Engineering Commons^™

A Decade Of Unmanned Aerial Systems In Irrigated Agriculture In The Western U.S., Jose L. Chavez, Alfonso F. Torres-Rua, Wayne E. Woldt, Huihui Zhang, Christopher Robertson, Gary W. Marek, Dong Wang, Derek M. Heeren, Saleh Taghvaeian, Christopher M. U. Neale

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Several research institutes, laboratories, academic programs, and service companies around the United States have been developing programs to utilize small unmanned aerial systems (sUAS) as an instrument to improve the efficiency of in-field water and agronomical management. This article describes a decade of efforts on research and development efforts focused on UAS technologies and methodologies developed for irrigation management, including the evolution of aircraft and sensors in contrast to data from satellites. Federal Aviation Administration (FAA) regulations for UAS operation in agriculture have been synthesized along with proposed modifications to enhance UAS contributions to irrigated agriculture. Although it is feasible …

Evaluation Of Low-Cost Depth Cameras For Agricultural Applications, Isabella C.F.S. Condotta, T. M. Brown-Brandl, Santosh Pitla, John P. Stinn, Késia O. Silva-Miranda

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Low-cost depth-cameras have been used in many agricultural applications with reported advantages of low cost, reliability and speed of measurement. However, some problems were also reported and seem to be technology- related, so understanding the limitations of each type of depth camera technology could provide a basis for technology selection and the development of research involving its use. The cameras use one or a combination of two of the three available technologies: structured light, time-of-flight (ToF), and stereoscopy. The objectives were to evaluate these different technologies for depth sensing, including measuring accuracy and repeatability of distance data and measurements at …

Classification Of Tactile And Motor Velocity-Evoked Hemodynamic Response In Primary Somatosensory And Motor Cortices As Measured By Functional Near-Infrared Spectroscopy, Mohsen Hozan, Jacob Greenwood, Michaela Sullivan, Steven M. Barlow

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Functional near-infrared spectroscopy (fNIRS) is an emerging technique in studying cerebral hemodynamics; however, consensus on the analysis methods and the clinical applications has yet to be established. In this study, we demonstrate the results of a pilot fNIRS study of cerebral hemodynamic response (HR) evoked by pneumotactile and sensorimotor stimuli on the dominant hand. Our goal is to find the optimal stimulus parameters to maximally evoke HR in the primary somatosensory and motor cortices. We use a pulsatile pneumatic array of 14 tactile cells that were attached to the glabrous surface of the dominant hand, with a patterned stimulus that …

Glucocorticoid Priming Of Nonviral Gene Delivery To Hmscs Increases Transfection By Reducing Induced Stresses, Andrew Hamann, Tyler Kozisek, Kelly Broad, Angela K. Pannier

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Human mesenchymal stem cells (hMSCs) are under study for cell and gene therapeutics because of their immunomodulatory and regenerative properties. Safe and efficient gene delivery could increase hMSC clinical potential by enabling expression of transgenes for control over factor production, behavior, and differentiation. Viral delivery is efficient but suffers from safety issues, while nonviral methods are safe but highly inefficient, especially in hMSCs. We previously demonstrated that priming cells with glucocorticoids (Gcs) before delivery of DNA complexes significantly increases hMSC transfection, which correlates with a rescue of transfection-induced metabolic and protein synthesis decline, and apoptosis. In this work, we show …

Ultrasmall Mixed Eu−Gd Oxide Nanoparticles For Multimodal Fluorescence And Magnetic Resonance Imaging Of Passive Accumulation And Retention In Tbi, Badrul Alam Bony, Hunter A. Miller, Aria W. Tarudji, Connor C. Gee, Anandakumar Sarella, Michael G. Nichols, Forrest Kievit

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Traumatic brain injury (TBI) is a leading cause of death and disability worldwide. TBI can have a long-term impact on the quality of life for survivors of all ages. However, there remains no approved treatment that improves outcomes following TBI, which is partially due to poor delivery of therapies into the brain. Therefore, there is a significant unmet need to develop more effective delivery strategies that increase the accumulation and retention of potentially efficacious treatments in the injured brain. Recent work has revealed that nanoparticles (NPs) may offer a promising approach for site-specific delivery; however, a detailed understanding of the …

Robotic Detection And Grasp Of Maize And Sorghum: Stem Measurement With Contact, Abbas Atefi, Yufeng Ge, James C. Schnable

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Frequent measurements of the plant phenotypes make it possible to monitor plant status during the growing season. Stem diameter is an important proxy for overall plant biomass and health. However, the manual measurement of stem diameter in plants is time consuming, error prone, and laborious. The use of agricultural robots to automatically collect plant phenotypic data for trait measurements can overcome many of the drawbacks of manual phenotyping. The objective of this research was to develop a robotic system that can automatically detect and grasp the stem, and measure its diameter of maize and sorghum plants. The robotic system comprises …

Rapeseed Stand Count Estimation At Leaf Development Stages With Uav Imagery And Convolutional Neural Networks, Biquan Zhao, Chenghai Yang, Yeyin Shi, Qingxi Liao, Guangsheng Zhou, Chufeng Wang, Tianjin Xie, Zhao Jiang, Dongyan Zhang, Wanneng Yang, Chenglong Huang, Jing Xie, Jian Zhang

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Rapeseed is an important oil crop in China. Timely estimation of rapeseed stand count at early growth stages provides useful information for precision fertilization, irrigation, and yield prediction. Based on the nature of rapeseed, the number of tillering leaves is strongly related to its growth stages. However, no field study has been reported on estimating rapeseed stand count by the number of leaves recognized with convolutional neural networks (CNNs) in unmanned aerial vehicle (UAV) imagery. The objectives of this study were to provide a case for rapeseed stand counting with reference to the existing knowledge of the number of leaves …

Optimal Depth Jump Height Quantified As Percentage Of Athlete Stature, Curtis L. Tomasevicz, Ryan Hasenkamp, Jack W. Ransone, David Jones

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Purpose: An individual’s optimal depth jump platform height provides a resistive force which allows an athlete to rebound with substantial velocity resulting in maximum power exertion. The objective of this investigation was to show that the optimal platform height in a depth jump can be quantified as a percentage of individual body stature which can serve as measurable quantified value. Although athlete height is not highly correlated to power ability nor does a universal height exist, this value can provide a basis for a rehabilitation or strength and conditioning program. The desired intensity of a program can be prescribed as …

Comparison Of Object Detection And Patch-Based Classification Deep Learning Models On Mid- To Late-Season Weed Detection In Uav Imagery, Arun Narenthiran Veeranampalayam Sivakumar, Jiating Li, Stephen Scott, Eric T. Psota, Amit J. Jhala, Joe D. Luck, Yeyin Shi

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Mid- to late-season weeds that escape from the routine early-season weed management threaten agricultural production by creating a large number of seeds for several future growing seasons. Rapid and accurate detection of weed patches in field is the first step of site-specific weed management. In this study, object detection-based convolutional neural network models were trained and evaluated over low-altitude unmanned aerial vehicle (UAV) imagery for mid- to late-season weed detection in soybean fields. The performance of two object detection models, Faster RCNN and the Single Shot Detector (SSD), were evaluated and compared in terms of weed detection performance using mean …

Temporal Trend Analysis Of Meteorological Variables And Reference Evapotranspiration In The Inter-Mountain Region Ofwyoming, Vivek Sharma, Christopher Nicholson, Antony Bergantino, Suat Irmak, Dannele Peck

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Long-term trends in reference evapotranspiration (ETref) and its controlling factors are critical pieces of information in understanding how agricultural water requirements and water resources respond to a variable and changing climate. In this study, ETref, along with climate variables that directly and indirectly impact it, such as air temperature (T), incoming solar radiation (Rs), wind speed (u), relative humidity (RH), and precipitation (P), are discussed. All variables are analyzed for four weather stations located in irrigated agricultural regions of inter-mountain Wyoming: Pinedale, Torrington, Powell, andWorland. Non-parametric Mann􀀀Kendall (MK) trend test and Theil–Sen’s slope estimator were used to determine the statistical …

Classification Of Tactile And Motor Velocity-Evoked Hemodynamic Response In Primary Somatosensory And Motor Cortices As Measured By Functional Near-Infrared Spectroscopy

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Functional near-infrared spectroscopy (fNIRS) is an emerging technique in studying cerebral hemodynamics; however, consensus on the analysis methods and the clinical applications has yet to be established. In this study, we demonstrate the results of a pilot fNIRS study of cerebral hemodynamic response (HR) evoked by pneumotactile and sensorimotor stimuli on the dominant hand. Our goal is to find the optimal stimulus parameters to maximally evoke HR in the primary somatosensory and motor cortices. We use a pulsatile pneumatic array of 14 tactile cells that were attached to the glabrous surface of the dominant hand, with a patterned stimulus that …

Review—Single Walled Carbon Nanotubes As Optical Sensors For Biological Applications, Eric M. Hofferber, Joseph A. Stapleton, Nicole M. Iverson

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Since the discovery of the band gap fluorescence from single walled carbon nanotubes (SWNT) many advancements have been made towards the use of these unique fluorophores as optical biosensors in vitro, ex vivo in vivo. Attention has been given to these pure carbon structures due to their photostability, tunable properties, and bright near infrared emission that falls in the tissue transparency window. This review highlights some of the major advancements in the field of SWNT biosensors over the last two decades with a focus given to recent advances in biological applications.

Predicting Total Petroleum Hydrocarbons In Field Soils With Vis–Nir Models Developed On Laboratory-Constructed Samples, Nuwan Wijewardane, Post Doc Research Associate, Yufeng Ge, Natasha Sihota, Thomas Hoelen, Toni Miao, David C. Weindorf

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Accurate quantification of petroleum hydrocarbons (PHCs) is required for opti- mizing remedial efforts at oil spill sites. While evaluating total petroleum hydro- carbons (TPH) in soils is often conducted using costly and time-consuming lab- oratory methods, visible and near-infrared reflectance spectroscopy (Vis–NIR) has been proven to be a rapid and cost-effective field-based method for soil TPH quantification. This study investigated whether Vis–NIR models calibrated from laboratory-constructed PHC soil samples could be used to accurately estimate TPH concentration of field samples. To evaluate this, a laboratory sample set was constructed by mixing crude oil with uncontaminated soil samples, and two field …

Representing Organic Matter Thermodynamics In Biogeochemical Reations Via Substrate-Explicit Modeling, Hyun-Seob Song, James C. Stegen, Emily B. Graham, Joon-Yong Lee, Vanessa A. Garayburu-Caruso, William C. Nelson, Xingyuan Chen, J. David Moulton, Timothy D. Scheibe

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Predictive biogeochemical modeling requires data-model integration that enables explicit representation of the sophisticated roles of microbial processes that transform substrates. Data from high-resolution organic matter (OM) characterization are increasingly available and can serve as a critical resource for this purpose, but their incorporation into biogeochemical models is often prohibited due to an over-simplified description of reaction networks. To fill this gap, we proposed a new concept of biogeochemical modeling—termed substrate-explicit modeling—that enables parameterizing OM-specific oxidative degradation pathways and reaction rates based on the thermodynamic properties of OM pools. Based on previous developments in the literature, we characterized the resulting kinetic …

Within-Field Variability In Granular Matrix Sensor Data And Its Implications For Irrigation Scheduling, T. Lo, H.C. Pringle Iii, Daran Rudnick, Geng Bai, L. Jason Krutz, D.M. Gholson, Xin Qiao

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Even when located within the same field, multiple units of the same soil moisture sensor rarely report identical values. Such within-field variability in soil moisture sensor data is caused by natural and manmade spatial heterogeneity and by inconsistencies in sensor construction and installation. To better describe this variability, daily soil water tension values from 14-23 sets of granular matrix sensors during the middle part of four soybean site-years in the Mississippi Delta were analyzed. The soil water tension data were found to follow approximately normal distributions, to exhibit moderately high temporal rank stability, and to show strong positive correlation between …

Teacher Level Factors And Student Achievement In A Cyber-Enabled Engineering Education Professional Development Program, Wei Zakharov, Johannes Strobel, Heidi A. Diefes-Dux

Department of Agricultural and Biological Systems Engineering: Faculty Publications

This study investigates the impact of an elementary engineering education teacher professional development program on student learning. The results show a significant increase in students’ knowledge in science from pre- to post-test as well as in engineering design from grade two to grade four. Further, the study uses multilevel modeling to quantitatively analyze the impact of differences among teachers on the engineering design achievement of their students. Different predictive relationships between demographic and social capital factors at the teacher level and student achievement are identified and implications for educational policymaking and practices are discussed.

Predicting Total Petroleum Hydrocarbons In Field Soils With Vis–Nir Models Developed On Laboratory-Constructed Samples, Nuwan K. Wijewardane, Yufeng Ge, Natasha Sihota, Thomas Hoelen, Toni Miaso, David C. Weindorf

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Accurate quantification of petroleum hydrocarbons (PHCs) is required for optimizing remedial efforts at oil spill sites. While evaluating total petroleum hydrocarbons (TPH) in soils is often conducted using costly and time-consuming laboratory methods, visible and near-infrared reflectance spectroscopy (Vis–NIR) has been proven to be a rapid and cost-effective field-based method for soil TPH quantification. This study investigated whether Vis–NIR models calibrated from laboratory-constructed PHC soil samples could be used to accurately estimate TPH concentration of field samples. To evaluate this, a laboratory sample set was constructed by mixing crude oil with uncontaminated soil samples, and two field sample sets (F …

Antibiotic Resistance Gene Profile Changes In Cropland Soil After Manure Application And Rainfall, Morgan A. Meyers, Lisa M. Durso, John E. Gilley, Heidi Waldrip, Lana Castleberry, Amy Schmidt

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Land application of manure introduces gastrointestinal microbes into the environ- ment, including bacteria carrying antibiotic resistance genes (ARGs). Measuring soil ARGs is important for active stewardship efforts to minimize gene flow from agri- cultural production systems; however, the variety of sampling protocols and target genes makes it difficult to compare ARG results between studies. We used polymerase chain reaction (PCR) methods to characterize and/or quantify 27 ARG targets in soils from 20 replicate, long-term no-till plots, before and after swine manure application and simulated rainfall and runoff. All samples were negative for the 10 b-lactamase genes assayed. For tetracycline resistance, …

Setback Distance Impacts On Transport And Antibiotic Resistance Phenotypes Of Fecal Indicators, Morgan A. Meyers, Lisa M. Durso, John E. Gilley, Daniel N. Miller, Xu Li, Amy M. Schmidt Schmidt

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Although the land application of livestock manure has numerous agronomic benefits, runoff from manured fields can degrade water quality. Setbacks instruct a minimum distance be maintained between manure application and surface waters. They are commonly used to manage nutrient contamination of surface waters; however, their utility for reducing microbial inputs remains unclear. Here we evaluated the efficacy of five setback distances in no-till wheat (Triticum aes- tivum L.) residue plots for reducing runoff fecal indicator concentrations from swine manure-amended fields. Also, since there is increasing interest in the use of water quality indicators to monitor antibiotic resistance in environmental sys- …

Innovative Extension Methods In The U.S. To Promote Irrigation Water Management, Daran Rudnick, Matt Stockton, Saleh Taghvaeian, Jason Warren, Michael D. Dukes, Amy Kremen, Christopher G. Henry, Jonathan Aguilar, Brenda Ortiz, Allan A. Andales, Chuck A. Burr, Xin Qiao, Wei‑Zhen Liang, Steven Walthour, Steve H. Amosson

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Promotion and adoption of irrigation water management (IWM) technology, tools, and best management practices are important as water availability concerns are addressed. Traditional extension programs have relied on lecture presentations, field tours, fact sheets, and on-station demonstrations to promote IWM practices and tools. However, these platforms tend not to provide the experience and opportunity for growers to identify and become comfortable with innovative solutions, such as new technology. To address these challenges and to appeal to an ever-changing client base, innovative and locally relevant extension and outreach programs have been devised to engage and educate growers. This article describes some …

Accumulation And Release Of Nutrients By Immersed Stalks Collected On Selected Dates Following Harvest, John E. Gilley, David B. Marx

Department of Agricultural and Biological Systems Engineering: Faculty Publications

The concentrations of phosphorus (P) and nitrogen (N) in runoff from cropland areas may be influenced by accumulation and release of P and N by stalk residues. A laboratory study was conducted to measure the effects of time since harvest and immersion period on accumulation and release of P and N by corn, soybean, and wheat stalks. Experimental variables included type of stalk material (corn, soybean, and wheat), time since harvest (six residue collection dates over an approximate 1-year period), and stalk immersion period (25 s (0.42 min), 250 s (4.2 min), 2500 s (42 min), 25,000 s (6.9 h), …

Effect Of Urea Fertilizer Deep Placement Days After Transplanting Using Brri Prilled Urea Applicator On Transplanted Boro Rice Yield, Muhammad Rashed Al Mamun, K. Naher, Md Towfiqur Rahman, Md Anwar Hossen

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Rice is the most important crop in the developing countries of Asia. In the south and south-east Asia, rain-fed and irrigated transplanted rice occupies nearly two-thirds of the rice-growing area and produces more than 80% of the rough rice. In these areas, prilled urea conventionally applied by farmers is very insufficient in the transplanted rice field, where severe losses occur (up to 60% of applied N) via NH₃volatilization, denitrification, leaching, and runoff. Considering loss minimization, an experiment was conducted during the Boro season at Bangladesh Agricultural Development Corporation (BADC) in Sylhet to evaluate the performance of BRRI Prilled …

Effect Of Rotary Blade Modification On Residue Retention Into Conservation Agriculture Practices, Md Talash Mahmud, Md Towfiqur Rahman, Md Mosharraf Hossain, Muhammad Ashik-E-Rabbani

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Conservation Agriculture (CA) has been a promising technique for better crop production. Manual seeding with conventional tillage practice is laborious and time consuming. However, Strip tillage (ST) method incorporating seeding machines minimizes human drudgery and optimizes the crop yield. Many problems associated with ST have been rectified e.g. tiny furrow backfill, inaccuracy of seed and fertilizer placement, leading to poor germination and curtailed outcomes. This article focused on the effects of residue retention for the rotary blades design on a versatile multi-crop planter (VMP). Four types of rotary blades of VMP differed by 15^o increment of tip angles were …

Regional Sustainable Development Of Renewable Natural Resources Using Net Primary Productivity On A Global Scale, Saket Dubey, Ashutosh Sharma, Venkatesh Kishor Panchariya, Manish Kumar Goyal, Rao Y. Surampalli, Tian C. Zhang

Department of Civil and Environmental Engineering: Faculty Publications

Ecological Indicators 127 (2021) 107768

The Fluxnet2015 Dataset And The Oneflux Processing Pipeline For Eddy Covariance Data, Gilberto Pastorello, Timothy Arkebauer, Dave P. Billesbach, Anatoly Gitelson, Adam Liska, Andrew Suyker, Elizabeth Walter-Shea, More Than 200 Other

Adam Liska Papers

The FLUXNET2015 dataset provides ecosystem-scale data on CO2, water, and energy exchange between the biosphere and the atmosphere, and other meteorological and biological measurements, from 212 sites around the globe (over 1500 site-years, up to and including year 2014). These sites, independently managed and operated, voluntarily contributed their data to create global datasets. Data were quality controlled and processed using uniform methods, to improve consistency and intercomparability across sites. The dataset is already being used in a number of applications, including ecophysiology studies, remote sensing studies, and development of ecosystem and Earth system models. FLUXNET2015 includes derived-data products, such as …

Brassinosteroids Inhibit Autotropic Root Straightening By Modifying Filamentous-Actin Organization And Dynamics, Louise De Bang, Ana Paez-Garcia, Ashley E. Cannon, Sabrina Chin, Jaydeep Kolape, Fuqi Liao, J. Alan Sparks, Qingzhen Jiang, Elison B. Blancaflor

Nebraska Center for Biotechnology: Faculty and Staff Publications

When positioned horizontally, roots grow down toward the direction of gravity. This phenomenon, called gravitropism, is influenced by most of the major plant hormones including brassinosteroids. Epi-brassinolide (eBL) was previously shown to enhance root gravitropism, a phenomenon similar to the response of roots exposed to the actin inhibitor, latrunculin B (LatB). This led us to hypothesize that eBL might enhance root gravitropism through its effects on filamentous-actin (F-actin). This hypothesis was tested by comparing gravitropic responses of maize (Zea mays) roots treated with eBL or LatB. LatB- and eBL-treated roots displayed similar enhanced downward growth compared with controls …

Functional Characterization Of Petiolule-Like Pulvinus (Plp) Gene In Abscission Zone Development In Medicago Truncatula And Its Application To Genetic Improvement Of Alfalfa, Juan Du, Shaoyun Lu, Maofeng Chai, Chuanen Zhou, Liang Sun, Yuhong Tang, Jin Nakashima, Jaydeep Kolape, Zhaozhu Wen, Marjan Behzadirad, Tianxiu Zhong, Juan Sun, Yunwei Zhang, Zeng-Yu Wang

Nebraska Center for Biotechnology: Faculty and Staff Publications

Alfalfa (Medicago sativa L.) is one of the most important forage crops throughout the world. Maximizing leaf retention during the haymaking process is critical for achieving superior hay quality and maintaining biomass yield. Leaf abscission process affects leaf retention. Previous studies have largely focused on the molecular mechanisms of floral organ, pedicel and seed abscission but scarcely touched on leaf and petiole abscission. This study focuses on leaf and petiole abscission in the model legume Medicago truncatula and its closely related commercial species alfalfa. By analysing the petiolule-like pulvinus (plp) mutant in M. truncatula at phenotypic level (breakstrength and …

Wastewater Treatment Fatty Acids For Biodiesel Production, Zachary Christman

Department of Agronomy and Horticulture: Dissertations, Theses, and Student Research

Wastewater scum is the thick oily substance that floats on top of the primary and secondary tanks within a wastewater treatment plant. Scum has a 30% to 60% lipid content making it an excellent resource for the biodiesel industry. Also the use of scum would reduce the cost of current management practices such as landfill disposal or incineration. In this article there is an overview of lipid byproducts currently being produced at wastewater treatment plants today. This is followed by a presentation showing a full length process for turning wastewater scum into biodiesel raw material.

Pharmaceutical Manufacturing In The 21st Century: Identification And Analysis Of Key Elements, Robert N. Mills

Honors Program: Senior Projects (Public)

The availability of quality pharmaceutical products impacts the lives of the global population on a daily basis. The importance of product availability and quality within pharmaceutical manufacturing requires that quality systems put into place are capable of accurately and robustly capturing the quality compliance, or lack thereof, of the various stages of production. This review intends to analyze current expert-recommended best practices within key elements of a pharmaceutical manufacturing quality control system and provide recommendations throughout. The quality elements discussed include Quality by Design method validation, necessary equipment determination, and equipment qualification, followed by documentation control and data flow.

On Geometric Design Rules And In-Process Build Quality Monitoring Of Thin-Wall Features Made Using Laser Powder Bed Fusion Additive Manufacturing Process, Aniruddha Gaikwad

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

The goal of this thesis is to quantify the link between the design features (geometry), in-process signatures, and build quality of parts made using the laser powder bed fusion (LPBF) additive manufacturing (AM) process. This knowledge is the foundational basis for proposing design rules in AM, as well as for detecting the impending build failures using in-process sensor data.

As a step towards this goal, the objectives of this work are two-fold:

1) Quantify the effect of the geometry and orientation on the build quality of thin-wall features. To explain further, the geometry related factor is the ratio of the …