Kamis, 24 November 2011

Physics of Digital imaging

Digital imaging or digital image acquisition is the creation of digital images, typically from a physical scene. The term is often assumed to imply or include the processing, compression, storage, printing, and display of such images. The most usual method is by digital photography with a digital camera but other methods are also employed.

Digital imaging was developed in the 1960s and 1970s, largely to avoid the operational weaknesses of film cameras, for scientific and military missions including the KH-11 program. As digital technology became cheaper in later decades it replaced the old film methods for many purposes.

Methods

A digital photograph may be created directly from a physical scene by a camera or similar device. Alternatively, a digital image may be obtained from another image in an analog medium, such as photographs, photographic film, or printed paper, by an image scanner or similar device. Many technical images—such as those acquired with tomographic equipment, side-scan sonar, or radio telescopes—are actually obtained by complex processing of non-image data. Weather radar maps as seen on television news are a commonplace example. The digitalization of analog real-world data is known as digitizing, and involves sampling (discretization) and quantization.

Finally, a digital image can also be computed from a geometric model or mathematical formula. In this case the name image synthesis is more appropriate, and it is more often known as rendering.

Digital image authentication is an issue [1] for the providers and producers of digital images such as health care organizations, law enforcement agencies and insurance companies. There are methods emerging in forensic photography to analyze a digital image and determine if it has been altered.

See also

References

External links

Selasa, 22 November 2011

Computational physics

Computational physics is the study and implementation of numerical algorithms to solve problems in physics for which a quantitative theory already exists. It is often regarded as a subdiscipline of theoretical physics but some consider it an intermediate branch between theoretical and experimental physics.

Physicists often have a very precise mathematical theory describing how a system will behave. Unfortunately, it is often the case that solving the theory's equations ab initio in order to produce a useful prediction is not practical. This is especially true with quantum mechanics, where only a handful of simple models admit closed-form, analytic solutions. In cases where the equations can only be solved approximately, computational methods are often used.


Applications of computational physics

Computation now represents an essential component of modern research in accelerator physics, astrophysics, fluid mechanics, lattice field theory/lattice gauge theory (especially lattice quantum chromodynamics), plasma physics (see plasma modeling), solid state physics and soft condensed matter physics. Computational solid state physics, for example, uses density functional theoryto calculate properties of solids, a method similar to that used by chemists to study molecules.

As these topics are explored, many more general numerical and mathematical problems are encountered in the process of calculating physical properties of the modeled systems. These include, but are not limited to

Computational physics also encompasses the tuning of the software/hardware structure to solve problems. Approaches to solving the problems are often very demanding in terms of processing power and/or memory requests.


See also


External links



* C20 IUPAP Commission on Computational Physics
* APS DCOMP
* IoP CPG (UK)
* SciDAC: Scientific Discovery through Advanced Computing
* Open Source Physics
* SCINET Scientific Software Framework

Minggu, 13 November 2011

Applied Physics

Applied physics is a general term for physics which is intended for a particular technological or practical use.[1] It is usually considered as a bridge or a connection between "pure" physics and engineering.[2]

"Applied" is distinguished from "pure" by a subtle combination of factors such as the motivation and attitude of researchers and the nature of the relationship to the technology or science that may be affected by the work.[3] It usually differs from engineering in that an applied physicist may not be designing something in particular, but rather is using physics or conducting physics research with the aim of developing new technologies or solving an engineering problem. This approach is similar to that of applied mathematics. In other words, applied physics is rooted in the fundamental truths and basic concepts of the physical sciences but is concerned with the utilization of these scientific principles in practical devices and systems.[4]

Applied physicists can also be interested in the use of physics for scientific research. For instance, people working on accelerator physics seek to build better accelerators for research in theoretical physics.



Journals by publisher

Institutions/organizations

References

Kamis, 10 November 2011

Agrophysics

Agrophysics



Agrophysics is a branch of science bordering on agronomy and physics, whose objects of study are the agroecosystem - the biological objects, biotope and biocoenosis affected by human activity, studied and described using the methods of physical sciences.

Agrophysics is closely related to biophysics, but is restricted to the biology of the plants, animals, soil and an atmosphere involved in agricultural activities and biodiversity. It is different from biophysics in having the necessity of taking into account the specific features of biotope and biocoenosis, which involves the knowledge of nutritional science and agroecology, agricultural technology, biotechnology, genetics etc.


Principles of physical sciences

Agrophysics is close to certain fundamental sciences like biology, whose methods and knowledge it utilizes (especially in the field of environmental ecology and plant physiology), and physics, from which it acquires the research methods, especially that of physical experiment and model.

The scope of interest of agrophysics is not focused solely on technical problems from agronomy and on practical implementation of sciences and that are aspects that makes it different from agricultural engineering which provides grounds for classifying agrophysics as the fundamental sciences.

Physical models, closely related to biophysics, are ready to solve either global or local aspects of behaviour of the complex ecosystems to be studied, including of energy consumption, food safety

etc....


Principles of history

The needs of agriculture, concerning the past experience study of the local complex soil and next plant-atmosphere systems, lay at the root of the emergnece of new branch - agrophysics dealing this with experimental physics. The scope of the branch starting from soil science (physics) and originally limited to the study of relations within the soil environment, expanded over time onto influencing the properties of agricultural crops and produce as foods and raw postharvest materials, and onto the issues of quality, safety and labeling concerns, considered distinct from the field of nutrition for application in food science.

A research centre that is focused on the development of the Science is the Institute of Agrophysics, Polish Academy of Sciences in Lublin. cyt: "Agrophysics, utilizing the achievements of Exact Sciences for solving major problems of Agriculture, is involved in study of materials and processes occurring in the production and processing of agricultural crops, with particular emphasis on the condition of the environment and the quality of farming materials and food productions."


See also

References

Minggu, 06 November 2011

Biophysics

The majority of graduates in the Biophysics program have been undergraduate majors in physics or physical chemistry, although others have come from areas such as biology and electrical engineering. Consequently, the course requirements for admission are somewhat elastic, with a focus on more quantitative areas. The degree program is designed to be completed in a maximum of six years. The program is highly flexible, and special effort has been devoted to minimizing formal requirements.

The first part of the program seeks to introduce the students directly to the faculty members and their research, enabling the student to make a considered choice of research advisor, and to involve the student in the diverse areas of biophysics through laboratory as well as course work. The first year's training in the Biophysics Program provides an introduction to five diverse areas of Biophysics:

1. Structural Molecular Biology
2. Cell and Membrane Biophysics
3. Molecular Genetics
4. Physical Biochemistry
5. Neuroscience

Biophysics, Introduction to Laboratory Research, brings professors from all over the University for one-hour seminars on their specific areas of research interest, allowing the students a period of time to familiarize themselves with research opportunities at their first laboratory rotation later in the first semester.

First Year:

Several rotations as well as course work are completed in the year to year-and-a-half of study. A year's work for a resident student normally consists of four courses (eight half-courses) of advanced grade.

Second Year:

Students continue with course work and laboratory rotations.
A semester of teaching is required in the second year.
Students chose their research advisor by the end of their second year.
Preliminary Qualifying examination must be completed by the end of the second year. Student must pass this exam before beginning thesis research.

Third Year and beyond:
Student meets at least annually with his or her Dissertation Advisory Committee (DAC).
Student engages in a period of intensive research culminating in publications and the receiving of the Ph.D. degree.

Areas of concentration and suggested course work is as follows:

* Structural Molecular Biology
o Genomics and Computational Biology
o Structure and Function of Proteins and Nucleic Acids
o Structural Biology of the Flow of Information in the Cell
o Crystal Symmetry, Diffraction, and Structure Analysis
o Chemical Biology
o Molecular Structure and Function
o Molecular Biology
o Proteins: Structure, Function and Catalysis
o Macromolecular NMR

* Molecular Genetics
o Molecular Genetics of Neural Development and Behavior
o Developmental Genetics and Genomics
o Molecular Mechanisms of Gene Control
o Principles of Genetics

* Physical Biochemistry
o Physical Chemistry
o Frontiers in Biophysics
o Molecular Biophysics and Biophysical Chemistry
o Topics in Biophysics
o Quantum Mechanics I
o Single-molecule Biophysics

* Cell and Membrane Biophysics
o Molecular and Cellular Immunology
o Biochemistry of Membranes
o Molecular Biology of the Cell
o Growth Factors and Signal Transduction

* Mathematical Biophysics
o Methods of Analysis and Applications
o Introduction to Systems Analysis with Physiological Applications
o Signals and Systems
o Nonlinear Dynamical Systems
o Population Genetics
o Population and Community Ecology
o Complex and Fourier Analysis
o Ordinary and Partial Differential Equations
o Mathematical Modeling
o Physical Mathematics I, II
o Fundamentals of Computational Biology
o Mathematics in Biology

* Neurosciences
o Systems Neuroscience
o Cellular Basis of Neuronal Function
o Experimental Neuroscience
o Molecular and Developmental Neurobiology
o Neural Signal Processing
o Introduction to Neurobiology
o Neurophysiology of Central Circuits
o Molecular Neurobiology


Biophysics is an interdisciplinary science that uses the methods of physical science to study biological systems.[1] Studies included under the branches of biophysics span all levels of biological organization, from the molecular scale to whole organisms and ecosystems. Biophysical research shares significant overlap with biochemistry, nanotechnology, bioengineering, agrophysics and systems biology.

Molecular biophysics typically addresses biological questions that are similar to those in biochemistry and molecular biology, but the questions are approached quantitatively. Scientists in this field conduct research concerned with understanding the interactions between the various systems of a cell, including the interactions between DNA, RNA and protein biosynthesis, as well as how these interactions are regulated. A great variety of techniques are used to answer these questions.

Fluorescent imaging techniques, as well as electron microscopy, x-ray crystallography, NMR spectroscopy and atomic force microscopy (AFM) are often used to visualize structures of biological significance. Conformational change in structure can be measured using techniques such as dual polarisation interferometry and circular dichroism. Direct manipulation of molecules using optical tweezers or AFM can also be used to monitor biological events where forces and distances are at the nanoscale. Molecular biophysicists often consider complex biological events as systems of interacting units which can be understood through statistical mechanics, thermodynamics and chemical kinetics. By drawing knowledge and experimental techniques from a wide variety of disciplines, biophysicists are often able to directly observe, model or even manipulate the structures and interactions of individual molecules or complexes of molecules.

In addition to traditional (i.e. molecular and cellular) biophysical topics like structural biology or enzyme kinetics, modern biophysics encompasses an extraordinarily broad range of research, from bioelectronics to quantum biology involving both experimental and theoretical tools. It is becoming increasingly common for biophysicists to apply the models and experimental techniques derived from physics, as well as mathematics and statistics (see biomathematics), to larger systems such as tissues, organs, populations and ecosystems.


Focus as a subfield

Biophysics often does not have university-level departments of its own, but has presence as groups across departments within the fields of molecular biology, biochemistry, chemistry, computer science, mathematics, medicine, pharmacology, physiology, physics, and neuroscience. What follows is a list of examples of how each department applies its efforts toward the study of biophysics. This list is hardly all inclusive. Nor does each subject of study belong exclusively to any particular department. Each academic institution makes its own rules and there is much overlap between departments.

Many biophysical techniques are unique to this field. Research efforts in biophysics are often initiated by scientists who were traditional physicists, chemists, and biologists by training.