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At least 19 recordsLinked to original sources
PubMed2006

Long term fire scar monitoring with remote sensing in Northern Namibia: relations between fire frequency, rainfall, land cover, fire management and trees.

A cost-effective method was developed to map fire scars on Quicklooks of Landat TM imagery. The method was compared with a full resolution Landsat image using visual interpretation and supervised classification using the Maximum Likelihood procedure, resulting in a high degree of agreement between methods. A long time series of fire scars was developed using all available Landsat Quicklooks between 1989 and 2001 for an area of 63000 sq km in north-east Namibia. Between 27 and 51% of the study area burned annually, while only 10% of the area did not burn between 1989 and 2001. Not-burned areas were mainly settled areas and permanent wetlands. 33% of the area burned between 5 and 7 times during the 13 years indicating a high frequency overall. Rainfall and livestock had little influence on burned areas. In 1996 formal fire management started in a portion of the study area consisting of building firebreaks and holding awareness programs. A comparison of burned areas before and after the intervention started allowed evaluating its effectiveness. The area where the formal fire management program was undertaken showed a significant decrease in burned area. It is suggested that awareness campaigns rather than firebreaks contributed to this decrease. Selected tree population data were compared with fire frequencies. Differences in tree occurrence, regeneration, and stem diameter distributions between low and high fire frequencies could be detected and explained with known responses of the species to fire. This suggests that the observed time series is representative of a long-term fire regime in the area.

Biomass↗
PubMed1983

Fire ant venom hypersensitivity. I. Comparison of fire ant venom and whole body extract in the diagnosis of fire ant allergy.

Levels of IgE antibody to fire ant whole body extract (FA-WBE) and fire ant venom (FAV) were evaluated in 60 patients with clinical histories of fire ant sting hypersensitivity and 11 frequently stung individuals without significant clinical reactivity to fire ant. An overlap of levels of IgE antibody to FA-WBE and FAV was seen between groups of patients with increasingly severe clinical reactivity; however, the group mean IgE antibody level of patients without significant clinical reactivity differed markedly from the group means of patients with more severe clinical reactivity (p less than 0.001). In 31 patients a good correlation (r = 0.6935) was found comparing FA-WBE IgE antibody level with FA-WBE skin tests, and in 26 patients a good correlation (r = 0.8564) was obtained comparing FAV IgE antibody levels with FAV skin tests. An excellent Spearman rank correlation coefficient (r = 0.9197) was found on comparison of FAV and FA-WBE IgE antibody levels in 71 individuals. Cross-reactivity of FAV and FA-WBE was demonstrated by the ability of these reagents to competitively inhibit the binding of IgE antibody to solid-phase FA-WBE and FAV in the radioallergosorbent test (RAST). From these results we conclude that FAV and FA-WBE both contain relevant allergens important in fire ant-allergic individuals and that skin tests and RAST are both valid as diagnostic tests for fire ant allergy. Finally, there is a good correlation between RAST and skin tests using FA-WBE or FAV as test reagents, since these reagents are highly cross-reactive as demonstrated by their ability to inhibit each other in the RAST.

Adolescent↗
PubMed2005

Using satellite fire detection to calibrate components of the fire weather index system in Malaysia and Indonesia.

Vegetation fires have become an increasing problem in tropical environments as a consequence of socioeconomic pressures and subsequent land-use change. In response, fire management systems are being developed. This study set out to determine the relationships between two aspects of the fire problems in western Indonesia and Malaysia, and two components of the Canadian Forest Fire Weather Index System. The study resulted in a new method for calibrating components of fire danger rating systems based on satellite fire detection (hotspot) data. Once the climate was accounted for, a problematic number of fires were related to high levels of the Fine Fuel Moisture Code. The relationship between climate, Fine Fuel Moisture Code, and hotspot occurrence was used to calibrate Fire Occurrence Potential classes where low accounted for 3% of the fires from 1994 to 2000, moderate accounted for 25%, high 26%, and extreme 38%. Further problems arise when there are large clusters of fires burning that may consume valuable land or produce local smoke pollution. Once the climate was taken into account, the hotspot load (number and size of clusters of hotspots) was related to the Fire Weather Index. The relationship between climate, Fire Weather Index, and hotspot load was used to calibrate Fire Load Potential classes. Low Fire Load Potential conditions (75% of an average year) corresponded with 24% of the hotspot clusters, which had an average size of 30% of the largest cluster. In contrast, extreme Fire Load Potential conditions (1% of an average year) corresponded with 30% of the hotspot clusters, which had an average size of 58% of the maximum. Both Fire Occurrence Potential and Fire Load Potential calibrations were successfully validated with data from 2001. This study showed that when ground measurements are not available, fire statistics derived from satellite fire detection archives can be reliably used for calibration. More importantly, as a result of this work, Malaysia and Indonesia have two new sources of information to initiate fire prevention and suppression activities.

Calibration↗
PubMed2005

Tremor in Parkinson's disease patients can be induced by uncontrolled activation and uninhibited synchronization of alpha2-motoneuron firing to which alpha1-motoneuron firing synchronizes.

With the surface electromyography (sEMG) and the single nerve-fibre action potential recording method a mechanism is measured how rhythmic muscle contraction and tremor in Parkinson's disease patients is generated. With sEMG it could be shown that the tremor started when alpha2-motor units (FR-type) spontaneously began to fire synchronizedly oscillatory. Two possibilities of alpha2-motor unit synchronization were observed. In one case one alpha2-motor unit started to fire oscillatory and other alpha2-motor units started to fire oscillatory in synchronization with the first alpha2-motor unit. In a second case several alpha2-motor units fired oscillatory, but not in a synchronized manner. With the synchronization of the oscillatory firing alpha2-motor units again synchronizedly oscillatory firing of several alpha2-motor units appeared. When later on, several additional alpha1-motor units (FF-type) started to fire and in synchrony with the synchronizedly oscillatory firing alpha2-motor units (FR-type), rhythmic muscle contraction and tremor were observed. Visible muscle contraction and tremor stopped, when the alpha1-motor units stopped firing, which could a.o. be achieved by the patient concentrating on the tremor. The single nerve-fibre action potential recording method showed that alpha1 and alpha2-motoneurons in the cauda equine nerve roots fired oscillatory, that they could synchronize their firing and that these oscillatory firing motoneurons could build up an external loop to the periphery in the way that gamma-motoneurons and muscle spindle afferents were included in the rhythmic coordinated firing But the synchronization of oscillatory firing was only transient and the building up of an external loop to the periphery only occurred in non-Parkinson patients upon strong repetitive reflex stimulation. It is therefore concluded that in patients with Parkinson's disease there is firstly a lack of inhibition, so that motoneurons can start to fire oscillatory upon nearly no stimulation and there is secondly lack of mutual inhibition between oscillatory firing motoneurons, so that oscillatory firing motoneurons can synchronize their firing to give rise to rhythmic muscle contraction and tremor.

Action Potentials↗
PubMed2001

Correlation between uncoupled conductance-based integrate-and-fire neurons due to common and synchronous presynaptic firing.

We investigate the firing characteristics of conductance-based integrate-and-fire neurons and the correlation of firing for uncoupled pairs of neurons as a result of common input and synchronous firing of multiple synaptic inputs. Analytical approximations are derived for the moments of the steady state potential and the effective time constant. We show that postsynaptic firing barely depends on the correlation between inhibitory inputs; only the inhibitory firing rate matters. In contrast, both the degree of synchrony and the firing rate of excitatory inputs are relevant. A coefficient of variation CV > 1 can be attained with low inhibitory firing rates and (Poisson-modulated) synchronized excitatory synaptic input, where both the number of presynaptic neurons in synchronous firing assemblies and the synchronous firing rate should be sufficiently large. The correlation in firing of a pair of uncoupled neurons due to common excitatory input is initially increased for increasing firing rates of independent inhibitory inputs but decreases for large inhibitory firing rates. Common inhibitory input to a pair of uncoupled neurons barely induces correlated firing, but amplifies the effect of common excitation. Synchronous firing assemblies in the common input further enhance the correlation and are essential to attain experimentally observed correlation values. Since uncorrelated common input (i.e., common input by neurons, which do not fire in synchrony) cannot induce sufficient postsynaptic correlation, we conclude that lateral couplings are essential to establish clusters of synchronously firing neurons.

Animals↗
PubMed2004

Prevention of residential roof fires by use of a class "A" fire rated roof system.

Because residential roof fires remain a life-threatening danger to residential homeowners in the United States, we describe in detail a national fire prevention program for reducing residential roof fires by use of an Underwriters Laboratories Inc. (UL) and National Fire Protection Association Class A fire rated roof system. This Class A system should comply with the test requirements for fire resistance of roof coverings, as outlined in UL 790 or in ASTM International (ASTM) E-108. Both the Asphalt Roofing Manufacturer's Association (ARMA) and the National Roofing Contractors Association (NRCA) have set up guidelines for selecting a new roof for the homeowner. Class A, fiber-glass-based asphalt roofing shingles represent an overwhelming share of the United States residential roofing market, and, as such, the Class A rated roofing system remains an excellent alternative to wood shingles and shakes. Fortunately, the Class A fire rating is available for certain wood shingle products that incorporate a factory-applied, fire resistant treatment. However, in this circumstance, wood products labeled as Class B shakes or shingles must be installed over spaced or solid sheathing that have been covered either with one layer of 1/4 in. (6.4 mm) thick noncombustible roof board, or with one layer of minimum 72-lb. fiber-glass-based mineral surfaced cap sheet, or with another specialty roofing sheet to obtain the Class A fire rating. Clay, tile, slate, and metal have been assigned Class A fire ratings in the codes (but often without testing). These alternative roofing materials are often considerably more expensive. Proper application, ventilation, and insulation of roofing systems are required to prevent heat and moisture buildup in the attic, which can damage the roofing system, making it more susceptible to water leakage as well as ignition in the event of a fire. The NRCA has devised excellent recommendations for the homeowner to prequalify the contractor. In addition, a warranty for any new roofing material is important for the homeowner to ensure that the roofing can be repaired by the contractor or manufacturer during the specified warranty period, in case of contractor error or a manufacturing defect. In addition, the homeowner should ensure that the warranty is transferable to any future owner of the home to allow the buyer to have the same warranty benefits as the original owner. The State of California has mandated strict roofing requirements to prevent residential fires. In the absence of this legislation in other states, the homeowner must follow the guidelines outlined in this collective review to ensure that a roofing system with Class A fire protection is installed. Other fire safety precautions that should also be considered mandatory are to include smoke alarms, escape plans, and retrofit fire sprinklers.

Fire Extinguishing Systems↗
PubMed2005

Fire regenerative syndromes of forest woody species across fire and climatic gradients.

Community resilience after fire is determined by species' ability to regenerate through two main mechanisms growth of new sprouts (resprouter species) and germination from surviving seed banks or from seeds arriving from neighbouring populations (seeder species). Both the mechanisms are present in Mediterranean communities. The occurrence of both the types in a community depends on fire history and the bio-geographical history determining the available species pool. Regenerative traits also covary with other functional attributes associated with resource acquisition and stress tolerance. As post-fire regenerative responses can be related to various ecological factors other than fire, we tested the hypothesis of a different proportional representation of post-fire regenerative syndromes in forest woody species along a climatic gradient in Catalonia (NE Spain) ranging from Mediterranean to temperate-boreal climates. Specifically, we expected seeder species to become less common with colder and moister conditions while resprouters would not be so influenced by the climatic gradient. We also tested the hypothesis of change in the relative abundance of regenerative syndromes in relation to recent fire history. We analysed a large database obtained from extensive forestry surveys and remote sensing fire records. After correction for spatial autocorrelation, we found an increase in the proportion of seeder species under more Mediterranean conditions and a decrease in fire-sensitive species (with no efficient mechanisms of post-fire recovery) in moister conditions. Resprouter species were similarly present across the whole gradient. A similar pattern was observed after excluding recently burnt plots. Therefore, post-fire regenerative syndromes segregate along the climatic gradient. Recent fires reduced the occurrence of fire-sensitive species and increased the proportion of seeder species. No significant effect was observed on resprouter species. Fire has a sorting effect, shaping the occurrence of species with different regenerative traits. Overall, fire seems to explain better the variability of the proportion of fire-sensitive species and climate the variability of seeder species. In addition, other factors (forestry practices and the covariation between regenerative and functional attributes) are likely to contribute to the regional pattern of regenerative syndromes.

Climate↗
PubMed2005

Factors controlling seedling germination after fire in Mediterranean gorse shrublands. Implications for fire prescription.

In Western Mediterranean areas, fires are frequent in forests established on old croplands where woody resprouting species are scarce and post-fire regeneration is limited to obligate-seeder species, such as Mediterranean gorse (Ulex parviflorus), that accumulate a great deal of fine dry fuel, increasing the risk of other severe fires. Under these conditions, fuel control techniques are required in order to prevent fires of high intensity and severity and the subsequent economic and ecological damage. Prescribed fires present an alternative to fuel control, and recent studies demonstrate that, under optimum climatic conditions, fire-line intensity values fall within the limits of those recommended for fire prescription. However, a better understanding of the consequences of fire on the regeneration of vegetation is needed in order to evaluate the suitability of prescribed fires as a technique for fuel reduction in Mediterranean gorse ecosystems. This paper analyses the factors controlling seedling germination after fire to make an evaluation from an ecological perspective of whether fire prescription is a suitable technique for fuel control in mature Mediterranean gorse shrublands. The results show that small differences in the composition of vegetation play a decisive role in fire behaviour, and have a decisive influence on the system's capacity for regeneration. Fire severity is low in mixed Mediterranean gorse communities with a low continuity of dead fine fuel (including Cistus sp., Rosmarinus sp., etc.) and fire creates a wide range of microhabitats where seedling emergence is high. In contrast, where U. parviflorus is more dominant, fire severity is higher and the regeneration of vegetation could be hindered. Our conclusions suggest that detailed studies of the composition of plant communities are required in order to decide whether prescribed burning should be applied.

Conservation of Natural Resources↗
PubMed1991

Occupational noise exposure and hearing loss in fire fighters assigned to airport fire stations.

The National Institute for Occupational Safety and Health (NIOSH) was requested to conduct a health hazard evaluation (HHE) at a large metropolitan fire department. The request concerned the hearing levels and noise exposures of fire fighters who were assigned to two fire stations serving the international airport. There was concern that these fire fighters were at a greater risk of accruing hearing loss than fire fighters located at other fire stations because of the addition of aircraft noise to their occupational noise exposures. The city also requested that NIOSH investigate other fire stations, not influenced by the airport, for noise exposures and hearing ability among a larger population of the fire fighters. NIOSH investigators conducted noise surveys at five fire stations and examined the hearing ability of 197 fire fighters. The noise surveys consisted of personal noise dosimetry on fire fighters assigned to the fire station for the entire 24-hr tour of duty over 2 consecutive days at each of the five stations. A NIOSH investigator accompanied the fire fighters on their vehicle to log response times and activities. The audiometric examinations were pure-tone, air conduction tests administered according to the Occupational Safety and Health Administration's (OSHA's) hearing conservation amendment. The noise dosimetry results revealed time-weighted averages (TWAs) that ranged from 60 to 82 dBA. However, the levels encountered during Code 3 responses (warning lights, sirens, and air horns) reached 109 dBA for a 1-min time period. The audiometric results showed that the average fire fighter exhibited a characteristic noise-induced permanent threshold shift.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Playing with fire: images of fire on toy packaging.

Despite prevention efforts designed to teach children that fire is not a toy, each year hundreds of children, primarily male, are injured while playing with fire. Mass-produced toys and games shape children's behaviors, and the fire images on toy packaging may send the message that fire is fun rather than dangerous. The purpose of this study was to determine the frequency of male fire-related injuries at our burn center and to investigate the use of fire images in toy packaging. An aisle-by-aisle search was conducted at a national toy store. Toys with fire images on their packaging were identified. Target gender and the setting in which the fire was displayed also were recorded. Only toys with clearly visible flames on their packaging were included. We reviewed our TRACS database from April 1997 to May 1999 for fire-related injuries to children admitted to our institution as a result of playing with fire. Review of toy stores revealed 404 toys with packaging containing fire images. Of these, 97% (393 of 404) were targeted to males. Video games were the leading category of flame-related packaging (208 of 404), followed by toy car/truck displays (84 of 404). Packaging for girls' toys had safe and contained settings, whereas boys' toys used settings that were uncontrolled and associated with speed and weapons. A total of 59 children, 52 males and 7 females, with a mean age of 10 +/- 0.6 years and mean TBSA burn of 12.3 +/- 2.1% were admitted to our facility with fire-related injuries during the study interval. Children imitate life with toys and use play to experiment with new behavior. Boys are receiving a powerful, consistent message from images of fire on toy packaging. These advertisements may help to contribute to the higher incidence of fire-related injuries in boys.

Accident Prevention↗
PubMed2005

Higher magnitude accumbal phasic firing changes among core neurons exhibiting tonic firing increases during cocaine self-administration.

Studies using i.v. cocaine self-administration in rats have documented rapid-phasic changes in the firing rate of nucleus accumbens neurons within seconds of cocaine-reinforced lever presses, as well as changes that occur over the course of the cocaine self-administration experiment, i.e. tonic changes in firing rate. During the self-administration period of the experiment, individual neurons exhibit either a tonic increase, a tonic decrease, or no tonic change in firing rate, relative to the neuron's firing rate during the pre-drug period. We evaluated whether rapid-phasic changes in firing were differentially associated with tonically reduced or tonically elevated firing of nucleus accumbens core and shell neurons in cocaine self-administering rats. Rapid-phasic firing patterns within seconds of the cocaine-reinforced lever press were exhibited predominantly by core neurons that also exhibited tonic increases in firing. Conversely, core neurons that did not exhibit such rapid-phasic firing patterns were more likely to show tonically reduced firing. Moreover, core neurons were more likely than shell neurons to exhibit: 1) tonic increases in firing and 2) rapid-phasic increases in firing preceding the cocaine-reinforced lever press. These differences between accumbens subterritories may be related to their distinct involvement in operant responding; the present findings are consistent with an emerging literature which implicates shell in contextual stimulus-induced responding, and core in processing the instrumental response via its discrete output to classic basal ganglia structures. The distinct tendency of the core to exhibit increased firing, coupled with its dichotomous firing outputs (i.e. tonic decreases without rapid phasic responses or tonic increases with rapid phasic responses), may reflect particular sensitivity of these neurons to excitatory limbic afferent signaling involved in instrumental responding. Enhanced phasic responsivity in the core may be an integral component of the mechanism inherent in normal reward processing which is subverted by chronic drug exposure.

Animals↗
PubMed2001

Apamin-induced irregular firing in vitro and irregular single-spike firing observed in vivo in dopamine neurons is chaotic.

Dopamine neurons of the substantia nigra often fire action potentials irregularly in vivo, but in vitro fire in a regular, pacemaker-like firing pattern. Bath application of apamin, a blocker of calcium-activated potassium channels, can shift a dopamine neuron from pacemaker-like to irregular firing. To determine whether the irregular firing was caused by intrinsic cellular mechanisms rather than random synaptic input or some other form of noise, spike density functions of interspike interval records were analyzed using non-linear forecasting methods to quantify any non-linear (non-periodic) structure. Intrinsic cellular mechanisms are capable of producing chaotic firing, which is deterministic, non-linear, and loses predictability exponentially with increasing forecast time.To determine whether forecasting spike density functions could reliably measure predictability, forecasting was first applied to spike density functions produced by computer simulations of pacemaker-like, chaotic, and random firing, as well as pacemaker-like and chaotic firing that were randomly synaptically driven. Exponential loss of predictability was successfully detected in both chaotic and randomly driven chaotic firing. Predictability scaled faster than exponentially for random spiking, and linearly (slower than exponentially) for randomly driven pacemaker firing. The method was then applied to experimental records of apamin-induced irregular firing of rat dopaminergic neurons of the substantia nigra in vitro and in vivo. Exponential loss of predictability was detected in both cases, consistent with chaotic firing. Experimental records of pacemaker-like firing in vitro showed linear scaling, consistent with a randomly driven pacemaker. Several schemes for neural encoding of synaptic inputs have been suggested, such as rate codes or temporal codes. However, our results suggest that under some conditions, the irregular firing of dopamine neurons does not reflect the random temporal dynamics of its inputs, but rather the intrinsic, deterministic dynamics of dopamine cells themselves, under the tonic neuromodulatory influence of apamin in vitro and possibly that of an unidentified endogenous modulatory substance in vivo.

Action Potentials↗
PubMed2003

Evaluation of the fire simulation processes of the National Fire Management System's Initial Attack Analysis processor.

The fire simulation processes of the National Fire Management System's (NFMAS) Initial Attack Analysis (IAA) processor were evaluated by conducting two types of sensitivity analysis: one based on a hypothetical set of data to assess IAA's outputs under a wide range of fire input values, and the other using an actual Stanislaus National Forest database to test IAA's validity with a real set of data. The results revealed that IAA's outputs (projected annual number of fires and area burned) were most sensitive, in descending order, to the input values of the fire spread rate, the productivity rates of the suppression forces, and the initial attack time, for all fuel models tested. In contrast, IAA's outputs were extremely insensitive to variations in the fire size at discovery. Changes are necessary in the ways IAA incorporates the fire size at discovery to facilitate the comparison among various fire detection options. The program's "escaped fire situation" analysis was found inadequate, because the projected annual frequencies and final sizes of the simulated escaped fire events produced unacceptable results with the Stanislaus National Forest database. Assigning final sizes to simulated escaped fires according to the fire intensity level in which they are historically expected to occur provides a consistent way of calculation of the projected annual area burned and the consequent cost plus net value change (C + NVC).

Conservation of Natural Resources↗
PubMed2001

Blood carbon monoxide and hydrogen cyanide concentrations in the fatalities of fire and non-fire associated civil aviation accidents, 1991-1998.

Blood samples submitted to the Civil Aeromedical Institute (CAMI) from aviation accident fatalities are analyzed for carbon monoxide (CO), as carboxyhemoglobin (COHb), and hydrogen cyanide, as cyanide (CN(-)). These analyses are performed to establish possible exposure of victims to smoke from in-flight/post-crash fires or to CO from faulty exhaust/heating systems. The presence of both gases in blood would suggest that the victim was alive and inhaled smoke. If only COHb is elevated, the accident (or a death) could be the result of CO contamination of the interior. Information pertaining to blood levels of these gases in aviation fatalities, in relation to the associated accidents, is scattered or not available, particularly with regard to toxicity. Therefore, considering that COHb> or =10% and CN(-)> or =0.25 microg/ml are sufficient to produce some degree of toxicological effects, the necessary information was extracted from the CAMI database. Samples from 3857 fatalities of 2837 aviation accidents, occurring during 1991-1998, were received; 1012 accidents, encompassing 1571 (41%) fatalities, were fire associated, whereas 1820 accidents were non-fire related. The remaining five accidents were of unknown fire status. There were fewer fire related fatalities and associated accidents in the (COHb> or =10% and CN(-)> or =0.25 microg/ml) category than that in the (COHb<10% and CN(-)<0.25 microg/ml) category. No in-flight fire was documented in the former category, but in-flight fires were reported in 14 accidents (18 fatalities) in the latter category. No non-fire accident fatality was found wherein levels of both gases were determined to be at or above the stated levels. There were 15 non-fire accidents with 17 fatalities wherein only COHb (10-69%) was elevated. The present study suggests that aviation fire accidents/fatalities were fewer than aviation non-fire accidents/fatalities and confirms that aviation accidents related to in-flight fires and CO-contaminated interiors are rare.

Accidents, Aviation↗
PubMed1999

Reexamining fire suppression impacts on brushland fire regimes

California shrubland wildfires are increasingly destructive, and it is widely held that the problem has been intensified by fire suppression, leading to larger, more intense wildfires. However, analysis of the California Statewide Fire History Database shows that, since 1910, fire frequency and area burned have not declined, and fire size has not increased. Fire rotation intervals have declined, and fire season has not changed, implying that fire intensity has not increased. Fire frequency and population density were correlated, and it is suggested that fire suppression plays a critical role in offsetting potential impacts of increased ignitions. Large fires were not dependent on old age classes of fuels, and it is thus unlikely that age class manipulation of fuels can prevent large fires. Expansion of the urban-wildland interface is a key factor in wildland fire destruction.

Journal Article↗
PubMed1984

The control of firing pattern in nigral dopamine neurons: burst firing.

In addition to firing in a single spiking mode, dopamine (DA) cells have been observed to fire in a bursting pattern with consecutive spikes in a burst displaying progressively decreasing amplitude and increasing duration. In vivo intracellular recording demonstrated the bursts to typically ride on a depolarizing wave (5 to 15 mV amplitude). Although the burst-firing frequency of DA cells showed little correlation with the base line firing rate, increases in firing rate were usually associated with an increase in burst firing. Increases in burst firing could also be elicited by intracellular calcium injection and could be prevented by intracellular injection of EGTA, suggesting a calcium involvement in bursting. Blockade of potassium conductances with extracellular iontophoresis of barium or intracellular injection of tetraethylammonium bromide could also trigger an increased degree of burst firing in DA cells. These data suggest that the increased calcium influx accompanying an increased firing rate triggers burst firing, possibly by inactivating a potassium conductance. A switch from a single spiking mode to a burst-firing mode may be important in modulating striatal DA release, as shown for burst firing in other preparations.

Action Potentials↗
PubMed2004

Fire in the OR--developing a fire safety plan.

Approximately 100 operating room fire occur each year in the United States. Although rare, fire in a perioperative setting can be disastrous for both patients and staff members. It is crucial that all perioperative departments have a well thought out and previously rehearsed fire plan in place. Multidisciplinary planning and implementation of regularly scheduled and scripted fire drills are essential to prevent adverse outcomes. Fire drills ensure that all staff members are familiar with the use and location of fire pull stations, fire extinguishers, and fire blankets. Fire drills also prepare staff members to evacuate the OR area if necessary. This article provides the information and framework necessary to develop and implement comprehensive OR fire safety plans that could make the difference between life and death in a fire emergency.

Boston↗
PubMed2004

Effect of simple spike firing mode on complex spike firing rate and waveform in cerebellar Purkinje cells in non-anesthetized mice.

Cerebellar Purkinje cells receive two different excitatory inputs from parallel and climbing fibers, causing simple and complex spikes, respectively. Purkinje cells present three modes of simple spike firing, namely tonic, silent and bursting. The influence of complex spike firing on simple spike firing has been extensively studied. However, it is unknown whether and how the simple spike firing mode may influence complex spike waveform and firing rate in vivo. We studied complex spike firing during tonic and silent mode periods in non-anesthetized mice. We found that complex spike firing rate is not influenced by simple spike firing modes, but that the complex spike waveform is altered following high frequency simple spike firing. This alteration is a specific decrement of the second depolarizing component of the complex spike. We demonstrate that the amplitude of the second depolarizing component is inversely proportional to the simple spike firing rate preceding the complex spike and that this amplitude is independent of previous complex spike firing. This waveform modulation is different from previously reported modulation in paired-pulse depression and refractoriness.

Action Potentials↗