Glossary of the key notions in Bionics and beyond

Partial fraction decomposition → A polynomial manipulation technique used to express a rational fraction function in additive terms, whose denominators consist only one factor.

Partial reflection → A phenomenon in which some light travelling from one medium to another is refracted at the boundary between the two media and some is refected. The amount of reflection in comparison to the amount of refraction depends upon the angle of incidence and the difference between the incidences of refraction of the two media.

Partially-implanted → Some parts of the implant are outside the body, while other parts are inside. This means that the otherwise closed system of the body is now open to the outside world, which increase the probability of infections.

Partition function → Z=∑exp(-Ei/kBT), where Z is the ~, Ei is the energy of the i’th microstate, kB is the Boltzmann constant and T is the temperature.

Partitional clustering → It groups the instances into mutually exclusive (disjoint) groups

Partitioning → The procedure when the domain of the fuction to be approximated is divided into disjuct parts

Parvalbumin → A calcium-binding protein found in a subset of GABAergic interneurons.

Passive → Elements consume (but does not produce) energy, i.e the work function is always positive

Passive dendrite → A dendrite without nonlinear (voltage-gated) conductances.

Passive membrane → Cell membrane which does not contain nonlinear (voltage-dependent) conductances. Such a membrane can be described by its membrane resistance and membrane capacitance. Usually includes a leakage current in series with a voltage source, to model the membrane channels and pumps which are responsible for the resting potential of the membrane.

Passive model → Neuronal model which contains no nonlinear (voltage-dependent) conductances.

Passive pixel sensor → The photosensitive device’s signal is not amplified in each pixel.

Passive transport → Ion transport through the cell membrane without energy investment.

Path loss → It is the reduction in power density of an electromagnetic wave as it propagates through wireless channel.

Patient Programmer → ~ is a device by which the neurostimulator can be programmed by radiofrequency way.

Pattern recognition problem → A problem, where inputs has to be classifed

Pauli → Wolfgang Ernst Pauli (1900–1958) was an Austrian theoretical physicist and one of the pioneers of quantum physics.

Pauli-principle → The Pauli exclusion principle is that no two identical fermions (particles with half-integer spin) may occupy the same quantum state simultaneously. The total wave function for two identical fermions is anti-symmetric.

P-Cell or parametric cell → P-cells are predrawn layout templates that can be resized.

PDB (Protein Data Bank) identification code → Structures deposited in the ~ are assigned a unique four letter code which is often called PDB accession code or PDB code. Because of the PDB’s importance as the central repository for biological macromolecular structures, the PDB code is often used in the scientific literature to refer to a particular structure which has been used in a study.

Peak error → The Deprez instrument has a small, but finite friction. If the index does not move, then the adhesive friction is always bigger than the sliding friction, therefore, it is a little harder to start moving the index. This is caused by the ~.

Peak value → ~ is the highest amplitude value of the measured signal.

PECVD Plasma enhanced CVD → ~reactors also operate under low pressure, but do not depend completely on thermal energy to accelerate the reaction processes. They also transfer energy to the reactant gases by using an RF-induced glow discharge (see Chemical Vapor Deposition, CVD).

Penetrating electrode → Penetrating electrodes are multichannel electrodes developed to make the insertion of the electrodes safer and increase the precision of electric stimulation.

Penzias → Arno Allan Penzias (1933 -), German-American astrophysicist (1978 Nobel Prize, shared).

Peptide bond → A special amide bond connecting amino acids to each other. It is formed between the α-amino group of one amino acid and the carboxyl group of an other.

Percent signal change → A measure of signal intensity that ignores the arbitrary baseline values often present in MR signal. A timecourse of signal can be viewed as a timecourse of changes from some baseline value, rendered in units of percent of that baseline value. The baseline is then chosen on a session-specific basis in some reasoned way, like “the mean of the timecourse over the whole session,” or “the mean of the signal during all rest periods.” This gets around the problem that MR signal is often scaled between sessions by some arbitrary value, due to how the scanner feels at that moment and the physiology of the subject. Two signal timecourses that are identical except for an arbitrary scaling factor will be totally identical when converted to percent signal change. Percent signal changes timecourses are thus used to show intensity timecourses from a given region or voxel during some experimental manipulation.

Perceptron → One layer McCulloch-Pitts neuron network

Perforant path → The perforant pathway provides an anatomical connection from the entorhinal cortex to all fields of the hippocampus.

Pericyclic reactions → Chemical reactions in which concerted reorganization of bonding takes place throughout a cyclic array of continuously bonded atoms. It may be viewed as a reaction proceeding through a fully conjugated cyclic transition state. The number of atoms in the cyclic array is usually six, but other numbers are also possible. The term embraces a variety of processes, including cycloadditions, cheletropic reactions, electrocyclic reactions, sigmatropic rearrangements, etc. (provided they are concerted).

Perimysium → ~ is a sheath of connective tissue that groups individual muscle fibers into bundles or fascicles

Period in time → The interval of time for a repetition, or cycle, of the motion is called a period (unit: second, symbol: T) while the number of periods per unit time is called the frequency.

Period length → The ~ is the elapsed time between the same states of a signal.

Period length meter → A ~ measures the period length of the voltage waveform.

Periodic table (of elements) → The presently known 118 chemical elements are organized into a tabular arrangement based on their specific properties of the atomic structure

Peripheral membrane proteins → Membrane proteins which are attached temporarily to the membrane.

Peripheral nerve → A ~, or simply nerve is an enclosed, cable-like bundle of peripheral axons (the long, slender projections of neurons).

Peripheral proteins → Proteins embedded in the membrane, but they do not span through the whole membrane.

Permeability → ~ is a constant that characterizes materials. In the case of solids, gases and liquids, it means the ability to let through.

Perpendicular polarizations → The polarization of light is described by specifying the orientation of the wave’s electric field at a point in space over one period of the oscillation. When light travels in free space, in most cases it propagates as a transverse wave, which means that the polarization is perpendicular to the wave’s direction of travel.

Persistent activity → Elevated neural activity, which persists in the absence of external input for up to many seconds, e.g., until the arrival of a new input or a behavioral response.

Personalized medicine → ~ is the concept to treat the patient with drugs tailored to his/her genotype.

Perturbation → ~ theory comprises mathematical methods that are used to find an approximate solution to a problem which cannot be solved exactly, by starting from the exact solution of a related problem. ~ theory is applicable if the problem at hand can be formulated by adding a “small” term to the mathematical description of the exactly solvable problem.

PH → pH is the quantity pH is defined in terms of the activity of hydrogen(1+) ions (hydrogen ions) in solution. (pH = -log[H3O+]).

Pharmacodynamics → The study of the physiological effects of drugs on the body or on microorganisms or parasites within or on the body and the mechanisms of drug action and the relationship between drug concentration and effect.[

Pharmacogenomics → ~ is the field of science that deals with the association between genome data and drug responses.

Pharmacokinetics → Intends to determine the fate of substances administered externally to a living organism.

Pharmacological MRI (phMRI) → fMRI to map the modulatory effects of psychopharmacological agents, inform about pharmacodynamics, pharmacokinetics

Phase diagram → p -T plot of the different states of a compound or element

Phase encoding → Encoding the distribution of sources of MR signals along a direction in space with different phases by applying a pulsed magnetic field gradient along that direction prior to detection of the signal. In general, it is necessary to acquire a set of signals with a suitable set of different phase-encoding gradient pulses in order to reconstruct the distribution of the sources along the encoded direction.

Phase measurement → Measurement of the phase shift of two signals which have the same frequency, same period length but different phase.

Phase precession → The phenomenon, when specific signals appear during the trough phase of the theta oscillation.

Phase space → A ~ is a space in which all possible states of a system are represented, with each possible state of the system corresponding to one unique point in the p~. For mechanical systems, the ~ usually consists of all possible values of position and momentum variables.

Phase portrait → A geometric representation of the trajectories of a dynamical system in the phase plane. Each set of initial conditions is represented by a different curve, or point.

Phase space → A space in which all possible states of a system are represented, with each possible state of the system corresponding to one unique point in the phase space. For example in mechanical systems, the phase space usually consists of all possible values of position and momentum variables.

Phasor → Phasor/phase vector is a representation of a sine wave whose amplitude, phase, and frequency are time-invariant. It is a subset of a more general concept called analytic representation. Phasors reduce the dependencies on these parameters to three independent factors, thereby simplifying certain kinds of calculations.

Phenols → ~ are compounds having one or more hydroxy groups attached to a benzene or other arene ring.

Phenomenological modeling → The term phenomenology (φαινόμενα ~ study of + λογία ~ research) in science is used to describe a body of knowledge which relates empirical observations of phenomena to each other, in a way which is consistent with fundamental theory, but is not directly derived from it.

Phenomenological thermodynamics → The area of thermodynamics where the macroscopic behaviour of material system are described by only abstract mathematical relationships based on empirical laws.

Phenylketonuria (PKU) → Tyrosine is synthesized from phenylalanine (Phe) by phenylalanine hydroxylase in the presence of tetrahydrobiopterin cofactor. If any of these components has a breakdown Phe is converted to phenylketons, and Phe level is elevated, resulting in mental retardation. The disease can be treated.

Pheromone → A secreted or excreted chemical factor that triggers a social response in members of the same species.

Phospholipids → A group of lipids having a phosphate group.

Phosphorus → ~ is the chemical element that has the symbol P and atomic number 15.

Phosphorylation → Post-translational modification of proteins through which a phosphate group is attached to the polypeptide chain.

Photo multiplier → A type of vacuum tubes, and more specifically phototubes, are extremely sensitive detectors of light. These detectors multiply the current produced by incident light.

Photocathode → A ~ is a negatively charged electrode in a light detection device such as a photomultiplier or phototube that is coated with a photosensitive compound.

Photocell → The ~ is a light-sensitive device based on photoelectric effect, which gives an electric response to the light waves.

Photoelectric effect → In the ~, electrons are emitted from matter as a consequence of their absorption of energy from electromagnetic radiation of very short wavelength, such as visible or ultraviolet light. Electrons emitted in this manner may be referred to as “photoelectrons”. First observed by Heinrich Hertz in 1887. Albert Einstein’s mathematical description of how the photoelectric effect was caused by absorption of quanta of light (now called photons), was in one of his 1905 papers (Nobel Prize in 1921).

Photoelectron → It is an electron ejected from an atom, molecule, or solid by an incident photon.

Photomultiplier → The ~ is made up of a photocatode and an electron multiplier. The incoming light raises the number of electrons emitted from the photocatode, while the electron multipliers amplify either the incoming electron itself, or the electron emitted secondarily by the incoming electron. The output current of the multipliers is proportional to the intensity of the incoming light and electron beams.

PhotoMultiplier Tube (PMT) → Photomultiplier tubes are light detectors that are useful in low intensity applications such as fluorescence spectroscopy. They consist of a photocathode and a series of dynodes in an evacuated glass enclosure. Due to high internal gain, PMTs are very sensitive detectors.

Photon emission → Emission is the process by which the energy of a photon is released by another entity.

Photons → A photon is an elementary particle, the quantum of the electromagnetic interaction and the basic unit of light and all other forms of electromagnetic radiation. It is also the force carrier for the electromagnetic force. The photon has no rest mass; this allows for interactions at long distances.

Photosynthesis → ~ (Greek φώτο ~ light + σύνθεσις ~ putting together/composition) is a process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight.

Phototoxicity → A toxic reaction provoked by light.

Phototransistor → The functioning of phototransistors is by light, hence these devices usually have two outputs only: an emitter and a collector output. The lightbeam reaches the emitter-base which is working as a photodiode, and photocurrent is starting to flow. The transistoramplifies this photocurrent as base current, so the collector current consists of an amplified photocurrent.

Phylogenetic tree → A type of two-dimensional graph illustrating the inferred evolutionary relationships among various organisms or genes

Phylogenic prediction → It is trying to construct phylogenetic trees based on available evidence

Physiological cross sectional area → ~ is the total area (that can be found in pennated muscles) where the cross sections are perpendicular to the muscle fibres.

Piezoelectric transducer → The ~ are based on the piezoelectric effect which can be observed at certain non-metallic materials. This effect basically means that these materials, when exposed to mechanical tension (e.g. pressure) are polarized on their surface, creating electric charges.

Pineal gland → A small cone-shaped endocrine gland located at the postero-dorsal corner of the third ventricle. It secretes melatonin.

Ping-pong reaction → Group-transfer reaction in which a functional group of a substrate is transferred onto an enzyme with release of a product, and the group is then transferred onto a second substrate with release of second product

Pipeline → An instruction ~ is a technique used in the design of computers and other digital electronic devices to increase their instruction throughput (the number of instructions that can be executed in a unit of time).

Pixel (digital imaging) → Smallest unit of a picutre in 2D. Also the smallest addressable unit in the screen.

Place field → A spatial area where a specific place cell exhibits increased activity.

Place cell → ~ are neurons in the hippocampus that exhibit a high rate of firing whenever an animal is in a specific location in an environment, corresponding to the cell’s “place field”.

Placefield-selectivity → Characteristics of hippocampal neurons, which manifests in their increased discharge rate, when the experimental animal enters their specific “encoded area” in the field.

Placode → Thickening of ectoderm in the head region

Planar system → Two-dimensional system

Planck → Max Karl Ernst Ludwig Planck (1858–1947) was a German physicist who is regarded as the founder of the quantum theory (Nobel Prize in 1918).

Planck’s constant → The ~, is a physical constant reflecting the sizes of quanta in quantum mechanics. It is named after Max Planck. It was first described as the proportionality constant between the energy of a photon and the frequency of its associated electromagnetic wave.

Planck’s law of blackbody radiation → Planck’s law describes the electromagnetic radiation emitted from a black body at absolute temperature. The Planck distribution of radiation is the unique stable distribution that can persist in thermodynamic equilibrium.The primary law governing blackbody radiation is the Planck Radiation Law, which governs the intensity of radiation emitted by unit surface area into a fixed direction (solid angle -- it is a measure of how large that object appears to an observer looking from that point.) from the blackbody as a function of wavelength for a fixed temperature.

Plasma → ~ is a state of matter similar to gas in which a certain portion of the particles are ionized. The basic premise is that heating a gas dissociates its molecular bonds, rendering it into its constituent atoms. Further heating leads to ionization (a loss of electrons), turning it into a plasma: containing charged particles, positive ions and negative electrons.

Plasmonics → ~ is a branch of photonics that employs surface plasmon polaritons, which arise from the interaction of light with collective oscillations of electrons at a metal’s surface.

Plethysmograph → A ~ is an instrument for measuring changes in volume within an organ or whole body. It was invented by Jan Swammerdam (1637-1680).

Plum pudding model → The ~ of the atom (J. J. Thomson) was discovered before the discovery of the atomic nucleus. In this model, the atom is composed of electrons surrounded by a soup of positive charge to balance the electrons’ negative charges, like negatively-charged “plums” surrounded by positively-charged “pudding”.

P–n diode → A ~ has a depletion region on the n-side and on the p-side. Mobile carriers (electrons on n-side, holes on p-side) are swept away from the depletion region. An ideal diode is conducting in one direction of bias and non-conducting in the reverse bias case.

P-n junction → p-n transition is created at the border of two differently contaminated materials.Iit is only a few µm wide. Because of the concentration difference of the charge carriers at the border of the two layers, diffusion takes place.

PO2 electrode → Measures the partial pressure of oxygen in fluids and gases

Poincaré → Jules Henri Poincaré (1854–1912) was a French mathematician, theoretical physicist, engineer, and a philosopher of science.

Point source → A single current source which, like a geometrical point, has no extent in space.

Pointer → A ~ is a programming language data type whose value refers directly to another value stored. elsewhere in the computer memory using its address

Point-like body/particle → A point particle (ideal particle or point-like particle) is an idealized object heavily used in physics. Its defining feature is that it lacks spatial extension: being zero-dimensional, it does not take up space. A point particle is an appropriate representation of any object whose size, shape, and structure is irrelevant in a given context. For example, from far enough away, an object of any shape will look and behave as a point-like object.

Poisson → Siméon Denis Poisson (1781–1840), was a French mathematician, geometer, and physicist.

Poisson equation → Poisson’s equation is a second order partial differential equation which arises in physical problems such as finding the electric potential of a given charge distribution. It is linear, and therefore obeys the superposition principle.

Polarization → ~ (waves) is the orientation of oscillations in the plane perpendicular to a transverse wave’s direction of travel. Plane polarized light (or other electromagnetic radiation) in which the electric and magnetic fields vibrate in phase. Circularly polarized light (or other electromagnetic radiation) whose electric or displacement vector rotates in a plane perpendicular to the propagation direction with constant angular velocity.

Pole → A ~ is a root of the denominator of a rational fraction function

Pole-zero plot → A ~ is used to describe the positions of the poles and zeroes of the transfer function in the complex plane.

Polygraphic records → Used mainly in sleep studies when different physiological variables are recorded beside the EEG.

Polymer → A large molecule (macromolecule) composed of repeating structural units. These subunits are connected by chemical bonds. The term polymer is sometimes taken to refer to plastics, it actually encompasses a large class of natural and synthetic materials with a wide variety of properties.

Polymerase Chain Reaction (PCR) → The most popular method for DNA amplification. A cell-free technique that uses thermostable DNA polymerase for replication.

Polynomial long division → A polynomial manipulation technique used to reduce the degree of the numerator to the denominator of a rational fraction function

Polysaccharides → Hydrolysis yields more than 6 monosaccharide units

Polysilicon → Polycrystal or amorphous silicon.

Polysynaptic reflex arc → One or more interneurons connect afferent (sensory) and efferent (motor) signals

Pons → A broad mass of chiefly transverse nerve fibers conspicuous on the ventral surface of the mammalian brain at the anterior end of the medulla oblongata