transported directly into cells. Once inside nerve cells, methamphetamine disrupts the release and metabolism of neurotransmitter molecules in the brain, impairing the development of the neurotransmitter system. Methamphetamine is a vasoconstrictor, similar to cocaine, and can have the same effect on the fetus through lack of blood flow.

Magnetic resonance imaging studies of children exposed to methamphetamine in utero have revealed abnormal brain structure in association with neurological developmental deficiencies. Newborn babies prenatally exposed to methamphetamine are usually underweight and have shown similar neurological effects as those exposed to cocaine. Animal models have demonstrated learning deficiencies, behavioral problems, and hyperactivity.

Heroin
is a short-acting opiate that, with repeated use and withdrawal, can cause muscle contractions, leading to premature labor. However, no studies have shown that heroin use during pregnancy causes central nervous system damage in the developing fetus. Opiates cross the placenta, so opiate abusers may give birth to addicted newborns who must subsequently undergo withdrawal. These newborns experience irritability, central nervous system difficulties, gastrointestinal disorders, and respiratory symptoms for up to eight days after birth. As in the case of cocaine, it is difficult to determine if these symptoms are caused by the mother’s heroin use or are consequences of other factors associated with the mother’s lifestyle.

Remedial Actions

It is difficult to attribute specific fetal deficiencies to illicit drug use because of the many other confounding factors in the drug-addicted woman’s life. These factors include smoking and poor nutrition, both of which may adversely affect the pregnancy too.

Residential treatment during pregnancy has demonstrated positive outcomes, but it is unclear if this outcome is from stabilization of the drug use or from an overall healthier lifestyle. Studies have shown that drug-addicted women who receive early intervention and extensive prenatal care and supervision can have pregnancy outcomes equivalent to women who do not use drugs. Comprehensive prenatal care can substantially reduce the risk of premature labor and low birth-weight infants among drug abusers.

It is recommended that pregnant women stop using cocaine during pregnancy, but the cocaine must be reduced in a measured fashion to avoid side effects, such as maternal seizures. Methadone treatment has been found to stabilize opiate abusers during pregnancy by allowing the women to gradually diminish opiate abuse through the pregnancy without the repeated use and withdrawal of heroin. The effect of drug abuse on infant mortality remains to be studied and delineated.

Bibliography

Burgdorf, Kenneth, et al. “Birth Outcomes for Pregnant Women in Residential Substance Abuse Treatment.” Evaluation and Program Planning 27 (2004): 199–204. Print.

Hepburn, Mary. “Substance Abuse in Pregnancy.” Current Obstetrics and Gynaecology 14 (2004): 419–25. Print.

Pinto, Shanthi M., et al. “Substance Abuse During Pregnancy: Effect on Pregnancy Outcomes.” European Journal of Obstetrics and Gynecology and Reproductive Biology 150 (2010): 137–41. Print.

Prentice, Sheena. “Substance Misuse in Pregnancy.” Obstetrics, Gynaecology, and Reproductive Medicine 20 (2010): 278–83. Print.

Roussotte, Florence, Lindsay Soderberg, and Elizabeth Sowell. “Structural, Metabolic, and Functional Brain Abnormalities as a Result of Prenatal Exposure to Drugs of Abuse: Evidence from Neuroimaging.” Neuropsychology Review 20 (2010): 376–97. Print.

Salisbury, Amy L., et al. “Fetal Effects of Psychoactive Drugs.” Clinical Perinatology 36 (2009): 595–619. Print.

Strathearn, Lane, and Linda C. Mayes. “Cocaine Addiction in Mothers: Potential Effects on Maternal Care and Infant Development.” Annals of the New York Academy of Science 1187 (2010): 172–83. Print.

Substance Abuse and Mental Health Services Administration. Results from the 2013 National Survey on Drug Use and Health: Summary of National Findings. Rockville: SAMHSA, 2014. PDF file.

What does the graveyard look like in The Adventures of Tom Sawyer by Mark Twain?

The graveyard is old and overgrown.

According to Huck, you can cure warts with a dead cat if you take it to the graveyard at midnight "when somebody that was wicked has been buried." You then have to say the chant 'Devil follow corpse, cat follow devil, warts follow cat, I'm done with ye!'  This ritual is supposed to get rid of the warts.

Huck and Tom visit the graveyard at night, and, as planned, Huck has the dead cat. The graveyard is full of tall grass, which the boys have to "wade" through. The graveyard is described as the "old-fashioned Western kind." The graveyard is on a hill not far from the village, and surrounded by a “crazy board fence.” Most of the headstones are no longer even legible.

Grass and weeds grew rank over the whole cemetery. All the old graves were sunken in, there was not a tombstone on the place; round-topped, worm-eaten boards staggered over the graves, leaning for support and finding none (Chapter 9).

Three huge elm trees are growing near the grave. The cemetery is oppressively silent. The only sound is the hooting of an owl in the distance, and the boys are clearly unnerved. The boys then hear three men arguing as they dig up one of the graves. These men turn out to be Injun Joe, Doctor Robinson, and Muff Potter.

Finally a spade struck upon the coffin with a dull woody accent, and within another minute or two the men had hoisted it out on the ground. They pried off the lid with their shovels, got out the body and dumped it rudely on the ground (Chapter 9).

Robinson and Potter get into a fight, and Robinson hits Potter with a headstone. While Potter is unconscious, Joe stabs Robinson while Potter. Joe then puts the knife in Potter’s hand and tells him he was the one who stabbed Robinson. Potter believes him and swears Joe to silence. Of course, the boys know what really happened.

When Popilius speaks to Cassius, does he know about the conspiracy?

In Act III, Scene 1 of Julius Caesar, Popilius enters along with a large group of other dignitaries. Popilius in an "Aside to Cassius" says, "I wish your enterprise today may thrive." Cassius is immediately alarmed. He asks, "What enterprise, Popilius?" Popilius merely answers, "Fare you well." Then the stage directions state, "He leaves Cassius, and makes to Caesar." Brutus asks, "What said Popilius Lena?" Cassius tells him, "He wished today our enterprise might thrive. / I fear our purpose is discovered."

It seems unlikely that Cassius could have spent so much time and energy trying to recruit men to his conspiracy without some word of his plan leaking out to other men who were either pro-Caesar or neutral. In going directly to Caesar after wishing Cassius good luck with his "enterprise," it is inferable that Popilius is looking out for his own best interests. He apparently knows about the plot against Caesar, but he may only be concerned about what will happen to him and his family whether the assassination succeeds or fails. He gives Cassius his best wishes in order to show he is on his side, and then goes straight to Julius Caesar and engages him in conversation. He is not warning Caesar, just making friendly conversation. As Brutus tells Cassius,

Cassius, be constant.
Popilius Lena speaks not of our purposes,
For look, he smiles, and Caesar does not change.

If Cassius and Brutus are successful, they will remember Popilius expressed his good wishes. If Caesar manages to thwart the assassination attempt, Popilius may be anxious to have him remember that he was behaving in such a cordial manner just before the conspirators attacked. 

Julius Caesar is feared by everyone. He might know all about the proposed assassination attempt and just be waiting to have all the conspirators arrested or killed on the spot. Popilius could be maneuvering to be on the winning side, regardless of which side wins. It is likely that other men know about the plot and hope to stay neutral in order to avoid the blood bath they would naturally expect to occur if Brutus and Cassius came out on top or if Caesar prevailed and went on to claim his crown. We see that Antony, Octavius, and Lepidus stage a blood bath when they emerge as the final victors, but Brutus is too high-principled to allow the same thing to happen during the short time he and his followers hold the power in Rome.

When Antony, Octavius, and Lepidus make a list of the men who are to be purged in Act IV, Scene 1, there is no mention of Popilius. In Act IV, Scene 2, when Brutus, Cassius, and Messala are talking about about the blood bath staged by Antony, Octavius, and Lepidus, Popilius is not mentioned. Even if Brutus and Cassius were to have staged their own blood bath after assassinating Caesar, they would not have included Popilius in their purge because, although he knew about their plot, he didn't warn Caesar. Popilius's brief appearance in Act III, Scene 1 serves to heighten the suspense and suggest the plausible danger that other men in the crowd know about the time and place of the assassination attempt and that Julius Caesar could therefore know about it himself!

What is the difference between figurative language and a figure of speech?

The terms "figurative language" and "figure of speech" are related to a certain extent. However, they are not terms that should be considered as interchangeable. 

It's best to consider a "figure of speech" as a smaller part of what might be considered "figurative language."

Figurative language is essentially the antithesis of a form of writing known as "realism." Realism disposes of the tropes of metaphor and simile to (hopefully) let the reader know that what they are reading is literal. When a piece compares a person or thing or place to another person or thing or place, the writer is using a metaphor, common in figurative language. Look for the words "like" or "as" and you have likely encountered a simile which is a clear indicator of figurative language.

A "figure of speech" on the other hand, does not necessarily indicate figurative language. In many realist dialogues, "figures of speech" are used to drive plot/character development/tone. A completely realist piece of writing may contain many figures of speech, usually in the form of dialogue. Without context, a reader should deduce the time and place of a story or article through a figure of speech.

For instance, a piece that forgoes figurative language could use, say, the colloquialism, "square," in place of it's literal meaning, "cigarette," and the reader would understand that said piece is set in an earlier time period.

It's best to consider these terms as two separate entities but helpful to consider that figures of speech may not always play a role in a work utilizing figurative language. I've never heard nor read anyone saying that the object of their affection was as "dizzy as an old basketball." This is a simile indicative of figurative language as it is not a commonly known "figure of speech." I know this because I just made it up.

Now, to call someone or their actions "sweet as pie," is commonly known as a figure of speech. This doesn't mean that it's inclusion in a piece of writing indicates that the piece consists of only figurative language.

In short, figurative language utilizes a writer's creativity by use of simile or metaphor to (ideally) achieve an apt and original comparison. It is possible to create one's own lexicon, a figure of speech is usually well-known, recognized phrase.

Hope this helps. Best of luck.