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PubMed1982

The photochemistry of the paleoatmosphere.

The ideas of Harold Urey on the origin and evolution of the atmosphere have dominated thinking in this area for 3 decades. Recent progress in this area is reviewed, with particular emphasis on photochemical modeling studies of atmospheric evolution. Research into the paleoatmosphere can be divided into 3 distinct areas: (1) The photochemistry/chemistry of the prebiological paleoatmosphere, (2) the evolution of oxygen and the transition to an oxidizing atmosphere, and (3) the origin and evolution of ozone. Photochemical calculations indicate that the stability of a heavily reducing paleoatmosphere of CH4--NH3 was extremely shortlived, if such a prebiological atmosphere ever existed at all. A more mildly reducing early atmosphere of CO2--N2 is favored by photochemical considerations. Recent calculations of O2 in the prebiological paleoatmosphere vary from less than 10(-14) of present atmospheric level (PAL) to 10(-1) PAL. Clearly, additional work is indicated. The evolution of O3 as a function of O2 level has been investigated with increasingly detailed photochemical models that have included the photochemistry/chemistry of the oxygen, hydrogen, nitrogen, carbon, and chlorine species, as well as the effects of eddy transport, the rainout of water-soluble species, dry deposition and lightning as a source of trace atmospheric gases.

Atmosphere↗
PubMed1991

Prebiotic chemistry in clouds.

In the traditional concept for the origin of life as proposed by Oparin and Haldane in the 1920s, prebiotic reactants became slowly concentrated in the primordial oceans and life evolved slowly from a series of highly protracted chemical reactions during the first billion years of Earth's history. However, chemical evolution may not have occurred continuously because planetesimals and asteroids impacted the Earth many times during the first billion years, may have sterilized the Earth, and required the process to start over. A rapid process of chemical evolution may have been required in order that life appeared at or before 3.5 billion years ago. Thus, a setting favoring rapid chemical evolution may be required. A chemical evolution hypothesis set forth by Woese in 1979 accomplished prebiotic reactions rapidly in droplets in giant atmospheric reflux columns. However, in 1985 Scherer raised a number of objections to Woese's hypothesis and concluded that it was not valid. We propose a mechanism for prebiotic chemistry in clouds that satisfies Scherer's concerns regarding the Woese hypothesis and includes advantageous droplet chemistry. Prebiotic reactants were supplied to the atmosphere by comets, meteorites, and interplanetary dust or synthesized in the atmosphere from simple compounds using energy sources such as ultraviolet light, corona discharge, or lightning. These prebiotic monomers would have first encountered moisture in cloud drops and precipitation. We propose that rapid prebiotic chemical evolution was facilitated on the primordial Earth by cycles of condensation and evaporation of cloud drops containing clay condensation nuclei and nonvolatile monomers. For example, amino acids supplied by , or synthesized during entry of, meteorites, comets, and interplanetary dust would have been scavenged by cloud drops containing clay condensation nuclei. Polymerization would have occurred within cloud systems during cycles of condensation, freezing, melting, and evaporation of cloud drops. We suggest that polymerization reactions occurred in the atmosphere as in the Woese hypothesis, but life originated in the ocean as in the Oparin-Haldane hypothesis. The rapidity with which chemical evolution could have occurred within clouds accommodates the time constraints suggested by recent astrophysical theories.

Aluminum Silicates↗
PubMed2000

[New vehicle technologies for supporting the mobility of the elderly].

Starting point for this analysis are the mobility needs and requirements of elderly, as well as problems concerning access and use of public transport. Elderly people as car drivers suffer from several performance deficits which are currently compensated by mobility restrictions and changed driving behaviour. Driver assistance systems, just available or soon on the market, are demonstrated and analysed with respect to their impact on elderly drivers. An expert evaluation comes to the conclusion that the most important systems for elderly are: emergency systems, enhanced vision systems and parking aids. Emergency systems can call rescue teams automatically or at driver's request, and direct them to the emergency location. Self imposed restrictions of elderly concerning night driving can partly be compensated by means of curve lightning and automatic dipping. Parking aids, using cameras or infrared technique are especially helpful for persons with moveability problems. The group of helpful, but not highly important driver assistance systems covers several means for longitudinal and lateral control of the car, comprising autonomous cruise control, antilock systems and electronic stability programmes. The value and impact of these systems are analysed in the light of risk homeostasis theory. Reduced work load and ease of mobility will at last result from user centered navigation systems, helping the elder driver also to move to new areas without orientational problems. The article demonstrates the particular importance of specific layouts of the man-machine-interface for elderly, to guarantee high acceptance and minimal distraction from traffic.

Accidents, Traffic↗
PubMed2003

Regeneration of Rhizophora mangle in a Caribbean mangrove forest: interacting effects of canopy disturbance and a stem-boring beetle.

Current theory predicts that in low-density, seed-limited plant populations, seed predation will be more important than competition in determining the number of individuals that reach maturity. However, when plant density is high, competition for microsites suitable for establishment and growth is expected to have a relatively greater effect. This dichotomous perspective does not account for situations in which the risk of seed predation differs inside versus outside recruitment microsites. We report the results of a field experiment and sampling studies that demonstrate such an interaction between microsite quality and the risk of propagule predation in mangrove forests on the Caribbean coast of Panama, where it appears to play a key role in shaping the demography and dynamics of the mangrove, Rhizophora mangle. Rhizophora's water-borne propagules establish wherever they strand, but long-term sampling revealed that only those that do so in or near lightning-created canopy gaps survive and grow to maturity. These microsites afford better growth conditions than the surrounding understory and, as importantly, provide a refuge from predation by the scolytid beetle, Coccotrypes rhizophorae. This refuge effect was confirmed with a field experiment in which Rhizophora seedlings were planted at different positions relative to gap edges, from 5 m inside to 20 m outside the gap. Mortality due to beetle attack increased linearly from an average of 10% inside a gap to 72% at 20 m into the forest. The interaction between canopy disturbance and propagule predation may be having a large impact on the composition of our study forests. Being shade-tolerant, Rhizophora seedlings that escape or survive beetle attack can persist in the understory for years. However, the high rate of beetle-induced mortality effectively eliminates the contribution of advance regeneration by Rhizophora saplings to gap succession. This may explain why the shade-intolerant mangrove, Laguncularia racemosa, is able to co-dominate the canopy in low intertidal forests at our study sites.

Animals↗
PubMed2001

Natural very-low-frequency sferics and headache.

Very-low-frequency (VLF) atmospherics or sferics are pulse-shaped alternating electric and magnetic fields which originate from atmospheric discharges (lightning). The objective of the study was threefold: (i) to analyse numerous parameters characterizing the sferics activity with regard to their suitability for field studies, (ii) to identify meteorological processes related to the sferics activity and (iii) to investigate the possible association of sferics with pain processes in patients suffering from migraine- and tension-type headaches. Over a period of 6 months (July through December) the sferics activity in the area of Giessen (Germany) was recorded. Three sferics parameters were chosen. The number of sferics impulses per day, the variability of the impulse rate during a day and the variability in comparison to the preceding day were correlated with weather processes (thunderstorm, temperature, vapour pressure, barometric pressure, humidity, wind velocity, warm sector). Significant correlations were obtained during the summer months (July, August) but not during the autumn months (October, November, December). During autumn, however, the sferics activity was correlated with the occurrence of migraine-type headaches (r=0.33, P<0.01) recorded by 37 women who had filled out a headache diary over a period of 6 months (July-December). While the thunderstorm activity was very intense during July and August, no relationship between sferics and migraine was found. In summer, tension-type headaches were associated with meteorological parameters such as temperature (r=0.42, P<0.01) and vapour pressure (r=0.28, P<0.05). Although the sferics activity can explain a small percentage of the variation in migraine occurrence, a direct influence was more likely exerted by visible or otherwise perceptible weather conditions (thunderstorms, humidity, vapour pressure, warm sector, etc.) than by the sferics activity itself.

Adolescent↗
PubMed2006

Supraorbital neuralgia.

Supraorbital neuralgia is a rare disorder clinically characterized by the following triad: 1) forehead pain in the territory supplied by the supraorbital nerve, without side shift; 2) tenderness on either the supraorbital notch or traject of the nerve; and 3) absolute, but transitory relief of symptoms upon supraorbital nerve blockade. The pain presents with a chronic or intermittent pattern. In addition, there may be signs and symptoms of sensory dysfunction (hypoesthesia, paresthesia and allodynia), and typical "neuralgic features" (lightning pain and exteroceptive precipitating mechanisms). However, sensitive and neuralgic features are not constantly present and seem to be more frequent in the secondary, usually post-traumatic, forms.

Analgesics↗
PubMed1976

Subarachnoid block and enlargement of the spinal canal in hypertrophic neuritis.

A case of Dejerine-Sottas hypertrophic neuritis is reported. The patient, a 45-year-old male, suffered from chronic hypertrophic polyneuropathy, abnormal pupils, fasciculations, tremor, back pain, impotence, sphincter disorders, cramps, and lightning pains in the lower extremities. Besides extensive subarachnoid block, there was X-ray evidence of enlargement of the bony spinal canal with scalloping of the lumbar vertebrae. Surgical exploration showed these abnormalities to be due to extreme hypertrophy of the cauda equina. Histologic findings in peripheral nerve and lumbar root biopsies were typical of hypertrophic neuropathy of the onion bulb type. Vertebral changes secondary to hypertrophied nerve roots appear not to have been described before in hypertrophic neuritis; however, knowledge of their possible occurrence may be of practical importance in the management of similar future cases. A simple way of visualizing enlarged peripheral nerves is briefly described.

Cauda Equina↗
PubMed1976

A study of the resolution of dental films and screens.

From the study of the resolution produced by 156 screen-film combinations at a film density between 1.41 and 1.59, the following conclusions are drawn: 1. Resolution is affected by screens, films, and observers. 2. The effect of screens on resolution is much greater than the effect of films. 3. Screens varied greatly in resolving ability. 4. Films did not differ greatly in resolving ability. 5. Cronex Lightning Plus screen and Radelin super high-speed screen produced the lowest resolution and Cronex detail screen produced the highest resolution. 6. In general, the slower the screen, the higher is the resolution and vice versa. 7. There were two groups of films with significant resolution differences. 8. Films designed to be processed automatically did not differ significantly in their resolving ability when processed manually. 9. There is significant interaction effect of screens and films on resolution. 10. Individual visual resolving ability plays a significant role in measuring resolution.

Radiographic Image Enhancement↗
PubMedDate not supplied

Atmospheric electromagnetism: individual differences in brain electrical response to simulated sferics.

The living organism is constantly affected by natural electromagnetic influences covering a wide range of frequencies and amplitudes. One of these natural influences is represented by a phenomenon called atmospherics or sferics. Sferics are very weak electromagnetic impulses generated by atmospheric discharges (lightning). With a newly developed simulation system it was possible to reproduce a previously registered sferics signal and present it to 52 subjects while recording the electroencephalogram (EEG). The repeated application of this stimulus for ten minutes evoked a significant decrease in alpha power in parietal and occipital regions compared to the control condition without sferics presentation. Two constitutional factors were revealed as mediators of sferics effectiveness: the general physical condition of the subjects, and their neuroticism. Individuals with many somatic complaints and a high degree of emotional lability did not respond to the sferics stimulation. This absence of a response is interpreted as an adaptational deficit in reaction to variations in atmospheric parameters.

Adolescent↗
PubMed1991

Circadian rhythms of somatostatin-immunoreactivity in the suprachiasmatic nucleus of the rat.

Twenty-four hour patterns in somatostatin (SS)-like immunoreactivity (LI) within the suprachiasmatic nucleus (SCN) were determined by enzyme immunoassay in rats blinded by bilateral orbital enucleation or kept sighted under light-dark conditions. A remarkable circadian rhythm was found in the concentration of SS-LI in the SCN under blinded conditions. The peak time appeared at about circadian time (CT) 4 in the early subjective day and the trough at around CT 16 or 20 in the subjective night. Light-dark cycles did not alter the circadian patterns of SS-LI observed in the blinded rat SCN. These results indicate the presence of an endogenous circadian rhythm in SS-LI in the rat SCN, independent of environmental lightning cycles.

Animals↗
PubMed1994

Epidemiology, morbidity, mortality and treatment of burn injuries--a study in a peripheral industrial hospital.

This is a retrospective study of 348 patients with burn injuries admitted to a peripheral industrial hospital over a period of 10 years. The patients were from all walks of life. The study compared the incidence of burns occurring in various industries and those in other situations, assessed the morbidity and mortality profile of burn injuries treated in a hospital devoid of a modern burn care unit and presents ways of improving the treatment of burn injuries. Out of the 348 patients 42.5 per cent had major burns and 57.5 per cent had minor burns. Children mostly received minor burns, females between the ages of 20 and 40 years commonly received major burns. Flame burns due to kerosene stoves, open flames and fireworks were the commonest causative agent (60.3 per cent). Scalds comprised 28.7 per cent of the injuries, the remainder being due to chemicals, electricity and lighting. Eighty-five per cent of the burns occurred in households; 12 per cent were industrial burns and rest were due to road traffic accidents and lightning. Out of 42 industrial burns, only two cases were of major severity. Most of the industrial burns were scalds. The overall mortality was 18.3 per cent. The average hospital stay was 17.5 days. The treatment given to the patients is briefly discussed and the importance of the introduction of modern methods of burn management in our hospital is also emphasized.

Accidents, Occupational↗
PubMed2005

The psychiatric nurse practitioner 1993-2003: a decade that unsettled a specialty.

Between 1993 and 2003, a debate raged in psychiatric mental health (PMH) nursing. It was a decade of discourse about the role and titling of PMH advanced practice nurses. The PMH role evolution that occurred throughout this decade was driven by several forces, not all of which were in the control of PMH nursing. This article traces the multiple dynamics that prompted the evolution of the PMH nurse practitioner role, foremost the ascendancy of primary care and the influence of managed care. It also analyzes the conflict created by the American Nurses Credentialing Center PMH Nurse Practitioner examination that became a lightning rod for the disruption occurring in the traditional PMH role. Although the controversy surrounding PMH advanced practice nurse titling is beginning to clear, with the clarity comes a new set of problems for the development of the PMH workforce.

Certification↗
PubMed2006

Electrophysiological and behavioral measures of the influence of literal and figurative contextual constraints on proverb comprehension.

Proverbs tend to have meanings that are true both literally and figuratively (i.e., Lightning really doesn't strike the same place twice). Consequently, discourse contexts that invite a literal reading of a proverb should provide more conceptual overlap with the proverb, resulting in more rapid processing, than will contexts biased towards a non-literal reading. Despite this, previous research has failed to find the predicted processing advantage in reading times for familiar proverbs when presented in a literally biasing context. We investigate this issue further by employing both ERP methodology and a self-paced reading task and, second, by creating an item set that controls for problems with items employed in earlier studies. Our results indicate that although people do not take longer to read proverbs in the literally and proverbially biasing contexts, people have less difficulty integrating the statements in literal than figurative contexts, as shown by the ERP data. These differences emerge at the third word of the proverbs.

Aphorisms and Proverbs as Topic↗
PubMed2006

Impact of weather and climate on the incidence of acute coronary syndromes.

BACKGROUND: First investigations of the interactions between weather and the incidence of acute myocardial infarctions date back to 1938. The early observation of a higher incidence of myocardial infarctions in the cold season could be confirmed in very different geographical regions and cohorts. While the influence of seasonal variations on the incidence of myocardial infarctions has been extensively documented, the impact of individual meteorological parameters on the disease has so far not been investigated systematically. Hence the present study intended to assess the impact of the essential variables of weather and climate on the incidence of myocardial infarctions. METHODS: The daily incidence of myocardial infarctions was calculated from a national hospitalization survey. The hourly weather and climate data were provided by the database of the national weather forecast. The epidemiological and meteorological data were correlated by multivariate analysis based on a generalized linear model assuming a log-link-function and a Poisson distribution. RESULTS: High ambient pressure, high pressure gradients, and heavy wind activity were associated with an increase in the incidence of the totally 6560 hospitalizations for myocardial infarction irrespective of the geographical region. Snow- and rainfall had inconsistent effects. Temperature, Foehn, and lightning showed no statistically significant impact. CONCLUSIONS: Ambient pressure, pressure gradient, and wind activity had a statistical impact on the incidence of myocardial infarctions in Switzerland from 1990 to 1994. To establish a cause-and-effect relationship more data are needed on the interaction between the pathophysiological mechanisms of the acute coronary syndrome and weather and climate variables.

Climate↗
PubMed2006

Unusual visual symptoms in a patient with bilateral vertebral artery dissection: a case report.

We present a previously unreported set of symptoms in a patient found to have bilateral vertebral dissections. Although visual symptoms are common in vertebral dissection, their pattern does not typically mimic those that commonly precede or accompany migraine headache. When they do occur, they usually take the form of diplopia or blurred vision. The patient we describe had visual symptoms that varied over three episodes of headache and included transient visual field loss and scintillations ("lightning bolts"), both common in migraine. However, our patient's new visual symptoms represented a change in pattern from those that had accompanied her previous migraines. This detailed history-taking prompted an evaluation for an etiology other than migraine and prevented a further delay in diagnosis and treatment.

Adult↗
PubMed2006

Ethnomycological aspects of the desert truffle among native Bahraini and non-Bahraini peoples of the Kingdom of Bahrain.

This research was conducted to assess the general knowledge, attitude, and practice of native Bahraini and non-Bahraini peoples of Bahrain about ethnomycological aspects and traditional folklore of the desert truffle. The findings were obtained through interviews and a specially designed structured questionnaire administered to subjects who were randomly recruited. A total of three species were identified from the southern parts of Bahrain. Tirmania nivea "Zubaidi" was found to be the most preferred expensive and common type of truffle in the region to both groups of respondents due to its good light smell, delicacy, and soft white tissues. This was followed by Terfezia claveryi "Ikhlasi". Non-Bahraini respondents are more likely to believe that rain and soil (34%) or heavy thunder rains (23.4%) are the main factors responsible in truffle development, while Bahrainis perceive that an early heavy rainy season (57.8%) or soil type coupled with heavy rains (26.5%) are the most important reasons in truffle formation. Both respondent groups agree that heavy rains (>200 mm) during mild to warm weather, locally recognized as "Al-Wasm", coupled with heavy evening or early morning dewfalls and thunder and lightning are considered essential requirements for truffle formation. Trufflers in both groups similarly agree that mainly enjoying a good time was their motivations to collect truffles and not medicinal purposes. Truffle collection as a means for financial supplement and to pass this tradition from one generation to the next is no doubt another factors contributing for the collection. An analogous response from both groups indicated their unwillingness to buy truffles at relatively high price (mean 64%) or even off season but never objected to affordable price (mean 80.5%). About 95% of the non-Bahraini and 72% of the Bahraini respondents indicated their readiness to eat truffles for sexual reasons based on a physician's advice. The method used by almost 71% of the Bahraini respondents includes looking for an earth bulge with cracks on smooth surfaced sandy-loam soil whereas non-Bahrainis search randomly in unexploited desert habitats (49%) but not always looking for truffles, but by the presence of its host plant Helianthemum spp. (16.3%). For both groups, boiling the cleaned sliced truffle in salts and spices (mean 31%), or by deep-frying in local lamb ghee and spices (26%) is the most preferred way of eating truffles, while eating raw truffles is very rare. Finally, chilling cleaned truffles (45.6%) is the main method of preservation for short periods used by the Bahraini respondents, otherwise freezing (30.4%) is used for prolonged preservation, compared to non-Bahraini respondents who prefer freezing as the primary method (51.4%). Some Bedouins preserve clean truffles by pickling in 3-6% vinegar and salt. The influence of soil and environmental factors on truffle development and the role of desert truffles on traditional information, socioeconomic, ecology and sociocultural folklore in Bahrain are discussed.

Anti-Infective Agents↗
PubMed2004

The role of adverse weather conditions in acute releases of hazardous substances, Texas, 2000-2001.

High winds, flooding, lightning, and other phenomena associated with adverse weather can cause power failures, equipment damage, and process upsets resulting in chemical releases. Of the 5000 events in Texas that were reported to the Hazardous Substances Emergency Events Surveillance (HSEES) system during 2000-2001, adverse weather conditions contributed to 110 (2%) events. Rain was the most frequent adverse weather condition. Most events to which adverse weather conditions contributed occurred during June or September; these months correspond with the high temperature and hurricane season in Texas. Most events occurred in coastal counties with large numbers of industrial facilities. Three industries reported the majority of events: industrial and miscellaneous chemicals manufacturing; petroleum refining; and plastics, synthetics, and resin manufacturing. Power failures were associated more often with adverse weather-related events than with nonweather-related events. Releases occurred most commonly from ancillary process equipment and process vessels. Events associated with adverse weather-related conditions involved nine victims. System and process design improvements, such as improved backup power generation and redesigned secondary containment systems, could be explored to reduce the potential negative effects of severe weather.

Accidents, Occupational↗
PubMed2004

Pediatric electrical injuries: a review of 38 consecutive patients.

BACKGROUND/PURPOSE: The aim of this study was to explore the mechanisms, complications, morbidity, and mortality associated with electrical injuries in children. METHODS: The charts of pediatric patients who had been admitted to the authors' center with electrical burn injuries (EBI) between January 1993 and October 2002 were reviewed retrospectively. RESULTS: Of the 764 acute burn admissions over a 9-year period, 5% (38 patients) had EBI. Mean age was 9.6 +/- 4.4 years (range, 1 to 16 years). Seventy-six percent of the EBI patients were boys (M to F, 29:9), and the extent of the burn wounds ranged from 1% to 50% of total body surface area (TBSA; mean, 18.6% +/- 14.7%). High-voltage (HV) electricity accounted for 63% of the EBI (1 lightning), and 37% were caused by low-voltage (LV) current. In 19 children, serious high-voltage injuries occurred by direct contact with outlet electrical transfer wires with a metal from a balcony or with manual contact while climbing to the pole. A total of 153 surgical procedures were performed on the EBI patients, and 26% of the cases (10 of 38) required amputations. Patients who sustained HV electrical injuries had associated major complications. All of the patients underwent close cardiac monitoring, and none had cardiac complications. The average hospital stay was 23.8 +/- 14.2 (range, 2 to 48) days. One patient died of wound sepsis. CONCLUSIONS: Although not frequent, EBI remain a serious problem, particularly in adolescent boys, and short- and long-term morbidity are significant. HV injuries occur mainly in the adolescent population and require more aggressive care. Balcony injury is a specific etiology for EBI, and special consideration is required to prevent this type of injury in our country.

Accidents, Home↗