Evolving Arctic maritime hazards: Declining sea ice and rising waves in the Northwest Passage.

The ongoing and projected retreat of Arctic sea ice has garnered international interest toward the utilization of Arctic maritime corridors for shipping, tourism, and development. Yet, with potential for increasing traffic in Arctic regions, it's important to consider additional environmental variables affected by climate change which may threaten maritime operations. Here, we use four climate model projections to produce ocean wave simulations and investigate the future magnitude and seasonality of sea ice risk coupled with wave hazards. Analyzing the potential 5 mo shipping season spanning July to November along the Northwest Passage maritime route between 2020 and 2070, our results show a substantial decline in sea ice risk over the analysis time period, resulting in near open-water conditions along the route for a 5 mo period by 2070. However, as seasonal ice coverage retreats, there is a significant upward trend in wave heights along the route during July and November, with the timing of the greatest wave height shifting away from September toward later in the season. This result is pertinent as the possibility of seasonally unprecedented extreme waves coupled with subfreezing late fall temperatures makes for an especially hazardous environment, thus emphasizing the importance of considering the interaction between evolving sea ice and interdependent hazards when predicting the risks and challenges faced by Arctic maritime operations.

Numerical modeling of wave attenuation: implications of representing vegetation found in coastal saltmarshes in the Chesapeake Bay.

Coastal communities are vulnerable to wave and storm surges during extreme events, highlighting the need to increase community resilience. The effectiveness of natural wetlands in attenuating waves is vital to designing strategies for protecting public safety. This study aimed to understand how vegetation attenuates waves and determine the best method for modeling vegetation's impact on wave dynamics. The researchers compared two different vegetation representations in numerical models, implicit and explicit, using SWAN and XBeach at varying spatial resolutions. The study focused on two marshes in the Chesapeake Bay, using field measurements to investigate the accuracy of each method in representing wave attenuation by vegetation and the implications of explicitly representing average characteristics of one vegetation species on a regional level. Results showed that explicit modeling using average vegetation characteristics provided more accurate results than the implicit model, which only showed wave attenuation due to topography. The finer scale resolution and site-specific vegetation characteristics further improved the accuracy of wave attenuation observed. Understanding the trade-offs between different vegetation representations in numerical models is essential to accurately represent wave attenuation and design effective protection strategies for coastal communities.

Quantifying the effects of sea level rise driven marsh migration on wave attenuation.

Sea level rise (SLR) is the most significant climate change-related threat to coastal wetlands, driving major transformations in coastal regions through marsh migration. Landscape transformations due to marsh migration are manifested in terms of horizontal and vertical changes in land cover and elevation, respectively. These processes will have an impact on saltmarsh wave attenuation that is yet to be explored. This study stands as a comprehensive analysis of spatially distributed wave attenuation by vegetation in the context of a changing climate. Our results show that: i) changes in saltmarsh cover have little to no effect on the attenuation of floods, while ii) changes in elevation can significantly reduce flood extents and water depths; iii) overland wave heights are directly influenced by marsh migration, although iv) being indirectly attenuated by the water depth limiting effects of water depth attenuation driven by changes in elevation; v) the influence of saltmarsh accretion on wave attenuation is largely evident near the marsh edge, where the increasing elevations can drive major wave energy losses via wave breaking. Lastly, vi) considering the synergy between SLR, marsh migration, and changes in elevation results in significantly more wave attenuation than considering the eustatic effects of SLR and/or horizontal marsh migration alone, and therefore should be adopted in future studies.

Energy Drink before Exercise Did Not Affect Autonomic Recovery Following Moderate Aerobic Exercise: A Crossover, Randomized and Controlled Trial.

Introduction: Energy drink (ED) intake could initiate physiological changes owing to its stimulant characteristics and, it improves endurance and athletic performance. We evaluated the acute effects of ED on autonomic heart rate (HR) control during recovery after a session of submaximal aerobic exercise.Method: The study was completed by submitting 29 healthy males between 18 and 30 years old to three conventions: (A) Maximum exercise test by the adapted Bruce protocol; (B) Placebo protocol (PP) - water intake 15 minutes prior to exercise, rest in dorsal decubitus for 15 minutes followed by 5 minutes of treadmill running at 1% inclination, initial speed of 5 km/h for 5 minutes 25 minutes with 60% of the velocity consistent to the maximum oxygen consumption (VO2max), and finally 60 minutes of recovery at rest in the supine position; (C) Experimental protocol (PE) - similar to PP previously, but with ED intake 15 minutes before physical exercise. The time, frequency and geometric indexes of HR variability (HRV) were inspected before and after exercise.Results: There was a significant (p < 0.05, <5%) effect on the HRV index (HR-nu and ms2, LF-nu and ms2, LF/HF, SD1, SDNN and RMSSD), indicating a reduction in HRV in the first 5 minutes after exercise in both protocols (PP and PE). Yet, no protocol interaction was detected, suggesting no effect of ED on HRV throughout recovery after submaximal aerobic exercise.Conclusion: There was no significant effect of ED on the autonomic control of HR in the recovery phase after submaximal aerobic exercise.

Complexity Measures of Heart-Rate Variability in Amyotrophic Lateral Sclerosis with Alternative Pulmonary Capacities.

OBJECTIVE: the complexity of heart-rate variability (HRV) in amyotrophic lateral sclerosis (ALS) patients with different pulmonary capacities was evaluated. METHODS: We set these according to their pulmonary capacity, and specifically forced vital capacity (FVC). We split the groups according to FVC (FVC > 50% (n = 29) and FVC < 50% (n = 28)). In ALS, the presence of an FVC below 50% is indicative of noninvasive ventilation with two pressure levels and with the absence of other respiratory symptoms. As the number of subjects per group was different, we applied the unbalanced one-way analysis of variance (uANOVA1) test after three tests of normality, and effect size by Cohen's d to assess parameter significance. RESULTS: with regard to chaotic global analysis, CFP4 (p < 0.001; d = 0.91), CFP5 (p = 0.0022; d = 0.85), and CFP6 (p = 0.0009; d = 0.92) were enlarged. All entropies significantly increased. Shannon (p = 0.0005; d = 0.98), Renyi (p = 0.0002; d = 1.02), Tsallis (p = 0.0004; d = 0.99), approximate (p = 0.0005; d = 0.97), and sample (p < 0.0001; d = 1.22). Detrended fluctuation analysis (DFA) (p = 0.0358) and Higuchi fractal dimension (HFD) (p = 0.15) were statistically inconsequential between the two groups. CONCLUSIONS: HRV complexity in ALS subjects with different pulmonary capacities increased via chaotic global analysis, especially CFP5 and 3 out of 5 entropies.

Ultrafine particles and children's health: Literature review.

The aim of this study was to review and synthesize the existing knowledge of the effects of ultrafine particles [UFPs] with a specific focus on children's health. An extensive literature search identified 16 studies fulfilling the criteria set for the review. One of the most important findings of the review was that, in general, there is an association between children's health and exposure to UFPs, especially among children with respiratory diseases, who commonly experience alterations in inflammatory biomarkers and deterioration in lung function as a result of UFP exposure. Notably, the health effects of UFPs are related to their ability to penetrate through different systems of the body due to their small size.

Secondary particles formed from the exhaust of vehicles using ethanol-gasoline blends increase the production of pulmonary and cardiac reactive oxygen species and induce pulmonary inflammation.

BACKGROUND: Ethanol vehicles release exhaust gases that contribute to the formation of secondary organic aerosols (SOA). OBJECTIVE: To determine in vivo toxicity resulting from exposure to SOA derived from vehicles using different ethanol-gasoline blends (E0, E10, E22, E85W, E85S, E100). METHODS: Exhaust emissions from vehicles using ethanol blends were delivered to a photochemical chamber and reacted to produce SOA. The aerosol samples were collected on filters, extracted, and dispersed in an aqueous solutions and intratracheally instilled into Sprague Dawley rats in doses of 700 µg/0.2 ml. After 45 min and 4 h pulmonary and cardiac chemiluminescence (CL) was measured to estimate the amount of reactive oxygen species (ROS) produced in the lungs and heart. Inflammation was measured by differential cell count in bronchoalveolar lavages (BAL). RESULTS: Statistically and biologically significant differences in response to secondary particles from the different fuel formulations were detected. Compared to the control group, animals exposed to SOA from gasoline (E0) showed a significantly higher average CL in the lungs at 45 min. The highest CL averages in the heart were observed in the groups exposed to SOA from E10 and pure ethanol (E100) at 45 min. BAL of animals exposed to SOA from E0 and E85S had a significant increased number of macrophages at 45 min. BAL neutrophil count was increased in the groups exposed to E85S (45 min) and E0 (4 h). Animals exposed to E0 and E85W had increased BAL lymphocyte count compared to the control and the other exposed groups. DISCUSSION: Our results suggest that SOA generated by gasoline (E0), followed by ethanol blends E85S and E85W, substantially induce oxidative stress measured by ROS generation and pulmonary inflammation measured by the recruitment of white blood cells in BAL.

Comparing the Aerobic Fitness of Professional Male Soccer Players and Soccer Referees.

We looked to compare the aerobic performance between professional soccer referees and players. Fifty male soccer referees and 61 male soccer players were tested on a treadmill. The referees and players possessed 15 ± 7 years and 7 ± 3 years of experience in soccer, respectively. Significant differences were observed between the referees and players with regards to: age (34.8 ± 4.6 years vs 20.8 ± 2.7 years; P < 0.001, maximum oxygen uptake (54.7 ± 5.4 mL·kg·min vs 58.8 ± 4.4 mL·kg·min; P < 0.001), and maximal heart rate in peak exercise (184 ± 11 bpm vs 192 ± 9 bpm, P < 0.001). Less significant differences also were observed and included; running speed at the maximum oxygen uptake (16.6 ± 1 km·h vs 16.4 ± 1.1 km·h), running speed at the ventilatory threshold (213.5 ± 1.1 km·h vs 13.2 ± 0.9 km·h), and percentage of maximal oxygen uptake at the ventilatory threshold (285.1% ± 3.2% vs 84.1% ± 6.2%). The effect size of most comparative variables between the two groups was small (<0.6). Older elite-level soccer referees are able to reach and maintain aerobic physical fitness levels similar to professional soccer players. Aerobic physical fitness may be a measurable factor for maintaining elite-level soccer licensure rather than age alone.

Heart Rate Variability and Cardiopulmonary Dysfunction in Patients with Duchenne Muscular Dystrophy: A Systematic Review.

Duchenne muscular dystrophy (DMD) is a genetic recessive disorder with progressive muscle weakness. Despite the general muscle wasting, degeneration and necrosis of cardiomyocytes have been the main causes of morbidity and death in individuals with DMD. Cardiac failure is generally preceded by disturbances in heart rate variability (HRV), and non-invasive measurement of the autonomic nervous system has been an important tool to predict adverse cardiovascular events. Hence, the application of HRV to study autonomic modulation in DMD individuals, and the establishment of correlations between HRV and heart/lung diseases, age, and mortality will have the potential to improve quality of life and life expectancy of individuals with DMD. In order to evaluate the state of the art in this field, we conducted a systematic search in Medline/PubMed and BVS (virtual library in health) databases. We selected 8 studies using pre-defined criteria and meta-analysis revealed decreased parasympathetic activity and increased sympathetic predominance in individuals with DMD as major observations. Moreover, there is a strong association between diminished HRV and myocardial fibrosis with DMD. These patterns are evident in patients at early-stage DMD and become more prominent as disease severity and age increase. Thus, data minning clearly indicates that HRV assessment can be used as a predictor for sudden death in individuals with DMD. The use of the HRV, which is inexpensive, ubiquitously available in clinics and hospitals, and a non-invasive analysis tool, can save lives and decrease the morbity in DMD by alerting care givers to consider autonomic nervous system intervention.

Hurricane Isaac: A Longitudinal Analysis of Storm Characteristics and Power Outage Risk.

In August 2012, Hurricane Isaac, a Category 1 hurricane at landfall, caused extensive power outages in Louisiana. The storm brought high winds, storm surge, and flooding to Louisiana, and power outages were widespread and prolonged. Hourly power outage data for the state of Louisiana were collected during the storm and analyzed. This analysis included correlation of hourly power outage figures by zip code with storm conditions including wind, rainfall, and storm surge using a nonparametric ensemble data mining approach. Results were analyzed to understand how correlation of power outages with storm conditions differed geographically within the state. This analysis provided insight on how rainfall and storm surge, along with wind, contribute to power outages in hurricanes. By conducting a longitudinal study of outages at the zip code level, we were able to gain insight into the causal drivers of power outages during hurricanes. Our analysis showed that the statistical importance of storm characteristic covariates to power outages varies geographically. For Hurricane Isaac, wind speed, precipitation, and previous outages generally had high importance, whereas storm surge had lower importance, even in zip codes that experienced significant surge. The results of this analysis can inform the development of power outage forecasting models, which often focus strictly on wind-related covariates. Our study of Hurricane Isaac indicates that inclusion of other covariates, particularly precipitation, may improve model accuracy and robustness across a range of storm conditions and geography.

Cardiac autonomic modulation of children with Down syndrome.

The aim of this study is to analyze the autonomic modulation in children with Down syndrome (DS). The study was conducted with a convenience sample of children with DS and without heart disease, from the Genetics Clinic of the Hospital Infantil Darcy Vargas and APAE São Paulo, São Paulo, SP, Brazil. The control group was matched for sex and age. The analysis of autonomic modulation was performed using the indices of heart rate variability (HRV). The children remained in the supine position with spontaneous breathing for 20 min. Heart rate was recorded beat-to-beat. HRV analysis was performed in time and frequency domain. For data analysis, we used Student's t test: unpaired and Mann-Whitney. It was considered statistically significant at p < 0.05. From 75 children with DS, 50 were excluded, a total of 25 children [16 boys, 8.6 (1.4) years] participated in this study, and the control group also consisted of 25 children [16 boys, 9.0 (1.2) years] without the syndrome. The BMI of the volunteers with DS was higher than the controls [19.1 (2.9) vs. 15.8 (1.2), p < 0.0001]. There were differences between groups in the indices in frequency domain: LFms(2) [1242.1 (788.25) vs. 786.44 (481.90), p = 0.040], LFun [69.104 (11.247) vs. 57.348 (11.683), p = 0.0004], HFun [30.896 (11.247) vs. 42.520 (11.634), p = 0.0004] and LF/HF [2.594 (1.104) vs. 1.579 (0.9982), p = 0.0004]. No differences were observed in time domain indices. The results indicate increased indices representing the sympathetic branch of the autonomic nervous system and those that indicate the overall modulation in children with DS.

Comparison of the effects of hydration with water or isotonic solution on the recovery of cardiac autonomic modulation.

Despite the importance of hydration during exercise, the impact of ingesting water or isotonic solution during and after exercise on the regulation of autonomic modulation is unclear. The study aimed to compare the effect of ingesting water or isotonic solution (Gatorade®, Brazil) on cardiac autonomic modulation in young people after submaximal aerobic exercise. Thirty-one young men were subjected to a protocol consisting of 4 steps: 1) incremental test, 2) control protocol without hydration, 3) protocol with ingestion of water, and 4) protocol with ingestion of isotonic solution. The protocol consisted of 10 min of rest, 90 min of treadmill exercise at 60% VO2peak, and 60 min of recovery at rest. In the hydration protocols, hydration occurred during and after exercise, every 15 min beginning after the 15th minute of exercise, with the amount ingested proportional to body mass lost in the control protocol. Autonomic modulation was evaluated by heart rate variability. The hydration protocols promoted a more efficient recovery of autonomic modulation, and for the exercise performed, regardless of the hydration administered, the effect on autonomic modulation was similar.

Response of cardiac autonomic modulation after a single exposure to musical auditory stimulation.

The acute effects after exposure to different styles of music on cardiac autonomic modulation assessed through heart rate variability (HRV) analysis have not yet been well elucidated. We aimed to investigate the recovery response of cardiac autonomic modulation in women after exposure to musical auditory stimulation of different styles. The study was conducted on 30 healthy women aged between 18 years and 30 years. We did not include subjects having previous experience with musical instruments and those who had an affinity for music styles. The volunteers remained at rest for 10 min and were exposed to classical baroque (64-84 dB) and heavy metal (75-84 dB) music for 10 min, and their HRV was evaluated for 30 min after music cessation. We analyzed the following HRV indices: Standard deviation of normal-to-normal (SDNN) intervals, root mean square of successive differences (RMSSD), percentage of normal-to-normal 50 (pNN50), low frequency (LF), high frequency (HF), and LF/HF ratio. SDNN, LF in absolute units (ms 2 ) and normalized (nu), and LF/HF ratio increased while HF index (nu) decreased after exposure to classical baroque music. Regarding the heavy metal music style, it was observed that there were increases in SDNN, RMSSD, pNN50, and LF (ms 2 ) after the musical stimulation. In conclusion, the recovery response of cardiac autonomic modulation after exposure to auditory stimulation with music featured an increased global activity of both systems for the two musical styles, with a cardiac sympathetic modulation for classical baroque music and a cardiac vagal tone for the heavy metal style.

Auditory stimulation with music influences the geometric indices of heart rate variability in response to the postural change maneuver.

It is poor in the literature the behavior of the geometric indices of heart rate variability (HRV) during the musical auditory stimulation. The objective is to investigate the acute effects of classic musical auditory stimulation on the geometric indexes of HRV in women in response to the postural change maneuver (PCM). We evaluated 11 healthy women between 18 and 25 years old. We analyzed the following indices: Triangular index, Triangular interpolation of RR intervals and Poincarι plot (standard deviation of the instantaneous variability of the beat-to beat heart rate [SD1], standard deviation of long-term continuous RR interval variability and Ratio between the short - and long-term variations of RR intervals [SD1/SD2] ratio). HRV was recorded at seated rest for 10 min. The women quickly stood up from a seated position in up to 3 s and remained standing still for 15 min. HRV was recorded at the following periods: Rest, 0-5 min, 5-10 min and 10-15 min during standing. In the second protocol, the subject was exposed to auditory musical stimulation (Pachelbel-Canon in D) for 10 min at seated position before standing position. Shapiro-Wilk to verify normality of data and ANOVA for repeated measures followed by the Bonferroni test for parametric variables and Friedman's followed by the Dunn's posttest for non-parametric distributions. In the first protocol, all indices were reduced at 10-15 min after the volunteers stood up. In the protocol musical auditory stimulation, the SD1 index was reduced at 5-10 min after the volunteers stood up compared with the music period. The SD1/SD2 ratio was decreased at control and music period compared with 5-10 min after the volunteers stood up. Musical auditory stimulation attenuates the cardiac autonomic responses to the PCM.

Cardiac autonomic regulation during exposure to auditory stimulation with classical baroque or heavy metal music of different intensities.

OBJECTIVES: The effects of chronic music auditory stimulation on the cardiovascular system have been investigated in the literature. However, data regarding the acute effects of different styles of music on cardiac autonomic regulation are lacking. The literature has indicated that auditory stimulation with white noise above 50 dB induces cardiac responses. We aimed to evaluate the acute effects of classical baroque and heavy metal music of different intensities on cardiac autonomic regulation. STUDY DESIGN: The study was performed in 16 healthy men aged 18-25 years. All procedures were performed in the same soundproof room. We analyzed heart rate variability (HRV) in time (standard deviation of normal-to-normal R-R intervals [SDNN], root-mean square of differences [RMSSD] and percentage of adjacent NN intervals with a difference of duration greater than 50 ms [pNN50]) and frequency (low frequency [LF], high frequency [HF] and LF/HF ratio) domains. HRV was recorded at rest for 10 minutes. Subsequently, the volunteers were exposed to one of the two musical styles (classical baroque or heavy metal music) for five minutes through an earphone, followed by a five-minute period of rest, and then they were exposed to the other style for another five minutes. The subjects were exposed to three equivalent sound levels (60-70dB, 70-80dB and 80-90dB). The sequence of songs was randomized for each individual. RESULTS: Auditory stimulation with heavy metal music did not influence HRV indices in the time and frequency domains in the three equivalent sound level ranges. The same was observed with classical baroque musical auditory stimulation with the three equivalent sound level ranges. CONCLUSION: Musical auditory stimulation of different intensities did not influence cardiac autonomic regulation in men.

The effects of different styles of musical auditory stimulation on cardiac autonomic regulation in healthy women.

The literature investigated the effects of chronic baroque music auditory stimulation on the cardiovascular system. However, it lacks in the literature the acute effects of different styles of music on cardiac autonomic regulation. To evaluate the acute effects of baroque and heavy metal music on heart rate variability (HRV) in women. The study was performed in 21 healthy women between 18 and 30 years old. We excluded persons with previous experience with music instrument and those who had affinity with the song styles. All procedures were performed in the same sound-proof room. We analyzed HRV in the time (standard deviation of normal-to-normal respiratory rate (RR) intervals, root-mean square of differences between adjacent normal RR intervals in a time interval, and the percentage of adjacent RR intervals with a difference of duration greater than 50 ms) and frequency (low frequency [LF], high frequency [HF], and LF/HF ratio) domains. HRV was recorded at rest for 10 min. Subsequently they were exposed to baroque or heavy metal music for 5 min through an earphone. After the first music exposure they remained at rest for more 5 min and them they were exposed again to baroque or heavy metal music. The sequence of songs was randomized for each individual. The power analysis provided a minimal number of 18 subjects. Shapiro-Wilk to verify normality of data and analysis of variance for repeated measures followed by the Bonferroni test for parametric variables and Friedman's followed by the Dunn's post-test for non-parametric distributions. During the analysis of the time-domain indices were not changed. In the frequency-domain analysis, the LF in absolute units was reduced during the heavy metal music stimulation compared to control. Acute exposure to heavy metal music affected the sympathetic activity in healthy women.

Cardiac autonomic modulation in response to postural transition during a virtual reality task in individuals with spinal cord injury: A cross-sectional study.

PURPOSE: The postural transition from sitting to standing is a moment of dysautonomic occurrence in individuals with Spinal Cord Injury (SCI). Different tools can be used to minimize this event, such as virtual reality. Thus, we aimed to analyze cardiac autonomic modulation in individuals with SCI during postural transition from the sitting to orthostatism position using a cognitive virtual reality (VR) task. METHODS: Individuals with and without SCI were positioned on the Easy Stand® device, sitting at rest, at 0° considering the angle between the seat and the floor, elevation at 45°, and orthostatism at 90°, for 5 minutes in each position. Heart rate variability (HRV) measures of sympathovagal balance were collected (heart rate receiver: Polar V800). The groups were subdivided into two groups, one that performed VR as an intervention during the postural angle changes and another group that did not perform VR. RESULTS: We evaluated 76 individuals, 40 with a medical diagnosis of SCI and 36 who composed the able-bodied control group without SCI, matched by age and sex. The HRV results showed that the SCI group who performed the task in VR demonstrated no significant difference in parasympathetic activation and global variability between the sitting versus 90° positions. There was better sympathovagal balance in SCI and able-bodied control groups who performed the VR task between the sitting versus 90° positions. CONCLUSION: The use of a VR task seems to contribute to better sympathovagal balance, with the potential to reduce dysautonomia during postural changes.

Do patients with electrocardiographic Brugada type 1 pattern have associated right bundle branch block? A comparative vectorcardiographic study.

AIMS: Previous studies have reported right bundle branch block in Brugada syndrome. Subsequent analysis of electrocardiograms (ECGs) found one-third of cases classified as right bundle branch block did not meet criteria of a wide final S wave in the left leads. We aimed to study the role of the vectorcardiogram to characterize Brugada type 1 ECG pattern. METHODS AND RESULTS: Compare Frank-method vectorcardiogram in 11 patients with Brugada type 1 ECG pattern (BrS group) with vectorcardiogram of 20 healthy individuals with ECGs depicting incomplete right bundle branch block (IRBBB group) and 12 patients with complete right bundle branch block (CRBBB group). Initial 10-20 ms vector of the QRS loop in the horizontal plane (HP): BrS and IRBBB groups: Vector heading anterior and leftward. CRBBB group: Vector directed anterior and rightward. Right end conduction delay of the QRS loop: BrS group: Upper right quadrant of the frontal plane, right posterior quadrant of the HP. IRBBB group: Upper right quadrant of the frontal plane (30%) and right anterior quadrant of the HP (90%). CRBBB group: Upper right quadrant on the frontal plane (30%); all cases in the right anterior quadrant of the HP. 0 point (onset of QRS loop) and J point (end of QRS loop) relationship: BrS group: Not coincidental. IRBBB and CRBBB groups: Coincidental. T loop morphology, size, and appearance: BrS group: Circular, with symmetrical afferent and efferent limbs in 10 cases (90%). IRBBB and CRBBB groups: Elliptical or linear with slow inscription of efferent limb and rapid inscription of afferent limb. CONCLUSIONS: Vectorcardiograms in patients with Brugada type 1 ECG pattern have distinctive characteristics compared with healthy individuals with incomplete and CRBBB. These differences relate to the spatial location of the end conduction delay (right superior and posterior quadrant in the BrS group) and the morphology, size, and velocity of inscription of afferent and efferent limbs of the T loop (circular, small, of symmetrical limbs) and with a 1:1 length/width ratio.

Sidestream cigarette smoke effects on cardiovascular responses in conscious rats: involvement of oxidative stress in the fourth cerebral ventricle.

BACKGROUND: Cigarette exposure increases brain oxidative stress. The literature showed that increased brain oxidative stress affects cardiovascular regulation. However, no previous study investigated the involvement of brain oxidative stress in animals exposed to cigarette and its relationship with cardiovascular regulation. We aimed to evaluate the effects of central catalase inhibition on baroreflex and cardiovascular responses in rats exposed to sidestream cigarette smoke (SSCS). METHODS: We evaluated males Wistar rats (320-370 g), which were implanted with a stainless steel guide cannula into the fourth cerebral ventricle (4th V). Femoral artery and vein were cannulated for mean arterial pressure (MAP) and heart rate (HR) measurement and drug infusion, respectively. Rats were exposed to SSCS during three weeks, 180 minutes, 5 days/week (CO: 100-300 ppm). Baroreflex was tested with a pressor dose of phenylephrine (PHE, 8 µg/kg, bolus) to induce bradycardic reflex and a depressor dose of sodium nitroprusside (SNP, 50 µg/kg, bolus) to induce tachycardic reflex. Cardiovascular responses were evaluated before, 5, 15, 30 and 60 minutes after 3-amino-1,2,4-triazole (ATZ, catalase inhibitor, 0.001 g/100 µL) injection into the 4th V. RESULTS: Central catalase inhibition increased basal HR in the control group during the first 5 minutes. SSCS exposure increased basal HR and attenuated bradycardic peak during the first 15 minutes. CONCLUSION: We suggest that SSCS exposure affects cardiovascular regulation through its influence on catalase activity.

Predicting flood damage using the flood peak ratio and Giovanni Flooded Fraction.

A spatially-resolved understanding of the intensity of a flood hazard is required for accurate predictions of infrastructure reliability and losses in the aftermath. Currently, researchers who wish to predict flood losses or infrastructure reliability following a flood usually rely on computationally intensive hydrodynamic modeling or on flood hazard maps (e.g., the 100-year floodplain) to build a spatially-resolved understanding of the flood's intensity. However, both have specific limitations. The former requires both subject matter expertise to create the models and significant computation time, while the latter is a static metric that provides no variation among specific events. The objective of this work is to develop an integrated data-driven approach to rapidly predict flood damages using two emerging flood intensity heuristics, namely the Flood Peak Ratio (FPR) and NASA's Giovanni Flooded Fraction (GFF). This study uses data on flood claims from the National Flood Insurance Program (NFIP) to proxy flood damage, along with other well-established flood exposure variables, such as regional slope and population. The approach uses statistical learning methods to generate predictive models at two spatial levels: nationwide and statewide for the entire contiguous United States. A variable importance analysis demonstrates the significance of FPR and GFF data in predicting flood damage. In addition, the model performance at the state-level was higher than the nationwide level analysis, indicating the effectiveness of both FPR and GFF models at the regional level. A data-driven approach to predict flood damage using the FPR and GFF data offer promise considering their relative simplicity, their reliance on publicly accessible data, and their comparatively fast computational speed.