22 results on '"Waqas A. Qazi"'
Search Results
2. Detection of Thermal Fronts in the Arabian sea through SAR (Synthetic Aperture Radar) imagery
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Nadia Jabeen and Waqas A. Qazi
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- 2021
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3. Protein Enrichment of Wheat Bread with Microalgae: Microchloropsis gaditana, Tetraselmis chui and Chlorella vulgaris
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Waqas Muhammad Qazi, Simon Ballance, Katerina Kousoulaki, Anne Kjersti Uhlen, Dorinde M. M. Kleinegris, Kari Skjånes, and Anne Rieder
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Health (social science) ,protein-quality ,Chemical technology ,digestive, oral, and skin physiology ,Tetraselmis chui ,Microchloropsis gaditana ,food and beverages ,Dough rheology ,TP1-1185 ,Plant Science ,Health Professions (miscellaneous) ,Microbiology ,dough rheology ,bread-quality ,microalgae ,Chlorella vulgaris ,Bread quality ,Protein quality ,Microalgae ,Protein‐quality ,Food Science - Abstract
Cell wall disrupted and dried Microchloropsis gaditana (Mg), Tetraselmis chui (Tc) and Chlorella vulgaris (Cv) microalgae biomasses, with or without ethanol pre-treatment, were added to wheat bread at a wheat flour substitution level of 12%, to enrich bread protein by 30%. Baking performance, protein quality and basic sensory properties were assessed. Compared to wheat, Mg, Tc and Cv contain higher amounts of essential amino acids and their incorporation markedly improved protein quality in the bread (DIAAS 57–66 vs. 46%). The incorporation of microalgae reduced dough strength and bread volume and increased crumb firmness. This was most pronounced for Cv and Tc but could be improved by ethanol treatment. Mg gave adequate dough strength, bread volume and crumb structure without ethanol treatment. To obtain bread of acceptable smell, appearance, and colour, ethanol treatment was necessary also for Mg as it markedly reduced the unpleasant smell and intense colour of all algae breads. Ethanol treatment reduced the relative content of lysine, but no other essential amino acids. However, it also had a negative impact on in vitro protein digestibility. Our results show that Mg had the largest potential for protein fortification of bread, but further work is needed to optimize pre-processing and assess consumer acceptance.
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- 2021
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4. Protein Enrichment of Wheat Bread with Microalgae
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Waqas Muhammad, Qazi, Simon, Ballance, Katerina, Kousoulaki, Anne Kjersti, Uhlen, Dorinde M M, Kleinegris, Kari, Skjånes, and Anne, Rieder
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dough rheology ,bread-quality ,protein-quality ,microalgae ,digestive, oral, and skin physiology ,Microchloropsis gaditana ,food and beverages ,Chlorella vulgaris ,Article ,Tetraselmis chui - Abstract
Cell wall disrupted and dried Microchloropsis gaditana (Mg), Tetraselmis chui (Tc) and Chlorella vulgaris (Cv) microalgae biomasses, with or without ethanol pre-treatment, were added to wheat bread at a wheat flour substitution level of 12%, to enrich bread protein by 30%. Baking performance, protein quality and basic sensory properties were assessed. Compared to wheat, Mg, Tc and Cv contain higher amounts of essential amino acids and their incorporation markedly improved protein quality in the bread (DIAAS 57–66 vs. 46%). The incorporation of microalgae reduced dough strength and bread volume and increased crumb firmness. This was most pronounced for Cv and Tc but could be improved by ethanol treatment. Mg gave adequate dough strength, bread volume and crumb structure without ethanol treatment. To obtain bread of acceptable smell, appearance, and colour, ethanol treatment was necessary also for Mg as it markedly reduced the unpleasant smell and intense colour of all algae breads. Ethanol treatment reduced the relative content of lysine, but no other essential amino acids. However, it also had a negative impact on in vitro protein digestibility. Our results show that Mg had the largest potential for protein fortification of bread, but further work is needed to optimize pre-processing and assess consumer acceptance.
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- 2021
5. Simultaneous X-ray Video-Fluoroscopy and Pulsed Ultrasound Velocimetry Analyses of the Pharyngeal Phase of Swallowing of Boluses with Different Rheological Properties
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Rashid Mansoor, Olle Ekberg, Johan Wiklund, Waqas Muhammad Qazi, and Mats Stading
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Review ,030507 speech-language pathology & audiology ,03 medical and health sciences ,Speech and Hearing ,0404 agricultural biotechnology ,Bolus (medicine) ,Rheology ,Ultrasound ,Newtonian fluid ,Humans ,Medicine ,Video-fluoroscopy ,Fluids ,Shear thinning ,Viscosity ,business.industry ,Cineradiography ,X-Rays ,Gastroenterology ,X-ray ,04 agricultural and veterinary sciences ,Velocimetry ,040401 food science ,Deglutition disorders ,Deglutition ,Ultrasonic Waves ,Otorhinolaryngology ,Flow velocity ,Pharynx ,0305 other medical science ,business ,Biomedical engineering - Abstract
The Ultrasound Velocity Profiling (UVP) technique allows real-time, non-invasive flow mapping of a fluid along a 1D-measuring line. This study explores the possibility of using the UVP technique and X-ray video-fluoroscopy (XVF) to elucidate the deglutition process with the focus on bolus rheology. By positioning the UVP probe so that the pulsed ultrasonic beam passes behind the air-filled trachea, the bolus flow in the pharynx can be measured. Healthy subjects in a clinical study swallowed fluids with different rheological properties: Newtonian (constant shear viscosity and non-elastic); Boger (constant shear viscosity and elastic); and shear thinning (shear rate-dependent shear viscosity and elastic). The results from both the UVP and XVF reveal higher velocities for the shear thinning fluid, followed by the Boger and the Newtonian fluids, demonstrating that the UVP method has equivalent sensitivities for detecting the velocities of fluids with different rheological properties. The velocity of the contraction wave that clears the pharynx was measured in the UVP and found to be independent of bolus rheology. The results show that UVP not only assesses accurately the fluid velocity in a bolus flow, but it can also monitor the structural changes that take place in response to a bolus flow, with the added advantage of being a completely non-invasive technique that does not require the introduction of contrast media. Electronic supplementary material The online version of this article (10.1007/s00455-020-10092-4) contains supplementary material, which is available to authorized users.
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- 2020
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6. Forest inventory and analysis in Gilgit-Baltistan: A contribution towards developing a forest inventory for all Pakistan
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Wu Ning, Hammad Gilani, Bhaskar Singh Karky, Kamran Hussain, Kiramat Hussain, Faisal Mueen Qamer, Anwar Ali, Waqas A. Qazi, Muhammad Umar Sohail, Rajan Kotru, and Ismail Ismail
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0106 biological sciences ,010504 meteorology & atmospheric sciences ,Geography, Planning and Development ,Forest management ,Tree allometry ,Management, Monitoring, Policy and Law ,Development ,lcsh:QC851-999 ,01 natural sciences ,Forest monitoring ,Diversity index ,Gilgit-Baltistan ,lcsh:Environmental sciences ,0105 earth and related environmental sciences ,lcsh:GE1-350 ,Global and Planetary Change ,Forest inventory ,Diameter at breast height ,Species diversity ,Forestry ,Environmental science ,Species evenness ,lcsh:Meteorology. Climatology ,Species richness ,REDD+ ,010606 plant biology & botany - Abstract
Purpose The purpose of the study is to analyse the occurrence and distribution of different tree species in Gilgit-Baltistan, Pakistan, as a baseline for further inventories, and estimate the biomass per species and plot. Furthermore, it aims to measure forest biodiversity using established formulae for tree species diversity index, richness, evenness and accumulative curve. Design/methodology/approach Field data were collected, including stratification of forest sample plots. Statistical analysis of the data was carried out, and locally appropriate allometric equations were applied for biomass estimation. Findings Representative circular 556 forest sample plots of 1,000 m2 contained 13,135 trees belonging to nine tree species with a total aboveground biomass of 12,887 tonnes. Sixty-eight per cent of the trees were found between 2,600 and 3,400 masl; approximately 63 per cent had a diameter at breast height equal to 30 cm, and 45 per cent were less than 12 m in height. The Shannon diversity index was 1.82, and Simpson’s index of diversity was 0.813. Research limitations/implications Rough terrain, long distances, harsh weather conditions and location of forest in steep narrow valleys presented challenges for the field crews, and meant that fieldwork took longer than planned. Practical implications Estimating biomass in Gilgit-Baltistan’s forests using locally developed allometric equations will provide transparency in estimates of forest reference levels, National Forest Monitoring System in Pakistan and devising Reducing Emissions from Deforestation and Forest Degradation national strategies and for effective implementation. Originality/value This paper presents the first detailed forest inventory carried out for the dry temperate and semi-arid cold region of Gilgit-Baltistan, Pakistan.
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- 2018
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7. Above Ground Biomass Estimation of Dalbergia sissoo Forest Plantation from Dual-Polarized ALOS-2 PALSAR Data
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Waqas A. Qazi, Shahbaz Baig, Aqeela Mobeen Akhtar, Hammad Gilani, Mirza Muhammad Waqar, Ahmad Ammar, and Syed Amer Mehmood
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Synthetic aperture radar ,010504 meteorology & atmospheric sciences ,biology ,Forest plantation ,Agroforestry ,0211 other engineering and technologies ,Biomass ,Dalbergia sissoo ,Forestry ,02 engineering and technology ,biology.organism_classification ,01 natural sciences ,law.invention ,Dual polarized ,Above ground ,Geography ,law ,General Earth and Planetary Sciences ,Satellite imagery ,Radar ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences - Abstract
In this study, ALOS-2 PALSAR L-band dual-pol (HH and HV) synthetic aperture radar (SAR) images were used for above ground biomass (AGB) estimation of Shisham (Dalbergia sissoo) tree species in the ...
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- 2017
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8. Integration of high-resolution optical and SAR satellite remote sensing datasets for aboveground biomass estimation in subtropical pine forest, Pakistan
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Sajid Rashid Ahmad, Waqas A. Qazi, Hammad Gilani, Aqeela Mobeen Akhtar, Syed Amer Mahmood, and Ansir Rasool
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Synthetic aperture radar ,010504 meteorology & atmospheric sciences ,Backscatter ,010501 environmental sciences ,Management, Monitoring, Policy and Law ,Forests ,01 natural sciences ,Normalized Difference Vegetation Index ,Forest ecology ,Satellite imagery ,Pakistan ,Biomass ,Ecosystem ,0105 earth and related environmental sciences ,General Environmental Science ,Remote sensing ,Pinus roxburghii ,Biomass (ecology) ,Radar ,biology ,General Medicine ,Vegetation ,biology.organism_classification ,Pinus ,Pollution ,Remote Sensing Technology ,Environmental science ,Environmental Monitoring - Abstract
In this study, we investigate stand-alone and combined Pleiades high-resolution passive optical and ALOS PALSAR active Synthetic Aperture Radar (SAR) satellite imagery for aboveground biomass (AGB) estimation in subtropical mountainous Chir Pine (Pinus roxburghii) forest in Murree Forest Division, Punjab, Pakistan. Spectral vegetation indices (NDVI, SAVI, etc.) and sigma nought HV-polarization backscatter dB values are derived from processing optical and SAR datasets, respectively, and modeled against field-measured AGB values through various regression models (linear, nonlinear, multi-linear). For combination of multiple spectral indices, NDVI, TNDVI, and MSAVI2 performed the best with model R2/RMSE values of 0.86/47.3 tons/ha. AGB modeling with SAR sigma nought dB values gives low model R2 value of 0.39. The multi-linear combination of SAR sigma nought dB values with spectral indices exhibits more variability as compared with the combined spectral indices model. The Leave-One-Out-Cross-Validation (LOOCV) results follow closely the behavior of the model statistics. SAR data reaches AGB saturation at around 120-140 tons/ha, with the region of high sensitivity around 50-130 tons/ha; the SAR-derived AGB results show clear underestimation at higher AGB values. The models involving only spectral indices underestimate AGB at low values (< 60 tons/ha). This study presents biomass estimation maps of the Chir Pine forest in the study area and also the suitability of optical and SAR satellite imagery for estimating various biomass ranges. The results of this work can be utilized towards environmental monitoring and policy-level applications, including forest ecosystem management, environmental impact assessment, and performance-based REDD+ payment distribution.
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- 2019
9. Protein enrichment of wheat bread with the marine green microalgae Tetraselmis chuii – Impact on dough rheology and bread quality
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Anne Kjersti Uhlen, John-Erik Haugen, Anne Rieder, Simon Ballance, Katerina Kousoulaki, and Waqas Muhammad Qazi
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0106 biological sciences ,Ethanol ,biology ,Chemistry ,Wheat flour ,food and beverages ,04 agricultural and veterinary sciences ,Wheat bread ,biology.organism_classification ,040401 food science ,01 natural sciences ,Protein enrichment ,chemistry.chemical_compound ,0404 agricultural biotechnology ,Algae ,Rheology ,010608 biotechnology ,Composition (visual arts) ,Food science ,Tetraselmis ,Food Science - Abstract
Marine green microalgae are a sustainable source of high-quality protein. However, due to their green pigmentation and composition of volatiles, their incorporation into food products is a challenge. Incorporation of cell-wall disrupted Tetraselmis chuii (Tc) into bread (0, 4, 8, 12 and 16% wheat flour substitution) affected dough rheology and bread quality negatively. These effects were more pronounced at addition levels necessary for a EFSA nutrition claim on protein enrichment (12 and 16%). Treatment of Tc with ethanol not only removed much of the green pigmentation and volatiles, but also reduced the negative impact on dough rheology and bread quality. Doughs prepared with ethanol treated Tc (TcEt) showed a clear improvement in dough rheology evident as increased dough-stability-time (DST), resistance to extension (Rmax) and elastic-recovery-compliance (Je) particularly at substitution levels >4%. This was accompanied by an increase in bread quality e.g. at 12% substitution level specific volume increased from 2.1 to 2.69 mL/g, crumb firmness decreased from 1358 to 297 g and slice brightness increased from 25.2 to 49.0. Ethanol treatment of algae may be a feasible strategy to address the sensory and structural challenges that hinder incorporation of algae into foods at levels that can potentially confer nutritional benefits.
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- 2021
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10. Inter-comparison of SMOS and AMSR-E soil moisture products during flood years (2010–2011) over Pakistan
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Roha Anam, Sajid Ghuffar, Imran Shahid, Waqas A. Qazi, and Farrukh Chishtie
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Atmospheric Science ,010504 meteorology & atmospheric sciences ,0211 other engineering and technologies ,02 engineering and technology ,Collocation (remote sensing) ,Monsoon ,01 natural sciences ,lcsh:Oceanography ,lcsh:GC1-1581 ,Computers in Earth Sciences ,Water content ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences ,General Environmental Science ,Remote sensing ,collocation ,Radiometer ,Flood myth ,Applied Mathematics ,lcsh:QE1-996.5 ,AMSR-E ,lcsh:Geology ,Salinity ,Geography ,Climatology ,Temporal resolution ,Soil moisture content (SMC) ,Satellite ,SMOS - Abstract
Global soil moisture products retrieved from various remote sensing sensors are becoming readily available with a nearly daily temporal resolution. With lack of ground observations in Pakistan, microwave sensors are viable technologies for retrieving soil moisture from space. Thus, this study compares soil moisture data from Soil Moisture and Ocean Salinity (SMOS) with Advanced Microwave Scanning Radiometer (AMSR-E) for 2010 and 2011, which were years where massive flooding occurred. We find suitable correlations (r = 0.47) for Level-2 soil moisture values for both satellites and report temporal variability during the pre-monsoon, monsoon, post-monsoon and winter seasons. This study motivates using satellite retrievals as a start towards more comprehensive studies in Pakistan.
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- 2017
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11. Evaluation of Three-Hourly TMPA Rainfall Products Using Telemetric Rain Gauge Observations at Lai Nullah Basin in Islamabad, Pakistan
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Asid Ur Rehman, Khunsa Fatima, Imran Shahid, Sajid Ghuffar, Farrukh Chishtie, and Waqas A. Qazi
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Wet season ,010504 meteorology & atmospheric sciences ,Science ,rainfall ,0211 other engineering and technologies ,02 engineering and technology ,TMPA ,Monsoon ,Atmospheric sciences ,TRMM ,3B42 ,validation ,telemetric rain gauge ,Lai Nullah ,Pakistan ,01 natural sciences ,Flash flood ,Precipitation ,Leaf area index ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences ,Rain gauge ,Tropics ,General Earth and Planetary Sciences ,Environmental science ,Surface runoff - Abstract
Flash floods which occur due to heavy rainfall in hilly and semi-hilly areas may prove deleterious when they hit urban centers. The prediction of such localized and heterogeneous phenomena is a challenge due to a scarcity of in-situ rainfall. A possible solution is the utilization of satellite-based precipitation products. The current study evaluates the efficacy of Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) three-hourly products, i.e., 3B42 near-real-time (3B42RT) and 3B42 research version (3B42V7) at a sub-daily time scale. Various categorical indices have been used to assess the capability of products in the detection of rain/no-rain. Hourly rain rates are assessed by employing the most commonly used statistical measures, such as correlation coefficients (CC), mean bias error (MBE), mean absolute error (MAE), and root-mean-square error (RMSE). Further, a diurnal analysis is performed to authenticate TMPA’s performance in specific hours of the day. In general, the results show the good capability of both TMPA products in the detection of rain/no-rain events in all seasons except winter. Specifically, 3B42V7 performed better than 3B42RT. Moreover, both products detect a high number of rainy days falsely in light rain ranges. Regarding rainfall measurements, TMPA products exhibit an overall underestimation. Seasonally, 3B42V7 underestimates rainfall in monsoon and post-monsoon, and overestimates in winter and pre-monsoon. 3B42RT, on the other hand, underestimates rainfall in all seasons. A greater MBE and RMSE are found with both TMPA rain measurements in monsoon and post-monsoon seasons. Overall, a weak correlation and high MBE between the TMPA (3B42RT, 3B42V7) and reference gauge hourly rain rates are found at a three-hourly time scale (CC = 0.41, 0.38, MBE = −0.92, −0.70). The correlation is significant at decadal (CC = 0.79, 0.77) and monthly (CC = 0.91, 0.90) timescales. Furthermore, diurnal rainfall analysis indicates low credibility of 3B42RT to detect flash flooding. Within the parameters of this study, we conclude that the TMPA products are not the best choice at a three-hourly time scale in hilly/semi-hilly areas of Pakistan. However, both products can be used at daily, yet more reliably above daily, time scales, with 3B42V7 preferable due to its consistency.
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- 2018
12. Identification and mapping of coral reefs using Landsat 8 OLI in Astola Island, Pakistan coastal ocean
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Naeem Shahzad, Majid Nazeer, Amir Iqbal, and Waqas A. Qazi
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geography ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,0211 other engineering and technologies ,02 engineering and technology ,Coral reef ,01 natural sciences ,Waves and shallow water ,Oceanography ,Water column ,Habitat ,Benthic zone ,Environmental science ,Marine protected area ,Ecosystem ,Marine ecosystem ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences - Abstract
Recent field surveys have reported the presence of corals in many places in the Pakistan coastal ocean; Astola Island especially has been a subject of interest with regards to corals and overall marine biodiversity, and has in fact recently been declared Pakistan’s first Marine Protected Area. This study presents an analysis of coral reefs identification and their spatial distribution through optical satellite remote sensing in the surrounding area of Astola Island. Besides remote sensing data, the study considers sea survey data collected by divers in recent years. A benthic map of ocean ecosystem habitats is generated, through processing of Landsat 8 OLI (Operational Land Imager) imagery. The satellite data was selected at low-tide time to get maximum sunlight penetration in shallow water. Water-column correction was used to generate the depth-invariant index on multiple band-pairs. Water column corrected depth-invariant index bands were then segmented and classified through object-based classification. The results from the remote sensing data processing over Astola Island show good agreement with the field survey data, with nearly all the field survey points of coral reefs falling within the coral reefs class. Use of remote sensing imagery such as Landsat 8, and application of the water column correction method can allow for regular monitoring and management of coral reefs and other benthic ecosystems in the coastal ocean of Pakistan and coastal Arabian Sea.
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- 2018
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13. Assessment of the Food-Swallowing Process Using Bolus Visualisation and Manometry Simultaneously in a Device that Models Human Swallowing
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Johan Wiklund, Waqas Muhammad Qazi, Reinhardt Kotzé, Olle Ekberg, and Mats Stading
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Manometry ,Shear rate ,Review ,Wall shear ,In Vitro Techniques ,030507 speech-language pathology & audiology ,03 medical and health sciences ,Speech and Hearing ,Thickened fluids ,0302 clinical medicine ,Bolus (medicine) ,Swallowing ,Consistency (statistics) ,Deglutition and deglutition disorders ,medicine ,Humans ,business.industry ,Viscosity ,Food swallowing ,Gastroenterology ,Bolus manometry ,Dysphagia ,Deglutition ,Otorhinolaryngology ,Food ,Ultrasound velocimetry ,medicine.symptom ,0305 other medical science ,business ,Rheology ,030217 neurology & neurosurgery ,Biomedical engineering - Abstract
The characteristics of the flows of boluses with different consistencies, i.e. different rheological properties, through the pharynx have not been fully elucidated. The results obtained using a novel in vitro device, the Gothenburg Throat, which allows simultaneous bolus flow visualisation and manometry assessments in the pharynx geometry, are presented, to explain the dependence of bolus flow on bolus consistency. Four different bolus consistencies of a commercial food thickener, 0.5, 1, 1.5 and 2 Pa s (at a shear rate of 50 s−1)—corresponding to a range from low honey-thick to pudding-thick consistencies on the National Dysphagia Diet (NDD) scale—were examined in the in vitro pharynx. The bolus velocities recorded in the simulator pharynx were in the range of 0.046–0.48 m/s, which is within the range reported in clinical studies. The corresponding wall shear rates associated with these velocities ranged from 13 s−1 (pudding consistency) to 209 s−1 (honey-thick consistency). The results of the in vitro manometry tests using different consistencies and bolus volumes were rather similar to those obtained in clinical studies. The in vitro device used in this study appears to be a valuable tool for pre-clinical analyses of thickened fluids. Furthermore, the results show that it is desirable to consider a broad range of shear rates when assessing the suitability of a certain consistency for swallowing.
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- 2018
14. A comparative study of ALOS-2 PALSAR and landsat-8 imagery for land cover classification using maximum likelihood classifier
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Waqas A. Qazi, Muhammad Zeeshan Ali, and Nasir Aslam
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lcsh:QB275-343 ,010504 meteorology & atmospheric sciences ,Pixel ,Computer science ,lcsh:Geodesy ,0211 other engineering and technologies ,02 engineering and technology ,Vegetation ,Land cover ,01 natural sciences ,Speckle pattern ,Cohen's kappa ,Geocoding ,General Earth and Planetary Sciences ,RGB color model ,Radiometric calibration ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences ,Remote sensing - Abstract
This study examines ALOS-2 PALSAR L-band dual-polarization (HH and HV) SAR data and Landsat-8 optical imagery for land cover classification. The SAR data has been preprocessed first, which included radiometric calibration, geocoding, and speckle filtering. The HH/HV band ratio has been used to create the third band, and thus a synthetic RGB SAR image was created. The Landsat-8 data was also preprocessed for the classification process. For land cover classification of both SAR and optical datasets, the supervised maximum likelihood classifier was used. Training samples were selected from the Landsat-8 optical imagery with the support of information available in Google Earth; the same pixel locations of training data were used to extract training data from SAR image as well. The Landsat-8 optical imagery was classified and also used for visual assessment of the SAR land cover classification results. Accuracy assessment has been done for both the results of SAR and Landsat-8 data. The SAR classified output gives us accuracy of 93.15% and the Landsat-8 classified map accuracy was 91.34%, while the Kappa coefficient for SAR and Landsat-8 classified images is 0.92 and 0.89, respectively. Classification limitations exist in some cases, such as roads being merged in vegetation areas and some of the barren land is merged in settlements. The land cover classification can be expected to be further improved using polarimetric decomposition methods and fusion of SAR data with optical data.
- Published
- 2018
15. Studying the Association between Green Space Characteristics and Land Surface Temperature for Sustainable Urban Environments: An Analysis of Beijing and Islamabad
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Mehdi Zamani, Shahid Naeem, Asid Ur Rehman, Chen Wei, Bipin Kumar Acharya, Chunxiang Cao, and Waqas A. Qazi
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Canopy ,urban thermal environment ,green space cool islands (GCIs) ,vegetation configuration ,vegetation composition ,GCI indicators ,surface urban heat islands ,010504 meteorology & atmospheric sciences ,Geography, Planning and Development ,lcsh:G1-922 ,010501 environmental sciences ,01 natural sciences ,Beijing ,Urbanization ,Earth and Planetary Sciences (miscellaneous) ,Impervious surface ,Satellite imagery ,Computers in Earth Sciences ,0105 earth and related environmental sciences ,Vegetation ,Spatial ecology ,Environmental science ,Spatial variability ,Physical geography ,lcsh:Geography (General) - Abstract
Increasing trends of urbanization lead to vegetation degradation in big cities and affect the urban thermal environment. This study investigated (1) the cooling effect of urban green space spatial patterns on Land Surface Temperature (LST); (2) how the surrounding environment influences the green space cool islands (GCI), and vice versa. The study was conducted in two Asian capitals: Beijing, China and Islamabad, Pakistan by utilizing Gaofen-1 (GF-1) and Landsat-8 satellite imagery. Pearson’s correlation and normalized mutual information (NMI) were applied to investigate the relationship between green space characteristics and LST. Landscape metrics of green spaces including Percentage of Landscape (PLAND), Patch Density (PD), Edge Density (ED), and Landscape Shape Index (LSI) were selected to calculate the spatial patterns of green spaces, whereas GCI indicators were defined by Green Space Range (GR), Temperature Difference (TD), and Temperature Gradient (TG). The results indicate that both vegetation composition and configuration influence LST distributions; however, vegetation composition appeared to have a slightly greater effect. The cooling effect can be produced more effectively by increasing green space percentage, planting trees in large patches with equal distribution, and avoiding complex-shaped green spaces. The GCI principle indicates that LST can be decreased by increasing the green space area, increasing the water body fraction, or by decreasing the fraction of impervious surfaces. GCI can also be strengthened by decreasing the fraction of impervious surfaces and increasing the fraction of water body or vegetation in the surrounding environment. The cooling effect of vegetation and water could be explained based on their thermal properties. Beijing has already enacted the green-wedge initiative to increase the vegetation canopy. While designing the future urban layout of Islamabad, the construction of artificial lakes within the urban green spaces would also be beneficial, as is the case with Beijing.
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- 2018
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16. Computing Ocean Surface Currents Over the Coastal California Current System Using 30-Min-Lag Sequential SAR Images
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William J. Emery, Baylor Fox-Kemper, and Waqas A. Qazi
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Synthetic aperture radar ,Pulse-Doppler radar ,Side looking airborne radar ,Geodesy ,Space-based radar ,law.invention ,Continuous-wave radar ,Inverse synthetic aperture radar ,law ,Radar imaging ,General Earth and Planetary Sciences ,Electrical and Electronic Engineering ,Radar ,Geology ,Remote sensing - Abstract
As compared with conventional methods for measuring ocean surface currents, spaceborne synthetic aperture radar (SAR) offers cloud-penetrating ocean-current observation capability at high spatial resolution. While some studies have shown the potential of SAR for studying ocean surface currents through feature tracking, they have only analyzed a few images to demonstrate the basic measurement technique, and no concise general technique has been developed. This paper shows the application of the maximum cross correlation (MCC) method to generate ocean surface currents from nearly two years of available sequential spaceborne C-band SAR imagery from the Envisat ASAR and ERS-2 Advanced Microwave Instrument SAR sensors over the coastal California Current System. The data processing strategies are discussed in detail, and results are compared with HF radar measured currents. One-dimensional wavenumber spectra of the SAR-derived surface currents agree with the $k^{-2}$ power law, as predicted by submesoscale resolution models. Comparisons with HF radar currents show encouraging results with MCC SAR vectors oriented slightly counterclockwise relative to HF radar vectors. MCC SAR surface currents are found to have larger magnitudes than HF radar currents ( $\approx$ 11 cm/s), which may be due to the fact that SAR penetrates only a few centimeters into the ocean surface whereas HF radar currents are averaged over the top 1 m of the ocean surface. The larger part of this magnitude difference is contained in the along-shore component, which can be attributed to higher HF radar accuracy in the direct radial cross-shore measurements as compared with along-shore components derived from multiple cross-shore radial measurements.
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- 2014
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17. Introduction to the special issue of the Egyptian Journal of Remote Sensing and Space Sciences on Microwave Remote Sensing
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Waqas A. Qazi, Salwa F. Elbeih, and Mamdouh M. Abdeen
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Remote sensing (archaeology) ,Computer science ,General Earth and Planetary Sciences ,Microwave remote sensing ,Space Science ,Remote sensing - Published
- 2018
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18. In Vitro Models for Simulating Swallowing
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Mats Stading and Waqas Muhammad Qazi
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Air transport ,Mechanical models ,Food transport ,Computer science ,digestive, oral, and skin physiology ,Pharyngeal phase ,04 agricultural and veterinary sciences ,040401 food science ,Dysphagia ,In vitro model ,Critical phase ,03 medical and health sciences ,0404 agricultural biotechnology ,0302 clinical medicine ,stomatognathic system ,Swallowing ,otorhinolaryngologic diseases ,medicine ,medicine.symptom ,030217 neurology & neurosurgery ,Biomedical engineering - Abstract
This chapter gives an overview of the in vitro models that are currently used for studying swallowing. The focus is on the construction, geometry, and performance of mechanical models. Swallowing simulations and mathematical modeling are also considered. The in vitro models that are concerned with the oral, pharyngeal, and esophageal phases of swallowing linked to bolus properties are discussed. The pharyngeal phase is given special consideration, as it is involved in both food transport to the stomach and air transport to the lungs, and therefore constitutes the most critical phase of swallowing.
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- 2017
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19. Comparison of forest aboveground biomass estimates from passive and active remote sensing sensors over Kayar Khola watershed, Chitwan district, Nepal
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Hammad Gilani, Mirza Muhammad Waqar, Shahbaz Baig, Ahmad Ammar, Waqas A. Qazi, and Ashwin Dhakal
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Synthetic aperture radar ,Hydrology ,L band ,Watershed ,010504 meteorology & atmospheric sciences ,Backscatter ,0211 other engineering and technologies ,Biomass ,02 engineering and technology ,01 natural sciences ,Remote sensing (archaeology) ,General Earth and Planetary Sciences ,Environmental science ,Aboveground biomass ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences ,Remote sensing - Published
- 2017
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20. Paleochannel delineation using Landsat 8 OLI and Envisat ASAR image fusion techniques in Cholistan desert, Pakistan
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Junaid Aziz Khan, Zaheer Ul Islam, Javed Iqbal, and Waqas A. Qazi
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Synthetic aperture radar ,geography ,Image fusion ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,0211 other engineering and technologies ,Aquifer ,02 engineering and technology ,Vegetation ,01 natural sciences ,law.invention ,Remote sensing (archaeology) ,law ,Palaeochannel ,General Earth and Planetary Sciences ,Radar ,Groundwater ,Geology ,021101 geological & geomatics engineering ,0105 earth and related environmental sciences ,Remote sensing - Abstract
Sustainability of desert ecosystem is highly dependent upon water availability from different sources. Paleochannels are important sources of groundwater, and exploiting such resources involves their identification/mapping and subsequent investigation for fresh groundwater. A study in which multisensor (optical/infrared Landsat 8 OLI and active microwave Envisat ASAR) images of the Cholistan desert of Pakistan were processed and analyzed to identify and map Hakra River paleochannels is presented. Radiometrically corrected optical and synthetic aperture radar datasets were fused using principal components image fusion method. The paleochannels were extracted from the analysis of this fused output, and normalized difference vegetative index analysis of Landsat 8 OLI atmospheric corrected images was used as supporting information. Identification and alignment of an identified paleochannel was validated with geophysical ground measurements (electrical resistivity and conductivity surveys) and historical records. The presence of high apparent electrical resistivity with corresponding low soil water conductivity values intersects well with the paleochannels identified from the remote sensing data. The results were also confirmed with historical evidence such as old wells beside forts and proposed ground water harvesting sites. The proposed methodology in this study could be adopted in other parts of the world for mapping of paleochannels.
- Published
- 2016
- Full Text
- View/download PDF
21. Using modified mixture of Gaussians for background modeling in video surveillance
- Author
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Waqas A. Qazi, K. Khan, and Humayun Shahid
- Subjects
Background subtraction ,Foreground detection ,Pixel ,Computer science ,business.industry ,Gaussian ,Pattern recognition ,Mixture model ,Object detection ,symbols.namesake ,symbols ,Artificial intelligence ,Hidden Markov model ,business ,Gaussian process - Abstract
Maintaining a reference background resides at the heart of any video surveillance system. Dynamic background presents impediment in the establishment of an accurate background model for video surveillance. Existing approaches utilize both statistical and non-statistical techniques for maintaining an approximation of the background. Statistical methods are computationally intensive but produce accurate results. Mixture of Gaussians is an efficient adaptive technique for background modeling. Different variants of the techniques are given in literature. In this research study, various novel approaches were proposed and employed for background representation through mixture of Gaussian models. Subtle improvement in foreground detection is reported in some specific cases.
- Published
- 2008
- Full Text
- View/download PDF
22. EONav - Copernicus Data in Support of Maritime Route Optimization
- Author
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Helong Wang, Joakim Moller, Dokken Sverre, Kris Lemmens, Yufang Ye, Lars Jonasson, Wengang Mao, Leif E. B. Eriksson, and Waqas A. Qazi
- Subjects
Synthetic aperture radar ,geography ,Service (systems architecture) ,geography.geographical_feature_category ,Computer science ,Real-time computing ,Ocean current ,0211 other engineering and technologies ,02 engineering and technology ,Plan (drawing) ,13. Climate action ,Sea ice ,Fuel efficiency ,Satellite ,14. Life underwater ,021101 geological & geomatics engineering ,Copernicus - Abstract
The EONav ship routing service uses near real time observations of ocean surface currents, waves, wind and sea ice conditions, in conjunction with forecasts from numerical weather and ocean models, to plan the optimal route for a vessel. Products from the Copernicus Marine Environment Monitoring Service (CMEMS) and several national weather services are used together with in-house products developed for Synthetic Aperture Radar (SAR) data from satellites such as Sentinel-1, Radarsat-2 and COSMO-SkyMed. A novel data selection algorithm automatically ranks the various data sets and combines them to provide the most reliable met-ocean information. A sail plan optimized e.g. to reduce fuel consumption is determined based on the met-ocean information and is communicated to the ships to assist captains in selecting the best route and speed pattern to their destination.
- Full Text
- View/download PDF
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