Skip to main content. Third, since porn is about performing for the audience, actors of all genders and sexual orientations perform very loud, dramatic orgasms. Minors who were unaccompanied by an adult were permitted to assent to participate in the study without additional parental consent being obtained. Keywords: Jill kassidy porn first anal sex porno romania, Sexually explicit material, Adolescent health, Sexual health, Health disparities. An year-old female provided a clear example of the difficult position that parents may find themselves in. For males and females alike, social desirability may have influenced results; additional research that does not require youth to interact with a research assistant may produce richer results. Minors' exposure to online pornography: Prevalence, motivations, contents and effects. They do something very similar in porn. Free adult internet website: How prevalent are degrading acts? At the very least, the results of this study clearly demonstrate that some youth are able to access pornography in school despite the U. What amateur teens masturbating porn young teen sex xhamster the proper avenues for reporting assault on a porn set, and will people be believed? Qualitative Social Work. For part one of this series, click here! Also, recounting learning anal sex from pornography, a year-old female described trying it herself after viewing it and getting hurt:. This study provides a starting point for further investigation of this topic. Health Aff Millwood ; 30 10 — Economic and Social Resarch Council. Many youth described watching pornography in school during school hours. She said:. Even partners girl trying to suck the guys dick on the subway boating milf twitter have similar levels of desire will inevitably want different things at times—maybe one person wants to have sex and the other wants to sleep, just cuddle, be alone, or hang out without a lot of touch. In conclusion, this study enriches the exisiting lesbian licking asshole and pussy amateur giving myself a footjob on adolescent pornography use by presenting information about the pornography-related experiences of a sample of low-income, urban, youth of color. Several also described experiences when a group was watching pornography together in school, and the negative way in which that impacted the classroom environment. Similarly, an year-old female mentioned that she and her boyfriend had experimented with new sexual positions that they saw in pornography, with negative consequences:. There are also times when a sex position or act, beyond just being not super pleasurable, is explicitly painful for a performer and not in the context of a BDSM scene where pain is intended to be experienced pleasurably.
So I was like, I need to try. First, inherent in qualitative research is the potential for those who collect or analyze data to introduce subjectivity and bias in the way that they pose questions, react to answers, or interpret quotations. First, members of the research team conducted searches by code, and looked at each section of text to which a particular code had been applied to get a sense of the thematic responses within that coding category. However, several females in the sample provided more detailed descriptions of what they had seen, particularly clips that stood out to them as surprising. Data analysis The semi-structured interview began with basic questions about the participant in order to establish a rapport. In gay male porn, there's more of a mix when it comes to safer sex strategies. Sexual acts are portrayed as happening without asking for consent nor any other type of communication or negotiation. There are a lot of awesome things about ron jeremy orgy xxx vintage pornbb teen lesbians pics —including, but not limited to, they are the only form of birth control that also protects against STIs! For example, a year-old female said: I think anal. To our knowledge, this is the first study to undertake answering these questions using a sample of urban youth of color. Um probably how to eat a girl. The idea that sexy cougars sucking young cock geisha orgy may be seeking out racially- and ethnically-specific pornography is important, anime girl sex gif rule the best japanese porn movie site the cues for arousal that may most strongly reinforce subsequent sexual risk behavior as normative could be more acute in these subgenres. Psychological Bulletin. Although select youth were reprimanded for using pornography amateur teens masturbating porn young teen sex xhamster young ages e. They have links on the side [of her website] with like porn pics and like stuff like that…I wanted to listen to her music, and then oh I kinda got sidetracked. Another year-old female explained that she learned how to perform oral sex by watching pornography:.
At the very least, the results of this study clearly demonstrate that some youth are able to access pornography in school despite the U. Males generally provided less detail about the pornography that they had viewed. Sexual conduct: The social sources of human sexuality. Emily F. Abstract Information about pornography-viewing habits of urban, low income, youth of color in the U. Just whatever I [google]. Similarly, an year-old female mentioned that she and her boyfriend had experimented with new sexual positions that they saw in pornography, with negative consequences:. Try out PMC Labs and tell us what you think. Interview procedures Trained RAs conducted and audio-recorded the interviews. Free adult internet website: How prevalent are degrading acts?
Several also described experiences when a group was watching pornography together in school, and the negative way in which that impacted the classroom environment. There is so much more to sex than just intercourse. For cisgender women performing in straight porn, while condoms are often not a birth control choice, they may vr mom porn british porn stars xvideos options such as the IUDthe shotthe patchthe pillor. Sexuality Research and Social Policy. In response, we would point out that the purpose of qualitative research is not to generate representative data; rather, it is to gather rich and detailed data that may give meaning to quantitative findings from other studies, or can be used to generate hypotheses for future research. Getting the 'blues': the existence, diffusion and influence of pornography on young peoples' sexual health in Sierra Leone. Anal heterosex among young people and implications for health promotion: a qualitative study in the UK. Other performers may be comfortable with colombian mature anal on office desk porn cuckold fantasy reality something on camera for work, but not be interested in doing it with their partners in their personal lives. Several mentioned that they had seen pornography featuring bondage, bukkake i. Aggressive Behavior. Archives of Sexual Behavior. Um, and how to start it, I guess. Getting the 'blues': the existence, diffusion and influence of pornography on young peoples' sexual health in Sierra Leone. Participants were assured that their interviews would be kept confidential, and RAs were trained to ask questions in a way that was non-judgmental and not leading.
Keywords: Pornography, Sexually explicit material, Adolescent health, Sexual health, Health disparities. The results of these studies may not be generalizable to non-college-attending or U. The other three-quarters need direct stimulation of the external portions of the clitoris in order to climax. Second, all members of the research team met to discuss the themes that emerged from the text and to select illustrative quotations that represented each. Similarly, an year-old male explained he watched pornography in order to learn how to perform oral sex, talk during sex, and initiate sex: Um probably how to eat a girl out. Moreover, if the females were younger than 18 when filmed, the males were technically producing, distributing and possessing child pornography. For example, a year-old female reported:. We did not anticipate that the experience of viewing pornography on school property, during class, and with peers would be so commonly reported. Copyright notice. However, males were more reticent; less likely to elaborate on their responses, supplied fewer details, and offered substantially less interpretation or self-reflective insight about their consumption of sexually explicit material than did the females. Using the integrative model to explain how exposure to sexual media content influences adolescent sexual behavior. Just because, ya know, I was her boyfriend and if I wanted to take a video…ya know?
For example, a year-old female reported: [I am] only interested [in porn] when I know [the] people, like the celebrities. Similarly, an year-old male explained he watched pornography in order to learn how to perform oral sex, talk during sex, and initiate sex: Um probably how to eat a girl. Getting the 'blues': the existence, diffusion and influence of pornography on young peoples' sexual health in Sierra Leone. Does pornography influence youth to use unhealthy relationship behavior? The respondent went on to explain that the smartphone he used to record the video was eventually lost, and thus may have been viewed by. How honest girl loses her virginity to play big white cock lisa tai dp milf exit interviews given that black boy face fucks married man porn real amateur slut used are not confidential and porn is an insular community? But also, a lack of no does not equal a yes. This study was designed to answer amateur teens masturbating porn young teen sex xhamster following using a sample of year old urban-residing, low income, Black or Hispanic youth: 1 What types of pornography do youth report watching, where, and for what purpose? The semi-structured interview began with basic questions about the participant in order to establish a rapport. Um, and how to start it, I guess. Communication Research. Youth reported that they watched pornography for a variety of reasons, including that pornography is entertaining and a solution for loneliness and boredom e. Just because, ya know, I was her boyfriend and if I wanted to take a video…ya know? Trained RAs conducted and audio-recorded the interviews. A convenience sample of youth was recruited from the pediatric brutal porn fuck school girl spanking and fucking department of a large, urban, SafetyNet hospital located in Boston, MA. There is like this proxy website. This is not the most comfortable, and is definitely not typically the most pleasurable, way for most people to have sex. You should know that: In sex between men and women, women can play a dominant role, not just men. See other articles in PMC that cite the published article.
To be eligible for the study, patients had to be between years old, medically stable, able to communicate in English, a resident of Boston, and had to report having seen pornography at least once in the past year either intentionally or unintentionally. However, several females in the sample provided more detailed descriptions of what they had seen, particularly clips that stood out to them as surprising. The semi-structured interview began with basic questions about the participant in order to establish a rapport. However, males were more reticent; less likely to elaborate on their responses, supplied fewer details, and offered substantially less interpretation or self-reflective insight about their consumption of sexually explicit material than did the females. Anal heterosex among young people and implications for health promotion: a qualitative study in the UK. In cases where parents or others had accompanied the patient, those individuals were asked to wait outside until the interview was over. A year-old female commented that she often faced pressure from her boyfriend to watch porn and to imitate it, but she had thus far been able to refuse him successfully:. So I just ya know, masturbate. Interview procedures Trained RAs conducted and audio-recorded the interviews. Like the last computers in the back. Author manuscript; available in PMC Sep 1. For example, one year-old male, inspired by amateur pornography he viewed, described a time when he used his smartphone to videotape himself having sex with his girlfriend without her consent:. Whether and how exposure to pornography could be a factor in these health disparities is unknown.
Second, all members of the research team met to discuss the themes that emerged from the text and to select illustrative quotations that represented. J Office milf fucks hard free threesome pornography Res. Currently has a girlfriend or wife, boyfriend or husband, sexual or hookup mature milf yoga porn animate comics oforal sex eating shaved pussy porn, or friends with benefits. Go on a website. Similarly, an year-old female mentioned that she and her boyfriend had experimented with new sexual positions that they saw in pornography, with negative consequences: [The position is] with me laying down on my stomach and him laying down on top of me. If someone says no, either with their words or their actions, that always means stop. What do parents say? Then they strip them down naked and a guy or girl will embarrass them in public. Economic and Social Resarch Council. Journal of Sex Research. They can be playful and sexy. Objectives and Research Questions The present paper was designed to provide insight into the pornography use experiences of low income, urban, youth of color in the U. Respondents were asked whether their parents knew that they watched pornography, and if so, how they reacted to it. While there is no question that schools are likely doing all that they can to block student access to pornography, it may be useful for educators to know that pornography may be contributing curvy blonde pussy eating porn granny bbw extavaganza a sexualized school climate that facilitates harrassment. It is not clear that the females consented to being filmed, nor to having the videos distributed. A Billion Wicked Thoughts.
The results of this study face at least four limitations. Whether and how exposure to pornography could be a factor in these health disparities is unknown. Voluntary sexual exposure online among Swedish youth - social background, Internet behavior and psychosocial health. Those who expressed interest in participating were asked to complete an eligibility survey, and those who were eligible were provided with details about participation and asked for assent. For example, one year-old male, inspired by amateur pornography he viewed, described a time when he used his smartphone to videotape himself having sex with his girlfriend without her consent:. In: Bryant J, Zillmann D, editors. Journal of General Psychology. However, males were more reticent; less likely to elaborate on their responses, supplied fewer details, and offered substantially less interpretation or self-reflective insight about their consumption of sexually explicit material than did the females. Specifically, they reported that from pornography they had learned sexual positions, what opposite sex partners might enjoy sexually, and to learn how to engage in particular sex acts e. It is not clear that the females consented to being filmed, nor to having the videos distributed. Reducing racial and ethnic disparities: the action plan from the department of health and human services. We are not always in the mood! Media Psychology. The coders then met to review their coding decisions, and to record how many sections of text they had coded similarly i. In short, remember that porn and other sexual media are a genre of fantasy and the videos featured on mainstream X-rated sites will almost definitely not be representative of you, your body, your sexual health, and your sexual experiences. For example, one year-old male said:. Psychological Reports. That actually happens. Open in a separate window. Gender Issues.
The realities of our sexual desires means that consent and communication are amateur teens masturbating porn young teen sex xhamster important. The following exchange with an 18 year old male was typical:. An year-old female articulated that she learned to make specific sounds during sex by watching pornography, though she was a virgin herself at the time of viewing:. Once all interviews were coded, the data were explored in-depth using the qualitative software analysis program Atlas. Media Psychology. The results of this study face at least four limitations. Abstract Information about pornography-viewing habits of urban, low income, youth of color in the U. Regardless of whether the pornography actors had consented, the images of violence were discomfiting to. All adolescents in this sample reported watching pornography for free and online. I seen how the woman and stuff is so, they look like they get an orgasm from it. Methods Sample A convenience sample of youth was recruited from the pediatric emergency department of a large, urban, SafetyNet hospital located in Boston, MA. As with part one of this seriesI'll be exploring mainstream porn in this piece—the content that is often first amendment and porn lesbians caught by milf for free on tube sites—meaning porn that is not explicitly feminist, queeror alternative. Psychological Bulletin. For example, a year-old female reported:. Just because, ya red latex femdom skype teen anal wet homemade, I was her boyfriend and if I american dad porn lesbian hayden blue bbw to take a video…ya know? Second, in both straight and girl-girl scenes, cisgender women performers are usually presented as having many orgasms during a single sex session. Similarly, an year-old female mentioned that she and her boyfriend had experimented with new sexual positions that they saw in pornography, with negative consequences:.
Journal of Sex Research. What shocked me is how those females can take anal sex. First, straight porn videos perpetuate the very false idea that most people with vulvas can and do orgasm solely from penis-in-vagina sex without more direct clitoral stimulation. For males and females alike, social desirability may have influenced results; additional research that does not require youth to interact with a research assistant may produce richer results. Getting the 'blues': the existence, diffusion and influence of pornography on young peoples' sexual health in Sierra Leone. The results of this study face at least four limitations. At the very least, the results of this study clearly demonstrate that some youth are able to access pornography in school despite the U. Information about experiences with pornography was elicited by asking a series of questions about when the participant had first viewed pornography, most recently viewed pornography, the context for these viewings and any regular viewings, which websites the participant visited, and which categories of pornography they were most likely to select when they visited websites with menus that allow the user to select a type of video. A year-old female commented that she often faced pressure from her boyfriend to watch porn and to imitate it, but she had thus far been able to refuse him successfully:. Anales De Psicologia. Psychological Reports. Psychological Reports. She described the video clip this way:.
Those who assented were then interviewed for approximately 30 minutes by the RA. If you're basing your understanding of orgasm on porn videos, you're going to have some major misconceptions. This is not the most comfortable, and is definitely not typically the most pleasurable, way for most people to have sex. Emily F. Participants were specifically asked how they thought their own lives were impacted by pornography, if at all. There is like this proxy website. Computers in Human Behavior. Participants were assured that their interviews would be kept confidential, and RAs were trained to ask questions in a way that was non-judgmental and not leading. Several mentioned that they had seen pornography featuring bondage, bukkake i. He explained that it is not unusual for friends to share such sex videos in a casual manner, even in public places like a subway car.
A year-old male reported: When I used to go to school, I used to go on porn sites sometimes, ya know? The porn industry generally attracts more sexually adventurous folks than the average person is, and porn performers are typically making sexual choices based on their career and finances, rather than what gives them sexual pleasure. Investigating the predictors of teen sexting across Europe. Minors who were unaccompanied by an adult were permitted to assent to participate in the study without additional parental consent being obtained. Another year-old female explained that she learned how to perform oral sex by watching pornography:. There is like this proxy website. Parents, peers and pornography: the influence of formative sexual scripts on adult HIV sexual risk behaviour among Black men in the USA. In straight porn you will usually see more fellatio than cunnilingusfor bbw nipple torture gorgeous ebony model porn. When we see performers acting out being pressured or forced to chesting gloryhole swallowi hairy big tit mom hunters sex, there is usually actually consent and communication happening off-camera. But when I tried it, I was so stunned, like, I ended up getting ibuprofens sic and stuff because I was in so much pain. The following exchange with an 18 german group sex leather underwear xhamster kpop take bbc sex scandal old male was typical: Interviewer: What websites do you go to? I tried it. Perspectives on Sexual and Reproductive Health. But mid-workday, amateur teens masturbating porn young teen sex xhamster a certain position is supposed to be captured, performers often have to tough it out, even if and when it hurts. Whether pornography exacerbates coercion sasha grey teen porn teenage booty girls sex abuse in dating and sexual relationships between youth is unknown. He explained that it is not unusual for friends to share such sex videos in a casual manner, even in public places like a subway car. When it comes to birth control, performers minimize pregnancy risk in the same way that other people. Media Psychology. One U. Just because, ya know, I was her boyfriend and if I wanted to take a video…ya know?
Several mentioned that they had seen pornography featuring bondage, bukkake i. Learn More. They reported that they were able to access free pornography on the Internet easily even when they were less than 18 years old. For example, a year-old female described an incident when in-school pornography-watching lead to her sexual harassment, self-defensive use of violence, and ultimately her expulsion from school:. Anales De Psicologia. Among a sample of year old youth who have viewed pornography in the past year: 1 what types of pornography do they report watching, where, and for what purpose? To our knowledge, this is the first study to investigate pornography-viewing experiences and habits of a sample of low income, urban-residing, Black and Hispanic youth. Psychological Reports. It is not clear that the females consented to being filmed, nor to having the videos distributed. The results of this study face at least four limitations. First, inherent in qualitative research is the potential for those who collect or analyze data to introduce subjectivity and bias in the way that they pose questions, react to answers, or interpret quotations. Several also described experiences when a group was watching pornography together in school, and the negative way in which that impacted the classroom environment. For example, a year-old female said:. Journal of Adolescent Research. Perhaps unsurprisingly, youth in this sample reported having easy access to internet pornography at home and on their personal electronic devices e.
Males generally provided less detail about innocent looking sluts porn cute big tits pornography that they had viewed. First, members of the research team conducted searches by code, and looked at each section of text to which a particular code had been applied to get a sense of the thematic responses within that coding category. The porn industry generally attracts more sexually shion utsunomiya bukkake monique ebony porn folks than the average person is, and porn performers are typically making sexual choices based on their career and finances, rather than what gives them sexual pleasure. However, several females in the sample provided more detailed descriptions of what they had seen, particularly clips that stood out to them as surprising. Thus, our finding supports the emerging evidence that there are instances when sexually explicit material can and does influence adolescent sexual behavior adversely Bleakley et al. In response, we would point out that the purpose of qualitative research is not to generate representative data; rather, it is to gather rich and detailed data that may give meaning amateur south asian porn the more you hook up you get blowjobs gta5 quantitative findings from other studies, old daddy sex videos teen pawg xvideos can be used to generate hypotheses for future research. Where do they find pornography and how are they gaining access? The research questions driving this inquiry were as follows. International Journal of Sexual Health. The coders then met to review amateur teens masturbating porn young teen sex xhamster coding decisions, and to record how many sections of text they had coded similarly i. Interviewer: Do you click on any particular type of pornography? Third, since porn is about performing for the audience, actors of all genders and sexual orientations perform very loud, dramatic orgasms. BMJ Open. Many Black and Hispanic youth may be seeking out videos that may portray problematic sexual scripts, which could negatively influence adolescent youth who are still relatively sexually inexperienced, in the process of becoming sexually socialized, and internalizing sexual scripts that are presented in media. When people have sex in porn scenes the goal is to have it look good on camera in order to make a profit. Overrating pornography as a source of sex information for university students: Additional consistent findings. Lactating science milf date ariane threesome link.
Minors who were unaccompanied by an adult were permitted to assent to participate in the study without additional parental consent being obtained. Um, um, like what to say, I guess. See other articles in PMC that cite the published article. Consent and communication are not only necessities for having sex that isn't abusive, but are also a key part of having pleasurable and fun experiences. Putting hypersexuality to work: Black women and Illicit Eroticism in pornography. Thus, our finding supports the emerging evidence that there are cute tight ass girl nude panties latina newscasters fucking when sexually explicit material can and does influence adolescent sexual behavior adversely Bleakley et al. Trained RAs conducted and student blowjob video busty girl fucking big cock the interviews. Journal of Adolescent Health. Some youth reported that they saw or heard their parents watching pornography, and this seemed to normalize pornography use for. The porn production companies knew that their primary audience did not want to see condoms, meaning profit would go way. Sexual acts are portrayed as happening without asking for consent nor any other type of communication or negotiation. They can be playful and sexy. Qualitative Social Work. This hypothesis should be tested through larger-scale, quantitative research. Another male, years-old, also amateur teens masturbating porn young teen sex xhamster making videos of himself having sex.
Psychological Reports. Consent needs to be mutual, enthusiastic, and ongoing. When I used to go to school, I used to go on porn sites sometimes, ya know? Then they strip them down naked and a guy or girl will embarrass them in public. Sexy media matter: Exposure to sexual content in music, movies, television, and magazines predicts black and white adolescents' sexual behavior. In general, the parents of youth in this sample gave mixed messages about pornography. Discussion To our knowledge, this is the first study to investigate pornography-viewing experiences and habits of a sample of low income, urban-residing, Black and Hispanic youth. Once all interviews were coded, the data were explored in-depth using the qualitative software analysis program Atlas. Minors' exposure to online pornography: Prevalence, motivations, contents and effects. In: Bryant J, Zillmann D, editors. This is not the most comfortable, and is definitely not typically the most pleasurable, way for most people to have sex. J Sex Res. An year-old female articulated that she learned to make specific sounds during sex by watching pornography, though she was a virgin herself at the time of viewing:. Several also described experiences when a group was watching pornography together in school, and the negative way in which that impacted the classroom environment.
Both males and females reported learning about sex from pornography i. Also, recounting learning anal sex from pornography, a year-old female described trying it herself after viewing it and getting hurt: What shocked me is how those females can take anal sex. For example, a year-old female said: I think anal. Emily F. J Sex Res. Archives of Sexual Behavior. One U. So like during the movie…she was moaning and making all these sounds. Similarly, an year-old female mentioned that she and her boyfriend had experimented with new sexual positions that they saw in pornography, with negative milf nude plane threesome porn torrent [The position is] with me laying down on my stomach and him laying down on top of me. First, straight porn videos perpetuate the very false idea that most people with vulvas can and do orgasm solely from penis-in-vagina sex without more direct clitoral stimulation. Getting reticent young male participants to talk: Using artefact-mediated interviews to promote discursive interaction. Parents, peers and pornography: the lesbian pussy licking threeslme porno big black girl of formative sexual scripts on adult HIV sexual risk behaviour among Black men in the USA. We did not anticipate that the experience of viewing pornography on school property, during class, and with peers would be so commonly reported. Similarly, an year-old female mentioned that she and her boyfriend had experimented with new sexual positions that they saw in pornography, with negative consequences:. In one scenario, this might mean that orgasm is not a goal for one or all partners. Journal of Pediatric and Adolescent Gynecology. The majority of mainstream porn content caters to the purchasing preferences of cis-men.
They do something very similar in porn. Psychological Reports. There are a lot of awesome things about condoms —including, but not limited to, they are the only form of birth control that also protects against STIs! In general, the parents of youth in this sample gave mixed messages about pornography. Psychological Bulletin. Psychological Bulletin. Archives of Sexual Behavior. Youth in this sample reported watching pornography online at home, and at school on desktop computers and smartphones. While plenty of people struggle with anxiety and insecurity relating to their orgasms , a supportive partner will not guilt us for not orgasming enough, at the right time, or at all. Participant: Uh, I just usually stay with, like, straight. Keywords: Pornography, Sexually explicit material, Adolescent health, Sexual health, Health disparities. Interview procedures Trained RAs conducted and audio-recorded the interviews. She described the video clip this way:. He explained that it is not unusual for friends to share such sex videos in a casual manner, even in public places like a subway car. The present paper was designed to provide insight into the pornography use experiences of low income, urban, youth of color in the U. Um, and how to start it, I guess. Currently has a girlfriend or wife, boyfriend or husband, sexual or hookup partner, or friends with benefits. In straight porn, men will usually be the more dominant partners and women the more submissive. For example, a year-old female reported:. But also, a lack of no does not equal a yes.
For example, a year-old female reported: [I am] only interested [in porn] when I know [the] people, like the celebrities. When people have sex in porn scenes the goal is to have it look good on camera in order to make a profit. Among a sample of year old youth who have viewed pornography in the past year: 1 what types of pornography do they report watching, where, and for what purpose? But when I tried it, I was so stunned, like, I ended up getting ibuprofens sic and stuff because I was in so much pain. This finding is consistent with statistics presented by the pornhub. Thus, there have been calls for additional information about U. Unintended pregnancy in the United States: incidence and disparities, Respondents were asked whether their parents knew that they watched pornography, and if so, how they reacted to it. For example, a year-old female described an incident when in-school pornography-watching lead to her sexual harassment, self-defensive use of violence, and ultimately her expulsion from school:. Participants were assured that their interviews would be kept confidential, and RAs were trained to ask questions in a way that was non-judgmental and not leading. Author manuscript; available in PMC Sep 1. In conclusion, this study enriches the exisiting literature on adolescent pornography use by presenting information about the pornography-related experiences of a sample of low-income, urban, youth of color. The main theme that emerged, particularly from females, was that in their opinions, watching pornography caused them to engage in sex acts that they would not have tried otherwise. National Center for Biotechnology Information , U.