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I'm unsure whether to call it a fruit or a vegetable. I found it on the road in a neighborhood and decided to pick it up before a car squashed it. (Thus, my initial guess was a squash.)
Should be a Papaya, thus a fruit, an outline of your geographical location would be helpful to determine it.
Difference between Living and Non-Living Objects | Biology
1. Each kind of plant or animal has a definite form and size, which may vary within narrow limits in different individuals of the same kind.
2. Living body is composed of protoplasm which is the physical basis of life. The protoplasm of a living indi­vidual is arranged in the form of one or more compartments —the cells—each of which is a structural as well as a func­tional unit of the living body.
3. A living body is well organ­ized. It is composed of cells, tissues, and organs with division of labour, to carry on its routine vital activities.
4. Metabolic changes such as nutrition, respiration, secretion of useful substances and excretion of waste products are going on constantly within the living body due to the vital activities of its own protoplasm. Life is the external manifestation of these internal protoplasmic changes.
5. The living body is automatic. It is a self-fuelling and self- cleansing machine. Nutrition is the means for energy-intake of the living apparatus and res­piration releases the energy to be utilised for its other activities. It cleanses itself by automatic excretion of its waste products.
6. Living body increases in bulk by intussusception, that is, by wedding in of new particles in between already existing particles of protoplasm. While growing, the living body utilizes substances other than its own protoplasm.
7. The living body is sensitive and can adapt itself to its environment in an admirable manner. It responds to stimuli with some definite purpose.
8. A living body can reproduce its own kind and thus perpetuate its race.
9. A living body is rhythmic. There is a rhythm regulating all the vital activities. An intense activity by an organ is followed by a period of pause or rest.
10. A living body has a life-cycle. Each kind has a definite period of duration at the limit of which it tends to grow old and dies.
Difference # Non-Living Objects:
1. Non-living objects, such as masses of clouds or collections of water have neither a definite size nor any precise form of the body.
2. Living protoplasm or cells are not found as component parts of the body in non-living objects.
3. No such organization exists in non-living objects.
4. None of the metabolic changes may be detected in a non-living object which contains no proto­plasm and therefore has no vital activity.
5. A man-made machine is never strictly automatic. It has no innate power to manage its own affairs and requires to be cleansed and re-fuelled by man from time to time.
6. Growth may occur occasionally in non-living object by accretion or deposition of particles only on the outer surface of the body. Increase of bulk takes place at the expense of substances chemi­cally identical to its own matter.
7. True sensitiveness is absent in non-living objects voluntary power of adjusting to changes in the environment is nil. At least there is no purposiveness in their behaviour when stimulated.
8. There is no power in non-living objects to reproduce its own kind.
9. There is no definite rhythm and periodic activity is never met with as a rule.
10. No cyclical phenomenon is observed in non-living objects. Period of duration is indefinite and there is neither senescence nor death.
Types of Microscopes
1. Compound Microscope
By far the most popular kind of microscope, the compound microscope uses two lenses to achieve up to 1000x or 2000x magnification. Specimens are backlit and may be viewed using either a monocular or binocular eyepiece.
You can find compound microscopes in one form of another in homes, science labs, and even hospitals. Oddly enough, it was the work of Robert Hooke using one of the first compound microscopes that inspired the invention of the simple microscope.
2. Confocal Microscope
Providing higher resolution than a compound microscope, a confocal microscope allows for 2D or 3D images of the subject matter. A slide containing a dyed sample is inserted into the microscope. The sample is then scanned using a laser light and, with the aid of a dichromatic mirror, appears on a computer monitor.
As laser light penetrates deeper than regular light, the user can get either a highly detailed look at opaque objects as far as the laser can penetrate, or the interiors of more translucent objects. This type of microscope is useful in cell biology, as well as various medical applications.
3. Fluorescence Microscope
A high-energy, short wavelength light is used for this microscope, exciting the electrons of certain molecules. These electrons shift into a higher orbit briefly. When they settle back, they emit a low energy, low wavelength (visible) light.
The amount of spatial resolution is limited, but the microscope is powerful enough to detect the presence of a single molecule. While fluorescence was first described in 1852 by Sir George G. Stokes, its almost essential use in biology and biomedical science wasn’t explored until the 1930s.
4. Scanning Electron Microscope (SEM)
An electron microscope uses electrons instead of light, allowing for incredible resolution. Scanning electron microscopes are used exclusively to view the surface of an object.
The object must be dehydrated, then lightly coated in a highly conductive material such as gold or palladium. A beam of focused electrons is bounced off of the specimen in a manner similar to sonar.
The resulting data is translated into a black and white image on a computer screen at a resolution chosen by the user. These microscopes have a wide range of scientific uses in both physical and medical science.
5. Scanning Probe Microscope
This optical microscope uses a physical probe to examine the sample. The scan is done using a raster (line by line) method. As a result, the scans can take some time but produce high-quality computer images.
These have a more limited magnification than electron microscopes but do not require a vacuum. Another great advantage is that the sample can be stimulated and the reactions or response may be observed, as well as the specimin’s properties.
In use since 1986, scanning probe microscopes are not only valued in the fields of biology and chemistry, but also physics.
6. Simple Microscope
As the name implies, this is the most basic type of microscope. It was created in the 17th century by Antony van Leeuwenhoek and involves a single convex lens and specimen holder.
Capable of magnifying 200x to 300x. This form of microscope is rarely used today.
7. Stereo Microscope
Sometimes referred to as a dissecting microscope, this type overcomes the need for slides, allowing the user to study opaque objects. While the magnification is only 300x, users can view and even manipulate 3D objects.
Stereo microscopes are used not only for biological and medical science, but can often be found in electronic fields such as circuit making. The tool works by having two optical paths set up at different angles, allowing for a detailed surface view of even living or inanimate objects.
8. Transmission Electron Microscope (TEM)
The counterpart to the SEM, a transmission microscope uses ultra-thin samples prepared on a slide. Once coated in a high conductivity material, the sample slide is scanned in a vacuum.
This allows the electrons to pass through the object with the beam being reflected by the denser parts. As a result, the black and white image allows for a high degree of magnification and resolution.
These microscopes are useful in a wide range of fields, from physical and biological science to forensics. It is also extremely useful in the development of nanotechnology and metallurgical analysis.
9. UV Microscope
Using ultraviolet light produced by a mercury arc or xenon burner, UV microscopes are able to get twice the resolution of visible light microscopes. Images are either photographed or scanned using a digital sensor to avoid harming the observer’s eyes.
10. X-Ray Microscope
Used in the observation of living cells, X-ray microscopes use electromagnetic radiation to create highly detailed images. This type of microscope is popular in both biological research and metallurgy.
A Biologist Explains: What Is Life?
Although biology is the study of life, even biologists don't agree on what 'life' actually is. While scientists have proposed hundreds of ways to define it, none have been widely accepted. And for the general public, a dictionary won't help because definitions will use terms like organisms or animals and plants -- synonyms or examples of life -- which sends you round in circles.
Instead of defining the word, textbooks will describe life with a list of half a dozen features based on what it has or what it does. For what life has, one feature is the cell, a compartment to contain biochemical processes. Cells are often listed because of the influential cell theory developed in 1837-1838, which states that all living things are composed of cells, and the cell is the basic unit of life. From single-celled bacteria to the trillions of cells that make up a human body, it does seem as though all life has compartments.
A list of features will also mention what life does -- processes like growth, reproduction, ability to adapt and metabolism (chemical reactions whose energy drives biological activity). Such views are echoed by experts such as biochemist Daniel Koshland, who listed his seven pillars of life as program, improvization, compartmentalization, energy, regeneration, adaptability and seclusion.
But the list approach is let down by the fact it's easy to find exceptions that don't tick every box on a checklist of features. You wouldn't deny that a mule -- the hybrid offspring of a horse and donkey -- is alive, for example, even though mules are usually sterile, so no tick for reproduction.
Entities on the border between living and non-living also undermine lists. Viruses are the most well-known fringe case. Some scientists claim that a virus isn't alive as it can't reproduce without hijacking the replication machinery of its host cell, yet parasitic bacteria such as Rickettsia are considered alive despite being unable to live independently, so you can argue that all parasites can't live without hosts. Meanwhile Mimivirus -- a giant virus discovered in an amoeba that's large enough to be visible under a microscope -- looks so much like a cell that it was initially mistaken for a bacterium. Humans are also creating fringe cases -- designer organisms like Synthia, which has few features and wouldn't survive outside a lab -- through synthetic biology.
Are entities such as viruses really life-forms, or merely life-like? Using a list definition, that largely depends on the criteria you choose to include, which is mostly arbitrary. An alternative approach is to use the theory considered to be a defining feature of life: Charles Darwin's theory of evolution by natural selection, the process that gives life the ability to adapt to its environment. Adaptability is shared by all life on Earth, which explains why NASA used it as the basis for a definition that might work in helping to identify life on other planets. In the early 1990s, an advisory panel to NASA's astrobiology program, which included biochemist Gerald Joyce, came up with a working definition: Life is a self-sustaining chemical system capable of Darwinian evolution.
The 'capable' in NASA's definition is key because it means astrobiologists don't need to watch and wait for extraterrestrial life to evolve, just study its chemistry. On Earth, the instructions for building and operating an organism is encoded in genes, carried on a molecule like DNA, whose information is copied and inherited from one generation to the next. On another world with liquid water, you would look for genetic material that, like DNA, has a special structure that might support evolution.
Detecting alien life is a harder task than collecting samples, however, as illustrated by the Viking mission. In 1977, NASA put landers on Mars and performed a variety of experiments to try and detect signs of life in the Martian soil. The results were inconclusive: while some tests returned positive results for the products of chemical reactions that might indicate metabolism, others were negative for carbon-based organic molecules. Decades later, astrobiologists are still limited to looking for life indirectly, searching for biosignatures -- objects, substances or patterns that might have been produced by a biological agent.
Given that scientists who look for life are fine with signatures, some say we don't actually need a definition. According to philosopher Carlos Mariscal and biologist W Ford Doolittle, the problem with defining life arises from thinking incorrectly about its nature. Their strategy is to search for entities that resemble parts of life and to think of all life on Earth as an individual. That solution might suit astrobiologists, but it wouldn't satisfy people who want to know whether or not something strange, like a virus, is alive.
A major challenge for both detecting and defining life is that, so far, we've only encountered one example in the Universe: terrestrial life. This is the 'N = 1 problem'. If we can't even agree on the distinction between living and non-living things, how can we expect to recognize weird forms of life?
It's life, but not as we know it
As science hasn't provided conclusive proof of extraterrestrials, we must turn to science fiction, and few series have explored such possibilities better than Star Trek: The Next Generation. The voyages of the starship Enterprise and "its continuing mission to explore strange new worlds and seek out new life and new civilizations" gave us everything from the god-like being Q to a huge Crystalline Entity that converts living matter to energy (a kind of metabolism). Perhaps most interestingly, as researchers get closer to creating an artificial intelligence that's smarter than a person, there's Data -- an android who had to prove human-like sentience but didn't reproduce until he built his own daughter. Would a god who exists beyond time, a spaceship-sized crystal or a robotic AI be considered 'alive'?
Is Data from 'Star Trek: The Next Generation' alive?
'What is life?' is not simply a question for biology, but philosophy. And the answer is complicated by the fact that researchers from different fields have differing opinions on what they believe ought to be included in a definition. Philosopher Edouard Machery discussed the problem and presented it as a Venn diagram with circles for three groups -- evolutionary biologists, astrobiologists and artificial-life researchers -- using hypothetical features upon which they would converge (some biologists think viruses are alive while others believe the cell is essential, so assuming members would agree is controversial). Machery claimed that no criteria could fall within the overlap of all three circles, concluding that "the project of defining life is either impossible or pointless."
But while philosophers can sidestep the problem without consequences, the conclusion that it's futile to define life is both unsatisfying and frustrating for regular folk (and also for those like me, who care about the public understanding of science). Regardless of whether researchers ever reach a consensus on a scientific definition, we still need a folk definition for practical purposes -- a sentence to explain the concept of life that the average person can understand.
Life may be a fuzzy concept, but that doesn't mean its meaning should be vague. As computational biologist Eugene Koonin pointed out, defining life isn't scientific because it's impossible to disprove, as we can always find an entity that meets all criteria but is 'clearly' not alive, or lacks certain features but is 'obviously' a life-form, and so "some kind of intuitive understanding of the living state superseding any definition is involved [. ] we seem to 'know it when we see it'." Koonin focused on whether a definition can provide biological insights (such as identifying novel life-forms) but mentions another area where defining life might be useful: "better teaching of the fundamentals of biology."
So how do we get a definition that teaches biology? This is partly an exercise in semantics. First, a popular definition should avoid technical jargon and use everyday language. Next we need a starting point. Since Aristotle first tried to define life around 350 BC, thinkers have engaged in seemingly endless philosophical discussions, In 2011, biophysicist Edward Trifonov tried to break the deadlock by comparing 123 definitions to find a consensus, grouping words into clusters and counting the ones used most frequently to produce a minimal or concise definition: Life is self-reproduction with variations.
The 'variations' in Trifonov's definition are mutants, the result of mutations (errors in copying) that occur during reproduction, which is what creates the variety in a population that allows 'survival of the fittest' individuals through evolution by natural selection. While Trifonov's consensus and NASA's working definition don't use the same words, they're two sides of the same coin and share a central concept: life is able to adapt to its environment.
Darwinian evolution is the way that life as we know it adapts. But what about things that might use alternative mechanisms of adaptation? As a narrow definition will exclude fringe cases and being broad would let us include a wide range of potential life-forms, our popular definition drops Trifonov's inclusion of 'self-reproduction' (allowing for immortal AIs that don't need to replicate) and also NASA's requirement for a 'chemical system' (allowing for organisms that don't carry genes on a DNA-like molecule). An 'environment' implies a habitat or ecosystem, not simply the surroundings, which rules-out a robot that adjusts its body to traverse a terrain and virtual objects that navigate a digital domain.
Lastly, we need a word for the 'thing' we describe as living. Scientists and philosophers use 'entity' without acknowledging that, just as a dictionary uses 'organism', it's effectively a fancy synonym for 'life' (Can you think of an 'entity' that doesn't imply some sort of life-form?) This slight logical circularity may not be ideal, but I can't think of a better option. An entity is a self-contained thing, which means the word can work whatever the level -- whether that's an individual organism, an AI, or all life on a planet.
Any definition should be necessary and sufficient, but it's important to first identify for whom. Because this article is aimed at a general audience (non-scientists), the goal is a folk definition. So what is life? Here's a suggestion:
Life is an entity with the ability to adapt to its environment.
While I think my 'popular definition' makes intuitive sense, it could still join the hundreds of scientific proposals that have failed to find acceptance. Unlike dictionary definitions, at least it isn't wrong, but only time will tell whether people think it's actually right.
It refers to an optical instrument that uses a lens or an arrangement of lenses to magnify an object. Also, they help to view different organisms. Furthermore, the light of a microscope helps to see microorganisms.
Types of Microscope
The scope is of various types. These are:
1. Compound Microscope
It is an instrument that has two lenses (set of two lenses) these lenses is objectives and ocular. Furthermore, they use visible light as a source of illumination.
2. Darkfield Microscope
These microscopes have a device that scatters light from the illuminator. In addition, it does this to make the specimen appear white against the black background.
3. Electron Microscope
It is a scope that instead of light uses a flow of electron to produce an image. Moreover, this microscope enhances the images of viruses, protein, lipids, ribosomes, and even small molecules.
4. Fluorescence Microscope
These scopes use ultraviolet light to illuminate specimens that fluoresce. Besides, mostly, a fluorescent antibody or dye is added on the viewed specimen.
5. Contrast/Phase Microscope
This scope uses a special condenser that allows the examination of structures inside the cells. Also, they use a compound light. Furthermore, these microscopes take advantage of different refractive indexes for the examination of live organisms.
In addition, the final image produced by these microscopes is a combination of light
Uses of Microscope
They are used in different fields for different purposes. Some of their uses are tissue analysis, the examination of forensic evidence, to determine the health of the ecosystem, studying the role of protein within the cell, and the study of atomic structure.
Parts of Microscope
It is in the back of the microscope and supports the objectives and ocular. Also, it is the part that we use to carry or lift it.
It’s the bottom of the scope. In addition, it houses the light source and the back section of base acts as a handle to carry the scope.
3. Course Focusing Knob
We use it to adjust the position of objective lenses. Also, this should be done keeping in mind that the objective should not hit the slide. In addition, it should be stopped when the object is completely visible through the ocular.
4. Fine Focusing Knob
We use it to bring the specimen in perfect focus once the specimen is visible through the course-focusing knob. Also, focus slowly to avoid contact between the objective and the specimen.
It is the light source of the microscope.
6. Numerical Aperture or Objective lens
It is found in a compound scope and is the lens that is closest to the specimen.
7. Ocular Lens
This is the lens closest to the viewer in a compound light microscope.
8. Oil immersion Lens
This is a 100x (100 times) objective lens. Also, this lens is small in order to attain high resolution and magnification. Furthermore, due to its size, it is important for the lens to get as much light as possible.
Moreover, by immersion of lens in oil it eliminates the refraction of light, it happens because the glass and oil have almost the same refractive index. Most noteworthy, in this way the light is maximized and gives the clearest image. Besides, It oil immersion lens is used without oil then the produced Image will become unclear and has a poor resolution.
Solved Question on Microscope
Question. Which of the flowing is not a common part of a microscope?
B. Oil Immersion Lens
C. Ocular lens
D. Focusing Knob
Answer. The correct answer is option B because it is a part of a compound microscope.
Functional studies of the ventral visual stream
By inserting a thin microelectrode into the brain, it is possible to monitor the spiking electrical activity of single neurons. This technique constitutes the basis for approximately four decades of studies on the responses of neurons in different parts of cortex to the presentation of visual stimuli. Ascending through the visual hierarchy, neurons show longer latencies to visual presentation, larger receptive field sizes and more complex feature preferences [29, 46, 47].
The pioneering studies of Hubel and Wiesel showed that (i) individual neurons in V1 have a location within the visual field that elicits a maximum response (called a receptive field), (ii) this receptive field changes smoothly over space forming a retinotopic map of the visual environment and (iii) individual V1 neurons are particularly responsive to the presentation of a bar of a specific orientation within their receptive field . Hubel and Wiesel proposed a simple model that could explain the responses of such orientation-tuned cells: this response pattern could arise by combining the responses of on-center lateral geniculate nucleus (LGN) cells that have adjacent and overlapping receptive fields and are aligned to the orientation of the V1 neuron preferences. V1 is by far the most studied part of visual cortex. Still, Hubel and Wiesel’s model is neither fully accepted nor disproved and several authors have claimed that we do not yet fully understand the responses of V1 neurons . Yet, the simple model of Hubel and Wiesel has inspired many computational models of visual cortex. For the purposes of the computational efforts discussed below, many authors model the responses of V1 simple neurons by using an oriented Gabor filter. It is beyond the scope of this article to discuss the multiple and more sophisticated models of V1 responses (see e.g. [49-52] among many others). Also, this article does not discuss the very important temporal aspects of the responses of V1 neurons and their motion direction selectivity or color preferences.
Compared to V1, much less work has been done to characterize and model the responses of neurons in V2, V4 and higher visual areas. Extending the ideas about how orientation selectivity may arise from LGN responses, several investigators have suggested that neurons in V2 are sensitive to angles (in its simplest form, two intersecting oriented bars) [53, 54]. V2 neurons also respond to illusory borders . At the level of V4, there are neurons that seem to prefer much more complex shapes such as spirals and contour patterns [56-59].
Electrophysiological recordings in IT cortex have revealed single neurons that respond selectively to complex objects including faces as well as other stimuli [47, 60-63]. One of the remarkable aspects of the IT responses is that they show high selectivity while at the same time maintaining robustness to many stimulus transformations. In particular, IT neuronal responses show invariance to scale and position changes [6, 61, 64-66], robustness to eye movements , invariance to the type of cue defining the shape , rotation  and other transformations. Therefore, IT is ideally positioned to resolve many of the fundamental challenges in visual object recognition discussed in the Introduction.
Little is known about the activity of individual neurons in the human brain . Single unit recordings in human epileptic patients have revealed that neurons in the medial temporal lobe also show a remarkable degree of selectivity and invariance to object transformations [69-72]. It remains unclear whether these responses are necessary for visual object recognition or instead constitute an important step in transforming explicit representations into visual memories.
In spite of the extensive work of several decades of research into the responses of IT neurons, we still lack a clear principled understanding of the types of features preferred by IT neurons (the equivalent to orientation preferences in primary visual cortex). Several investigators have tried to start from the responses of an IT neuron to complex objects and gradually decompose the preferences into different object part preferences [73-76].
Two other pieces of evidence point to the key role of IT in object recognition. First, electrical stimulation of networks of neurons in IT cortex can bias a monkey’s performance in recognition tasks . Secondly, functional imaging evidence from humans have revealed areas that are presumably related to the macaque monkey inferior temporal cortex that respond to the presentation of complex visual stimuli (see e.g. [78, 79]).
Show/hide words to know
Action potential: a small electrical event which is how information is passed from neuron to neuron.
Dermis: the inner layer of skin beneath the epidermis, composed of connective tissue, blood and sweat glands. It contains the nerves that process touch and pain information.
Epidermis: the outermost layer of cells that cover an organism.
Millimeter: a unit of length that is one thousandth the size of a meter, and one tenth size of a centimeter.
Nervous system: organ system made of a network of specialized cells called neurons that coordinate the actions of an animal and transmit signals to and from different parts of the body. more
Receptor: a molecule on the surface of a cell that responds to specific molecules and receives chemical signals sent by other cells.
Stimulus: a signal that can activate or excite a response from an organism. Foods, sounds, and other triggers that cause specific behaviors or sensory experiences are stimuli.
Gunnar and others hope to reveal more of the underlying biology behind the reboot.
This study also opens the door for other control measures that alter the biology of locusts themselves.
It expects women and men to behave very differently, from birth forward, simply on the basis of their biology .
Now researchers have proposed a new learning method more closely tied to biology , which they think could help us approach the brain’s unrivaled efficiency.
One key contender is CRISPR, the fast-advancing gene-editing technology that stands to revolutionize synthetic biology and treatment of genetically linked diseases.
For his tireless assault on evolutionary biology and downsizing the deity to fit within science, I give Meyer second place.
Complementarity as conservative Catholics use the term, however, is more than biology .
“In the long term, I am more worried about biology ,” he told The Telegraph.
Essentially he is arguing that there are functional trade-offs in developmental biology .
People are starting to recognize that depression must relate to biology , because who would give up such an outwardly gifted life?
Its backbone should be the study of biology and its substance should be the threshing out of the burning questions of our day.
“Botany is that branch of biology which treats of plant life” has in it the same error.
“ Biology ” is not so well understood as “botany,” though it is a more general term.
It follows that biology is the foundation rather than the house, if we may use so crude a figure.
It is time to abandon the notion that biology prescribes in detail how we shall run society.
Convection Heat Transfer
Convection describes heat transfer between a surface and a liquid or gas in motion. As the fluid or gas travels faster, the convective heat transfer increases. Two types of convection are natural convection and forced convection. In natural convection, fluid motion results from the hot atoms in the fluid, where the hot atoms move upwards toward the cooler atoms in the air--the fluid moves under the influence of gravity. Examples of this include the rising clouds of cigarette smoke, or heat from the hood of a car that rises upwards. In forced convection, the fluid is forced to travel over the surface by a fan or pump or some other external source.
CytoHubba: identifying hub objects and sub-networks from complex interactome
Background: Network is a useful way for presenting many types of biological data including protein-protein interactions, gene regulations, cellular pathways, and signal transductions. We can measure nodes by their network features to infer their importance in the network, and it can help us identify central elements of biological networks.
Results: We introduce a novel Cytoscape plugin cytoHubba for ranking nodes in a network by their network features. CytoHubba provides 11 topological analysis methods including Degree, Edge Percolated Component, Maximum Neighborhood Component, Density of Maximum Neighborhood Component, Maximal Clique Centrality and six centralities (Bottleneck, EcCentricity, Closeness, Radiality, Betweenness, and Stress) based on shortest paths. Among the eleven methods, the new proposed method, MCC, has a better performance on the precision of predicting essential proteins from the yeast PPI network.
Conclusions: CytoHubba provide a user-friendly interface to explore important nodes in biological networks. It computes all eleven methods in one stop shopping way. Besides, researchers are able to combine cytoHubba with and other plugins into a novel analysis scheme. The network and sub-networks caught by this topological analysis strategy will lead to new insights on essential regulatory networks and protein drug targets for experimental biologists. According to cytoscape plugin download statistics, the accumulated number of cytoHubba is around 6,700 times since 2010.