Height Correlation Research Articles

Crop Height Monitoring Using a Consumer-Grade Camera and UAV Technology

Recent advances in the ability to capture high spatial resolution images by unmanned aerial vehicles (UAVs) have shown the potential of this technology for a wide range of application including exploring the effects of different external stimuli when monitoring environmental and structural variables. In this paper, we show the application of UAV technology for crop height monitoring and modelling to provide quantitative crop growth data and demonstrate the remote sensing and photogrammetric capabilities of the technology to the farming industry. This study was carried out in a field trial involving a combination of six wheat varieties and three different fungicide treatments. The UAV imagery of the field trial site was captured on five occasions throughout crop development. These were used to create digital surface models from which crop surface models (CSMs) were extracted for the cropped areas. Crop heights are estimated from the photogrammetric derived CSMs and are compared against the reference heights captured using Real-Time Kinematic Global Navigation Satellite System (GNSS) to validate the CSMs. Furthermore, crop growth differences among varieties are analysed; and crop height correlations with grain yield as well as with independently estimated vegetation indices are evaluated. These evaluations show that the technology is suitable (with average bias range 2–10 cm depending on wind conditions relative to GNSS height) and has potential for quantitative and qualitative monitoring of canopy and/or crop height and growth.

Tsunami hazard and risk assessment for multiple buildings by considering the spatial correlation of wave height using copulas

Abstract. It is necessary to evaluate aggregate damage probability to multiple buildings when performing probabilistic risk assessment for the buildings. The purpose of this study is to demonstrate a method of tsunami hazard and risk assessment for two buildings far away from each other, using copulas of tsunami hazards that consider the nonlinear spatial correlation of tsunami wave heights. First, we simulated the wave heights considering uncertainty by varying the slip amount and fault depths. The frequency distributions of the wave heights were evaluated via the response surface method. Based on the distributions and numerically simulated wave heights, we estimated the optimal copula via maximum likelihood estimation. Subsequently, we evaluated the joint distributions of the wave heights and the aggregate damage probabilities via the marginal distributions and the estimated copulas. As a result, the aggregate damage probability of the 99th percentile value was approximately 1.0 % higher and the maximum value was approximately 3.0 % higher while considering the wave height correlation. We clearly showed the usefulness of copula modeling considering the wave height correlation in evaluating the probabilistic risk of multiple buildings. We only demonstrated the risk evaluation method for two buildings, but the effect of the wave height correlation on the results is expected to increase if more points are targeted.

Molecular dynamics study of pristine and defective hexagonal BN, SiC and SiGe monolayers

The structural and thermodynamical properties of 2D honeycomb hybrids are investigated over a wide temperatures range by carrying out atomistic simulations using Tersoff-type interatomic empirical potential. The variance of the radial distribution as well as the height correlation functions in terms of temperature and buckling parameter are discussed for the SiC, SiGe and BN compounds. A non-monotonic growth of mean square displacement is observed when increasing the defect concentration. The energetic of Stone–Wales defects and vacancies as well as the magnitude of thermally excited ripples for both pristine and defective monolayers increase significantly at higher temperatures, which is caused by the increase in bond lengths and atom’s velocities, resulting in higher kinetic energy. It follows that thermal rippling is intricately related to thermal expansion.

The network effects on conscripts’ height in the central provinces of Russian empire in the middle of XIX century – at the beginning of XX century

Background: We investigated average body height in the central provinces of the Russian empire in the middle of XIX century in view of the concept of "community effects on height". We analyzed body height correlations between neighboring districts at this time. We added information about secular changes in body height during the 19th century of this territory. Material and methods: The study used height data of conscripts, which were born in the years 1853-1863, and age 21 at the time of measurement. The territory of seven provinces was considered as a network with 105 nodes, each node representing one district with information on average male body height. In order to define neighboring districts three different approaches were used: based on the "common borders" method, based on Euclidean distances (from 60 to 120 km), based on real road connections. Results: Small but significant correlation coefficients were observed between 1st order districts in the network based on Euclidean distance of 100 km (r = 0.256, p-value = 0.006) and based on "the common borders" approach (r = 0.25, p-value = 0.02). Wherein no significant correlations were observed in the network based on road connections and between second order neighbors regardless of the method. Conclusion: Height correlation coefficients between 1st order neighboring districts observed in the Russian districts were very similar to values observed in the Polish study (r = 0.24). The considered Russian territory and the territory of Poland have a lot in common. They consist of both plains without mountains. In contradistinction to Poland the transport infrastructure in Russia was weakly developed in the middle of XIX century. In addition, the mobility of people was limited by serfdom. In this context the absent of significant correlation of second order neighbors can be explained by low population density and lack of migration and communication between the districts.

Higher Weight and Weight Gain after 4 Years of Age Rather than Weight at Birth Are Associated with Adiposity, Markers of Glucose Metabolism, and Blood Pressure in 5-Year-Old Ethiopian Children

Fetal and early life growth is associated with adult risk of obesity and cardiometabolic disease. However, little is known about the relative importance of birth weight and successive periods of weight gain on markers of cardiometabolic risk in childhood in low-income populations. The objective was to study associations of birth weight and weight gain velocities in selected age intervals from birth to 60 mo with height, fat-free mass (FFM), and markers of adiposity and cardiometabolic risk at 60 mo. In a prospective cohort study of 375 Ethiopian children aged 60 mo, we estimated individual weight gain velocities in the periods between birth and 3, 6, 24, 48, and 60 mo using linear-spline mixed-effects modeling. Subsequently, we analyzed associations of birth weight, weight gain velocities, and current weight with height, FFM, and markers of adiposity and cardiometabolic risk. Weight gain from 48 to 60 mo and weight at 60 mo rather than birth weight were the strongest correlates of insulin, C-peptide, HOMA-IR, blood pressure, height, FFM, waist circumference, and fat mass at 60 mo. For instance, 1 SD higher (1 SD=50 g/mo) weight accretion from 48 to 60 mo was associated with a higher insulin of 23.3% (95% CI: 9.6%, 38.8%), C-peptide of 11.4% (2.7%, 20.8%), systolic blood pressure of 1.4 mm Hg (0.6, 2.3 mm Hg), fat mass of 0.72 kg (0.59, 0.85 kg), and FFM of 0.70 kg (0.56, 0.85 kg). Weight gain from 0 to 3 mo was positively associated with LDL cholesterol, systolic blood pressure, height, and the body composition indices, and weight gain from 24 to 48 mo was inversely associated with blood glucose. In 60-mo-old Ethiopian urban children, weight gain and weight after 48 mo rather than weight at birth may represent a sensitive period for variations in markers of adiposity and glucose metabolism. The birth cohort is registered at https://www.isrctn.com/ as ISRCTN46718296.

Acoustic correlates of talker height in children’s voices

In a recent study, we investigated listeners’ ability to judge talker height from CVC syllables spoken by children. The present study extends this research by examining acoustic variables that predict talker height. We analyzed recordings of the sustained vowel /a/ produced by children 5 through 18 years of age, taken from a larger children's speech database. In addition to measures previously found to predict speaker height (GMFF and G0, the geometric mean of the lowest three formant frequencies and fundamental frequency, respectively) we investigated measures related to the glottal source reflecting breathiness and spectral tilt. Multiple regression models incorporating these measures provided accurate estimates of talker height (mean average error of 9.3 cm). Consistent with our previous findings for age, a model specifying the sex of the talker predicts talker height significantly more accurately than a model that excludes sex.

Validation of the Center-Center Technique for Intraoperative Syndesmosis Fixation Alignment

Category:AnkleIntroduction/Purpose:Distal tibiofibular syndesmosis sprain has been reported among 13% to 23% of all ankle fractures, often requiring surgery. However, post-operative malreduction rates have been reported to range from 0 to 54%. Optimal reduction is a significant predictor of overall functional outcome.The centroids of the tibia and fibula align the theoretically ideal axis of syndesmosis fixation alignment. The “Center-Center” method for syndesmosis fixation is a recently described intraoperative technique for aligning the central axes of the tibia and fibula on the ankle lateral fluoroscopic view, seemingly aligning the centroids. There is a lack of validation and outcomes data to support this technique.This study was performed in order to determine how reliably the ”center-center” technique aligns with the centroid axis of the fibula and tibia.Methods:This was a quantitative descriptive study utilizing 30 axial computed tomography scans from July 1, 2016 to June 30, 2018. Eighteen males and 12 females were included with an average age of 44-years-old. CT measurements were made using Visage 7. Three observers measured the maximum difference in degrees between the Center-Center and Centroid measurements at 10 mm, 20 mm, and 30 mm proximal to the tibial plafond for each patient. The Center-Center axis was established by internally rotating the CT image until the fibula aligned within the center of the tibia. The centroid measurement was established using a tool that calculated the centroid of each bone. Finally, the difference in external rotation required to obtain the Center-Center measurements were observed at levels 10 mm versus 20 mm, 20 mm versus 30 mm, and 10 mm versus 30 mm.Results:The Center-Center and Centroid axes were highly consistent within and between subjects and levels, differing on average by a mean 0.39 degrees (95% CI 0.29 to 0.49 degrees) across all comparisons. These axes externally rotated a mean 3.10 degrees (95% CI 2.56 to 3.64 degrees) from 10 mm to 20 mm and a mean 2.72 degrees (95% CI 2.35 to 3.09 degrees) from 20 mm to 30 mm. There were no statistically significant differences in the mean values obtained between observers for any axis at any height (p-value range 0.4 to 1.0) and intraclass correlation indicated excellent to near perfect interobserver agreement (ICC range, 0.876 to 0.988).Conclusion:The Center-Center technique consistently and closely aligns the fibula and tibia along the Centroid axis. These two axes externally rotate approximately 3 degrees for each 10 mm above the plafond. The Center-Center technique may offer the highly accurate means sought for achieving accurate and consistent intraoperative syndesmosis fixation alignment due to its highly consistent relationship to the Centroid axis. Surgeons should be aware of the external rotation of these axes between heights as the axes externally rotated a mean 3 degrees for each 10 mm height increase. Failure to correct limb rotation for each height could result in iatrogenic malreduction.

Relationships between Plant Architecture Traits and Cotton Yield within the Plant Height Range of 80–120 cm Desired for Mechanical Harvesting in the Yellow River Valley of China

Mechanical harvesting has become inevitable for cotton production in China due to the rising labor cost in the country. It usually requires a moderate plant height and compact plant architecture. Correlation and stepwise regression were employed to analyze databases of our 24 field experiments between 2010 and 2017 in Hebei Province. The purpose is to identify the relationships between plant architecture traits and seed cotton yield within natural plant height range (58.6–163.2 cm) or preferred plant height range (80–120 cm) for mechanical harvesting in the Yellow River Valley of China, and define some important factors affecting seed cotton yield. Under natural plant height range across all experiments, there was a significantly negative correlation (r = −0.452) between plant height and yield. On limited plant height range desired for mechanical harvesting, the degree of this negative correlation decreased to r = −0.366. The correlation of plant height with seed cotton yield varied greatly with year, cultivar, plant density and mepiquat chloride (MC) application. Moreover, stepwise regression analysis picked internode length of the 1st (generally including 1st–7th mainstem node from bottom), 2nd (8th–12th node) and 4th (above 17th node) mainstem section and the length of lower fruiting branch (LFB) as significant factors influencing seed cotton yield under plant height range of 80–120 cm. The results have implications for precise control of cotton plant architecture preferred for mechanized harvesting in China.

Effect of Bath Depth and Nozzle Geometry on Spout Height in Submerged Gas Injection at Bottom

Spout height is a widely used parameter to quantitatively analyze the performance of the submerged gas injection in industrial applications. However, the effect of bath depth and nozzle geometry on spout height in submerged gas injection is still unclear. In this work, the effect of bath depth and nozzle geometry on spout height in submerged gas injection at bottom was experimentally investigated. Circular-shaped, three-leaf-shaped, four-leaf-shaped, and four-flower-shaped nozzles were used for this study. Spout height was extracted from the images captured by high-speed camera and analyzed by digital image processing. The results indicate that the effect of nozzle geometry on spout height is as important as gas flow rate and bath depth. Through dimensional analysis, predictive correlations of spout height from circular shape and four-leaf shape were developed with dimensionless bath depth and a modified Froude number using orifice perimeter and opening area as characteristic parameters. Experimental data were compared with the correlations from literature and good agreement was found.

Prediction of genetic gain in Ficus variegata progeny trial based on breeding value

Abstract. Haryjanto L, Prastyono, Hadiyan Y, Susanto M. 2019. Prediction of genetic gain in Ficus variegata progeny trial based on breeding value. Biodiversitas 20: 2994-2999. Prediction of genetic gain in Ficus variegata Blume progeny trial based on breeding values. The aim of this study was to estimate the breeding value based on components variance and genetic gain prediction of Ficus variegata Blume using REML/BLUP. A total of 17 families of Ficus variegata Blume were evaluated at three years after planting at progeny trial in Mangunan, Bantul, Yogyakarta laid out in Randomized Completely Block Design (RCBD). Estimation of variance family (height and diameter) were ± 5% of total variance. Narrow-sense individual heritability was moderate (0.27 and 0.21 respectively) indicated promising genetic improvement. Strong genetic correlation of height and diameter (rG=0.9) indicated that improving a trait will improving others. BLUP analysis for diameter trait showed that the best individual value from best family selection was appropriated with restriction 10 family and 5 individual per family and genetic gain prediction was 15.83% gave acceptable rate of inbreeding 2% per generation.

SEMANTIC SEGMENTATION OF AIRBORNE IMAGES AND CORRESPONDING DIGITAL SURFACE MODELS – ADDITIONAL INPUT DATA OR ADDITIONAL TASK?

Abstract. We analyze the effects of additional height data for semantic segmentation of aerial images with a convolutional encoder-decoder network. Besides a merely image-based semantic segmentation, we trained the same network with height as additional input and furthermore, we defined a multi-task model, where we trained the network to estimate the relative height of objects in parallel to semantic segmentation on the image data only. Our findings are, that excellent results are possible for image data only and additional height information has no significant effect – neither when employed as extra input nor when used for multi-task training, even with differently weighted losses. Based on our results, we, thus, hypothesize that a strong encoder-decoder network implicitly learns the correlation of object categories and relative heights.

Wave characteristics of vertical upward adiabatic annular flow in pipes

Annular flow exists in many engineering applications, such as refrigerators, oil extraction, nuclear reactors and so on, due to its high heat and mass transfer efficiencies. Annular flow is characterized by liquid film on the wall and gas core at the center of the flow duct. The interface between the gas and liquid is composed of many different waves that play important role in mass, momentum and energy transfers between gas and liquid phases. Here three important parameters regarding wave characteristics, namely, wave velocity, base film thickness and wave height have been studied. For wave velocity, correlation has been proposed by two methods which are derived from liquid interfacial velocity and interfacial shear stress, respectively. For correlations of base film thickness and wave height, they are proposed in similar forms as that of average film thickness previously developed by the authors. These newly proposed correlations are functions of gas and liquid Weber numbers, and are simpler and more straightforward to use as compared to the existing ones. The newly proposed wave velocity, base film thickness and wave height correlations, respectively, have mean absolute percentage errors of 9.56%, 14.6% and 12.1% compared to current databases. They have shown an improved prediction accuracy compared to the other correlations in the literature.

Research on the interaction between two line jet fires with unequal heat release rate at different burner distances

This paper investigated the merging behavior and flame height of two jet fires at varying burner distances (D). Two identical line burners with different heat release rates (HRRs) were placed parallel to each other and propane was used as fuel. The experimental results showed that when the burner distance was within a certain small range and the HRR of small fire was fixed, the merging probability of two flames increased firstly and then decreased with the increased HRR of the big fire. Two parameters, the critical distance of touching DPm and flame height changing DZf, were introduced to divide the flame behavior into three stages. When D>DPm, the two fires were independent; When DZf<D<DPm, the two flames tilted to each other and merged intermittently. Because the two mechanisms (unburned fuel diffusion and flame tilting) caused by the restriction of air entrainment competed with each other and were in equilibrium, the merging flame height maintained unchangeable; When D<DZf, the merging flame height increased obviously with decreasing the burner distance. Meanwhile, the merging flame heights for two fires with fixed total HRRs were nearly identical as the burner distance changes regardless of the ratio of big and small HRR. But when the small fire height was less than 0.28 times of the big fire height, the existence of small fire will have no influence on the merging flame height. Based on the analysis of air entrainment, correlations of flame height were proposed and validated by data in the literature, which presented high reliability.

One‐step deposition of nano‐to‐micron‐scalable, high‐quality digital image correlation patterns for high‐strain in‐situ multi‐microscopy testing

AbstractDigital image correlation (DIC) is of vital importance in the field of experimental mechanics, yet producing suitable DIC patterns for demanding in‐situ (micro)mechanical tests remains challenging, especially for ultrafine patterns, despite the large number of patterning techniques reported in the literature. Therefore, we propose a simple, flexible, one‐step technique (only requiring a conventional physical vapour deposition machine) to obtain scalable, high‐quality, robust DIC patterns, suitable for a range of microscopic techniques, by deposition of a low‐melting temperature solder alloy in the so‐called island growth mode, without elevating the substrate temperature. Proof of principle is shown by (near‐)room temperature deposition of InSn patterns, yielding highly dense, homogeneous DIC patterns over large areas with a feature size that can be tuned from as small as ~10 nm to ~2 μm and with control over the feature shape and density by changing the deposition parameters. Pattern optimisation, in terms of feature size, density, and contrast, is demonstrated for imaging with atomic force microscopy, scanning electron microscopy, optical profilometry, and optical microscopy. Moreover, the performance of the InSn DIC patterns and their robustness to large deformations is validated in two challenging case studies of in‐situ micromechanical testing: (a) self‐adaptive isogeometric digital height correlation of optical surface height profiles of a coarse, bimodal InSn pattern providing microscopic 3D deformation fields (illustrated for delamination of Al stretchable interconnects on a PI substrate) and (b) DIC on scanning electron microscopy images of a much finer InSn pattern allowing quantification of high strains near fracture locations (illustrated for rupture of a polycrystalline Fe foil). As such, the high controllability, performance, and scalability of the DIC patterns, created by island growth of a solder alloy, offer a promising step towards more routine DIC‐based in‐situ micromechanical testing.

Phenotypic variation in Australian wild Cajanus and their interspecific hybrids

Wild species are potential sources of genetic diversity for crop improvement. Variation in agronomically important traits has been reported in the wild Cajanus species however, the Australian wild species have not been characterized to date. A subset of four Australian wild Cajanus acutifolius (F.Muell.) Maesen accessions and 57 interspecific hybrids of C. acutifolius, Cajanus lanuginosus (S.T.Reynolds & Pedley) Maesen, Cajanus lanceolatus (W.Fitzg.) Maesen, and two C. cajan genotypes were investigated to assess the phenotypic diversity for 17 qualitative and six quantitative traits. Significant variation in stem thickness, days to 50% flowering (dff) (f.pr < 0.001), and raceme number (f.pr < 0.021) within a group, and plant height, stem thickness, leaf size and dff (f.pr < 0.001) between groups was found. In contrast to earlier reports, some wild C. acutifolius accessions were found to be early (AGG31815WCAJ with 117 days) and medium (AGG316925WCAJ with 140 days) maturating types. Positive correlation of plant height with stem thickness (r = 0.714), and dff (r = 0.780) was observed in late maturing types. Positive correlation of stem thickness with leaf size (r = 0.709), and dff (r = 0.760) were identified in all groups. Even though there was a slight negative correlation of the number of racemes with plant height (r = − 0.126) and stem thickness (r = − 0.190), a considerable positive correlation was observed with secondary (r = 0.536) and tertiary (r = 0.500) branches. The F1s produced with wild Cajanus acutifolius as the female parent were sterile demonstrating the potential for use in hybrid breeding programs.

POST-FIRE FORESTRY RECOVERY MONITORING USING HIGH-RESOLUTION MULTISPECTRAL IMAGERY FROM UNMANNED AERIAL VEHICLES

Abstract. In recent years unmanned aerial vehicles (UAVs) have been used in several applications and research studies related to environmental monitoring. The works performed have demonstrated the suitability of UAVs to be employed in different scenarios, taking advantage of its capacity to acquire high-resolution data from different sensing payloads, in a timely and flexible manner. In forestry ecosystems, UAVs can be used with accuracies comparable with traditional methods to retrieve different forest properties, to monitor forest disturbances and to support disaster monitoring in fire and post-fire scenarios. In this study an area recently affected by a wildfire was surveyed using two UAVs to acquire multi-spectral data and RGB imagery at different resolutions. By analysing the surveyed area, it was possible to detect trees, that were able to survive to the fire. By comparing the ground-truth data and the measurements estimated from the UAV-imagery, it was found a positive correlation between burned height and a high correlation for tree height. The mean NDVI value was extracted used to create a three classes map. Higher NDVI values were mostly located in trees that survived that were not/barely affected by the fire. The results achieved by this study reiterate the effectiveness of UAVs to be used as a timely, efficient and cost-effective data acquisition tool, helping for forestry management planning and for monitoring forest rehabilitation in post-fire scenarios.

Experimental study on flame morphologic characteristics of wall attached non-premixed buoyancy driven turbulent flames

This work investigates the effects of the wall on the morphologic characteristics of non-premixed buoyancy driven turbulent flames attached to the wall. Experiments are carried out with rectangular burners having their long side attached to a wall. The investigation is based on dimensional analysis and comprehensive experimental data, including comparison of the flame characteristics of the wall attached flames with free flames. Results show that the non-dimensional flame heights of wall attached flames experience a two-dimensional to three-dimensional transition as free flames do. The critical dimensionless heat release rate for this transition is smaller for the wall attached flames (0.30) than that of the free flames (0.39). The flame height fluctuation of wall attached flames is smaller than that of free flames and decreases with an increase in the nozzle aspect ratio. The ratio of flame thickness (or flame width) to flame height of wall attached flames is smaller than that of free flames. New correlations for flame height, width and thickness of the wall attached flames are proposed based on the mirror-approach of the rectangular source relative to that of a free flame, where the burner perimeter is found to be an appropriate length scale. This work provides important knowledge on the effect of wall on flame characteristics of buoyancy driven turbulent flames, which is essential to the design and risk assessment of the laying of gaseous fuel transportation pipelines in the city and also provides data for validation of computational fluid dynamics (CFD) models.

Anatomic Evaluation of the Quadriceps Tendon in Cadaveric Specimens: Application for Anterior Cruciate Ligament Reconstruction Graft Choice

PurposeThe quadriceps tendon (QT) is an autograft option for primary and revision anterior cruciate ligament (ACL) reconstruction. Techniques for predicting the appropriate graft size are limited. The purpose of this study was to evaluate the morphologic features of the QT in cadaveric specimens and compare the findings to recent MRI studies.Materials and MethodsMacroscopic dissections were performed on 10 cadaveric knees. Using the distal myotendinous junction of the rectus femoris and superior pole of the patella as anatomic landmarks, the QT was isolated. Tendon length, width, and thickness were recorded at 10 millimeter (mm) increments. A central 80 mm x 10 mm graft was harvested, after which the graft was measured in an identical fashion. Specimen anthropometric data was collected. Subgroup analysis and linear regression were then performed using Microsoft Excel 2011 Office Analysis ToolPak.ResultsThe mean QT length was 83.3 +/- 14.4 mm, ranging from 63 to 108 mm. The mean percentage of remaining QT volume following graft harvesting was 63.3%. QT length showed significant correlation with patient height (correlation coefficient: 0.719, p = 0.027). QT thickness remained relatively constant, while the width is greatest at its patellar insertion and gradually decreases proximally towards the myotendinous junction.ConclusionThe QT has the anatomical features to produce a robust autograft for ACL reconstruction. During preoperative evaluation of graft size and quality, patient height should be considered as it is strongly correlated with the length of the potential graft. Our findings support the use of MRI as a way to preoperatively assess the QT as an autograft when performing an ACL reconstruction.

Passage of a bubble through the interface between a shear-thinning heavier liquid and a Newtonian lighter liquid

Numerical simulations are carried out to study the phenomenon of passage of a bubble through the interface between two initially quiescent liquids. The heavier liquid is a viscous shear-thinning liquid whereas the lighter liquid is a viscous Newtonian liquid. The computational model, which is based on axisymmetric computational domain and VOF (volume of fluid) method, is validated by using the data reported in literature. The validated computational model is then used to perform parametric analysis to understand the effects of bubble diameter, interfacial tension between the two liquids and flow index of the heavier liquid on the drainage time, drainage height, retention time and retention height of the bubble at the liquid–liquid interface. Finally, correlations for retention time and retention height are proposed.

The Cardio-respiratory Fitness in Medical Students by Queen’s College Step Test: A Cross-sectional Study

Introduction: Cardio-respiratory fitness indicates the ability of circulatory system to supply oxygen toworking muscles during continuous physical activity. Maximum oxygen uptake (VO2max) is a single bestmeasure of cardio-respiratory fitness and is considered gold standard to quantify aerobic capacity. Methods:Eighty students of age group 18-25 years were taken by simple random sampling. VO2max was estimatedindirectly by following the protocol of Queen’s College Step Test (QCST) method. Results: Mean value ofVO2max for male (51.61±6.26 ml/Kg/min) and female (36.02±3.71 ml/Kg/min) was compared, which wasfound significantly higher in males than in females (p&lt;0.001). There was negative correlation of gender(r = -0.838), body mass index (BMI) (r = -0.339), obesity category (r = -0.275), obese vs non-obese (r =-0.264) and basal pulse rate (r = -0.456) with VO2max and positive correlation of height (r = 0.592) and hoursof study(r = 0.309) with VO2max. Conclusion: This study showed that increased BMI is associated withdecreased level of VO2max in young adults. One can improve VO2max by maintaining BMI within normallimits.