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PubMedDate not supplied

Bi-sensory, striped representations: comparative insights from owl and platypus.

Bi-sensory striped arrays are described in owl and platypus that share some similarities with the other variant of bi-sensory striped array found in primate and carnivore striate cortex: ocular dominance columns. Like ocular dominance columns, the owl and platypus striped systems each involve two different topographic arrays that are cut into parallel stripes, and interdigitated, so that higher-order neurons can integrate across both arrays. Unlike ocular dominance stripes, which have a separate array for each eye, the striped array in the middle third of the owl tectum has a separate array for each cerebral hemisphere. Binocular neurons send outputs from both hemispheres to the striped array where they are segregated into parallel stripes according to hemisphere of origin. In platypus primary somatosensory cortex (S1), the two arrays of interdigitated stripes are derived from separate sensory systems in the bill, 40,000 electroreceptors and 60,000 mechanoreceptors. The stripes in platypus S1 cortex produce bimodal electrosensory-mechanosensory neurons with specificity for the time-of-arrival difference between the two systems. This "thunder-and-lightning" system would allow the platypus to estimate the distance of the prey using time disparities generated at the bill between the earlier electrical wave and the later mechanical wave caused by the motion of benthic prey. The functional significance of parallel, striped arrays is not clear, even for the highly-studied ocular dominance system, but a general strategy is proposed here that is based on the detection of temporal disparities between the two arrays that can be used to estimate distance.

Animals↗
PubMed2006

Marketing dietary supplements in the United States: a review of the requirements for new dietary ingredients.

Since the passage of the Dietary Supplement Health and Education Act in 1994, the marketplace for dietary supplements has experienced dramatic growth. New products have redefined the entire marketplace, and new ingredients are introduced to consumers at lightning speed. As part of this act, laws were passed to ensure the safety of new dietary ingredients introduced into the United States marketplace. But more than 11 years later, these laws are frequently misunderstood, and more frequently ignored. This article reviews the regulatory landscape of new dietary ingredients and defines the issues manufacturers must contend with to legally market dietary supplements with new dietary ingredients in the U.S.

Dietary Supplements↗
PubMed2005

In-field measurements of PCDD/F emissions from domestic heating appliances for solid fuels.

Within this project the emissions into the atmosphere of polychlorinated dibenzo-p-dioxins and -furans (PCDD/F) of 30 domestic heating appliances in Austrian households were tested. The appliances were single stoves (kitchen stove, continuous burning stove and tiled stove) and central heating boilers for solid fuels up to a nominal heat input of 50 kW. A main objective of this survey was to determine the PCDD/F emissions of domestic heating units under routine conditions. Therefore, the habitual combustion conditions used by the operators were not influenced. The original fuels and lightning supports were used and the operation of the units was carried out by the householders according to their usual practice. The data obtained were used to calculate in-field PCDD/F-emission factors. Most of the appliances have shown PCDD/F emissions within a concentration range of 0.01-0.3 ng TEQ/MJ. Modern fan-assisted wood heating boilers with afterburning and units for continuously burning of wood chips and wood pellets had the lowest emissions. High emissions were caused by unsuitable heating habits such as combustion of wastes and inappropriate operation of the appliances. There were only small differences between single stoves and central heating boilers or between wood and coal-fired appliances. The emission factors calculated are higher than those cited in literature, which are mainly derived from trials on test stands under laboratory conditions.

Air Pollutants↗
PubMed1999

Release of polychlorinated dibenzo-p-dioxins and dibenzofurans by setting off fireworks.

Selected pyrotechnic articles were set off under laboratory conditions. Residues and vapors of smoke as well as unburnt charges were analyzed for polychlorinated dibenzo-p-dioxins, dibenzofurans (PCDD/F) and their precursors chlorinated benzenes and phenols. The contamination of the selected products with these organic xenobiotics proved to be very variable. Remains of fireworks contained octachlorinated dioxins and furans up to 142 ng I-TEQ/kg as well as hexachlorobenzene in the range of 0.05 to 1,400 mg/kg. The deflagration of detonating compositions usually resulted in a dispersion of contaminants, whereas continuously burning flare compositions partially led to a thermal decomposition of organic pollutants. A significant rate of formation of polychlorinated dioxins and furans was observed when setting off blue-lightning rockets and fountains. Further investigations revealed that even high temperatures during the deflagration of black powder charges could not suppress the formation of PCDD/F from appropriate precursors.

Benzofurans↗
PubMed1997

Pediatric electrical burns: management strategies.

The purpose of the present study was to analyse the course of patients hospitalised with electrical burn wounds in the past 25 years at a major children's hospital in the United States in order to devise safe and cost effective management strategies for these patients. The study was a retrospective chart review of patients with electrical injuries admitted to the hospital between 1971 and 1995. We identified 127 children who were included in the study. Injuries resulted from biting an electrical cord (oral injury) (n = 48), placing an object into an electrical socket (outlet injury) (n = 33), contacting a low voltage wire or appliance indoors (low voltage household injury) (n = 25), contacting a high voltage wire outdoors (high voltage wire injury) (n = 18), or being struck by lightning (n = 3). A retrospective review revealed that the great majority of patients with low voltage electrical injuries did not need admission to the hospital and could have been cared for on an outpatient basis. Almost every patient with high voltage injury had a justified admission due to the severity of the injury. On the basis of these results we conclude that we can safely reduce the number of admissions to the hospital for children with low voltage minor electrical injuries.

Adolescent↗
PubMed1999

Evaluation of a standardised procedure to assess the shape of pellets using image analysis.

The influence of threshold definition, number of pellets counted, image magnification and lightning technique on the assessment of pellet shape has been investigated using three batches of pellets and an image analysis system. The pellet parameters measured were 'aspect ratio', 'circularity', 'projection sphericity', 'e(R)' and 'Feret diameter.' The methodical error, reproducibility and repeatability of the results were chosen as statistical test parameters. The position of the light source is crucial in providing an accurate particle size value. Top light was identified as the illumination technique that gave a mean pellet size similar to the true pellet size. The use of a light table produced significantly larger pellet size values. A minimum pixel resolution appears necessary for an accurate shape parameter definition. One pixel should not cover more than 30 microm for pellets of an average particle size of 1.2 mm. Shape descriptors, which are based on a multiple combination of area and perimeter data such as the circularity, are greatly dependent on the number of pellets counted. Shape factors, which do not (aspect ratio) or only as a single value do involve an area or perimeter measurement (e(R), projection sphericity) are, however, nearly independent of the number of pellets counted, as long as the magnification is sufficiently large and the pellets are randomly drawn from the batch. For nearly spherical particles, the methodical error is below 1%, but for elongated particles this error can reach 5%. The repeatability is also very good for nearly spherical particles (<2%), but increases to very large values if the particles are clearly elongated. The limiting values for the various shape factors should be reconsidered. An upper value for the aspect ratio of 1.1 and a lower value of 0.6 for e(R) are recommended. The circularity should not be used as the shape factor to characterise spheres, because errors in image recognition can affect strongly the applicability of this shape factor. The projection sphericity has only a limited sensitivity to variations in particle shape.

Chemistry, Pharmaceutical↗
PubMed2002

Electrocution--autopsy study with emphasis on "electrical petechiae".

Fatalities caused by electrocution (n = 37) were re-examined on the basis of the autopsy records, the police reports and the technical expertise. Accidents including two lightning deaths caused 2/3rd and suicides 1/4th of the fatalities and there were two homicides. Carelessness or ignorance were a major reason for accidental deaths while technical defects could be verified in five cases only. Low-voltage ac and male victims predominated. Electrical burns or current marks were detected in 81% including all high voltage electrocutions. The seven victims lacking burns were electrocuted in a wet environment including six cases of suicide in the bathtub with a hair drier. Petechial haemorrhages were present in 74% of the cases and the favourite sites were the skin of the eyelids, conjunctivae, visceral pleura, and the epicard. The presence of petechiae did not depend on the voltage or the current pathway relative to the heart. It is, therefore, suggested that the petechiae are not caused by asphyxia but by a combination of venous congestion due to cardiac arrest and a sudden rise in blood pressure induced by muscle contractions. Consequently, "electrical petechiae" represent a non-specific but typical finding in electrocution irrespective of the mechanism leading to death. Unlike electrical burns, petechiae also indicate the vital origin of the events. The relevance of this typical morphological sign in the examination of possible electrocution fatalities is therefore emphasised.

Accidents↗
PubMed2004

[Pediatric brain death and donation in Asturias].

BACKGROUND: Brain death is the irreversible cessation of intracranial neurologic function and is considered as the person's death. The objective of this study was to describe the characteristics of pediatric donors in the Hospital Central de Asturias from October 1995 to October 2002. METHODS: We performed a retrospective and descriptive study of the dead children who were potential donors in the pediatric intensive care unit (PICU). RESULTS: Of 43 dead children, 15 (34.9 %) were diagnosed with brain death. In four patients (family refusal in one, sepsis in two and brain tumor in one) there was no donation. In all patients, the diagnosis of brain death was based on clinical examination and electroencephalogram. Doppler ultrasonography and technetium-99m hexamethylpropyleneamineoxamine (Tc-99-HMPAO) scanning was also performed in three and nine patients respectively. The mean age of the donors was 8.1 years (range: 13 months-15 years). The male/female ratio was 3/1. The cause of death was multiple trauma in six children, brain hemorrhage in three, cardiac arrhythmias in three, lightning strike in one, diabetic ketoacidosis in one, septic shock in one and hypovolemic shock in one. The median interval between admission and brain death was 1.4 days (range: 3 hours-12 days). The time of organ support between brain death and donation was 8.4 hours (range: 6-13 hours). The most frequent complications after brain death were central diabetes insipidus in 90.9 % of the patients, hyperglycemia in 54.5 % and hypokalemia in 45.4 %. During support 72.7 % of the patients required inotropic aid. CONCLUSIONS: In our PICU more than one-third of the dead children suffered brain death, and most became donors. The most frequent cause of brain death was multiple trauma. Coordination with the transplant team and the training of medical staff are important to achieve a high percentage of donations.

Adolescent↗
PubMed2002

Mass spectrometric contributions to problems related to the chemistry of atmospheres.

Recent mass spectrometric studies of species and processes relevant to the chemistry of atmospheres are reported. New species have been detected, including HO(3); a stratospheric reservoir of OH radicals; the [H(2)O(+)O(2)(-)] charge transfer complex, central to the atmospheric photonucleation theory; and the OSOSO oxide and its cation, likely present in the Io's atmosphere. As to ionic processes, a new route to tropospheric N(2)O in air ionized by lightning and coronas is reported, as well as the complex chemistry promoted by ionization of ozone/freon and ozone/carbonyl sulfide mixtures and the formation of O(5)(+), relevant to the problem of (18)O excess in stratospheric ozone.

Air Ionization↗
PubMed2005

Phosphine from rocks: mechanically driven phosphate reduction?

Natural rock and mineral samples released trace amounts of phosphine during dissolution in mineral acid. An order of magnitude more phosphine (average 1982 ng PH3 kg rock and maximum 6673 ng PH3/kg rock) is released from pulverized rock samples (basalt, gneiss, granite, clay, quartzitic pebbles, or marble). Phosphine was correlated to hardness and mechanical pulverization energy of the rocks. The yield of PH3 ranged from 0 to 0.01% of the total P content of the dissolved rock. Strong circumstantial evidence was gathered for reduction of phosphate in the rock via mechanochemical or "tribochemical" weathering at quartz and calcite/marble inclusions. Artificial reproduction of this mechanism by rubbing quartz rods coated with apatite-phosphate to the point of visible triboluminescence, led to detection of more than 70 000 ng/kg PH3 in the apatite. This reaction pathway may be considered a mechano-chemical analogue of phosphate reduction from lightning or electrical discharges and may contribute to phosphine production via tectonic forces and processing of rocks.

Geological Phenomena↗
PubMed2006

High-resolution apertureless near-field optical imaging using gold nanosphere probes.

An apertureless near-field scanning optical microscope (ANSOM) that utilizes the enhanced field around a gold nanosphere, which is attached to the end of an atomic force microscope (AFM) tip, is used to image the local dielectric constant of the patterned metallic surfaces and local electric field around plasmonic nanosphere samples. A colloidal gold nanosphere (approximately 50 nm diameter) is linked to the extremity of the conventional etched-silicon probe. The scattering of laser radiation (633 or 532 nm) is modulated by the oscillating nanosphere-functionalized silicon tip, and the scattered radiation is detected. The approach curve (scattering intensity as a function of the tip-sample distance), the polarization dependence (scattering intensity as a function of the excitation polarization direction), and ANSOM image contrast confirm that the spherical nanosphere attached to the silicon tip acts as a point dipole that interacts with the sample surface via a dipole-dipole coupling, in which the dipole created by the field at the tip interacts with its own image dipole in the sample. The image obtained with the nanoparticle functionalized tip provides a dielectric map of the sample surface with a spatial resolution better than 80 nm. In addition, we show that the functionalized tip is capable of imaging the local electric field distribution above the plasmonic nanosphere samples. Overall, the result shows that high-resolution ANSOM is possible without the aid of the lightning-rod effect. With an improved tip-fabrication method, we believe that the method can provide a versatile high-resolution chemical imaging that is not available from usual forms of ANSOM.

Journal Article↗
PubMed2000

Allozyme variation in Busycon whelks (Gastropoda: Melongenidae).

Large Busycon whelks are used in physiological research and are key predators in shallow water marine communities in eastern North America. Allozyme analysis of 16 loci in Busycon carica (knobbed whelk), B. sinistrum (left-handed or lightning whelk), and the closely related outgroup Busycotypus spiratum (pear whelk) was performed. Striking differences in within-species genetic differentiation were observed. Geographic variation in B. carica is moderate (FST = 0.051). In B. sinistrum, however, FST is 0.625, suggesting the existence of either highly distinct subspecies or unresolved species. The pattern of genetic variation in B. sinistrum may be congruent with that in other taxa that have experienced Gulf-Atlantic and eastern-western Gulf vicariance events. The data are compatible with an evolutionary rate of 0.046 Nei D/million years.

Animals↗
PubMed2002

The nature of regularity and irregularity: evidence from Hebrew nominal inflection.

Most evidence for the role of regular inflection as a default operation comes from languages that confound the morphological properties of regular and irregular forms with their phonological characteristics. For instance, regular plurals tend to faithfully preserve the base's phonology (e.g., rat-rats), whereas irregular nouns tend to alter it (e.g., mouse-mice). The distinction between regular and irregular inflection may thus be an epiphenomenon of phonological faithfulness. In Hebrew noun inflection, however, morphological regularity and phonological faithfulness can be distinguished: Nouns whose stems change in the plural may take either a regular or an irregular suffix, and nouns whose stems are preserved in the plural may take either a regular or an irregular suffix. We use this dissociation to examine two hallmarks of default inflection: its lack of dependence on analogies from similar regular nouns, and its application to nonroots such as names. We show that these hallmarks of regularity may be found whether or not the plural form preserves the stem faithfully: People apply the regular suffix to novel nouns that do not resemble existing nouns and to names that sound like irregular nouns, regardless of whether the stem is ordinarily preserved in the plural of that family of nouns. Moreover, when they pluralize names (e.g., the Barak-Barakim), they do not apply the stem changes that are found in their homophonous nouns (e.g., barak-brakim "lightning"), replicating an effect found in English and German. These findings show that the distinction between regular and irregular phenomena cannot be reduced to differences in the kinds of phonological changes associated with those phenomena in English. Instead, regularity and irregularity must be distinguished in terms of the kinds of mental computations that effect them: symbolic operations versus memorized idiosyncrasies. A corollary is that complex words are not generally dichotomizable as "regular" or "irregular"; different aspects of a word may be regular or irregular depending on whether they violate the rule for that aspect and hence must be stored in memory.

Humans↗
PubMed2002

The properties of geophysical fields and their effects on elephants and other animals.

Geophysical properties of acoustic, seismic, electric, and magnetic waveforms create opportunities and constraints for animals' communication and sensory monitoring of the environment. The geometric spreading of waves differs; at some frequencies, transmission is most efficient and has minimal noise. The spreading properties of seismic waves favor long-distance propagation for communication and environmental monitoring, and would benefit elephants (Elephas maximus and Loxodonta africana), such as in locating subsurface water. Extending C. E. O'Connell-Rodwell, B. T. Amason, and L. A. Hart (2000), a man jumping at 1.11 km propagated seismic waves at 10-40 Hz. Given the noise of lightning and the Schumann resonances, near field magnetic and electric transmission by animals would be most efficient around 1000 Hz.

Animal Communication↗
PubMed2005

When static media promote active learning: annotated illustrations versus narrated animations in multimedia instruction.

In 4 experiments, students received a lesson consisting of computer-based animation and narration or a lesson consisting of paper-based static diagrams and text. The lessons used the same words and graphics in the paper-based and computer-based versions to explain the process of lightning formation (Experiment 1), how a toilet tank works (Experiment 2), how ocean waves work (Experiment 3), and how a car's braking system works (Experiment 4). On subsequent retention and transfer tests, the paper group performed significantly better than the computer group on 4 of 8 comparisons, and there was no significant difference on the rest. These results support the static media hypothesis, in which static illustrations with printed text reduce extraneous processing and promote germane processing as compared with narrated animations.

Adolescent↗
PubMed1996

Sleep and anxieties in Brazilian children: the role of cultural and environmental factors in child sleep disturbance.

To test the contextual hypothesis of sleep disturbance, disadvantaged urban Brazilian children's self-reported fears were correlated with parental reports of children's sleep disturbance. Fears of death at the hands of "death squads," environment-related worries and other fears reflecting Brazil's political, religious, and collective culture all correlated with sleep disturbance. Results are contrasted with findings of earlier studies on sleep and anxieties in samples of learning-disabled adolescents and victims of lightning.

Anxiety Disorders↗
PubMed2000

Moist convection as an energy source for the large-scale motions in Jupiter's atmosphere. Galileo Imaging Team

Jupiter's dominant large-scale weather patterns (dimensions approximately 10,000 km) are zonal jets and long-lived ovals. The jets have been flowing east and west at constant speeds of up to 180 m s(-1) for over 100 years. These jets receive energy from small-scale eddies, which pump eastward momentum into the eastward jets and westward momentum into the westward jets. This momentum transfer was predicted by numerical models before it was observed on Jupiter. The large ovals roll between the jets in an anticyclonic direction-clockwise in the northern hemisphere and counterclockwise in the southern hemisphere--where they regularly assimilate small anticyclonic eddies. But from where the eddies receive their energy has been an open question. Here we argue that the eddies, which ultimately drive both the jets and the ovals, receive their energy from moist convection. This hypothesis is consistent with observations of jovian lightning, which is an indicator of moist convection. It also explains the anticyclonic rotation and poleward drift of the eddies, and suggests patterns of upwelling and downwelling that resemble the patterns of large-scale axisymmetric overturning in the Earth's atmosphere.

Journal Article↗
PubMed2003

Gigantic jets between a thundercloud and the ionosphere.

Transient luminous events in the atmosphere, such as lighting-induced sprites and upwardly discharging blue jets, were discovered recently in the region between thunderclouds and the ionosphere. In the conventional picture, the main components of Earth's global electric circuit include thunderstorms, the conducting ionosphere, the downward fair-weather currents and the conducting Earth. Thunderstorms serve as one of the generators that drive current upward from cloud tops to the ionosphere, where the electric potential is hundreds of kilovolts higher than Earth's surface. It has not been clear, however, whether all the important components of the global circuit have even been identified. Here we report observations of five gigantic jets that establish a direct link between a thundercloud (altitude approximately 16 km) and the ionosphere at 90 km elevation. Extremely-low-frequency radio waves in four events were detected, while no cloud-to-ground lightning was observed to trigger these events. Our result indicates that the extremely-low-frequency waves were generated by negative cloud-to-ionosphere discharges, which would reduce the electrical potential between ionosphere and ground. Therefore, the conventional picture of the global electric circuit needs to be modified to include the contributions of gigantic jets and possibly sprites.

Journal Article↗