Drop In Barometric Pressure Research Articles

Barometric pressure decrease induces density-dependent changes in foraging behaviour in a parasitoid fly.

Barometric pressure is an environmental factor involved in the modulation of a variety of activities in insects. Generally, a drop in barometric pressure precedes the arrival of weather conditions that can affect insect activities and life expectancy. We simulated different scenarios of pressure drop in a modified hermetic chamber and studied their influence on the host-seeking behaviour of the larvae of the robber fly Mallophora ruficauda using air stationary olfactometers. In addition, we studied whether larval density modulates orientation to the host under the same scenarios of pressure drop. We found that motivation to search for hosts is affected by the same slope of pressure drop in both low- and high-density larvae. However, larval density modulates the onset of the responses to pressure decrease, as low-density larvae stop searching for hosts more quickly than high-density larvae. This result reflects an avoidance strategy according to which low-density larvae would have a reduced host range and higher risk of mortality and fewer chances to find a suitable host under adverse pressure conditions. Low-density larvae, known to prefer healthy hosts, do not search for parasitized hosts under normal pressure conditions nor under a range of pressure drops, strongly suggesting that host selectivity is not modulated by barometric pressure. This study paves the way to a better understanding of the changes in crucial insect behaviours induced by weather conditions, and provides more knowledge about the risk factors likely to affect insect survival in the context of foraging ecology.

Hitna medicinska stanja tokom komercijalnih letova avionom - "Ima li lekara u avionu?"

Almost four billion passengers travel aboard commercial airliners every year. Last year In-flight medical emergencies (IMEs) were relatively common and occurred in a complex environment with limited medical resources. More recent data shows that IMEs occur in one passenger for every 604 flights or 24-130 IMEs for every one million passengers, more often in people over 70 years old. Due to the drop in barometric pressure, there are specific conditions in the aircraft passenger cabin that can affect the occurrence of IMEs. Most importantly it is hypobaric hypoxia, which can lead to the development of hypoxia-related symptoms in chronic patients with respiratory, cardiovascular, and hematological diseases. With reduced barometric pressure gases in body cavities and medical equipment can expand by 30%, this can lead to IMEs in recently operated patients (wound dehiscence, bleeding), middle ear and sinus diseases, subocclusions, and lung problems (pulmonary bulla). Other factors that contribute to the occurrence of IMEs are limited movement (deep vein thrombosis), dry and cold air (dehydration), jet lag, turbulence, and psychological stress. IMEs most commonly involve syncope or near-syncope (32.7%), gastrointestinal (14.8%), respiratory (10.1%), and cardiovascular (7.0%) symptoms. Because of ethical, and in some countries also legal responsibilities, doctor-passengers are a great help in the treatment of IMEs. Emergency landing of the aircraft when an IME occurs happens in an estimated 4.4% of cases. Knowing the influence of the specific ambient conditions in the plane on physiological processes in the body is of great importance for determining the absolute and relative contraindications for flying by plane. Doctor-passengers have an important role in the treatment of IMEs. This work aims to introduce us to the specific ambient conditions in the aircraft cabin and their influence on the physiology of the human body, the most common IMEs that occur under the influence of those conditions, the role of the doctorpassenger as well as the absolute and relative contraindications for flying by plane.

High Altitude Pulmonary Physiology

High altitude is defined as regions above 2400 meters above sea level. Almost 2% of the world’s population dwells in high-altitude regions of the world. The respiratory system plays an important role in determining survival and undergoes a series of adaptive changes to compensate for hypobaric hypoxic states (decreased barometric pressure with increasing altitude) including increased alveolar ventilation, diffusion capacity, pulmonary vascular vasoconstriction, increased cardiac output, shifted of oxyhemoglobin dissociation curve and polycythemia. Being at a high altitude suddenly without compensation can be bad and cause medical problems that will arise when at an altitude due to a decrease in PaO2 caused by a drop in barometric pressure.

ЗАКОНОМЕРНОСТИ ИЗМЕНЕНИЯ ГАЗОДИНАМИЧЕСКОЙ И ГЕОМЕХАНИЧЕСКОЙ ОБСТАНОВКИ НА КАЛИЙНЫХ РУДНИКАХ

Mining operations in potash and salt deposits are complicated by gas emissions and gas dynamic phenomena. The analysis of a large number of gas dynamic phenomena and intense gas emissions at potash mines in Russia and Belarus allowed the authors to identify some patterns. In particular, it was found that the maximum number of gas dynamic phenomena occurs in the 7–10 year of operation of the mines. The purpose of the study is to analyze and identify available information on the influence of heliophysical and manmade factors on the state of rock massifs, which will allow purposefully predicting and preventing the manifestations of these factors, increasing labor safety and efficiency of mining enterprises. Research methods: methods of a full-scale mine experiment to determine the gas content of rocks and the gas content of workings, as well as analysis of statistical data. The results of the study showed that the analysis of data on 84 cases of gas dynamic phenomena at the mines of PJSC Uralkali revealed an increase in the volume of gas emissions from the developed lavas spaces at the mines of JSC Belaruskali as a result of a drop in barometric pressure on the surface. In conclusion, it can be noted that the combination of natural factors together with a powerful man-made impact on the environment creates certain prerequisites for disasters of various scales, ranging from destructive earthquakes to subsidence of mountain pressure, gas dynamic phenomena and intense gas emissions in mines and mines. The set of established patterns formed the basis for the development of a number of preventive measures that increase the safe working conditions of miners and the efficiency of mining enterprises.

Exercise-Induced Hypoxemia in Endurance Athletes: Consequences for Altitude Exposure.

Exercise-induced hypoxemia (EIH) is well-described in endurance-trained athletes during both maximal and submaximal exercise intensities. Despite the drop in oxygen (O2) saturation and provided that training volumes are similar, athletes who experience EIH nevertheless produce the same endurance performance in normoxia as athletes without EIH. This lack of a difference prompted trainers to consider that the phenomenon was not relevant to performance but also suggested that a specific adaptation to exercise is present in EIH athletes. Even though the causes of EIH have been extensively studied, its consequences have not been fully characterized. With the development of endurance outdoor activities and altitude/hypoxia training, athletes often train and/or compete in this stressful environment with a decrease in the partial pressure of inspired O2 (due to the drop in barometric pressure). Thus, one can reasonably hypothesize that EIH athletes can specifically adapt to hypoxemic episodes during exercise at altitude. Although our knowledge of the interactions between EIH and acute exposure to hypoxia has improved over the last 10 years, many questions have yet to be addressed. Firstly, endurance performance during acute exposure to altitude appears to be more impaired in EIH vs. non-EIH athletes but the corresponding physiological mechanisms are not fully understood. Secondly, we lack information on the consequences of EIH during chronic exposure to altitude. Here, we (i) review research on the consequences of EIH under acute hypoxic conditions, (ii) highlight unresolved questions about EIH and chronic hypoxic exposure, and (iii) suggest perspectives for improving endurance training.

Migraine Triggers: An Overview of the Pharmacology, Biochemistry, Atmospherics, and Their Effects on Neural Networks.

We define a migraine trigger to be an endogenous agent or agency such as the menses or an exogenous agent or agency such as red wine or a drop in barometric pressure, and their ability to reduce the threshold of a migraine attack in those predisposed to migraine. This definition excludes agents with idiosyncratic mechanisms that may trigger a migrainous (migraine-like) headache in non-migraineurs such as benign cough headaches or headaches due to altitude-sickness. We also assume as axiomatic that migraine has as its basis the activation of the trigeminovascular pathway (TVP) and the key role of serotonin and the calcitonin gene-related peptide (CGRP). The network activation of the visual/auditory association cortices and the rostrodorsal pons (locus ceruleus and raphe nucleus) are also accepted as key features of activation of the TVP. In addition, we outline the role of the superior salivatory nucleus-sphenopalatine ganglion-greater superficial petrosal nerve (SSN-SPG-GSPN) arc in migraine activation.We also explore how olfactory afferents intermingle with trigeminal nerve collaterals in the glomeruli of the olfactory bulb thus allowing volatile molecules to activate the TVP and induce a migraine. The classification of migraine triggers is complex, as there is a wide panorama of inciting agents, including atmospheric conditions, a wide-ranging variety of foods and beverages, endogenous hormonal influences, synthetic alkaloids and dyes, and volatile molecules (odorants). We will explore the high-frequency migraine-provoking agents in each category. There are exciting and intriguing hypotheses regarding the role of atmospheric chemistry when the barometric pressure drops; the role of hot, dry desert winds and lightning discharges in the generation of cations and the turnover of serotonin in the nervous system. We will explore the effects of a drop in barometric pressure on the vestibular nuclei and the modulation of sympathetically mediated pain. The role of volatile odorants and their activation of the transient receptor potential ankyrin-1 (TRPA-1) receptor will be outlined. We will streamline the highly complex role of estrogen fluctuation in the precipitation of migraine headaches, its pharmacodynamic effects, and the role of the sexually dimorphic nucleus of the preoptic area (SDN-POA) of the hypothalamus. We will also adumbrate the protean effects of alcohol and its congeners and the role of stress and sleep disturbances in the allostatic load model of salience network-pain perception.

Spawning Drivers and Frequency of Endangered Atlantic Sturgeon in the York River System

AbstractDespite over 100 years of commercial exploitation for their eggs, there is limited information about the spawning behavior of Atlantic Sturgeon Acipenser oxyrinchus oxyrinchus. Spawning return intervals for males and females have been estimated in the most general of time spans, and researchers have established only in the last 25 years that Atlantic Sturgeon eggs and larvae are freshwater obligates, dispelling the notion that spawning occurred in estuaries. In this study, capture data from 2013 to 2019 for Atlantic Sturgeon were analyzed to estimate spawning return intervals to the York River system, a tributary to the Chesapeake Bay in Virginia. Then, using the data for female capture, we examined the abiotic influences that appear to drive egg deposition. Both males and females return to spawn at more frequent intervals than has been reported in the literature, with males returning once every 1.13 years and females returning once every 2.19 years. Three females were documented returning to spawn in consecutive years—one of them returning 5 out of 6 years. All of the females that were captured on the spawning grounds were gravid, with eggs at stage 5 or further progressed. In all of the years, 105 fall adult females were caught: 73 were at stage 5, 26 at stage 6, and 6 at stage 7. Of the 26 stage‐6 females, 13 were actively releasing eggs when they were captured. Egg deposition was correlated with photoperiod, water temperature, and a drop in barometric pressure in the 24 h prior to capture. Ten of 13 females that were releasing eggs were caught during day lengths that were within 30 min of the autumn equinox. Females that were releasing eggs were only captured at water temperatures that were between 21.5°C and 25.1°C. This information should provide the foundation of predictive models that allow researchers and managers to understand how this endangered species is likely to respond to climate change.

Hollow Object

Hollow Object Amity Gaige (bio) Beth tried to reach her daughter first thing on Sunday morning. When her daughter didn’t answer the phone, a feeling of alarm arose and, like a weather balloon, kept sending Beth disquieting signals all day. Beth and Vanessa had a relationship marked by an almost occult sense of the other’s welfare. Over the years, mother and daughter often called one another just to “check in” when they sensed something amiss, and often, in some related way, they were right. This constant fear for her daughter’s wellbeing was uncomfortable for Beth. But the truth was, without it, she feared they would drift apart. Sundays. The day of the week that bonded all peoples of the world in laziness. And this one was hot, rendering shade a currency. Beth knew that Vanessa hardly ever left her house on Sundays. She lived with the baby less than ten miles north of the college town in which she’d been raised, in a two-bedroom apartment in a sprawling old house at the edge of a Christmas tree farm. The big house was sectioned into separate apartments, but over time the residents of the house had developed a culture of their own. Now it seemed to Beth more like a commune. Residents wandered in and out of each other’s apartments at all hours, and often cooked meals together. Most of them were single people, all of ambiguous early middle age. Beth often wondered why none were married, and what psychic wounds had led them there. But she was smart enough not to inquire. Vanessa was the only resident in the house with a child. The child—a boy named Chance—was eighteen months old. Beth tried to reach Vanessa again at one o’clock, and then again at five. No answer. The little weather balloon soared across the backyard, the decking, the birdfeeder, sending its shadowy transmissions from an increasingly colder part of the mesosphere. Even as she sat with her iced tea and watched what looked like a rare waxwing visit the birdfeeder, her disquiet grew. That’s what it felt like—a drop in barometric pressure, a hushing, an intimidation. With sudden sharpness, she remembered one of the many experiments she had conducted with the children, back in the years she’d had all three of them at home. [End Page 66] Her husband, Gene, had been packing for a business trip to the Midwest, when she noticed little Vanessa looking disappointed at the sight of her daddy packing again. So Beth improvised an experiment. She instructed each of the three children to give their father a hollow object. He would pack these objects in his suitcase and fly with them, so that the children could observe the effects of air pressure upon the objects. Vanessa, the eldest, gave her father an empty water bottle, the cap of which she instructed him to screw tightly at cruising altitude, for she already anticipated the outcome of the experiment. The middle child gave his father a can of aerosolized spray butter that he hoped would explode in the cargo hold. The littlest, not quite understanding the basic premise, gave her daddy an orange. While Gene was airborne, a cold front descended from Canada, and gale force winds swept the Plains. Beth didn’t know any of this at the time—she wouldn’t have heard the radio anyway over the sounds of three children squalling in the bathtub—but at that very moment her husband was riding through darkness in crash position, the plane plummeting. The crisis lent the return of the children’s pressurized objects more than a little profundity. The water bottle was warped, taking on strangely human proportions, tiny-wasted and crouched like a skeleton. The aerosol can had not exploded, but leaked a buttery juice onto the contents of Gene’s suitcase. Only the orange was unchanged. The orange sat there on the bedspread like some kind of unholy icon. Something so simple as to mock curiosity. Sitting on the bed, one hand bandaged, Gene lit a cigarette and shook his head. The baby toddled to the bed and retrieved her...

The Emperor's Old Clothes: An Inconvenient Truth About Currently Accepted Vapor Intrusion Assessment Methods

The Emperor's Old Clothes: An Inconvenient Truth About Currently Accepted Vapor Intrusion Assessment Methods

Episodic dynamics of a sand wave field

The morphodynamics of a sand wave field in a flood-dominant channel inside Moriches Inlet was monitored for eight weeks during the summer of 2005. Bathymetric data show sand waves on average are 15 m long and 39 cm high with shallow slip faces. The sand waves remained stationary over the eight-week study. The maximum peak current speeds recorded during this study only reached 60 cm/s. This velocity was not sufficient to cause measurable sand wave migration. Analysis based on work by van Rijn suggests that the sand waves of this size would be created when the current velocity exceeds 80 cm/s, conditions not observed during this study. Water level data from Sandy Hook, NJ, and Shinnecock Inlet, NY, show that large tidal ranges occur when a drop in barometric pressure increases the elevation of high tide and strong north winds decrease the low-tide elevation. During these events the current velocity may reach 80 cm/s, which is predicted to be strong enough to produce these sand waves. This study demonstrates that high-energy, episodic events may control sand wave morphology at Moriches Inlet.

A time-series analysis of any short-term effects of meteorological and air pollution factors on preterm births in London, UK

Although much is known about the incidence and burden of preterm birth, its biological mechanisms are not well understood. While several studies have suggested that high levels of air pollution or exposure to particular climatic factors may be associated with an increased risk of preterm birth, other studies do not support such an association. To determine whether exposure to various environmental factors place a large London-based population at higher risk for preterm birth, we analyzed 482,568 births that occurred between 1988 and 2000 from the St. Mary's Maternity Information System database. Using an ecological study design, any short-term associations between preterm birth and various environmental factors were investigated using time-series regression techniques. Environmental exposures included air pollution (ambient ozone and PM 10) and climatic factors (temperature, rainfall, sunshine, relative humidity, barometric pressure, and largest drop in barometric pressure). In addition to exposure on the day of birth, cumulative exposure up to 1 week before birth was investigated. The risk of preterm birth did not increase with exposure to the levels of ambient air pollution or meteorological factors experienced by this population. Cumulative exposure from 0 to 6 days before birth also did not show any significant effect on the risk of preterm birth. This large study, covering 13 years, suggests that there is no association between preterm births and recent exposure to ambient air pollution or recent changes in the weather.

Running before the storm: blacktip sharks respond to falling barometric pressure associated with Tropical Storm Gabrielle

A small population of juvenile (<1 year old) blacktip sharks Carcharhinus limbatus responded to the approach of a tropical storm by moving to deeper water. Examination of meterological variables suggested that the movement of the blacktip sharks was triggered by a drop in barometric pressure associated with the approach of the storm. This response was consistent for all the fish being studied, and all blacktip sharks returned to the shallow nursery area after the storm's passage, suggesting that this was an innate behaviour.

Lateral gas transport in soil adjacent to an old landfill: factors governing gas migration.

Field experiments investigating lateral gas transport in soil adjacent to an old landfill in Denmark during a one-year period were conducted. A significant seasonal variation, with low concentrations of methane and high concentrations of carbon dioxide in the summer, caused by methane oxidation was observed. There was a good correlation between pressure above the barometric pressure and the methane concentration in the soil, indicating that advective flow was the controlling process. This was confirmed by calculations. Diurnal measurement during a drop in barometric pressure showed that lateral migration of landfill gas was a very dynamic system and the concentrations of LFG at a specific place and depth changed dramatically within a very short time. The experiments showed that change in barometric pressure was an important factor affecting gas migration at the Skellingsted landfill in Denmark.

Lateral gas transport in soil adjacent to an old landfill: factors governing emissions and methane oxidation.

Field investigations of lateral gas transport and subsequent emissions in soil adjacent to an old landfill in Denmark have been conducted during a one-year period. A significant seasonal variation in the emissions with high carbon dioxide and low methane fluxes in the summer (May to October) was observed. This was attributed to methane oxidation. Diumal measurements during a drop in barometric pressure showed that the fluxes of landfill gas changed dramatically within a very short time. The concentrations and the soil moisture content in the upper part of the soil profile had significant influence on the fluxes, as did the distance from the landfill border, temperature, barometric pressure and the pressure gradient. Statistical analyses proved that soil moisture described the largest part of the variation. No methane at all emitted during the summer. Calculations and isotope analyses showed that very high fractions of the laterally migrating methane were oxidised.

Lateral gas transport in soil adjacent to an old landfill: factors governing gas migration.

Field experiments investigating lateral gas transport in soil adjacent to an old landfill in Denmark during a one-year period were conducted. A significant seasonal variation, with low concentrations of methane and high concentrations of carbon dioxide in the summer, caused by methane oxidation was observed. There was a good correlation between pressure above the barometric pressure and the methane concentration in the soil, indicating that advective flow was the controlling process. This was confirmed by calculations. Diurnal measurement during a drop in barometric pressure showed that lateral migration of landfill gas was a very dynamic system and the concentrations of LFG at a specific place and depth changed dramatically within a very short time. The experiments showed that change in barometric pressure was an important factor affecting gas migration at the Skellingsted landfill in Denmark.

Lateral gas transport in soil adjacent to an old landfill: factors governing emissions and methane oxidation.

Field investigations of lateral gas transport and subsequent emissions in soil adjacent to an old landfill in Denmark were conducted during a 1-year period. A significant seasonal variation in the emissions with high carbon dioxide and low methane fluxes in the summer (May to October) was observed. This was attributed to methane oxidation. Diurnal measurements during a drop in barometric pressure showed that the fluxes of landfill gas changed dramatically within a very short time. The concentrations and the soil moisture content in the upper part of the soil profile had significant influence on the fluxes, as did the distance from the landfill border, temperature, barometric pressure and the pressure gradient. Statistical analyses proved that soil moisture described the largest part of the variation. No methane is emitted during the summer. Calculations and isotope analyses showed that very high fractions of the laterally migrating methane were oxidised.

The location of abandoned mine workings using thermal techniques

Between 1926 and 1956, laboratory experiments and underground observations demonstrated the relationship between barometric pressure decrease and the efflux gas in mines. This resulted in the establishment of early warning systems in some British mines when significant falls of atmospheric pressure were expected. In 1993, ‘frost circles’ were observed on the ground surface, above abandoned mine shafts. These were caused by warmer mine air escaping into the atmosphere, via the mine shafts. The temperature of the ground above, and in the vicinity of, abandoned mines was subsequently monitored using digital thermometers, a precision radiation thermometer and infrared thermal photography. This was followed by the use of a longer-term, ground temperature monitoring technique, using digital temperature recorders, which monitored the ground temperature every 2.5 minutes for a period of 14 days. The ground temperatures above the abandoned mine shafts were also found to be related to fluctuations in barometric pressure, agreeing with the earlier observations. During periods of high barometric pressure mine gases were prevented from escaping into the atmosphere and accumulated in the mine voids. Following a drop in barometric pressure the mine gases were capable of escaping into the atmosphere, where they underwent oxidation. This produced an increase in ground temperature in the order of a few degrees centigrade. The temperature differential may be sufficient to be detected by remote thermal imaging techniques, provided that they are undertaken in suitable climatic conditions. This type of remote, reconnaissance technique, is particularly applicable to the British Isles due to the abundance of abandoned mines workings and the regular fluctuations in climatic conditions.

Association between significant decrease in barometric pressure and onset of labor

To determine whether there is any correlation between sudden decrease in barometric pressure and onset of labor, a non-experimental, retrospective study at a 948-bed tertiary care hospital was done. Pregnant patients of 36 weeks gestation or more who presented with spontaneous onset of labor during the 48 hours surrounding the 12 occurrences of significant drop in barometric pressure in 1992 were included in the study. Significantly more occurrences of onset of labor were identified in the 24 hours after a drop in barometric pressure than were identified in the 24 hours prior to the drop in barometric pressure ( P < 0.05). Therefore, the overall number of labor onsets increased in the 24 hours following a significant drop in barometric pressure.

Aquifer Response to Record Low Barometric Pressures in the Southeastern United States

AbstractA late‐winter cyclone classified as one of the most intense of the 20th century moved across the Southeastern states of Georgia and South Carolina and onto the Northeast during March 12–14, 1993. Record low barometric pressures were recorded in Augusta, Georgia (28.93 inches of mercury) and Columbia, South Carolina (28.63 inches of mercury) on March 13, 1993, and pressures returned to normal values (near 30 inches of mercury) within one day following these record lows. This relatively unusual event provided an opportunity to examine the attendant water‐level response in continuously monitored ground‐water wells in regional Atlantic Coastal Plain, Piedmont, and Blue Ridge aquifers in the Southeast. Water levels in all wells examined responded inversely to the short duration, extreme drop in barometric pressure. Barometric efficiencies (Δground‐water level/Δbarometric‐pressure level) calculated were dependent on depth to screened‐ or open‐interval midpoint (highest correlation coefficient, r2= 0.89) and, to a lesser extent, total thickness of confining material above the aquifer tapped (highest r2= 0.65). Wells in crystalline‐rock aquifers had a correlation with depth to open‐interval midpoint (r2= 0.89) similar to the sedimentary aquifers examined. The magnitude of barometric efficiency was also strongly related to a well's increased distance from aquifer outcrop areas in the Cretaceous aquifers in South Carolina (r2= 0.95) and the upper Brunswick aquifer in Georgia (r2= 0.90), because these aquifers are more deeply buried toward the coast. This relation between barometric efficiency, well depth, and extent of confinement suggests that barometric efficiency determinations can provide useful information to hydrologists concerned with examining an aquifer's degree of confinement and corresponding isolation from land surface, particularly when the aquifer is used as a source for public supply.

Peak expiratory flow at altitude.

The mini Wright peak flow meter is a useful, portable instrument for field studies but being sensitive to air density will under-read at altitude. True peak expiratory flow will increase at altitude, however, because of the decreased air density, given that dynamic resistance is unchanged. The effect of simulated altitude on peak expiratory flow (PEF) was determined in six subjects with both the mini Wright meter and a volumetric spirometer (which is unaffected by air density). With increasing altitude PEF as measured by the spirometer increased linearly with decreasing pressure, so that at a barometric pressure of 380 mm Hg* (half an atmosphere, corresponding to an altitude of 5455 m) there was a 20% increase over sea level values. The mini Wright flow meter gave readings 6% below sea level values for this altitude--that is, under-reading by 26%. Measurements of PEF made at altitude with the mini Wright meter should be corrected by adding 6.6% per 100 mm Hg drop in barometric pressure.