bluuebunny/crossref_metadata_2025_split huggingface dataset:
Deep Space Network, Evolution of Technology
Authors: Layland James W. , Rauch Lawrence L. , Mudgway Douglas J. , Lesh James R. 
Published: October 2003

AbstractThe Deep Space Network (DSN), managed by the California Institute of Technology's Jet Propulsion laboratory (JPL), has provided vital communications and navigation services for NASA deep space exploration missions for more than 40 years. The remarkable technical achievements of the planetary exploration program executed by NASA would not have been possible without the extensive and sophisticated communications and data handling systems that comprise the Deep Space Network.The principal facilities of the DSN are three major ground station complexes, one in the United States (Goldstone, California), one near Madrid, Spain, and one near Canberra, Australia. Each of the complexes has several tracking antennae; the largest has a diameter of 70 meters, and smaller ones have diameters of 11–34 meters. In addition to antennae, the DSN also has a complex of computers and signal processing capabilities that permit very thorough and sophisticated analysis of signals sent back from distant spacecraft.In addition to receiving data from very distant spacecraft, the facilities of the network are also used to control the spacecraft. The network and the associated spacecraft are designed so that if a failure of a spacecraft should occur, there are often means available to effect a recovery. The continuing improvements in the technology of the network have greatly increased the useful lives and capabilities of the spacecraft that use the network.No history of the DSN would be complete without full appreciation of the contribution made by advanced technology to the successful development of the Network. The wellspring of new and innovative ideas for increasing the existing capability of the Network, improving reliability, operability, and cost‐effectiveness, and for enabling recovery from potential mission‐threatening situations has resided, from the very beginning of the Network's history, in a strong program of advanced technology, research, and development.
Venus Missions
Authors: Moroz Vasily I. , Bazilevsky Alexander T. 
Published: October 2003

Abstract
Launches of Soviet spacecraft to Venus were started in 1961. A full list of them is presented. The first success in space studies of Venus was achieved by the Soviets in 1967. Venera 4 reached the planet and fulfilled its mission. It was separated from the bus and entered the atmosphere, slowing as it descended. The parachute opened, and measurements of the atmospheric properties were taken down to an altitude 25 km above the surface. The probe was destroyed there due to high density and/or high temperature. Venera 4 was the first successful planetary atmospheric probe. The U.S. flyby probe, Mariner 5, arrived at Venus 1 day after Venera 4 and conducted some remote studies of the atmosphere. Then for about 10 years, NASA did nothing to explore Venus besides the Mariner 10 flyby on its way to Mercury. In contrast, the Soviet Union at that time was sending missions to Venus regularly, in the beginning using each astronomical window (about a 1.5‐year gap) and later each second window (about 3 years).
This article briefly outlines the Soviet scientific output. Results of the studies include the atmosphere and its interaction with the solar wind and details on the surface of Venus. A lot of valuable information about Venus was obtained by the Soviet (and also U.S.) missions to this planet. Most of the data (although still not all) has been carefully analyzed. A set of new goals and new possibilities was identified by this activity. Possibly it is time now for a return to the exploration of Venus on a new level.
Cardiovascular System in Space
Authors: Ramsdell Craig D. , Cohen Richard J. 
Published: October 2003

AbstractThe microgravity environment of space is well tolerated by the cardiovascular system over during periods ranging from weeks to several months. In many ways, the heart, peripheral vasculature, and central cardiovascular control system are exposed to fewer challenges in microgravity than on Earth. Consider the simple act of standing upright in the normal gravity field of Earth. Assumption of an upright posture on Earth causes a redistribution of blood volume to the lower parts of the body, resulting in an increase in blood pressure in dependent blood vessels and a decrease in arterial blood pressure above the level of the heart. The cardiovascular system must quickly compensate for these changes by altering the heart rate, the force of contraction of the heart, and the resistance of the blood vessels to maintain enough blood flow to the brain to prevent loss of consciousness. Under weightless conditions, however, there are no postural changes in blood volume and pressure, which greatly reduces the demands placed on the cardiovascular system to maintain homeostasis. Furthermore, moving about in microgravity requires far less energy than required in gravity, which places less demand on the cardiovascular system.During the long term, however, many physiological systems become dysfunctional when they are not required to perform at a normal level. For example, the muscles and bones of a leg immobilized in a cast for a month or two become atrophied and weak. Similarly, the relatively unchallenging environment of microgravity ultimately results in dysfunctional changes in the heart, the vasculature, and the central cardiovascular control system that may have harmful consequences during spaceflight and upon reexposure of the human organism to a gravitational field.For example, many astronauts cannot maintain normal blood pressure and feel dizzy or faint when standing upright immediately following spaceflight, a condition calledorthostatic intolerance. This may impair their ability to get out of a spacecraft quickly should an emergency arise, or to perform meaningful work upon arrival in a gravitational field, for example, after a trip to Mars. There are also reports of rhythmic disturbances of the heart (cardiac arrhythmias) during spaceflight and of loss of muscle mass of the heart (cardiac atrophy). The latter two conditions, though less well documented than orthostatic intolerance, represent potentially life‐threatening alterations in cardiovascular function. Before these problems in are discussed in detail. A brief review of normal cardiovascular physiology is also presented.
Digital Video
Authors: Netravali Arun N. 
Published: October 2003

Abstract
Analog television was developed and standardized in the forties, mainly for over‐the‐air broadcast of entertainment, news, and sports. While a few upward compatible changes have been made in the intervening years, such as color, multi‐channel sound, closed captioning, and ghost cancellation, the underlying analog system has survived a continuous technological evolution that has pervaded all other media. Television has stimulated the development of a global consumer electronics industry that has brought high‐density magnetic recording, high‐resolution displays, and low‐cost imaging technologies from the laboratory into the living room. A vast array of video production processing technologies make high‐quality programming an everyday reality, real‐time on‐site video the norm rather than the exception, and video the historical medium of record throughout the world. Emergence of personal computers and high speed networks has given rise to desktop video to improve productivity for businesses.

In spite of this impressive record and a large invested base, we are on the threshold of a major disruption in the television industry. After fifty years of continuous refinement, the underlying technology of television is going to be entirely redone. Digital video is already proliferating in a variety of applications such as video‐conferencing, multimedia computing, and program production; the impediments that have held it back are rapidly disappearing. The key enabling technologies are (
1
) mature and standardized algorithms for high‐quality compression; (
2
) inexpensive and powerful integrated circuits for processing, storing, and reconstructing video signals; (
3
) inexpensive, high‐capacity networks for transporting video; (
4
) uniform methods for storing, addressing, and accessing multimedia content; and (
5
) evolution of computer architecture to support video I/O. The market drivers include: (
1
) direct consumer access for content providers, (
2
) convergence of video with other information sources such as print; (
3
) the emergence of a fast growing consumer market for personal computing, (
4
) the evolution of the Internet and other networks in the commercial domain, and (
5
) the removal of various regulatory barriers.

This article deals with the technology of digital television. This articles starts with the way the television signal is sampled (scanning) and digitized. A discussion of techniques of compression to reduce the bit rate to a manageable level is given. The emerging standards for compression is described.
Gravure Multi‐Copy Printing
Authors: Lee Barry 
Published: October 2003

Abstract

Gravure
, also known as
rotogravure
, is an
intaglio
(from the Italian word “intagliare” meaning to engrave) printing process. The intaglio printing processes are characterized by printing plates (image carriers) images with have been etched or engraved into a hard surface. To print from an intaglio image carrier, the recessed images must be flooded, or filled with ink and the surface of the image carrier must be cleared of ink, usually by a metal wiping blade known as a “doctor blade.” The paper or other substrate is pressed against the intaglio image carrier, and the resulting contact between substrate and ink‐filled image areas causes the ink to transfer from the image carrier to the substrate.

Gravure printing has evolved from early intaglio printing processes, and has been adapted to a rotary printing process capable of higher resolution, higher speeds, and greater production capacity than the traditional intaglio processes. The primary differences between gravure and printing from a conventional intaglio plate involve the type of ink used for each process and the variation of the image carrier.
The gravure printing process utilize much more fluid, low viscosity ink. This ink has been adapted to dry quickly on a variety of substrates. The gravure printing process is currently the third most common process used in the United States and the second most commonly used process in Europe and Asia. Three distinctly different market segments use the gravure process: publication, packaging, and specialty. Gravure printed publication products include magazines, Sunday newspaper supplements, catalogs and newspaper advertising inserts. Gravure packaging presses are designed to handle the specific substrates used in the packaging industry. Gravure‐printed packaging products include folding cartons, usually printed on paperboard, flexible packaging, usually printed on polyethylene or polypropylene, and labels and wrappers. The most interesting and diverse segment of gravure printing is known as the product or specialty segment e.g., wallcoverings, gift wrap, vinyl flooring, etc. The strength of gravure derives from the simplicity of operation—fewer moving parts. This allows for a more stable and consistent production process.
Image Formation
Authors: Hornak Joseph P. 
Published: October 2003

Abstract
An imaging system consists of ten loosely defined components or subsystems: the imaged object, probing radiation, measurable property, image formation, detected radiation, detector, processing, storage, display, and end user subsystems. The image formation subsystem maps spectroscopic information from the imaged object, person, or phenomenon onto a detector so that the processing subsystem can create an image. In one of the simplest optical systems, a camera, the image formation component is a lens, the spectroscopic property is the reflected light from the imaged object, and the detector is a sheet of photographic film.
There are seven general classes of image formation techniques: optical, tomographic, holographic, scanning, triangulation, projection, and hybrid. Optical techniques are the most common, perhaps because they are based on the first imaging system, the animal eye. Current optical imaging systems use lenses, mirrors, and waveguides. Tomographic techniques produce images of a thin slice through an object. They are used for clinical and nondestructive analysis. Magnetic resonance imaging (MRI), ultrasound imaging, and computed tomographic imaging are a few examples of systems that use tomographic image formation techniques. Holographic techniques produce three‐dimensional images based on the interference patterns between light waves from the imaged object and a reference. This article focuses on image formation techniques based on scanning, triangulation, projection, and combinations of the others (hybrid).
Image Quality Metrics
Authors: Burningham Norman , Pizlo Zygmunt , Allebach Jan P. 
Published: October 2003

AbstractImages produced on monitors, printers, copiers, and films contain a variety of elements, including text, graphics, and pictorial segments. As viewers evaluate the quality of images, they may notice that various image elements are not well formed or do not communicate the desired intent. Examples of some of the most significant deficiencies seen in images that have pictorial segments include lack of clarity in details, noise in areas expected to be smooth, loss of information in highlights or darker areas, and inaccurate representation of color. These characteristics form the basis for defining sharpness, graininess, tone scale, and color rendition, respectively. These four attributes are significant factors that viewers consider when judging image quality. In images containing text and graphics, perception of quality is critically affected by roughness of edges or lines that should be smooth, blurred edges, or nonuniform density. These defects in image rendering.In addition to the imperfections described, artifacts are often introduced into the images because of mechanical or material problems during imaging.In this article, physical and perceptual aspects of image quality are discussed. Objective methods, which relate the design parameters to the physical parameters of the image are reviewed. Psychophysical methods that are used to characterize the percept in terms of the underlying perceptual or physical scale are then reviewed. Finally, the problem of formulating and validating computational models of image fidelity is discussed.
Over the Horizon (OTH) Radar
Authors: Anderson S. J. , Barnes R. I. , Colegrove S. B. , Earl G. F. , Sinnott D. H. 
Published: October 2003

AbstractIn this article starts with a description of over‐the‐horizon radar in general terms and current implementations. Subsequent sections expand in more detail on propagation and scattering issues, OTHR in operation (includes discrete target surveillance and monitoring, and geophysical sensing operations) and system implementation (includes subsystem hardware design, signal processing, and limitations).
Scanning Electrochemical Microscopy
Authors: Wipf David O. 
Published: October 2003

AbstractScanning electrochemical microscopy (SECM) is one of a number of scanned probe microscopy (SPM) techniques invented following the demonstration of the scanning tunneling microscope. The use of an electrochemical process for image formation defines SECM. In most applications of the method, an ultramicroelectrode (UME) is used as the probe and the probe signal is the Faradic current arising from the electrolysis of solution species. In other cases, the use of an ion‐selective electrode (ISE) as the probe provides a probe signal proportional to the logarithm of the activity of an ion in solution (eg., pH). In SECM, the primary interaction between probe tip and sample is mediated by diffusion of solution species between the sample and the tip of the probe, which distinguishes SECM from other SPM methods that may use an electrochemically active probe. An electrochemically active probe permits a versatile range of experiments, an essential aspect of which is chemical sensitivity or control of chemical processes occurring at a substrate surface.Forming an image in an SPM technique requires that the probe signal be perturbed in a reproducible fashion by some aspect of the imaged substrate. There are two principal image‐forming modes in SECM: feedback and generation/collection (GC). The feedback mode uses the Faradaic current that flows from electrolysis of an intentionally‐added or naturally present mediator species at an UME probe.Imaging in the feedback mode provides topographic images of blocking or conducting surfaces. Images of many types of surfaces have been obtained in the feedback mode; examples include images of electrodes, polymer films, and immiscible liquid interfaces.It is possible to manipulate the SECM imaging conditions to produce images that representing chemical and electrochemical activity.The generation/collection (GC) mode uses the probe to detect changes in the concentration of a chemical species at the surface of the imaged material. Ideally, the probe acts as a passive sensor to produce concentration maps of a particular chemical species near the substrate surface. GC mode imaging is described further by the type of sensing probe used. In amperometric GC imaging, the probe is an UME, which detects species by electrolysis. First reported as a method to map electrochemically active areas on electrodes, amperometric GC is used to make high‐resolution chemical concentration maps of corroding metal surfaces, biological materials, and polymeric materials. In addition, measurements of ion fluxes through porous materials, such as skin and dental material, are useful applications. In potentiometric GC imaging, the probe is an ISE, which has the advantage of increased sensitivity to nonelectroactive ions and improved selectivity for imaging a desired ion concentration.
Electrophotography
Authors: Hauser O. G. 
Published: October 2003

AbstractElectrophotography, also called xerography, is a process for producing high quality copies or images of a document. Electrophotography is based on forming an electrostatic charge pattern or image of the original document that is made visible by ultrafine electrically charged particles.The advent of the personal computer and desktop publishing created a need for convenient, low‐cost, point‐of‐need printing. At first, typewriters were adapted to perform impact printing, followed by dot matrix printers, but these concepts had many disadvantages. Small (and slow) ink jet printers have come to dominate the low‐volume desktop publishing market at this time. The mid‐volume and high‐volume markets, however, are presently dominated by faster and more reliable laser and light‐emitting‐diode (LED) electrophotographic printers. The print quality of these modern printers approaches that of offset lithography quite closely, so many electrophotographic machines compete effectively with the offset press. There are business advantages for each type of printer, however, and offset print shops are certainly not going to go out of business in the foreseeable future. Because of the popularity of electrophotographic printers, both large and small, color and black only, this article explores the fundamentals involved in producing hard copy by this process.This article first presents an overview of the essential elements in an electrophotographic imaging system. Then, each of the commercialized process steps is covered in some detail to lead the reader from corona sensitization of the photoconductor to fixing of the final image. An extension of the electrophotographic process to color printing is discussed in the final section.In a form of electrophotography called xeroradiography, the X‐ray portion of the electromagnetic spectrum is used to form a latent image on a photoconductor.
Deletion of the distal long arm of chromosome 10; is there a characteristic phenotype? A report of 15 de novo and familial cases
Authors: Irving Melita , Hanson Helen , Turnpenny Peter , Brewer Carole , Ogilvie Caroline Mackie , Davies Angela , Berg Jonathan 
Published: October 2003

AbstractIt has been suggested previously that patients with terminal deletions of chromosome 10q have a recognizable phenotype including a characteristic facial appearance combined with other abnormalities including mental retardation, cardiac and anogenital anomalies. We report the largest published series of new cases of terminal 10q deletion, including eight familial and four de novo cases and three cases with interstitial deletions involving chromosome bands 10q25.2‐26.3. The deleted regions were defined by FISH using YAC probes, as well as standard karyotyping. The most consistent clinical features in our cases are cranial anomalies including facial asymmetry, prominent nose and nasal bridge, prominent ears, thin upper lip, along with growth retardation, developmental delay, and digital abnormalities. Visceral abnormalities were only identified in a small number of the patients, with renal involvement in three cases and structural cardiac malformations in two others. Learning difficulties of varying severity were found in 11 cases and behavioral problems described in four. Candidate genes for behavioral and learning difficulties within the deleted region include Calcyon. Other genes in the region that might have a role in causing the phenotype include the genes coding for fibroblast growth factor receptor type 2 (FGFR2) and C‐terminal binding protein 2 (CTBP2). © 2003 Wiley‐Liss, Inc.
Preliminary data on changes in neural tube defect prevalence rates after folic acid fortification in South America
Authors: Castilla Eduardo E. , Orioli Iêda M. , Lopez‐Camelo Jorge S. , Dutra Maria da Graça , Nazer‐Herrera Julio ,   for the ECLAMC: Latin American Collaborative Study of Congenital Malformations
Published: October 2003

AbstractSeveral South American countries are fortifying wheat flour with folic acid. However, only Chile started in 2000 to add 2.2 mg/kg, providing 360 μg daily per capita, an acceptable dosage for preventing the occurrence of some neural tube defect (NTD) cases. ECLAMC (Spanish acronym for the Latin American Collaborative Study of Congenital Malformations) routinely monitoring birth defects in South America since 1976, surveyed the impact of this fortification. Data from 361,374 births occurred in 43 South American hospitals, distributed in five different countries, active throughout the 1999–2001 triennium, were selected from the ECLAMC network. Birth prevalence rates for three different congenital anomalies with similar expected prevalence rates, were surveyed by the Cumulative Sum Method (CUSUM) method. They were NTD, oral clefts (OC), and Down syndrome (DS). Expected values were derived from observations made in 1999, and CUSUM was applied to the consecutive series of 24 months covering years 2000 and 2001. Only one of three congenital anomaly types, NTDs, in only one of five sampled out countries, Chile, showed a significant decrease, of 31%, during the 2000–2001 biennium, corresponding to the birth of the periconceptionally fortified infants. The level of significance (P < 0.001) was reached in the 20th month after fortification started, corresponding to August 2001. This is the first observation of a significant decrease in the occurrence of NTD after folic acid food fortification in a population little influenced by confounders common in the developed world as pre‐existing secular decreasing trends, and partially unregistered induced abortions. © 2003 Wiley‐Liss, Inc.