Damming the rivers of the Amazon basin.

More than a hundred hydropower dams have already been built in the Amazon basin and numerous proposals for further dam constructions are under consideration. The accumulated negative environmental effects of existing dams and proposed dams, if constructed, will trigger massive hydrophysical and biotic disturbances that will affect the Amazon basin's floodplains, estuary and sediment plume. We introduce a Dam Environmental Vulnerability Index to quantify the current and potential impacts of dams in the basin. The scale of foreseeable environmental degradation indicates the need for collective action among nations and states to avoid cumulative, far-reaching impacts. We suggest institutional innovations to assess and avoid the likely impoverishment of Amazon rivers.

The Great 2011 Thailand flood disaster revisited: Could it have been mitigated by different dam operations based on better weather forecasts?

This paper revisits the 2011 Great Flood in central Thailand to answer one of the hotly debated questions at the time "Could the operation decisions of the flood control structures substantially mitigate the flood impacts in the downstream areas?". Using a numerical modeling approach, we develop a hypothesis such that the two upstream dam reservoirs: Bhumibol and Sirikit had more accurately forecasted the typhoon-triggered abnormal rainfall volumes and released more water earlier to save the storage capacity via 17 different scenarios or alternative operation schemes. We subsequently quantify the potential improvements, or reduced flood impacts in the downstream catchments, solely by changing the operation schemes of these two dam reservoirs, with all other conditions remaining unchanged. We observed that changing the operation schemes could have reduced only the flood depth while offering very limited improvements in terms of inundated areas for the lower Chao Phraya River Basin. Among 17 scenarios simulated, the inundated areas could have been reduced at most by 3.68%. This result justifies the limited role of these mega structures in the upstream during the disaster on one hand, while pointing to the necessity of handling local rainfall differently on the other. The paper expands the discussion into how the government of Thailand has drawn the lessons from the 2011 flood to better prepare themselves against the lurking flood risk in 2021, also triggered by tropical cyclones. The highlighted initiatives, both technical and institutional, could have provided important references for the large river catchment managers in Southeast Asia and with implications of our method beyond the present application region.

Adaptive capacity of high- and low dyke farmers to hydrological changes in the Vietnamese Mekong delta.

This research assesses the adaptive capacity of farmers in the Vietnamese Mekong Delta's floodplains (VMD) with respect to hydrological changes. Currently, climate change and socio-economic developments induce extreme- and diminishing floods, which in turn increase farmers' vulnerability. This research assesses farmers' adaptive capacity to hydrological changes using two prevalent farming systems: high dykes featuring triple-crop rice farming and low dykes where fields are left fallow during the flood season. We examine (1) farmers' perceptions on a changing flood regime and their current vulnerabilities and (2) farmers' adaptive capacity through five sustainability capitals. Methods include a literature review and qualitative interviews with farmers. Results show that extreme floods are becoming less frequent and damaging, depending on arrival time, depth, residence time, and flow velocity. In extreme floods, farmers' adaptive capacity is generally strong, and only low dyke farmers experience damage. As for diminishing floods, which is an emerging phenomenon, the overall adaptive capacity of farmers is remarkably weaker and varies between high- and low dyke farmers. Financial capital is lower for low dyke farmers due to their double-crop rice system, and natural capital is low for both farmer groups due to a decrease in soil- and water quality, affecting yields and increasing investment costs. Farmers also struggle with an unstable rice market due to strong fluctuating prices for seeds, fertilizers, and other inputs. We conclude that both high- and low dyke farmers have to cope with new challenges, including fluctuating flood patterns and the depletion of natural resources. Increasing farmers resilience should focus on exploring better crop varieties, adjusting crop calendars, and shifting to less water-intensive crops.

Deep well injection for the waste brine disposal solution of potash mining in Northeastern Thailand.

Under the pressure of the existing world population growth trends, the dercreasing pastoral fields and the increasing duration and incidences of drought and heat stress, the potash fertilizers demand dramaticly increase to enhance the world food production. Asia currently consumes 40% of the world's potash market, yet 70% of world potash exports come from mines in Canada and Europe. Weak collective efforts to produce potassium fertilizers economically pose the risk of global shortages of potash goods and threatening global food security. While the Khorat Plateau in Northeastern Thailand is noted to contain active and promising regional potash deposits, developing a proper potash industry in the region has largely been unsuccessful due to major constraints such as the challenge of establishing a brine disposal solution. This study demonstrates the performance of deep well injection (DWI) as an environmentally friendly alternative to secure waste brine production from the potash mine. The groundwater numerical model demonstrates the movement and penetration of the concentrate during and after deep well injection. The boundary condition was utilized from the regional hydrogeology data. The waste brine injection is based on the waste products of the mine factory. Our simulation shows that the DWI can isolate waste brine with freshwater by injecting it into the deep formation based on the geologic structure and properties analysis. With high porosity and low specific yield, the Khok Kruat formation within Khrat Basin shows a high potential injection rate of 200,000 m3/day, which is 200 times higher than current water brine production rates. Moreover, the salinity can easily dissolve into the target domain with specific formation properties. Hence, the DWI not only boosts the potash industry's image in the long term but also enable sustainable potash mining development in the region. Finally, we recommend that government agencies with regulatory oversight over the DWI must promote further research associated with site characterization, well construction and injection technologies, and monitoring tools in the long term.

Spatial-social evaluations of ecosystem services of adaptive aquaculture models using SAR and multivariate analyses: a case in the Vietnamese Mekong Delta.

The presented study is conducted to investigate the efficiency of two important aquaculture models of the Vietnamese Mekong Delta (VMD)'s Soc Trang province via quantifying and mapping the supporting ecosystem services (ES). The study targets the two most prevalent rearing practices, intensive and semi-intensive, covering four rural districts: My Xuyen, Tran De, Cu Lao Dung, and Vinh Chau. A mixed-method approach was applied, combining remote sensing, grass-root social survey, and multivariate statistical analyses. First, image analysis using Sentinel-1A time-series data was conducted to detect the aquaculture areas across the study area based on temporal changes of VV backscatter of different land use/land cover (LULC) types, in which aquaculture receives relatively low backscatter values compared to other LULC categories except river and deeper water surfaces. Our analysis yields an overall accuracy of 91% with a kappa coefficient of 0.82. Second, using semi-structured questionnaires, a total of 140 shrimp farming households across the four focused districts were interviewed for their rearing experience. Thereupon, the collected responses were analyzed using two multivariate analyses, including principal component analysis (PCA) and hierarchical cluster analysis (HCA). In general, the intensive model could have generated more economic values of ecosystem services than the artisanal/semi-intensive model. Our analyses also took note of the potential barriers hindering the semi-intensive farmers from achieving higher economic income. These include (i) geographical factors, i.e., locations; (ii) social factors, i.e., experience, farming calendar, education; (iii) financial factors, i.e., investments; and (iv) technical factors, i.e., farm areas, productivity, rearing concentration. Since semi-intensive food is more appropriate for small-scale farming households, it is recommendable that addressing these factors can enhance the efficiency of this model as a profitable livelihood option.

Randomized controlled trial of a quadratus lumborum block with liposomal bupivacaine for postoperative analgesia in laparoscopic donor nephrectomy.

Perioperative pain management is an important consideration in early recovery and patient satisfaction following laparoscopic donor nephrectomy. Transmuscular quadratus lumborum block has been described to reduce pain and opioid usage following several abdominal surgeries. In this prospective single-blind randomized controlled trial, we compared 52 patients who adhered to our institutional donor nephrectomy Early Recovery After Surgery pathway, which includes a laparoscopic-guided transversus abdominus plane block, to 40 patients who additionally received a transmuscular quadratus lumborum block with liposomal bupivacaine. Compared to control patients, those who received the block spent longer in the operating room prior to the surgical start (65.4 vs. 51.6 min, P < .001). Both groups had similar total hospital length of stay (33.3 h vs. 34.4 h, P = .61). Pain scores from postoperative days 0-30, number of patients requiring opioids, postoperative nausea, and pain management satisfaction were similar between both groups. Patients who received the block consumed less opioid on postoperative day 1 compared to controls (P = .006). No complications were attributable to the block. The quadratus lumborum block provides a safe pain management adjunct for some patients, and may reduce opioid use in the early postoperative period when combined with our standard institutional protocol for kidney donors.

Socio-geographical evaluation of ecosystem services in an ecotourism destination: PGIS application in Tram Chim National Park, Vietnam.

Ecotourism in national parks of developing countries is increasingly recognised as a promising option to achieve sustainable development goals, regardless, might imply various paradoxical managerial challenges. This paper, therefore, seeks to contribute a methodological framework utilising ES-based social landscape metrics (SLM) to address the potential barriers in managing ecotourism-integrated multi-functional national parks. We present a mixed-method case study in Vietnam's Tram Chim National Park (TCNP), conducted via semi-structural interviews and PGIS with tourists and locals. Multiple key informants, i.e. TCNP's authorities were also interviewed to provide their managerial insights and assist in verifying the PGIS results obtained from the tourists and locals. Via the quantified and mapped SLMs, the study reveals the differences between tourists and locals in terms of how and where they perceive and appreciate the intangible values of TCNP. Through spatial statistics, we reported important spatial correlations (i) between different categories of Ecosystem Services (ES) and (ii) between ES richness and diversity on different TCNP's land covers. As a contribution to the decision-making outlook, we remarked potential areas to expand of ecotourism activities based on the spatial hot and cold spots. This study concludes by highlighting opportunities for future research in expanding on socio-geographical assessments of ES, especially in the fields of ecotourism.

Differentiating Sitting, Standing, and Walking Through Regional Plantar Pressure Characteristics.

Prolonged static weight bearing (WBR) is thought to aggravate plantar heel pain and is common in the workplace, which may put employees at greater risk of developing plantar heel pain. However, objective measures of physical activity and sedentary behaviors in the workplace are lacking, making it difficult to establish or refute the connection between work exposure and plantar heel pain. Characterizing loading patterns during common workplace postures will enhance the understanding of foot function and inform the development of new measurement tools. Plantar pressure data during periods of sitting, standing, and walking were measured in ten healthy participants using the F-Scan in-shoe measurement system (Tekscan Inc, Boston, MA). Peak and average pressure, peak and average contact area, and average pressure differential were analyzed in ten different regions of the foot. A two-way repeated measures analysis of variance (ANOVA) assessed the posture by foot region interaction for each measurement parameter; significant effects of posture by foot region were identified for all five measurement parameters. Ten foot region by measurement parameter combinations were found to significantly differentiate all three postures simultaneously; seven used pressure measures to differentiate while three used area measures. The heel, lateral midfoot (LM), and medial and central forefoot (CFF) encompassed nine of ten areas capable of differentiating all postures simultaneously. This work demonstrates that plantar pressure is a viable means to characterize and differentiate three common workplace postures. The results of this study can inform the development of measurement tools for quantifying posture duration at work.

Inferring floodplain bathymetry using inundation frequency.

This study proposes a new method to retrieve the bathymetry of turbid-water floodplains from the inundation frequency (IF) data derived from over 32 years of composite optical remote sensing data. The new method was tested and validated over the Curuai floodplain in the lower Amazon River, where the entire bathymetry was surveyed in 2004, and water level gauge data has been available since 1960. The depth was estimated based on the relationship derived from IF and surveyed depth data, and the results were compared to those retrieved from bare-Earth DEM. We further assessed the sensitivity of the approach by analyzing the deepest part of the lake (i.e., permanent water body ~ 8m) with high IF, as well as the effect of gradual sedimentation in the lake over time. The results showed that the model is highly accurate and sensitive to IF changes even in the permanent water body areas, suggesting that this model can be used in other seasonal lakes worldwide with turbid-waters, where large-scale bathymetry surveys are not feasible due to high operation costs.

Large lake gauging using fractional imagery.

Large floodplain lakes provide riparian habitat, are sediment and nutrient sinks, help control flow connectivity and flooding along rivers, and are both used by humans and strongly impacted by human activity. However, water level in many remote large floodplain lakes, especially in developing countries, is often monitored inconsistently or not at all. In this study, a novel method for estimating large lake water level using passive, optical remote sensing data combined with any digital elevation model (DEM) is presented. The method obtains water level estimates at 30 m2 resolution using Landsat, in this case in conjunction with SRTM elevation data, nested within a 240 m2 grid "fishnet". A probabilistic mean of elevation values for all water-designated pixels (between 5% and 95% filled within each grid) produces lake water levels often accurate to within ±50 cm of gauged reference data on Lake Curuai in the Amazon River and Tonle Sap Lake along the Mekong River. The method is relatively insensitive to cloud cover, especially as lake size increases. This study is the first to use solely passive optical remote sensing data for water level estimation and thus could be used to produce accurate, long-term estimations of water level in many large lakes globally. The use of optical sensors to obtain lake water level is both an important complement and potential alternative to methods that use active sensors.

Usefulness of Preoperative Ultrasound for the Evaluation of Testicular Rupture in the Setting of Scrotal Gunshot Wounds.

PURPOSE: A scrotal gunshot wound may result in testicular injury, necessitating urgent scrotal exploration and attempted testicular salvage. Scrotal ultrasound is highly sensitive and specific for testicular rupture in the setting of blunt scrotal trauma but it has been poorly studied in the setting of scrotal gunshot wounds. Our objective was to determine the accuracy of scrotal ultrasound to identify testicular rupture following a scrotal gunshot wound. MATERIALS AND METHODS: We retrospectively reviewed the records of patients with a scrotal gunshot wound from 2003 to 2014 in whom preoperative ultrasound was done prior to scrotal exploration. A heterogeneous echo pattern of testicular parenchyma with contour loss was considered a positive examination for testicular rupture. Patients underwent scrotal exploration within 24 hours of presentation. The sensitivity and specificity of ultrasound were estimated and compared to operative findings. ROC curve analysis was done. RESULTS: Of 75 patients who sustained a scrotal gunshot wound ultrasound was positive in 30 and negative in 45. No ultrasound revealed bilateral injuries. Scrotal exploration demonstrated a total of 40 testicular ruptures in 35 patients, of which 30 testicles were salvaged. Ten orchiectomies were performed. The sensitivity and specificity of ultrasound were 60% and 95%, respectively, with 16 missed injuries and 6 false-positive findings. Positive predictive value was 80% and negative predictive value was 87%. The ROC AUC was 0.79. In 6 of the 16 missed injuries there was an ipsilateral hematocele or hematoma. CONCLUSIONS: The sensitivity of scrotal ultrasound is limited for evaluating testicular rupture after a scrotal gunshot wound. Large coincident hematoceles or hematomas may obscure the diagnosis of testicular rupture. Negative ultrasound should not preclude scrotal exploration after a scrotal gunshot wound is sustained.

Epithelioid angiomyolipoma metastasis to the rectus abdominis.

A 37-year-old female presented with abdominal pain. An abdominal computed tomography scan demonstrated a 10 cm x 13 cm left renal mass. An open adrenal-sparing radical nephrectomy was performed. The pathological diagnosis was epithelioid angiomyolipoma. Five-year surveillance did not demonstrate recurrence of disease. However, a 1.8 cm x 2.5 cm mass on the rectus abdominis muscle was identified after 5 years. Biopsy of the mass demonstrated histologic findings consistent with the primary tumor. Herein, we report a case of metastatic renal epithelioid angiomyolipoma to the rectus abdominis muscle more than 5 years after resection of primary renal tumor.

Systematic Review and Meta-Analyses of Perinatal Death and Maternal Exposure to Tobacco Smoke During Pregnancy.

We conducted a systematic review and 3-part meta-analysis to characterize the relationship between smoking and perinatal death, defined as the combination of stillbirth and neonatal death. The PubMed database was searched (1956-August 31, 2011) with keywords, and manual reference searches of included articles and Surgeon Generals' reports were conducted. The full texts of 1,713 articles were reviewed, and 142 articles that examined the associations between active or passive smoking and perinatal death were included in the meta-analyses. Data were abstracted by 2 reviewers. Any active maternal smoking was associated with increased risks of stillbirth (summary relative risk (sRR) = 1.46, 95% confidence interval (CI): 1.38, 1.54 (n = 57 studies)), neonatal death (sRR = 1.22, 95% CI: 1.14, 1.30 (n = 28)), and perinatal death (sRR = 1.33, 95% CI: 1.25, 1.41 (n = 46)). The risks of stillbirth, neonatal death, and perinatal death increased with the amount smoked by the mother. Biases in study publication, design, and analysis were present but did not significantly affect the results. These findings strengthen the evidence that women should not smoke while pregnant, and all women of reproductive age should be warned that smoking increases the risks of stillbirth, neonatal death, and perinatal death.

An integrated microfluidic chip for immunomagnetic detection and isolation of rare prostate cancer cells from blood.

The quantitative and qualitative analysis of circulating tumor cells (CTCs) has the potential to improve the clinical management of several cancers, including prostate cancer. As such, there is much interest in the isolation of CTCs from the peripheral blood of cancer patients. We report the design, fabrication, and proof-of-principle testing of an integrated permalloy-based microfluidic chip for immunomagnetic isolation of blood-borne prostate cancer cells using an antibody targeting prostate surface membrane antigen (PSMA). The preliminary results using spiked blood samples indicate that the proposed device is consistently capable of isolating prostate cancer cells with high sensitivity (up to 98 %) at clinically relevant low concentrations (down to 20 cells/mL) and an acceptable throughput (100 µL/min).

FFA-induced hepatic insulin resistance in vivo is mediated by PKCδ, NADPH oxidase, and oxidative stress.

Fat-induced hepatic insulin resistance plays a key role in the pathogenesis of type 2 diabetes in obese individuals. Although PKC and inflammatory pathways have been implicated in fat-induced hepatic insulin resistance, the sequence of events leading to impaired insulin signaling is unknown. We used Wistar rats to investigate whether PKCδ and oxidative stress play causal roles in this process and whether this occurs via IKKß- and JNK-dependent pathways. Rats received a 7-h infusion of Intralipid plus heparin (IH) to elevate circulating free fatty acids (FFA). During the last 2 h of the infusion, a hyperinsulinemic-euglycemic clamp with tracer was performed to assess hepatic and peripheral insulin sensitivity. An antioxidant, N-acetyl-L-cysteine (NAC), prevented IH-induced hepatic insulin resistance in parallel with prevention of decreased IκBα content, increased JNK phosphorylation (markers of IKKß and JNK activation, respectively), increased serine phosphorylation of IRS-1 and IRS-2, and impaired insulin signaling in the liver without affecting IH-induced hepatic PKCδ activation. Furthermore, an antisense oligonucleotide against PKCδ prevented IH-induced phosphorylation of p47(phox) (marker of NADPH oxidase activation) and hepatic insulin resistance. Apocynin, an NADPH oxidase inhibitor, prevented IH-induced hepatic and peripheral insulin resistance similarly to NAC. These results demonstrate that PKCδ, NADPH oxidase, and oxidative stress play a causal role in FFA-induced hepatic insulin resistance in vivo and suggest that the pathway of FFA-induced hepatic insulin resistance is FFA → PKCδ → NADPH oxidase and oxidative stress → IKKß/JNK → impaired hepatic insulin signaling.

Systematic review and meta-analysis of miscarriage and maternal exposure to tobacco smoke during pregnancy.

We conducted a systematic review and meta-analysis to characterize the relationship between smoking and miscarriage. We searched the PubMed database (1956-August 31, 2011) using keywords and conducted manual reference searches of included articles and reports of the US Surgeon General. The full text of 1,706 articles was reviewed, and 98 articles that examined the association between active or passive smoking and miscarriage were included in the meta-analysis. Data were abstracted by 2 reviewers. Any active smoking was associated with increased risk of miscarriage (summary relative risk ratio = 1.23, 95% confidence interval (CI): 1.16, 1.30; n = 50 studies), and this risk was greater when the smoking exposure was specifically defined as during the pregnancy in which miscarriage risk was measured (summary relative risk ratio = 1.32, 95% CI: 1.21, 1.44; n = 25 studies). The risk of miscarriage increased with the amount smoked (1% increase in relative risk per cigarette smoked per day). Secondhand smoke exposure during pregnancy increased the risk of miscarriage by 11% (95% CI: 0.95, 1.31; n = 17 studies). Biases in study publication, design, and analysis did not significantly affect the results. This finding strengthens the evidence that women should not smoke while pregnant, and all women of reproductive age should be warned that smoking increases the risk of miscarriage.

Biometric system for measuring gait and fall characteristics captured on video.

This paper presents a methodology that quantifies gait and fall characteristics from video of real-life fall events. The method consists in selecting on-screen the points on the ground where the feet are in contact with the ground. The essence of the method lies in establishing a transformation from the video frames to the "real world." In projected images, geometric properties such as lengths, angles, and parallelism are not preserved; thus, concepts of projective geometry are applied, namely homography. Because the ground is an invariant plane, using this plane for homography results in a constant transformation. The homographic transformation relies on the accuracy in the selection of on-screen points. An optimization algorithm that minimizes the errors caused by inaccurate on-screen point selection improves the results of the homographic transformation. Experimental trials are conducted at three walking velocities (slow, preferred, and fast) using two video cameras and a GAITRite walkway system. Spatial parameters of two independent video analyses are compared with the GAITRite system, yielding a limit of agreement of step length from -2.12 cm to 2.03 cm. Temporal parameters are less confident due to the existence of dropped frames in the video footage. This method is then used to analyze two real fall events as demonstrative cases. First, the gait characteristics are analyzed before imbalance, and subsequently, the characteristics of stepping are analyzed during the fall. In particular, we propose the stepping/impact angle as the metric that quantifies how much stepping affected the direction of the fall.

Sand mining in the Mekong Delta: Extent and compounded impacts.

Sand mining has accelerated in recent years primarily due to population increase and rapid urbanization. To meet demand, the rate of sand extraction often exceeds the rate of natural replenishment with serious environmental consequences. In this review paper, the Vietnamese Mekong Delta (VMD), a global hotspot for sand mining with a prolonged history of intensive riverbed extraction, is used as a representative case study to highlight the extent and compounded impacts of this activity. The sand mining budget of the VMD ranged from 8.5 to 45.7 Mm3/yr. The large difference is due to the use of different methods to determine the sand mining budget as well as the difficulties associated with measuring the volume of sand extracted from the riverbed. Widespread illegal mining in the region further exacerbates the mismatch. The environmental consequences of riverbed sand mining include deeply incised riverbeds that result in riverbank and coastal erosion. Massive sediment removal has also led to river water level reductions, disrupted hydrological connectivity, and diminished floodplain inundation. In addition, the augmented backwater effect that results from riverbed lowering, amplifies the extent of saltwater intrusion in the dry season. While the physical and hydrological impacts of sand mining is well studied, studies on the ecological and socio-economic ramifications remain sparse. In addition, the ways in which upstream dams, irrigation infrastructure, excessive groundwater extraction, and sea-level rise (SLR) have amplified the effects of sand mining was also considered in this review. This paper concludes by advocating for the adoption of remote sensing-based approaches for effective mapping of sand mining activities and the need to mine sustainably to balance developmental needs with environmental conservation.

Soil salinization in agriculture: Mitigation and adaptation strategies combining nature-based solutions and bioengineering.

Soil salinization is among the most critical threats to agriculture and food security. Excess of salts adversely affects soil structure and fertility, plant growth, crop yield, and microorganisms. It is caused by natural processes, such as dry climates and low precipitations, high evaporation rate, poor waterlogging, and human factors, such as inappropriate irrigation practices, poor drainage systems, and excessive use of fertilizers. The growing extremization of climate with prolonged drought conditions is worsening the phenomenon. Nature-based solutions (NBS), combined with precision or conservation agriculture, represent a sustainable response, and offer benefits through revitalizing ecosystem services. This perspective explores NBS that can be adopted, along with their challenges and implementation limitations. We also argue that NBS could not be enough to combat hunger in the world's most vulnerable regions and fully achieve the Sustainable Development Goal - Zero Hunger (SDG2). We therefore discuss their possible combination with salt-tolerant crops based on bioengineering.

Theoretical analysis of the state of balance in bipedal walking.

This paper presents a theoretical analysis based on classic mechanical principles of balance of forces in bipedal walking. Theories on the state of balance have been proposed in the area of humanoid robotics and although the laws of classical mechanics are equivalent to both humans and humanoid robots, the resulting motion obtained with these theories is unnatural when compared to normal human gait. Humanoid robots are commonly controlled using the zero moment point (ZMP) with the condition that the ZMP cannot exit the foot-support area. This condition is derived from a physical model in which the biped must always walk under dynamically balanced conditions, making the centre of pressure (CoP) and the ZMP always coincident. On the contrary, humans follow a different strategy characterized by a 'controlled fall' at the end of the swing phase. In this paper, we present a thorough theoretical analysis of the state of balance and show that the ZMP can exit the support area, and its location is representative of the imbalance state characterized by the separation between the ZMP and the CoP. Since humans exhibit this behavior, we also present proof-of-concept results of a single subject walking on an instrumented treadmill at different speeds (from slow 0.7 m/s to fast 2.0 m/s walking with increments of 0.1 m/s) with the motion recorded using an optical motion tracking system. In order to evaluate the experimental results of this model, the coefficient of determination (R2) is used to correlate the measured ground reaction forces and the resultant of inertial and gravitational forces (anteroposterior R² = 0.93, mediolateral R² = 0.89, and vertical R² = 0.86) indicating that there is a high correlation between the measurements. The results suggest that the subject exhibits a complete dynamically balanced gait during slow speeds while experiencing a controlled fall (end of swing phase) with faster speeds. This is quantified with the root-mean-square deviation (RMSD) between the CoP and the ZMP, a relationship that grows exponentially, suggesting that the ZMP exits the support area earlier with faster walking speeds (relative to the stride duration). We conclude that the ZMP is a significant concept that can be exploited for the analysis of bipedal balance, but we also challenge the control strategy adopted in humanoid robotics that forces the ZMP to be contained within the support area causing the robot to follow unnatural patterns.