The effect of oxygen supply and oxygen distribution on single-head tunnel with different altitudes under mixed ventilation

Hypoxia plays a major role in limiting the construction of the high-altitude mine. Understanding the effect and the distribution of diffused oxygen supply at different altitudes is the premise for the design of a mine with oxygen supply system and the full utilization of oxygen resources. For the optimal design of an oxygen supply mode and ventilation system, a multi-component fluid model of the diffused oxygen supply of a single-head tunnel was developed. This study reveals the variation law of the average oxygen mass fraction at different altitudes. The relationship between the distance from the heading face and the oxygen mass fraction at each altitude was fitted. The results show that the distribution of oxygen mass fraction in a single head tunnel at different altitudes presents a similar trend of increasing first and then decline. In addition, the change of the average oxygen mass fraction with the increase of altitude is not linear, and the dispersion loss is larger in high-altitude areas. The largest oxygen enrichment area is distributed at the altitudes of 4000–4500 m. This study provides theoretical support for improving the hypoxic environment of high-altitude metal mines excavation work.

Impact of Living in Different Altitudes on Intracytoplasmic Sperm Injection (ICSI) Outcomes for Infertile Couples in Southwestern Region of Saudi Arabia, a Retrospective Study

Objective: The aim of this study was to determine the effect of different altitudes in the Southwestern region of Saudi Arabia on ICSI outcomes, fertilization rate, embryo quality, pregnancy rate, and miscarriage rates for infertile couples. Materials and Methods: This is a retrospective study on 551 infertile couples carried out in the Assisted Reproductive Technology unit at the Maternity and Childern Hospital in Abha, Saudi Arabia between 2018 and 2019 to compare ICSI outcomes in different altitudes. Low altitude (205 patients), mild altitude (86 patients) and high altitude (260 patients). Main result measurements: fertilization rates, embryo quality, clinical pregnancy and miscarriage rates at different altitudes. Results: The data showed that there were no significant differences (P>0.67) in fertilization rates and the number of good-quality embryos between different altitudes. Importantly, clinical pregnancy rates were similar between groups and there was no significant difference in the miscarriage rates between high, mild and low altitudes. Conclusions: This study demonstrates that there is now increased risk of miscarriage or low pregnancy rates with different altitudes in Southwestern region of Saudi Arabia. This suggests that altitude changes has no obvious risk on pregnancy rate and pregnancy outcome.

Physiological Response and Production Ability of Beef Cattle Raised Based on Different Altitudes in Sinjai Regency

The breeders' knowledge of the suitability of the breeding environment for cattle breeds may increase livestock productivity. Determining the differences in microclimate environmental conditions, physiological responses, and production capabilities of Bali and Limousine crossbred cattle raised at different altitudes in Sinjai Regency were the aim of this study. The research was carried out on people's farms in Sinjai, which were divided into three locations based on the height of different rearing places; low areas (0-100 masl) were represented by East Sinjai sub-district, South Sinjai sub-district for medium plains areas (100-400 masl), and highland areas (>400 masl) were represented by West Sinjai sub-district. The selection was based on the height of the place and beef cattle business in the area. The materials used were 30 Balinese cattle and 24 Limousine hybrids. This research was conducted from July to September 2020. The method of the research used direct observation in the field. Data collection used the method of direct observation in the field. The parameters observed were; microclimate conditions, physiological responses, and beef cattle production capabilities. The research found that the altitude of keeping Bali cattle and Limousine breeding affected the microclimate conditions such as air temperature and humidity in the highlands. The air temperature is lower in the highlands but the humidity is higher than the lowlands. Besides, on the physiological response parameters, the altitude effected on the Limousine hybrid as well as respiratory frequency and pulse rate of Bali cattle. Respiratory and pulse rates are lower at high altitudes. The height of the breeding ground also affected the height of the Bali cattle, and the chest circumference of the Limousine hybrid.

A Survey of the Vitamin and Mineral Content in Milk from Yaks Raised at Different Altitudes

In this study, the content of vitamins and of toxic and beneficial (macro- and micro-) minerals in milk from yaks raised at different altitudes (3,215, 4,340, and 5,410 m) was investigated. For comparison, the components in cow’s milk were also measured. At higher altitudes, a significant ( P < 0.05 ) increase in vitamin A and vitamin E was observed in the yak’s milk, whereas the opposite was observed for vitamin B1 and vitamin B2. No significant statistical difference in vitamin C, Ca, P, Na, K, and Mg concentrations was observed in milk from yaks raised at different altitudes. The concentrations of Zn in milk from yaks raised at different altitudes showed no statistical difference, whereas the Mn and Fe concentrations in milk from yaks raised at 3,215 m were lower than those raised at higher altitudes. The concentrations of Pb and Cd in yak’s milk did not exceed the maximum permissible concentrations (Codex Alimentarius Commission), whereas their concentrations were higher in milk from yaks raised at 3,215 m than at higher altitudes. These findings indicated that the contents of vitamins and minerals in yak milk varied in different altitudes.

[Transiting species, phenologies and their trends]

[In order to contribute to the knowledge of the spatio-temporal progression of post-nuptial migration of birds across the Italian Alps, we present in detail the results of the analysis carried out for 69 species (4 non-Passeriformes; 65 Passeriformes) of the 191 ringed within the Progetto Alpi. Data were collected in 40 ringing stations located in different habitats and at different altitudes (mountain passes, slopes and valley floors) and active in the post-breeding migratory period (1 August - 30 November). Among these, those (n=15) with continuous activity (at least one month) and known sampling effort (daily capture effort described as product of net area in square meters by operating time in hours) were selected. Data from the 6 stations that operated continuously over the years (2001-2017) and with standardised capture effort were used for trend analyses. Species covered refer to those with more than 100 birds ringed within the first eight hours after sunrise (excluding local retraps). Species accounts contain detailed data from datasets from all stations participating in the Alps Project (1997-2017)]. [Article in Italian]

Identification of key parameters producing rainfall

o"kkZ ds eq[; izkpyksa dk irk yxkus ds fy, bl 'kks/k i= ls 'kks/kdrkZvksa us m".kdfVca/kh; o"kkZ ekiu fe’ku ¼Vh- vkj- ,e- ,e-½ mixzg vk¡dM+k vk/kkj dh tk¡p dh gSA bl rF; dks le>us ds mijkUr fd c<+us okys ok;q iklZy ds }kjk ikuh ds ok"ihdj.k] ok"i ds la?kuu vkSj m"ek ÅtkZ ds laogu ls es?k cursa gS vkSj o"kkZ gksrh gSA 'kks/kdrkZvksa us ok;qeaMy dh fofHkUu Å¡pkbZ;ksa ij o"kkZ izfØ;k ds eq[; lg;ksfx;ksa ds :i esa es?k nzo ty ¼lh-,y-MCY;w-½] o"kZ.k ty ¼ih-MCY;w-½ rFkk xqIr m"ek ¼,y-,p-½ ds ckjs esa tkudkjh izkIr djuh vkjaHk dj nh gSSA bu vk¡dM+ksa dks cgq lekJ;.k fun’kZ esa Mkyk x;k gSA ;g ik;k x;k gSS fd o"kkZ vkSj bu izkpyksa esa egRoiw.kZ lglaca/k gSA blls LFkkfir gq, dk;kZRed laca/kksa ls fdlh Hkh le; o"kkZ dk vkdyu fd;k tk ldrk gS c’krZs dkWyeuj lh-,y-MCY;w-] ih-MCY;w- vkSj ,y-,p- eku miyC?k gksaA ,d ;k nks ds LFkku ij bu lHkh rhuksa izkpyksa dks cgq lekJ;.k fun’kZ esa 'kkfey djus ds QyLo:i o"kkZ dk csgrj iwokZuqeku yxk;k tk ldk gSA lh- ,y- MCY;w-] ,y- ,p- vkSj ih- MCY;w- ds chp egRoiw.kZ lglaca/k gSaA In search of the key parameters causing rainfall, the authors have explored Tropical Rainfall Measuring Mission (TRMM) satellite data base. By realizing the fact that evaporation of water, condensation of vapour and transport of heat energy by a rising air parcel are all about formation of cloud and rain, the authors have started their quest considering cloud liquid water (CLW), precipitation water (PW) and latent heat (LH) at different altitudes of the atmosphere as major contributors to rainfall mechanism. These data have been fitted to multiple regressions. It is found that significant correlations exist between rainfall and these parameters. The functional relationships so established are able to estimate surface rainfall at any instant, provided columnar CLW, PW and LH values are available. Inclusion of all the three parameters in multiple regression leads to better predictability of rainfall, instead of one or two. Significant correlations exist between CLW, LH and PW.

Comparison of quasi-biennial oscillations of stratospheric winds and atmospheric temperatures at different altitudes

During 1959-89, the 12-month running means of 50 hPa zonal winds, the average atmospheric temperatures in the northern and southern hemisphere at four altitude slabs (950 hPa, 850- 300 hPa, 300-100 hPa and 100-50 hPa), Pacific and Atlantic sea surface temperature (SST) and-30hPa temperatures at North Pole and average for (10°-90° N), all showed quasi-biennial oscillations (QBO). However, whereas the wind QBO had an average spacing of 29 months, only temperatures at 300-100 hPa and Atlantic SST had similar average spacing. Other temperatures as also SO index (represented by Tahiti minus Darwin atmospheric pressure) had larger average spacing. Spectral analysis showed that whereas wind QBO had only one prominent peak at T=2.33 years, other parameters had weak QBOs near T=2.5-2.6 years except Pacific SST and 30 hPa North Pole temperature which had small peaks near T=2.3 years. All the temperatures had prominent peaks in the 3-6 year region which matched with similar peaks in the SO index. There is some indication that stratospheric wind QBO had some relation with parameters at all altitudes in tropics and with North Pole, while ENSO had considerable influence at other latitudes/altitudes.

Altitudinal Gradient Characteristics of Spatial and Temporal Variations of Snowpack in the Changbai Mountain and Their Response to Climate Change

The variations in the snowpack in water towers of the world due to climate change have threatened the amount and timing of freshwater supplied downstream. However, it remains to be further investigated whether snowpack variation in water towers exhibits elevational heterogeneity at different altitude gradients and which climatic factors mainly influence these differences. Therefore, Changbai Mountain, a high-latitude water tower, was selected to analyze the changes in the snowpack by the methods of modified Mann–Kendall based on the daily meteorological data from the China Meteorological Data Service Centre. Meanwhile, the responses of snowpack change to climatic factors over recent decades were assessed and generalized using additive models. The results showed that the snow depth was greater in the higher altitude areas than in the lower elevation areas at different times. Areas with a snow depth of over 70 mm increased significantly in the 2010s. Increasing trends were shown at different altitudes from December to March of the next year during 1960~2018. However, a significant decreasing trend was shown in April, except for altitudes of 600–2378 m. The snow cover time at different altitudes showed a trend of first increasing and then decreasing during 1960~2018. The date of maximum snow depth appears to be more lagged as the altitude increases. In addition, the spring snowpack melted significantly faster in the 2010s than that in the 1960s. The snowpack variation in low-altitude regions is mainly influenced by ET and relative humidity. However, the mean temperature gradually became an important factor, affecting the snow depth variation with the increase in altitude. Therefore, the results of this study will be beneficial to the ecological protection and sustainable development of water towers.

Bharat mein teen laghu akshaansh kendron ke oopar ozone ke oordhvaadhar vitaran kee ozone sonde aankadon ke dvaara pradarshit pravrtti

This study examines the trends in the vertical distribution of ozone over three low latitude stations in India. The stations are Delhi (28° N, 77° E), Pune (18° N, 74° E) and Thiruvananthapuram (8° N, 76° E) lying in the almost same longitude belt (74-77°) but separated by10o latitude. The balloon ozonesonde data of 45 years (1969 – 2012) have been analyzed. It has been found that ozone trends at different altitudes are different for three stations. The peak value and the altitude of peak value vary from year to year. This is due to solar UV-B variation.