Altitude Difference Research Articles

Tendências Espaço-Temporais das Precipitações na Bacia do Rio Ivaí (PR) e a Relação com Alagamentos, Enxurradas e Inundações

Os eventos extremos de precipitação causam severos danos no espaço urbano e rural. A bacia hidrográfica do Ivaí abrange uma grande amplitude latitudinal, longitudinal e topográfica, tornando seus estudos complexos e necessários, além de se uma importante área de produção agrícola. Objetivou-se neste trabalho analisar a variabilidade sazonal e a tendência pluviométrica e os seus impactos por meio de ocorrências de alagamento, enxurradas e inundações na mesma. Para a análise da tendência utilizou-se os testes de Correlação Linear (R²), Mann-Kendall Significance (MK Z) e a Monotonic Trend (MC Tau) para as quatro estações do ano. Identificou-se que o verão e o outono são as estações que tiveram as tendências pluviométricas negativas mais acentuadas, principalmente nas regiões sul e leste da bacia. Enquanto as ocorrências de desastres naturais vinculados à precipitação são alarmantes na região, ao todo 127 decretos de situações de emergência foram registrados.

Effect of perfusate oxygenation on inflammatory response in congenital heart disease children from low versus high altitude

ObjectiveTo examine the altitude differences in the optimal perfusate oxygenation (PpO2) in patients who underwent cardiac surgery. MethodsWe included children (aged 1 month to 18 years) with congenital heart diseases surgically repaired between 2012 and 2018. We included only patients who underwent cardiac surgery with arrested heart cardiopulmonary bypass. Primary outcome was severe systemic inflammatory response syndrome (SIRS). Logistic regression was used to evaluate the association between arterial PpO2 on continuous and categorical scales and severe SIRS by altitude. We established PpO2 thresholds that equated to a risk probability of roughly 0.185 or greater for developing severe SIRS in each group of altitude. ResultsAmong 3918 patients from low altitudes and 2384 from high altitudes, high-altitude patients were older (median, 42.3 [interquartile range 22.8-75.8] vs 37.1 [17.7-69.1] months, P < .001) and had lower arterial PpO2 (289 [237-342] vs 301 [246-362] mm Hg, P < .001). Greater PpO2 was associated with increased risk of severe SIRS overall (adjusted odds ratio, 1.221 [95% confidence interval, 1.167-1.278] per standard deviation increase), with a stronger monotonic associations for low-altitude patients than for high-altitude patients (adjusted odds ratio, 1.302 [95% confidence interval, 1.229-1.379] vs adjusted odds ratio, 1.083 [95% confidence interval, 1.003-1.170] per standard deviation increase) (Pinteraction = .0003). A PpO2 level of 310 mm Hg identified low-altitude patients with a risk probability of roughly 0.185 or greater of severe SIRS, whereas the cutoffs ranged from 200 mm Hg to 325 mm Hg for high-altitude patients. ConclusionsThis study suggests altitude differences in the association of arterial PpO2 with inflammatory response following pediatric cardiac surgery.

Changes of water clarity in large lakes and reservoirs across China observed from long-term MODIS

Water clarity is a well-established first-order indicator of water quality and has been used globally by water regulators in their monitoring and management programs. Assessments of water clarity in lakes over large temporal and spatial scales, however, are rare, limiting our understanding of its variability and the driven forces. In this study, we developed and validated a robust Secchi disk depth (ZSD) algorithm for lakes across China based on two water color parameters, namely Forel-Ule Index (FUI) and hue angle α, retrieved from MODIS data. The MODIS ZSD model shows good results when compared with in-situ measurements from 17 lakes, with a 27.4% mean relative difference (MRD) in the validation dataset. Compared with other empirical ZSD models, our FUI and α-based model demonstrates improved performance and adaptability over a wide range of water clarity and trophic states. This algorithm was subsequently applied to MODIS measurements to provide a comprehensive assessment of water clarity in large lakes (N = 153) across China for the first time. The mean summer ZSD of the studied lakes between 2000 and 2017 demonstrated marked spatial and temporal variations. Spatially, the ZSD of large lakes presented a distinct spatial pattern of “high west and low east” over China. This spatial pattern was found to be associated with the significant differences in lake depth and altitude between west and east China while China's population, GDP, temperature, and precipitation distribution have also contributed to a certain extent. Temporally, the ZSD of most lakes increased during this period, with an overall mean rate of 3.3 cm/yr for all lakes. Here, 38.6% (N = 59) of the lakes experienced a significant increase in their ZSD value during the past 18 years while only 8.5% (N = 13) showed a significant decreasing trend. Significant increases in lake ZSD were observed in west China, which were found to correlate with the increase of air temperature and lake surface area. This is possibly a response of the lakes in west China to climate change. In the lake systems of east China, which are predominately used as a drinking water source, the increase in lake ZSD was found to be strongly correlated with changes in local GDP (gross domestic production), NDVI (normalized difference vegetation index) and lake surface area, suggesting a combined effect of the implemented management practices and climatic variability. The results of this study provide important information for water quality conservation and management in China, and also highlight the value of satellite remote sensing in monitoring water quality over lakes at a large scale and long-term.

Organik ve geleneksel çay tarımı uygulamalarının bazı toprak kalite parametreleri ile mikro besin elementi elverişliliği üzerine etkileri

Bu araştırma, Rize ili koşullarında organik ve geleneksel çay tarımı uygulamalarının, bazı toprak kalite parametreleri (tekstür, toprak reaksiyonu, elektriksel iletkenlik, organik madde, katyon değişim kapasitesi) ve mikro besin elementlerinin elverişlilikleri üzerine etkilerini belirlemek üzere yürütülmüştür. Araştırmaya ait toprak örnekleri, Rize ili Çayeli ilçesi Senoz Vadisi’nde belirlenen iki koordinat arasında kalan hat üzerinde bulunan parsellerden (0-20cm) alınmıştır. Toprak örnekleri üzerinde yapılan analiz ve değerlendirmeler sonucun da ölçülen toprak kalite parametreleri (tekstür, toprak reaksiyonu, elektriksel iletkenlik, organik madde, katyon değişim kapasitesi) üzerinde, uygulama ve rakım farkının etkisi olduğu saptanmıştır. Daha düşük rakıma sahip geleneksel tarım uygulamalarının yapıldığı yerlerde organik madde miktarı ortalama %8,75 belirlenirken, daha yüksek rakıma sahip organik tarım uygulamalarının yapıldığı yerlerde organik madde miktarı ortalama %5,76 olarak belirlenmiştir. Gerek organik ve gerekse geleneksel tarım uygulamaların yapıldığı parsellerde Fe, Cu, Zn ve Mn içeriklerinin yeterli düzeyde bulundukları tespit edilmiştir.

Impacts of Aerosol and Environmental Conditions on Maritime and Continental Deep Convective Systems Using a Bin Microphysical Model

AbstractA series of model simulations were conducted to investigate the effects of cloud condensation nuclei (CCN) loading and convective available potential energy (CAPE) on tropical maritime and midlatitude continental deep convection. Dynamical downscaling from global aerosol reanalysis was used to represent aerosol fields for the two convective regimes. We describe a control run and multiple sensitivity experiments using a limited‐area model, employing spectral‐bin cloud microphysics. The CCN loading is perturbed between the target maritime and continental conditions, roughly 40–2,000 cm−3 at 850 hPa and 1% supersaturation. Surface precipitation rates monotonically increase with increasing CCN loading for both the maritime and continental situations, while these monotonic increases are disrupted in the simulations with reduced CAPE. The increase in precipitation is in the form of convective precipitation, at the expense of stratiform precipitation. CCN increases promote increases in supercooled cloud water, in agreement with previous modeling studies. However, in the simulations investigated herein, the changes in supercooled water have different impacts on the cloud microphysics in the maritime and continental simulations. Increased supercooled water contents lead to more hail and less graupel in the continental simulation. For the maritime simulation, enhanced supercooled cloud water contents promote an increase in graupel since little or no hail is produced. This distinction is due to the difference in relative magnitudes and peak altitudes of supercooled water and snow amounts, which is further attributable to moisture and dynamical differences in the two cases.

Evaluation of the Impacts on Water Quality from Meteorological Changes Due to Differences in Altitude by GIS: A Comparison for Two Morphologically Different Lakes

Bu çalışmada doğal ve yapay su kaynaklarının su kalitesini etkileyen etkenlerden birisi olarak saptanan deniz seviyesine olan yükseklikten kaynaklı meteorolojik değişimlerin CBS ortamında bir değerlendirmesi yapılmıştır. Ordu İli sınırları içerisinde 68 m rakıma sahip Gaga Gölü Sulak Alanı’nın ve 1732 m rakıma sahip Çambaşı Göleti’nin fiziksel ve kimyasal su kalitesi değerlerinin karşılaştırılması ve iki çalışma noktası arasındaki rakım farkının bu su ekosistemlerinin su kaliteleri üzerindeki etkileri mekânsal olarak analiz edilmiştir. Göllerdeki yüzey suyu kalitesinde oluşabilecek etkilerin daha iyi anlaşılabilmesi için 3 mevsim sürdürülen ölçüm çalışmalarından elde edilen bulgular dağılım haritaları vasıtasıyla karşılaştırılmıştır. Tüm veri analizi sonuçlarıyla beraber her iki su ekosisteminin bulunduğu bölge arasındaki meteorolojik, ekolojik ve sosyolojik farklılıklar göz önüne alınarak çevre kalite standartlarında görülen etkilerin değerlendirmesi yapılmış ve bölgeye özgü yoğun mevsimsel geçişler yaşanması nedeniyle bazı fiziko-kimyasal parametrelerin olumsuz yönde etkilendiği görülmüştür. Çalışmanın son bölümünde arazi kullanım farkı, noktasal ve yayılı kirletici kaynaklara olan yakınlığın oluşturduğu trofik düzeydeki değişimlerin sonuçları tartışılmış ve Yerüstü Su Kalitesi Yönetmeliği çerçevesinde sınıflandırma kriterleri göz önüne alınarak bu su kaynaklarının daha verimli kullanımı, korunması ve sürdürülebilir yönetimi konusunda bazı öneriler geliştirilmiştir.

Does altitude affect blood gases in hemodialysis patients?

This study aimed to determine whether predialysis blood gases is affected by altitude differences in hemodialysis patients with arteriovenous fistulas living in Turkey at three different altitudes. Patients' predialysis blood gases were compared by standardizing both arterial blood gases collections and working methods for patients undergoing hemodialysis using a dialysate with the same properties at altitudes of 30 m (sea level), 1020 m (moderate altitude), and 1951 m (high altitude). Blood gases disorders were detected in 32 (82.1%) high altitude group patients, whereas 49 (74.2%) sea level group patients had no blood gases disorders (P < 0.001). pH values in the high altitude group were significantly lower than those in the other groups, and the pH increased as altitude decreased (P < 0.001). The partial pressure of carbon dioxide (PaCO2 ) values was higher in the sea level group than in the other groups and increased at lower sea levels (P < 0.001). Bicarbonate values were significantly higher in the sea level group than in the other groups and increased at lower sea levels, similar to PaCO2 values (P < 0.001). The partial pressure of oxygen (PaO2 ) values in the high altitude and sea level groups were significantly higher and increased at lower sea levels (P < 0.001). The oxygen saturation (SaO2 ) values were significantly lower in the high altitude group than in the other groups and increased gradually at lower sea levels (P < 0.001). Predialysis metabolic acidosis was more pronounced in patients undergoing hemodialysis at high altitudes, whereas PaCO2 , PaO2 , and SaO2 values were lower.

TUNNEL DESIGN CHALLENGES AT THE EXAMPLE OF DIVAČA KOPER RAILWAY LINE

New Divača-Koper railway runs through the karst area associated with the major thrust fault, whichdivides limestone and flysch strata known as the Karst Edge. Due to some 400m high difference inaltitude between Divača and Koper most of the railway line runs underground, featuring two six toseven kilometers long tunnels. Two types of tunneling methods were considered: TBM and drill andblast method based on NATM. The advantages and shortcomings of each method are discussed andthe set of reasons is given why TBM was not selected as a preferred solution. The main designchallenges encompassing the overcoming of the karst phenomena and protection of the waterresources are presented in the paper.

A Digital Approach to Evaluate the Effect of Berry Cell Death on Pinot Noir Wines’ Quality Traits and Sensory Profiles Using Non-Destructive Near-Infrared Spectroscopy

Berry cell death (BCD) is linked to the development of flavors and aromas in berries and wine. The BCD pattern and rate within a growing season start at around 90–100 days after anthesis (DAA), and the rate until harvest depends on environmental factors. This study assessed the BCD effects on berry and wine composition from a boutique commercial vineyard in Victoria, Australia, using fluorescent imaging. Results showed differences in wine sensory profiles from the two blocks studied, mainly related to variations in BCD, due to differences in altitude between blocks. Furthermore, two machine learning (ML) models were constructed using near-infrared spectroscopy (NIR) measurements from full berries as inputs and living tissue (LT) and dead tissue (DT) from berries as targets (Model 1). Model 2 was developed using Brix, LT, DT from the east and west sides of canopies as inputs and using 19 sensory descriptors from wines as targets. High correlation and performances were achieved for both models without signs of overfitting (R = 0.94 and R = 0.80, respectively). These models could be used for decision-making purposes as an objective and comprehensive berry maturity assessment obtained in a non-destructive, accurate, and in a real-time fashion close to harvest, to secure specific wine styles.

Study of Uplink Interference in UMTS Network: ASIACELL Company, Iraq

Universal Mobile Telecommunications System (UMTS), is the third generation (3G) of mobile communication which is based on the wideband code division multiple access (W-CDMA) radio access to provide bandwidth and spectral efficiency. Interference in 3G system is significantly lower compared to the preceded generations. However, it does not mean 3G is free from the issues associated with interferences, such as low signal quality and call drop. The interference level in UMTS can be measured by using the well-known parameter Received Total Wideband Power (RTWP). This parameter is affected by many factors such as number of the users connected to the system, combining second generation (2G) and 3G frequencies within the same geographical area, geographical causes (difference of Altitude), and hardware impairment. In this paper we intensively study how these factors affect the uplink interference level (i.e. RTWP value) in 3G system used by a particular telecommunications company, Asiacell company, Iraq. The obtained data shows that call drop is the most serious issue raised due to high value of RTWP in 3G system. We demonstrate that system enhancement, in terms of lower RTWP level, are obtained by adding second carrier to the sites, separating 2G band from 3G band using special filter, and optimizing the hardware components.

The Saffron (Crocus sativus L.) Cultivation Introduction in Mountainous Oases of Algeria

Abstract An FNR project entitled “Promotion of Saffron (Crocus sativus L.) cultivation for the profit of arid and semi-arid regions’ women” is led by the CRSTRA. The investigations made during 2013 and 2014 in different arid and semi-arid regions of Algeria have permitted to install Saffron (Crocus sativus L.) cultivation in five principle sites: Ain Zaatout, Beni Souik, Branis, Djemorah and Maafa (Algeria). These mountainous oases are characterised especially by lack of water. After analysing the investigation results, saffron corms were distributed to women to be cultivated. The sowing was realised on different dates. The results obtained in the first year of saffron cultivation in mountainous oases of Algeria are promising. The flowering took place in the same year in four sites; it is the case of Ain Zaatout, Beni Souik, Djemorah and Maafa. However, the flowering took place in the second year in the site of Branis. The difference in saffron flowering occurrence can be attributed to the difference in altitude, the pedo-climatic difference as well as the difference in the date of sowing.

Performance of Biochemical Compounds and Cup Quality of Arabica Coffee as Influenced by Genotype and Growing Altitude

Arabica coffee (Coffea arabica) cultivation in the medium altitude (700-900 m above sea level, asl.) will face problems such as decreasing productivity, physical, biochemical and cup quality and increasing intensity of pest and diseaseattacks. Utilization of plant material that has good productivity and cup quality, resistance to pests and diseases is an effort that can be done to overcome theseproblems. The aims of this study is to evaluate performance of Arabica coffee quality grown at high and medium altitude area, as well as biochemical compound and cup quality changes that occur due to influence of genotypes and genotype × altitude interactions. Eight genotypes of Arabica coffee were evaluated at two locations namely KP Andungsari (1,250 m asl.) and Kalibendo (700 m asl.). The field design for each location was randomized complete block design with three replicates. Observations were made on the two quality aspects, namely the biochemical compounds and cup qualities. The result on the biochemical compounds showed that the altitude significantly affect to the content of caffeine, sucrose, and trigonelline. Effect of genotype × altitude occured to the caffeine, trigonelline, and sucrose content. Diversity of chlorogenic acid content was caused by the genotype effect. Cup test results showed that genotypes grown at high altitude had a better cup quality than genotypes on medium altitude. Cup quality variables that were changed due to altitude difference were fragrance and aroma, flavor, aftertaste, acidity, balance, and overall, while the cup quality variable that did not changed was the body. Characters of coffee aroma at the high altitude were floral, spicy and fruity, while at the medium altitude were herbal, green and grassy. The best quality genotype at the high altitude was K8, while at the medium altitude was K29. Environment (altitude) gives greater influence to the formation of coffee flavor variations produced compared to genotypes.

Altitudinal-modulated sediment inputs rather than the land-uses determine the distribution of lead in the riparian soils of the Three Gorges Reservoir.

Lead (Pb) as a toxic metal has potential ecological hazards for aquatic quality. However, the variation in the distribution patterns of Pb and its fractions in flooding soils with frequent and anti-seasonal water-level fluctuation and various human disturbances remains unclear. In this study, the distribution of Pb and its fractions in the riparian soils of the Three Gorges Reservoir (TGR) were delineated based on the differences in altitude and land-uses including farmland, orchard, forest and residential area. Then, we assessed the contamination and eco-risk of Pb in the soils and deciphered the key factors determining the distribution of Pb and its fractions. The results showed that the concentrations of Pb and its fractions in the soils decreased significantly with altitude, while the significant difference was not observed among the land-uses. The contamination of Pb in the soils reached a moderate level, and its eco-risk was very low by the potential eco-risk index and mobile Pb fraction. The source of soil Pb at the upper zone (> 160m) was mainly from natural inputs, while the source at the lower zone (≤ 160m) was attributed to anthropogenic contributions including ores mining, fossil fuel combustion, vehicle emissions and atmospheric deposition indicated by Pb isotopic ratios. With the limited effect of land-uses, the sediment inputs regulated by frequent water-level fluctuation determined the altitudinal distribution of Pb and its fractions in the flooding soils. The soil particle size dominated the migration and transformation of Pb over other soil properties such as pH and organic matters. The results of this study indicate that the anthropogenic Pb mainly exists in the soils of lower riparian zone in the TGR, and the frequent and anti-seasonal dry and rewetting alternation aggravates the potential for the Pb migration downstream due to the determinant of soil particles.

Strong increase in dust devil activity at Gale crater on the third year of the MSL mission and suppression during the 2018 Global Dust Storm

The Rover Environmental Monitoring Station (REMS) instrument in the Mars Science Laboratory (MSL) mission has collected atmospheric data from Gale crater for more than three Martian years. These data correspond to a path travelled by the Curiosity rover of 18 km in length with differences in altitude of 400 m through a variety of terrains in terms of the thermal inertia and nearby topography in the complex environment formed by Gale crater and Aeolis Mons. Pressure measurements obtained by REMS contain sudden drops on day-time hours caused by convective vortices passing nearby, which in some cases raise dust and become dust devils. Pressure measurements also contain pressure drops at night-time possibly caused by atmospheric turbulence and showing a strong seasonality. We present an analysis of these pressure drops for 2224 sols of the MSL mission extending previous results. The new data obtained over the third Martian year of the mission show a large increase in the frequency and intensity of vortices accompanied by a dramatic increase of dust devils that are simultaneously detected by lower values of UV radiation measured with REMS photodiodes. These dust devil events increased from one to two per Martian year in the two first Martian years of the MSL mission to 36 events in the third Martian year of the mission. We argue that this increase in dust devil activity is related to two different factors: (i) more intense vortices produced by a combination of the higher elevation of the terrain and lower thermal inertia of the environment favouring larger thermal differences between the ground and the air close to the terrain; (ii) a higher dust availability in the terrains traversed during the third Martian year of the MSL mission. An alternative explanation is that dust devils may need a minimum central pressure drop threshold to raise dust, and that a slightly enhanced convective activity after the second Martian year of the mission largely increased the dust devil events. Our observations suggest a minimum pressure drop of 3.5 Pa value for high dust loads in the terrain studied with the MSL mission. The new measurements also cover the period of activity of the Global Dust Storm of 2018. During the roughly 100 sols that the storm lasted, all dust devil activity ceased. Nocturnal pressure drops similar to daytime convective vortices continued to be a strongly seasonal effect and were not affected by the Global Dust Storm.

Evaluation of ERA-Interim Air Temperature Data over the Qilian Mountains of China

In this study, 2 m air temperature data from 24 meteorological stations in the Qilian Mountains (QLM) are examined to evaluate ERA-Interim reanalysis temperature data derived from the European Centre for Medium-Range Weather Forecasts (ECMWF) for the period of 1979–2017. ERA-Interim generally captures the monthly, seasonal, and annual variation very well. High daily correlations ranging from 0.956 to 0.996 indicate that ERA-Interim captures the daily temperature observations very well. However, an average root-mean-square error (RMSE) of ±2.7°C of all stations reveals that ERA-Interim should not be directly applied at individual sites. The biases are mainly attributed to the altitude differences between ERA-Interim grid points and stations. The positive trend (0.457°C/decade) is significant over the Qilian Mountains based on the 1979–2017 observations. ERA-Interim captures the warming trend very well with an increase rate of 0.384°C/decade. The observations and ERA-Interim both show the largest positive trends in summer with the values of 0.552°C/decade and 0.481°C/decade, respectively. We conclude that in general ERA-Interim captures the trend very well for observed 2 m air temperatures and ERA-Interim is generally reliable for climate change research over the Qilian Mountains.

South African peatlands: A review of Late-Pleistocene-Holocene dvelopments using radiocarbon dating

South Africa has a limited number of peatlands and most of them are relatively small compared to those in cooler temperate regions in the northern hemisphere. We gathered 40 basal peat samples representative of South Africa’s peatlands to explore their development during the Late Pleistocene and Holocene. Depth profiles of nine of them were also investigated using radiocarbon dating, which yielded information on past environmental changes affecting South African peatlands. The data showed three peaks in the frequency of peatland initiation, which are consistent with available climatic and sea level fluctuation data: one after the Last Glacial Maximum (LGM) and two during the Mid to Late Holocene. Inland peatlands in mountain valleys showed optimal growing conditions during the glacial-interglacial transition, continuing until the Early-Holocene. This is due to the switch to the wet and warm interglacial climate. In contrast, coastal peatlands showed optimal initiation conditions over two phases during the Holocene, which is consistent with sea level rise peaks that led to optimal moist conditions occurring ca. 6,000–3,000 and 1,000 years ago. Sea level rise reduced groundwater drainage, which led to a rise in the primary groundwater table. However, data from some of the coastal peatlands indicate independence from the sea level fluctuation, and that they are rather controlled by climatic conditions and their local hydrogeomorphic setting, e.g. perched groundwater aquifers. Some peatland complexes show a pattern of phased initiation with peat initiation consistent with altitude difference, which could be due to a positive feedback of blocking caused by peat accumulation in lower reaches, reducing groundwater drainage to the sea.

Spatio-temporal differentiation of climate warming (1959–2016) in the middle Qinling Mountains of China

Based on air temperature observation data from 32 meteorological stations, temperature changes in the middle Qinling Mountains from 1959 to 2016 were analysed with respect to the north-south, seasonal and altitude differences. Our research mainly showed the following results. The annual temperature (TA) rose approximately 0.26°C/10a within the past 58 years. This warming trend was stronger on the northern slope than on the southern slope, and a warming trend reversal occurred in 1994 on the northern slope, which was three years earlier than on the southern slope. The temperature changes for the four seasons were not synchronized, and the trend in spring contributed the most to the TA trend, followed by winter, autumn, and summer. The temperature difference between summer and winter (TDSW) decreased significantly over the past 58 years. The temperature change in the middle Qinling Mountains was clearly dependent on altitude. With increases in altitude, the TA increased gradually and became stronger while the TDSW decreased gradually and became weaker. Differences in temperature change between the north and south were mainly observed in low-altitude areas. With increase in altitude, the differences gradually tended to disappear.

Influence of physical strain at high altitude on the quality of cardiopulmonary resuscitation

BackgroundHigh quality cardiopulmonary resuscitation is a key factor in survival with good overall quality of life after out-of-hospital cardiac arrest. Current evidence is predominantly based on studies conducted at low altitude, and do not take into account the special circumstances of alpine rescue missions. We therefore aimed to investigate the influence of physical strain at high altitude on the quality of cardiopulmonary resuscitation.MethodsAlpine field study. Twenty experienced mountaineers of the Austrian Mountain Rescue Service trained in Basic Life Support (BLS) performed BLS on a manikin in groups of two for 16 min. The scenario was executed at baseline altitude and immediately after a quick ascent over an altitude difference of 1200 m at 3454 m above sea level. The sequence of scenarios was randomised for a cross over analysis.Quality of CPR and exhaustion of participants (vital signs, Borg-Scale, Nine hole peg test) were measured and compared between high altitude and baseline using random-effects linear regression models.ResultsThe primary outcome of chest compression depth significantly decreased at high altitude compared to baseline by 1 cm (95% CI 0.5 to 1.3 cm, p < 0.01). There was a significant reduction in the proportion of chest compressions in the target depth (at least 5 cm pressure depth) by 55% (95% CI 29 to 82%, p < 0.01) and in the duration of the release phase by 75 ms (95% CI 48 to 101 ms, p < 0.01). No significant difference was found regarding hands-off times, compression frequency or exhaustion.ConclusionPhysical strain during a realistic alpine rescue mission scenario at high altitude led to a significant reduction in quality of resuscitation. Resuscitation guidelines developed at sea level are not directly applicable in the mountain terrain.

An improved weighted mean temperature (Tm) model based on GPT2w with Tm lapse rate

Global pressure and temperature 2 wet (GPT2w) is an empirical model providing the mean values plus annual and semiannual amplitudes of weighted mean temperature (Tm), which makes it a widely used tool in converting zenith wet delay (ZWD) to precipitable water vapor (PWV) in GNSS meteorology. The model meets the needs of real-time Tm anywhere in the world without relying on any other meteorological observations compared with traditional Tm calculation methods. It outperforms the other empirical Tm models released in recent years. Due to the lack of the Tm vertical adjustment in the model, the accuracy of Tm estimated by the model is subject to certain constraints, especially at sites which have large altitude differences compared with the GPT2w grid points. We explored the Tm lapse rate for the vertical adjustment using 10 years of 37 monthly mean pressure level data from the European Center for Medium-Range Weather Forecasts (ECMWF) and extended the GPT2w model to a new one called the GPT2wh model. Three schemes with different height ranges were established to fit the Tm lapse rate, and the most appropriate scheme was selected by adopting the goodness of fit measures, including the coefficient of determination (R-squared) and the root mean square error (RMSE). In addition to the mean value, annual and semiannual amplitudes for Tm lapse rate on a regular 1° grid were determined and stored in the GPT2wh model. The performance of the new model was assessed against the GPT2w model using different data sources in 2011, i.e., the ECMWF data and globally distributed radiosonde data. The numerical results show that the GPT2wh model outperforms the GPT2w model with an improved RMSE of 7.36/5.00/2.45/1.37/0.51/0.03 K at different height levels in the ECMWF comparison. In comparison with the radiosonde data, the mean RMSE of the GPT2wh model improves by 0.33 K from 4.16 to 3.83 K, i.e., an approximately 8% improvement against the GPT2w model. The impact of Tm on GNSS-PWV was analyzed, showing that the GPT2wh model can effectively improve the accuracy of the converted PWV.

The extent of reliability for vehicle-to-vehicle communication in safety critical applications: an experimental study

Vehicle-to-vehicle (V2V) communication using Dedicated Short Range Communications (DSRC) technology promises to help drastically reduce vehicle collisions. DSRC allows vehicles in a highly mobile and complex network to send and receive safety messages with more reliability and lower latency compared with other wireless technologies used for automotive communications. However, there are many factors that could cause a safety-critical automotive application to become unreliable due to communication failures. While the reliability of V2V communication has been a subject of study by several researchers, there are still open questions regarding how the placement of the DSRC devices (inside or outside the host vehicle), the vehicle’s interior elements and the differences in altitude can affect the V2V communications. This article provides experimental testing data and analyses in order to quantify the impacts of relative vehicle speeds, altitude differences between vehicles, and interior obstacles on V2V communication range and reliability for opposite traffic, in both city and highway environments. We discuss how these results can adversely affect the design parameters of safety critical applications by considering the V2V application “Safe Pass Advisory” on two-lane rural highways.