Human Babies Laugh Just Like Chimpanzees

Babies are especially good when they are laughing, which they start to do at around three and a half months old. Babies laugh when other people do things, like tickle them or play peek-a-boo, or when other people are laughing.

The laugh of a human baby is distinct from (and significantly more excellent than) the laugh of a human adult. That’s because babies are much cuter than adults, but it’s also because, unlike adults, babies laugh both on the inhale and on the exhale, as described by new research presented at the Acoustical Society of America’s 176th Meeting.

Babies have that pattern in common with non-human primates, like chimpanzees, which also laugh both when they’re inhaling and when they’re exhaling. Adult humans, on the other hand, laugh almost exclusively on the exhale.



Disa Sauter, a psychologist and associate professor at the University of Amsterdam in the Netherlands, and her team studied recordings of laughter from 44 children between the ages of three months and 18 months. Student listeners coded the recordings, noting when the laughter was on an inhale versus an exhale.

As the babies got older, the proportion of their laughter that was on the inhale decreased, according to the initial findings. “Our results so far suggest that this is a gradual, rather than a sudden, shift,” Sauter said in a statement. However, she noted that professional phoneticians are re-checking the results to confirm that the transition was actually happening.

It’s not clear why babies and chimpanzees laugh in this way. But laughter and laugh-like vocalizations in humans and non-human primates both probably evolved from common ancestry. Selection for traits that allowed humans to talk might have pushed humans towards a more speech-related laugh sound—and Sauter said it’s possible that babies start to laugh more like adults as they start to learn to speak.


So, the next time you are lucky enough to witness a laughing baby, see if you can pick up on those primate-like, inhale-exhale giggles

Source:gizmodo.com

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Same-sex mammals can make babies Scientists say

A team of scientists in China has successfully generated offspring created from the DNA of two same-sex mice. This is the first time such a feat has been accomplished with mammals, and it could have huge implications for humans.

In a paper entitled “Generation of Bimaternal and Bipaternal Mice from Hypomethylated Haploid ESCs with Imprinting Region Deletions,” recently published on ScienceDirect, the scientists describe the incredibly complex process. In creating same-sex offspring the team worked with both bipaternal (two dads) and bimaternal (you guessed it, two moms) DNA sequences with varying degrees of success.

The offspring resulting from bimaternal DNA, edited using CRISPR, were found healthy and capable of reproducing with regular mice. According to the scientists they were indistinguishable from mice conceived under normal circumstances.

Bipaternal mice weren’t quite so resilient. Only about two percent of the attempts to create offspring by manipulating the DNA of two male mice resulted in success, and of those none lived longer than a few days.

The method by which the team created the offspring isn’t exactly what most people would consider natural. SingularityHub’s Shelly Fan called it a “Frankenstein-ish process,” and we agree.

In order to create bimaternal mice offspring, the team mutated specific DNA-carrying cells to present with only half their normal information, these are called “haploid cells.”

The reason they only have half the info is so that they can be combined with a cell from the other mother to make a complete fertilized egg, much like what happens when sperm and egg combine. The resulting mom-to-mom cell mashup is then implanted in the womb of a surrogate mouse-mom, and the rest is business as usual.


The offspring resulting from bimaternal parents were able to reproduce normally.
It’s a lot more complex than that, but the gist is that scientists created psuedo-sperm from the DNA of a female mouse and combined it with another female mouse’s DNA to make a baby. According to the research, the team was able to produce 29 live mice from 210 embryos and zero contributions from male mice.

Making a baby from two dads is more complex, and prone to failure. Since male mice don’t have eggs, and eggs are so far a vital part of mammal reproduction, the team used one from a female mouse. They basically hollowed it out, getting rid of all existing DNA and then filled it with a similar mix to the bimaternal effort. As mentioned, however, none of the offspring resulting from a bipaternal source ended up viable.

There’s obviously work to be done before this ground-breaking research starts informing human fertility and reproductive science, but the writing is on the wall: The age-old paradigm for mammalian reproduction is no longer the only valid solution.

The modern world is full of brave new ideas on sex, sexuality, and reproduction. And, with tools like CRISPR at our disposal, it’s apparent that humanity’s future has more options than its past.

Source:thenextweb.com

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RADIOACTIVITY

                                                     Radioactivity

Radioactivity is the spontaneous/induced  disintegration or decay of unstable atomic nuclide  resulting in the emission of particles or radiation such as alpha particles, beta particles and gamma rays.

Factors that contribute to radioactivity. All nuclei except H (hydrogen) contains two kids of fundamental particles called protons and neutrons. Some nuclei are unstable. The stability of a nucleus depends on the protons and neutron ratio. When the nucleus becomes unstable it undergoes spontaneous decay or disintegration to emit particles and radiation.  All elements which have atomic number greater than 83 are radioactive. A radioactive substance is one that’s capable of undergoing spontaneous decay to emit particles and radiation. When a nuclide is bombarded with a proton(s) and neutron(s) they undergo a change in neutralization  or process called nuclear transmutation. 

14   7

N +

4 2

He →

17   8

O +

1 1

H

Nuclear Stability. The stability of any nucleus is determined by the difference between the force of repulsion and short range attraction. If the nucleus disintegrates emitting particles and radiations. If attraction prevails the nucleus will be stable. The main factor for determining whether a nucleus is stable in the proton-neutron ratio. For stable atoms of elements of low z n: p value is closer to 1. The presence of large excess neutrons over protons also distracts the stability of the nucleus.

The half-life of the nucleus. The half-life of a radioactive isotope provides a quantitative measure of its relative stability and remains constant and unique for each radioactive decay process. The shorter the half-life the faster and the more unstable it is. On the other hand the longer the half –life the slower the decay process and the more stable the isotope.

                                                               Types of Radioactivity

Natural radioactivity: It is the spontaneous disintegration or decay of unstable atomic nuclei resulting in the emission of particles or radiation such as Alpha, Beta and Gamma rays

Artificial radioactivity: It is the decay of atomic nuclei which have been rendered unstable by bombarding them with subatomic particles resulting in the emission of particles and radiation such as alpha, beta gamma rays.

                                  Particles emitted by radioactivity

Alpha particle. They consist of two protons and two neutrons that act as a single particle. It is identical to the nucleus of helium atom. It has a mass of 4amu and a charge of 2+. It is represented as

Alpha decay. It is the emission of an alpha particle during radioactivity. When an alpha particle is emitted from unstable radioactive nucleus the atom is transmitted into different elements. Any nucleus which emits an alpha particle has its Z reduced by 2 and A reduced by 4.

Beta Particles. Beta particles are fast moving electrons. Each beta particle carries a charge of -1 and has a mass of 1/2000amu. It is represented as

Beta decay. Emission of beta particles during radioactivity can occur in two ways. A neutron turns into protons by emitting 2 negatively charged particles and other particles called anti-neutrino.

Proton can also turn into neutron by emitting two (2) neutrino and a positron. After the decay the nucleus of the atom contains either one less or one more proton. Beta decay transmutes the atom into new elements that is represented by different atomic number.

Gamma rays. Mass-less and changeless radiation with high energy. They are emitted from the nucleus of an atom when it under goes radioactive decay. The energy of a gamma ray account for the difference in energy between the nucleus and the decayed products. Typically they have about the same energy as a high energy X it represented by the symbol

                                                    Penetration Power of Sub Atomic Particles

Gamma rays. They are the most energetic and have the highest penetration power. This makes them injurious than any radioactive emission. It can penetrate a card few millimeters thickness of aluminum and can only be stopped by a concrete wall or shield of lead metal.

Beta Particle. They are less energetic and have less penetration power than gamma rays. This makes them less injurious than the gamma rays. The however have a greater penetration power and more injurious than alpha particles. It can penetrate a card but can be stopped by few millimeters thickness of aluminum.

Alpha particle. They are the least energetic with the lowest penetration power and as such the least injurious. It can be stopped by a card.

                              Behavior of radioactive emissions in magnetic and electric fields

Gamma rays are neither deflected by electric or magnetic field. They therefore move in a straight path when passing through an electric or magnetic field. Beta particles are attracted to a positive plate repelled by the negative plate of an electric field.
Alpha particles are attracted to the negative plate but repelled by the positive plate of an electric field. Since alpha particles are more massive than beta particle, they are deflected to a lesser extent than the latter in a magnetic  and electric field.

  The Nature of radioactive particle in tabulated form

Type of Radiation	Alpha particle	Beta particle	Gamma ray
Symbol	or or	or
Mass (amu)	4	1/2000	0
Charge	+2	-1	0
Speed	slow	fast	very fast (speed of light)
Ionising ability	high	medium	0
Penetrating power	low	medium	high
Stopped by:	paper	aluminium	lead

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                                                                      Uses of Radioactivity
Sterilization of surgical equipment.

Carbon dating

Sterilization of pests

Irradiation

Determining of molecular size

Cure cancer

                                                            Harmful effect of radioactivity

Leukemia

Environmental pollution

Mutation

Harmful radiations (bombs)

Cancer 

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Periodic Chemistry

Periodic chemistry is a study of variation of properties of elements with their atomic number. This brings out the hidden order and pattern among elements. In 1869 Mendeleev a Russian Scientist stated that, the properties of the element are a periodic function of their atomic number. This periodic law means that if elements are arranged in increasing relative atomic number or masses, elements of similar properties appear at regular intervals. Mendeleev’s periodic table was incomplete because many element example noble gases were not known at that time and it contain several errors which have since been corrected. A modern form of the periodic table contains element in order of their proton numbers or atomic numbers. The horizontal rows are periods and the vertical columns are called groups.

Electrons and empty space surrounding the nucleus accounts for almost for almost all the volume of an atom. The electrons in an atom can move in seven different shells or energy level. Represented by. K ,L,M,N, O, P, Q

The number of electrons in each shell depends on the atomic number of element. The closer the shells to the nucleus, the lower the energy of its electrons compared to the energy of the electrons further away.

The arrangement of electrons on atoms is known as electron configuration .This can be represented by drawing or writing the number of electrons in the shell.

Bohr’s assumption established the foundation of quantum mechanics i.e. the study of laws of motion that governs the behavior of small particles and also applied to large bodies. The basic principle is that only specified energy levels are possible for electrons in an atom. These energy levels are numbered starting with the lowest 1 then 2,3 etc.

The second principle of quantum  mechanics is that the electron population of any energy level is limited to 2n2 where  n is principle quantum number. This means that for the lowest energy n=1. The maximum population is 2(1)2=2 be in K shell or the innermost orbit. These electrons are the ones most tightly bound to the nucleus. For the second energy  level  2(2)2=8 and is L.

The higher energy levels are number n=3,4,5 etc. or lettered M ,N, O. Higher energy levels are referred to as outer energy levels. Hence the electrons in the outermost shell have the highest energy. They are called valency electrons and the shell in which they are found is called valency shell. The valency electron are least attracted to the protons and hence they can easily be lost, shared or gained by other electrons. They are therefore responsible for chemical properties of the element.

                                      

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