Tag Archives: forensic

Sexually Transmitted Microorganisms in Forensic Investigations: A Potential Tool

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The male and female genitals provide a clear environment for microorganisms

Artur Plawgo/Getty Images

Sexual partners transfer their unique genital microbiota to one another during sexual intercourse. This can affect forensic investigations of sexual assault.

Brendan Chapman Murdoch University in Perth, Western Australia and his colleagues collected swabs from the genitals of 12 monogamous heterosexual couples and used RNA gene sequences to identify microbial signatures for each participant. Researchers asked couples to refrain from sex for two days to two weeks, and took follow-up samples several hours after sex.

“We found that these genetic signatures from female bacteria can be detected in male partners and vice versa,” Chapman says. As the team infused it, this change in a person's “sexome” could prove useful in criminal investigations, he says.

The amount of transfers varies from couple to couple, and the team found that even the use of condoms completely prevented the movement of the Sensomem from one partner to another. However, one major limitation of the outcome was the significant changes in female sexsomes during the period.

Chapman says there may be long-term homogenization of the microbiota of monogamous couples, but the bacterial population clearly differs between genders.

“The big advantage we have in our penis and vaginal microbiota is that we observe very different types of bacteria in each because there are huge differences in the two environments,” says Chapman. “For example, the penis is primarily a skin-like surface and therefore reflects similarity to the skin microbiota. There are a variety of anaerobic bacteria in the vagina, and the aerobic type in the penis. .”

So many of these bacteria cannot last indefinitely in the opposite environment, he says. “It's like comparing land to sea animals. Some live exclusively in one or the other and die if removed, but they willingly move and last.”

After establishing bacterial movement during sex, the team wants to prove that individual sexsomes are unique, like fingerprints and DNA. “I think every person's Sensomem contains enough diversity and uniqueness, but there's still something to do to demonstrate it with robust enough techniques to meet the forensic challenges. There is,” says Chapman.

If researchers can prove this, it can help investigate sexual assaults, particularly those in which male suspects do not ejaculate, have had vascular resections, or use condoms. “The genetic profile of a bacterial may be able to support or oppose propositions or testimony about what happened in the allegations of sexual assault,” he says. Dennis McNevin At Sydney Institute of Technology, Australia.

In such cases, the standard profile of human DNA is always preferred due to the great power of distinguishing individuals, he says, but sexomes may offer useful alternatives. “Bacterial genetic profiles may one day complement DNA evidence, or may help refer to the perpetrator of a rare sexual assault where DNA profiles are not available,” McNevin says.

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Source: www.newscientist.com

Understanding Traitors: Exploring the Intersection of Forensic Psychology and Evolutionary Biology

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Claudia Winkleman, The Traitors host

BBC /Studio Rambert

Food -up, torch light, knife Sharp: Viewers in the UK are ready for different delicious finale Traitor Tonight, at a video game show, a TV game show is trying to drive away the ruthless (strictly non -realistic) murderers walking between them.

For psychologists -Experts and armrests- Traitor This is the gold mine of the unauthorized human behavior, which is disassembled and analyzed. And it's not just psychology. Game theory, human evolution, and criminal science are only a few of the scientific fields that provide clues to Makabeli's dynamics.

I found something that I really needed to win to investigate a betrayal (academically speaking …) Traitor。 Warning: If there is no latest information on the show, there is a spoiler first.

Please be careful about compatible bias

“Having a strong feature seems to be that others are influential and potentially intimidating,” says a forensic psychologist. Kuala LightHost A Podcast About Traitor With a colleague at the British Chester University. She selects contestants such as shadows (too intelligent), Ellen (too emotional), and Armani (too much confidence).

Their falls are likely to be linked Compatible biasThe characteristics of human beings that most of us comply with social norms. Individuals who do not fit may be hated or distrustful.

This is not a place of altruism

Emily EmotThe London University College's evolution anthropologist says that players should not be able to “do not actually exist in evolutionary literature.”

“Remember, it's not a cooperative game,” she says. “It's a deceptive game, a survival game. You need to be there to win, so it's a mistake to commit some players because they trust the nearby people. “

Emot says that we have evolved to go ahead of others. Therefore, altruistic behaviors found in the show are said to have selfish benefits behind them. And such obvious altruism is not a bad tactic, whether you are faithful or traitor.

“In the context of the game, cooperative is functioning as a signal for reliability. A good example may not be open to the shield. [which protects you from the next murder] During the show task. “

However, here is Makabeli's intelligence. Because everyone knows the rules of the game, excellent players do not take altruistic actions at face value. “In this game, you may have an impure motivation for you, so it’s not a honest signal,” says Emot.

So be careful of wonderful people. an Thousands of messages analysis Between players DiplomacyGames that share similarities TraitorExcessive polite players have discovered that they are more likely to betray others.

Be careful of bias in the group

“We know from social psychology that they have what they are called when they form a social group. Bias in the groupAnd this can really accelerate TraitorLight says. “”[Contestants] Display priority actions to those in the group with them. This is why everything did not work for Mina after recruiting Charlotte as a traitor.

Charlotte is recruited as a traitor by Mina

BBC /Studio Rambert

For Mina, who was always looking for a female traitor, her group was a so -called sister relationship she created. “She identified it as a sister relationship. She used this word well,” says Light. “The problem is that Charlotte had already had a faithful person and a strong group's identity, and when she was hired by her will, she did not have the loyalty to the new group. did.”

And what happened? Charlotte immediately crossed Mina, and Mina was voted the next night.

Light says that the same group's bias can lead to a flock thinking when the player is voting, which can lead to an unrogical trust in people in the game.

What is a good liar?

A nervous or inconsistent answer to the question is generally considered doubtful, even if someone tells the truth. That's because these actions are tied to a stereotype about what a liar is doing. The better gifts are always those who say the same thing. Emma BarrettPsychologist and criminal scholar at the University of Manchester University.

“One of the most notable things is the same story in the exact same way, and they don't really explain it in detail when they re -speak it,” she says. The story may sound plausible, but repeatedly adds details as you remember. “People sometimes make a mistake in consistency, but that's not a way to work with real memories.”

Think like a scientist

Hunting for the traitor -Introduction to the 3rd season of the traitor

BBC /Studio Rambert

Faithful people are not very good at it TraitorBut another tactic that they can use is to encourage suspicious traitor to speak more than they want. Barrett says.

“If you are faithful, the good strategy to detect a traitor is to subtly encourage them as they speak.” “For example, if you want to know if you are a police officer and someone gave you a false address, one of the questions you might ask is,” Oh, how do you get there? What is your nearest station?

If you are suspicious, try a game theory?

The majority of information is always lost to the minority based on sufficient information. Based on this, it was created by Russian psychologist Dimitry Davidoff mafia -Which parlor game Traitor Based on the 1980s. since then, mafia It is used as the basis of many game theory experiments and models.

The good news is that Davidoff is not correct at all. He believed that the probability of a faithful person to keep the bad guys away is better than a coincidence. But many the study The model discovered that the possibility of victory was almost equal, and was leaned in support of people who were faithful to live games for the weight of the lie that the traitor had to talk about.

In other words, forget cold mathematics. If you really want to win TraitorYou must be just injustice than anyone else.

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Source: www.newscientist.com

Exploring the Future of Forensic Medicine: Blood Droplets in Microgravity

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High blood splatter

“Get ready!” This immortal motto of the Scout movement will come to the mind of many readers who read the paper “Dynamics of bloodstain patterns in microgravity environment: Pilot study observations on the next frontier of forensic medicine.”

Reader Sarah Rosenbaum flagged feedback on the study’s first clearly stated purpose: “Investigating the ultimate violent criminal acts that occur outside of the global environment.”

This is the most futuristic forensic science. “It’s almost here.” The most effective approach is joint criminal investigation between the United Kingdom and the United States. The researchers are from Staffordshire University and Hull University in the UK, and the University of Louisville in Kentucky and Roswell Police in Georgia in the US.

“We hypothesize that the calculated impact angles would be more accurate if gravity were removed as a force acting on the blood droplet in flight,” they write.

They performed tests, or rather flew, aboard a parabolic flight research airplane that took off and landed at Fort Lauderdale-Hollywood International Airport. (Fort Lauderdale, like many cities in Florida, is no stranger to blood splatter. We see a steady increase in the number of violent crimes According to statistics reported by the local police department’s crime analysis department, it will occur between 2020 and 2023.)

In the experiment, “a 1 cc syringe containing a blood analogue was used to inject the liquid onto a flight path approximately 20 cm long, which was intercepted by a 16.5 cm x 16.5 cm target.” [made of] Fifty pound paper adhered to foam board backing.

The study found that droplets that hit paper at a 90-degree angle behaved as predicted by the traditional forensic blood droplet equation. But while this is a blood-stirring challenge for forensic scientists and true crime enthusiasts alike, someone needs to come up with a better equation for predicting what will happen from the other angle.

Thinking: Inside the box

Seeing sometimes leads to believing. Feeling, hearing, and reasoning are equally powerful when combined.

Shorey Croom, Hanbei Chow, and Chaz Firestone of Johns Hopkins University in Baltimore, Maryland, explain this in the magazine. PNAS How did they try to answer the question “?” “Can you tell what another person is trying to learn just by observing their movements?”

They filmed a volunteer shaking an opaque box and attempting to measure i) the number of objects hidden inside, or ii) the shape of the objects inside. He then asked others to watch the video and tried to determine “who is shaking because of the numbers and who is shaking because of the shapes.” Most observers were pretty good at recognizing who was shaking and why.

Back in 2017, Milte Plesier of Delft University in the Netherlands and Jeroen Smeets of Vrije Universiteit Amsterdam spoke to attendees of the IEEE World Haptics Conference in Fürstenfeldbruck, Germany, about a project they called “How many objects are in this box?”

Their method was simple. “We investigated how accurately participants could determine the number of wooden balls inside a box by shaking it.” They found that while they were able to perform the task accurately, they systematically underestimated the number of more spheres. The larger numbers they tested were 4 and 5. The situation with larger quantities remains theoretically unknown.

stick to fruit

Many scientists will not be able to determine whether the metal sticks to the fruit.

Generally speaking, if properly persuaded, they will. News about this can be found at “Reversibly attaching metals and graphite to hydrogels and tissues” by Wenhao Xu, Faraz Burni, and Srinivasa Raghavan of the University of Maryland.

writing in diary ACS Central Science “We have discovered that hard conductors (such as metals and graphite) can be bonded to soft aqueous materials (such as hydrogels, fruit, and animal tissue) without the use of adhesives.” The adhesion is caused by a low direct current electric field… [This] It can also be achieved underwater, where normal adhesives cannot be used.

“The experiment is very simple,” the study says, anticipating that many people would be surprised by such a simple, hitherto essentially unknown effect.

Accidental genital glow

Faraz Alam sent us the results of his research with colleagues at Imperial College London, published in the journal 2013. PLoS One “This is the paper on which I accidentally made my genitals glow in the dark.” The title is “Non-invasive monitoring of Streptococcus pyogenes vaccine efficacy using intravital optical imaging”. Those reproductive organs belonged to mice.

This spurred feedback that reminded me of a paper on humans published in 1950 by P. A. MacDonald and M. Sidney Margolese. Obstetrics and gynecology questionnaire. They called it “Luminous phenomenon of female external genitalia”.

These are both examples of how scientists perceive the wonders of biology.

Mark Abrahams hosted the Ig Nobel Prize ceremony and co-founded the magazine Annals of Improbable Research. Previously, he was working on unusual uses of computers.his website is impossible.com.

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Source: www.newscientist.com

Bloodstains at crime scene reveal forensic evidence from tail

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Recent research published in fluid physics Scientists at Boston University and the University of Utah have introduced a new aspect of bloodstain analysis. This study focused on the “tail” of the bloodstain, which could provide additional information about the blood droplet’s size, velocity, and impact angle. These discoveries represent a major advance in forensic science, with implications for crime scene reconstruction and verification of eyewitness testimony.

New research in forensic science has revealed that the “tail” of a bloodstain provides important information about the origin of the blood droplet, enhancing crime scene analysis and evidence interpretation.

Forensic science has taken the public imagination by storm, as evidenced by the abundance of “true crime” media over the past decade or so. Evidence such as blood left at a crime scene can now reveal key information for investigating and understanding the circumstances of a crime, and scientific methods can help interpret that information. , now almost everyone knows.

in fluid physicsA group of scientists from Boston University and the University of Utah have demonstrated in AIP Publishing how bloodstains can yield even more valuable details than those typically collected by detectives, forensic scientists, and crime scene investigators. The researchers studied how these “tails” form by examining protrusions that deviate from the boundaries of oval bloodstains.

“These protrusions are typically only used to figure out the direction in which the droplet has moved, and are otherwise ignored,” says author James Byrd.

Within a few milliseconds, tiny droplets of blood impact the solid surface, forming the shape of a stain. Of particular interest is a protrusion that occurs on the right side and deviates from the boundaries of the oval stain.Credit: James C. Byrd

In fact, previous studies have mainly focused on large blood droplets that fall vertically onto flat or inclined surfaces, where gravity can distort the shape of the tail and make it difficult to see. In contrast, the new study involved a series of high-speed experiments in which droplets of human blood, less than a millimeter in diameter, were bombarded with horizontal surfaces at different angles.

“We showed that the precise flow that determines the length of the tail is different from the flow that is responsible for the size and shape of the oval part of the stain,” Bird said. “In other words, the tail length contains additional, independent information that helps analysts reconstruct where the blood drop actually came from.”

Indeed, the tail length may reflect information about the size, impact velocity, and impact angle of the blood droplet that formed the stain. Measuring multiple blood stains within a stain pattern allows the trajectory of the droplet to be traced back to its presumed origin.

Although their analysis only used horizontal planes to examine impact velocity dynamics, Byrd and colleagues hope this will spark further research focusing on the tail length of bloodstain patterns. Masu. They believe that incorporating tail length into standard bloodstain analysis will provide more robust evidence information.

“Knowing the origin of bloodstains at a crime scene can help detectives determine whether the victim was standing or sitting, and corroborate or challenge eyewitness testimony,” Byrd said. said.

Reference: “Bloodstain Tail: Asymmetry helps reconstruct oblique shocks” by Garam Lee, Daniel Attinger, Kenneth F. Martin, Samira Shiri, and James C. Byrd, November 2023 21st of the month fluid physics.
DOI: 10.1063/5.0170124

Source: scitechdaily.com