Path Following for Autonomous Mobile Robots with Deep Reinforcement Learning.

Autonomous mobile robots have become integral to daily life, providing crucial services across diverse domains. This paper focuses on path following, a fundamental technology and critical element in achieving autonomous mobility. Existing methods predominantly address tracking through steering control, neglecting velocity control or relying on path-specific reference velocities, thereby constraining their generality. In this paper, we propose a novel approach that integrates the conventional pure pursuit algorithm with deep reinforcement learning for a nonholonomic mobile robot. Our methodology employs pure pursuit for steering control and utilizes the soft actor-critic algorithm to train a velocity control strategy within randomly generated path environments. Through simulation and experimental validation, our approach exhibits notable advancements in path convergence and adaptive velocity adjustments to accommodate paths with varying curvatures. Furthermore, this method holds the potential for broader applicability to vehicles adhering to nonholonomic constraints beyond the specific model examined in this paper. In summary, our study contributes to the progression of autonomous mobility by harmonizing conventional algorithms with cutting-edge deep reinforcement learning techniques, enhancing the robustness of path following.

The roles of sex hormones in the pathophysiology of age-related sarcopenia and frailty.

Background: Sarcopenia is an age-related condition characterized by a progressive and systemic decline in skeletal muscle mass, quality, and strength. The incidence of sarcopenia contains sex-specific aspects, indicating the contribution of sex hormones to its pathophysiology. This review focuses on changing trends in sarcopenia, discusses alterations in definitions and diagnostic criteria, and emphasizes the association between sarcopenia and sex hormones. Methods: A literature search was performed on PubMed for related articles published between 1997 and December 2023 using appropriate keywords. Main Findings Results: Advances in research have emphasized the significance of muscle quality and strength over muscle mass, resulting in new diagnostic criteria for sarcopenia. Androgens demonstrated anabolic effects on skeletal muscles and played a significant role in the pathophysiology of sarcopenia. In clinical settings, androgen replacement therapy has exhibited certain positive outcomes for treating sarcopenia, despite concerns about potential side effects. Conversely, estrogen is involved in skeletal muscle maintenance, but the detailed mechanisms remain unclear. Moreover, results regarding the clinical application of estrogen replacement therapy for treating sarcopenia remained inconsistent. Conclusion: The elucidation of molecular mechanisms that involve sex hormones is eagerly awaited for novel therapeutic interventions for sarcopenia.

A Real-Time Application for the Analysis of Multi-Purpose Vending Machines with Machine Learning.

With the development of mobile payment, the Internet of Things (IoT) and artificial intelligence (AI), smart vending machines, as a kind of unmanned retail, are moving towards a new future. However, the scarcity of data in vending machine scenarios is not conducive to the development of its unmanned services. This paper focuses on using machine learning on small data to detect the placement of the spiral rack indicated by the end of the spiral rack, which is the most crucial factor in causing a product potentially to get stuck in vending machines during the dispensation. To this end, we propose a k-means clustering-based method for splitting small data that is unevenly distributed both in number and in features due to real-world constraints and design a remarkably lightweight convolutional neural network (CNN) as a classifier model for the benefit of real-time application. Our proposal of data splitting along with the CNN is visually interpreted to be effective in that the trained model is robust enough to be unaffected by changes in products and reaches an accuracy of 100%. We also design a single-board computer-based handheld device and implement the trained model to demonstrate the feasibility of a real-time application.

Identification of histopathological and clinical spectrum of diabetic kidney disease based on an unsupervised hierarchical clustering analysis of elderly autopsy specimens.

AIM: Diabetic kidney disease (DKD), a chronic kidney disease caused by diabetes and other comorbidities, is the leading cause of end-stage renal disease. The pathogenesis of DKD is diverse and influenced by various causes, some but not all of which cause proteinuria. Some factors such as hypertension can modify DKD. Therefore, the spectrum of DKD is difficult to elucidate and remains unsolved. This study aims to classify and characterize DKD. METHODS: We examined autopsy specimens from type 2 diabetes mellitus (DM) (n = 44) and non-DM (n = 21) groups. RESULTS: The frequency of interstitial fibrosis and tubular atrophy was higher in patients with proteinuric DKD than in those with non-proteinuric DKD. The presence of polar vasculosis was associated with hypertension in DKD. In addition, an unsupervised hierarchical clustering analysis revealed the spectrum of renal histopathology findings for more-proteinuric and less-proteinuric DKD. With changes in the diagnostic criteria for hypertension and advances in antihypertensive drugs, the pathogenesis of DKD may be changing. Furthermore, a decision tree model suggested how diabetes, hypertension, and dyslipidemia interacted in predicting the characteristics of DKD. CONCLUSION: Polar vasculosis is a good indicator of the presence of DM and hypertension. Furthermore, the histopathological and clinical spectrum of DKD were related to the interaction of diabetes, hypertension, and dyslipidemia. These histopathological and clinical results may help to show the range of patient characteristics when conducting clinical trials and could help to determine whether chronic kidney disease is caused by DM or some other cause.

Stereotactic body radiotherapy using a hydrogel spacer for localized prostate cancer: A dosimetric comparison between tomotherapy with the newly-developed tumor-tracking system and cyberknife.

PURPOSE: With a new tumor-tracking system (Synchrony®) for tomotherapy (Radixact®), the internal and set-up margins can be tightened, like cyberknife (CyberKnife®), in the planning of stereotactic body radiotherapy (SBRT) for prostate cancer. Recently, the usefulness of placing a hydrogel spacer between the prostate and rectum has been established in prostate radiotherapy. We evaluated the characteristics of tomotherapy plans with the tumor-tracking system and compared them with cyberknife SBRT plans for localized prostate cancer using a hydrogel spacer. METHODS: In 20 patients, two plans were created and compared using tomotherapy and cyberknife. All patients underwent hydrogel spacer injection behind the prostate before simulation CT and MRI for fusion. For all plans, 36.25 Gy in 7.25-Gy fractions for a minimum coverage dose of 95% of planning target volume (PTV) (D95%) was prescribed. The D99% of PTV and D0.1 ml of the PTV, urethra, bladder, and rectum were intended to be > 90%, 110-130%, 100-110%, <110%, and <100%, respectively, of the prescribed doses. RESULTS: All plans using tomotherapy and cyberknife achieved the intended dose constraints. The cyberknife plans yielded better median PTV-V110% (volume of PTV covered by 110% isodose line, 54.8%), maintaining lower median D0.1 ml of the urethra (37.5 Gy) and V80% of the bladder (11.0 ml) compared to the tomotherapy plans (39.0%; p < 0.0001, 38.2 Gy; p < 0.0001, and 18.3 ml; p < 0.0001, respectively). The tomotherapy plans were superior to the cyberknife plans for the rectum (V80% = 0.4 vs. 1.0 ml, p < 0.001; D1ml = 26.4 vs. 29.0 Gy, p = 0.013). CONCLUSIONS: Our results suggested that tomotherapy with the tumor-tracking system has reasonable potential for SBRT for localized prostate cancer using a hydrogel spacer.

[A case of hyperammonemia caused by urinary tract infection due to urease-producing bacteria in dementia with Lewy bodies].

An 87-year-old woman diagnosed with dementia with Lewy bodies (DLB) 2 years earlier was referred to our institution because of difficulty walking. She was diagnosed with urinary tract infection and admitted to our hospital. During hospitalisation, she became delirious, which prompted the administration of haloperidol. Afterwards, an altered level of consciousness was noted, measuring 300 on the Japan coma scale. A blood test revealed hyperammonaemia without liver damage. Urine culture detected the presence of Corynebacterium urealyticum. Therefore, we diagnosed this case as one of hyperammonaemia due to urinary tract infection caused by urease-producing bacteria. Soon after the insertion of a urethral catheter, the ammonia level decreased, and the consciousness level improved. In this case, the patient took medication to preserve her bladder function, which is frequently associated with DLB. We suspected that the drug caused urinary retention, resulting in hyperammonaemia. Hyperammonaemia due to these bacteria should be considered in DLB patients with an impaired consciousness, especially in those using regulators of the urinary bladder function.

Defective renal autoregulation in the chronic bile duct ligation model of liver failure.

BACKGROUND: Cirrhosis of the liver is often associated with an impairment of renal function that is usually not associated with consistent structural abnormalities of the renal parenchyma, but is thought to be the functional consequence of arterial underfilling and reduced arterial blood pressure. METHOD: We have used the cirrhosis model of chronic bile duct ligation (BDL) to assess the response of renal blood flow to a change of blood pressure. We have measured renal haemodynamics in BDL rats. RESULT: Three weeks after BDL, rats showed elevated levels of total bilirubin, AST, and ALT as well as reduced arterial blood pressure. Creatinine clearance was significantly reduced, and plasma creatinine and urea nitrogen were elevated. Renal blood flow at baseline blood pressure was significantly lower in the BDL group than in the sham group. Clamp-induced reductions of renal perfusion pressure caused significantly greater changes of renal blood flow in BDL than control rats. The autoregulatory index over a comparable blood pressure range averaged 0.28 ± 0.35 in control rats and 1.26 ± 0.6 in BDL rats (p = 0.0004) indicating impairment of renal autoregulation in liver cirrhosis. CONCLUSION: Tubuloglomerular feedback (TGF) responses were significantly attenuated in BDL rats, especially in the subnormal flow range. Impairment of renal blood flow autoregulation, to some extent mediated by reduced TGF-mediated vasodilatation, may contribute to the renal vascular constrictor state in liver cirrhosis by preventing the full dilatory response to the blood pressure reduction.

Assessment of the Secondary Copper Reserves of Nations.

The sustainable use of metals demands consideration not only of primary metals in the natural environment but also of secondary metals in society as alternative resources. This study applied our proposed classification framework of secondary resources to copper (1) to investigate the applicability of the framework and (2) to assess the secondary copper reserves and resources of selected countries. To estimate secondary copper reserves, we introduced the variable "secondary reserve ratio": the fraction of in-use copper stocks that is technically and economically recoverable. Our estimates showed that the United States and China have secondary copper reserves of 44 and 33 Mt, respectively, and showed that global secondary copper reserves are about 30% of global primary reserves. The application of the classification framework showed that considerable amounts of secondary copper resources are in landfills, which are potential targets of future extraction of secondary copper through landfill mining. Overall, the classification framework provides a better understanding of the current size of available secondary resources and waste deposits. It also highlights the need for integrated management of primary and secondary resources.

[Current Status and Perspective of Chemoradiotherapy for Uterine Cervical Cancer].

Fifteen years has passed since the NCI announced the clinical importance of concurrent chemoradiotherapy (CCRT) in radiotherapy for patients with locoregionally advanced uterine cervical cancer. Numerous clinical trials have been performed to further improve the outcomes of CCRT. In addition to investigations of chemotherapeutic regimens and schedules, adaptation of novel radiotherapy methods such as image-guided brachytherapy (IGBT) and intensity-modulated radiotherapy (IMRT) is encouraged in CCRT for cervical cancer.

Exploring China's materialization process with economic transition: analysis of raw material consumption and its socioeconomic drivers.

China's rapidly growing economy is accelerating its materialization process and thereby creating serious environmental problems at both local and global levels. Understanding the key drivers behind China's mass consumption of raw materials is thus crucial for developing sustainable resource management and providing valuable insights into how other emerging economies may be aiming to accomplish a low resource-dependent future. Our results show that China's raw material consumption (RMC) rose dramatically from 11.9 billion tons in 1997 to 20.4 billion tons in 2007, at an average annual growth rate at 5.5%. In particular, nonferrous metal minerals and iron ores increased at the highest rate, while nonmetallic minerals showed the greatest proportion (over 60%). We find that China's accelerating materialization process is closely related to its levels of urbanization and industrialization, notably demand for raw materials in the construction, services, and heavy manufacturing sectors. The growing domestic final demand level is the strongest contributor of China's growth in RMC, whereas changes in final demand composition are the largest contributors to reducing it. However, the expected offsetting effect from changes in production pattern and production-related technology level, which should be the focus of future dematerialization in China, could not be found.

Exercise-induced vitamin D receptor and androgen receptor mediate inhibition of IL-6 and STAT3 in muscle.

Background: Skeletal muscle produces interleukin-6 (IL-6) during exercise as a myokine. Although IL-6 is required for skeletal muscle regeneration, its action increases the expression of myostatin and other proteins involved in muscle atrophy, resulting in skeletal muscle atrophy. In this study, we clarified the effects exercise-induced vitamin D receptor (VDR) and androgen receptor (AR) expression on IL-6 and signal transducer and activator of transcription 3 (STAT3) in vivo and in vitro. Method: C2C12 myotubes were subjected to electric pulse stimulation (EPS) in vitro. To evaluate VDR and AR function, a VDR/AR agonist and antagonist were administered before EPS to C2C12 myotubes. C57BL6 mice underwent 4 weeks of exercise. The expression levels of proteolytic-associated genes, including CCAAT/enhancer-binding protein delta (C/EBPδ) and myostatin, were measured by quantitative real-time polymerase chain reaction, and phosphorylated and total STAT3 levels were measured by Western blot analysis. Result: The expression of VDR and AR mRNA was induced following EPS in C2C12 myotubes. IL-6 mRNA expression was also increased with a peak at 6 h after EPS and p-STAT3/STAT3 ratio reciprocally decreased. Although VDR/AR agonist administration decreased IL-6 mRNA expression and p-STAT3/STAT3 ratio, these two endpoints increased after treatment with VDR/AR antagonist, respectively. Exercise in mice also increased the expression of VDR/AR and IL-6 mRNA and decreased p-STAT3/STAT3 ratio. Conclusion: Exercise-induced VDR and AR expression results in the suppression of IL-6 mRNA and STAT3 phosphorylation in skeletal muscle.

Usefulness of assessment of the Clinical Frailty Scale and the Dementia Assessment Sheet for Community-based Integrated Care System 21-items at the time of initiation of maintenance hemodialysis in older patients with chronic kidney disease.

INTRODUCTION: We examined whether the Clinical Frailty Scale (CFS), a widely adopted tool for stratifying the degree of frailty, and the Dementia Assessment Sheet for Community-based Integrated Care System 21-items (DASC-21), a simple tool for simultaneous assessment of impaired cognition and impaired ADL, at the time of initiation of hemodialysis is useful tool of older patients for the outcome and prognosis. METHODS: Data for 101 patients aged 75 years or older (mean age, 84.3 years) with ESRD who were initiated on hemodialysis and could be followed up for a period of 6 months were reviewed. RESULTS: The 6-month survival curves showed a significantly higher number of deaths in the frailty (CFS≥5) group than in the normal to vulnerable (CFS<5) group (p<0.01). The CFS level was also significantly higher (6.5±1.5) in patients who died within 6 months of dialysis initiation as compared with that (4.6±1.7) in patients who survived (p<0.01). On the other hand, the total score of DASC-21 was related to need for inpatient maintenance dialysis (p<0.01). The total score on the DASC-21 were found as showing significant correlations with the CFS level. The IADL outside the home was identified in the DASC-21 sub-analyses as being correlated with CFS. CONCLUSIONS: The CFS and the DASC-21 appeared to be a useful predictive tool of outcome and prognosis for older patients being initiated on hemodialysis. Assessment by the CFS or the DASC-21 might be useful for selecting the renal replacement therapy by shared decision-making and for advance care planning.

A Case of Mesangial Proliferative Nephritis Caused by Slow Cryoglobulin.

The patient was a woman in her 60s. She was found to have proteinuria on a health checkup. She did not have any particular subjective symptoms, and no definitive diagnosis was made, despite serological findings indicative of immune abnormalities. A renal biopsy was performed. Light microscopy of renal tissue section revealed mesangial proliferative nephritis. Electron microscopic findings included electron-dense deposits and fibrillar/tubular structures with a diameter of 20-30 nm. These findings suggested the presence of cryoglobulin (CG), but CG was not detected in qualitative or quantitative hematologic tests. Thus, the serum samples were stored at 37°C for a long period of time and then cooled to 4°C. When the obtained precipitates were examined, CG was successfully detected. CG that precipitates only after a long period of time is referred to as slow cryoglobulin (sCG), and sCG is extremely rare. The present case is the first documented case, to our knowledge, of renal disorders caused by sCG. It should be noted that there are some cases in which it takes much time for CG to precipitate. Thus, when CG cannot be detected, it is necessary to spend much time to determine whether CG precipitates.

Erythropoiesis-stimulating agent responsiveness and mortality in hemodialysis patients: results from a cohort study from the dialysis registry in Japan.

BACKGROUND: Patient responsiveness to erythropoiesis-stimulating agents (ESAs), notoriously difficult to measure, has attracted attention for its association with mortality. We defined categories of ESA responsiveness and attempted to clarify their association with mortality. STUDY DESIGN: Cohort study. SETTING & PARTICIPANTS: Data from Japan's dialysis registry (2005-2006), including 95,460 adult hemodialysis patients who received ESAs. PREDICTOR: We defined 6 categories of ESA responsiveness based on a combination of ESA dosage (low [<6,000 U/wk] or high [≥6,000 U/wk]) and hemoglobin level (low [<10 g/dL], medium [10-11.9 g/dL], or high [≥12 g/dL]), with medium hemoglobin level and low-dose ESA therapy as the reference category. OUTCOMES: All-cause and cardiovascular mortality during 1-year follow-up. MEASUREMENTS: HRs were estimated using a Cox model for the association between responsiveness categories and mortality, adjusting for potential confounders such as age, sex, postdialysis weight, dialysis duration, comorbid conditions, serum albumin level, and transferrin saturation. RESULTS: Median ESA dosage (4,500-5,999 U/wk) was used as a cutoff point, and mean hemoglobin level was 10.1 g/dL in our cohort. Of 95,460 patients during follow-up, 7,205 (7.5%) died of all causes, including 5,586 (5.9%) cardiovascular deaths. Low hemoglobin levels and high-dose ESA therapy were both associated with all-cause mortality (adjusted HRs, 1.18 [95% CI, 1.09-1.27] for low hemoglobin level with low-dose ESA and 1.44 [95% CI, 1.34-1.55] for medium hemoglobin level with high-dose ESA). Adjusted HRs for high-dose ESA with low hemoglobin level (hyporesponsiveness) were 1.94 (95% CI, 1.82-2.07) for all-cause and 2.02 (95% CI, 1.88-2.17) for cardiovascular mortality. We also noted the interaction between ESA dosage and hemoglobin level on all-cause mortality (likelihood ratio test, P = 0.002). LIMITATIONS: Potential residual confounding from unmeasured factors and single measurement of predictors. CONCLUSIONS: Mortality can be affected by ESA responsiveness, which may include independent and interactive effects of ESA dose and hemoglobin level. Responsiveness category has prognostic importance and clinical relevance in anemia management.

Telomere shortening and karyotypic alterations in hepatocytes in long-term transplanted human liver allografts.

The long-term fate of aged liver allografts in young recipients who received grafts from older donors is unknown. We evaluated graft aging by analyzing hepatocytic telomere length and karyotypic changes. Seventeen pediatric individuals who underwent living-donor liver transplantation for congenital biliary diseases were selected. At a median of 10.4 years post-transplant, ten had tolerated grafts with weaned off immunosuppressants, and seven had idiopathic post-transplantation hepatitis. Fluorescence in situ hybridization was used to evaluate the telomere signal intensity (TI) and karyotypic changes. First, we measured predictive age-dependent TI decline with regression analysis of donor livers. The mean TI at the earliest (within a year) and latest biopsies was significantly lower than the predicted TI of the studied allografts. With univariate analysis, a higher abnormal karyotype ratio in the donor liver was correlated with development of idiopathic post-transplantation hepatitis. With multivariate analysis that included clinical parameters, a greater TI decline at the earliest biopsy was correlated with the development of idiopathic post-transplantation hepatitis. In conclusion, graft aging as measured by TI decline and donor abnormal karyotype ratio was associated with idiopathic post-transplantation hepatitis of long-term transplanted liver allografts.

A case of adefovir-induced membranous nephropathy related to hepatitis B caused by lamivudine-resistant virus after liver transplant due to Byler's disease.

We report on how adefovir-induced membranous nephropathy related to hepatitis B was caused by lamivudine-resistant virus after a liver transplant due to Byler's disease. In 1980, a 2-year-old girl was diagnosed with Byler's disease (familial progressive familial intrahepatic cholestasis). In 1994 (at the age of 14 years) she underwent a liver transplant with her father as the donor. In 2003, hematuria and proteinuria appeared and shortly afterwards her renal function rapidly decreased. A renal biopsy showed atypical membranous nephropathy, which suggested the possibility of a secondary renal disease. The patient had suffered from chronic hepatitis type B (HBV). In 2001 she was administered lamivudine which is an antiviral drug; it was around this time that hematuria and proteinuria appeared as well as an increase of the virus titer. We believed the HBV-related membranous nephropathy was the cause of the virus titer and the renal histology. We concluded that the patient's condition had become resistant to lamivudine medication. Therefore, in February 2004 we administered adefovir, a new drug at the time, to treat the HBV. In April 2004, the HB virus titer decreased and the hematuria and proteinuria decreased. The patient's renal function also showed improvement. HBV-associated nephropathy is caused by HBV antigen deposition in the glomeruli. Generally the first choice of treatment is antivirus therapy. There are many reports demonstrating that administration of interferon and lamivudine are effective; however, there are few reports that show adefovir as an effective treatment for HBV-associated nephropathy.

Determination of Waste Management Workers' Physical and Psychological Load: A Cross-Sectional Study Using Biometric Data.

Waste management workers experience high stress and physical strain in their work environment, but very little empirical evidence supports effective health management practices for waste management workers. Hence, this study investigated the effects of worker characteristics and biometric indices on workers' physical and psychological loads during waste-handling operations. A biometric measurement system was installed in an industrial waste management facility in Japan to understand the actual working conditions of 29 workers in the facility. It comprised sensing wear for data collection and biometric sensors to measure heart rate (HR) and physical activity (PA) based on electrocardiogram signals. Multiple regression analysis was performed to evaluate significant relationships between the parameters. Although stress level is indicated by the ratio of low frequency (LF) to high frequency (HF) or high LF power in HR, the results showed that compared with workers who did not handle waste, those who did had lower PA and body surface temperature, higher stress, and lower HR variability parameters associated with higher psychological load. There were no significant differences in HR, heart rate interval (RRI), and workload. The psychological load of workers dealing directly with waste was high, regardless of their PA, whereas others had a low psychological load even with high PA. These findings suggest the need to promote sustainable work relationships and a quantitative understanding of harsh working conditions to improve work quality and reduce health hazards.

Small dose of oral gastrografin for computed tomography-based image-guided brachytherapy in patients with uterine cervical cancer.

Oral administration of a water-soluble iodine contrast agent (gastrografin) was reported to assist in the appropriate contouring of the small intestine on computed tomography (CT)-based radiotherapy (RT) planning. The efficacy and optimal dose of gastrografin in CT-based image-guided brachytherapy (IGBT) for cervical cancer remain unknown. This study aimed to investigate the efficacy of pretreatment oral administration of gastrografin at a small dose of 50 ml in CT-based IGBT for cervical cancer. A total of 422 sessions in 137 patients who underwent CT-based IGBT with 50 ml of oral gastrografin (concentration, 3% or 4%) were analyzed. Preparation of gastrografin was judged as effective when the small intestine was contrast-enhanced at the area where the small intestine was in contact with the uterus/adnexa. About 287 out of 422 sessions (68%) were judged as effective with gastrografin preparation. The 135 ineffective sessions were considered as follows: (i) the contrast enhancement of the small intestine was not confirmed (n = 36), (ii) the small intestine was not in contact with the uterus/adnexa despite the confirmation of the contrast enhancement of the small intestine (n = 34), and (iii) gastrografin was absent in the small intestine at the area in contact with the uterus/adnexa, even when gastrografin was observed in the small intestine at the area not in contact with the uterus/adnexa (n = 65). In conclusion, pretreatment oral administration of a small dose gastrografin achieved moderate efficacy for accurate contouring of the small intestine close to the uterus/adnexa in CT-based IGBT for cervical cancer.

The default methods in the 2019 Refinement drastically reduce estimates of global carbon sinks of harvested wood products.

BACKGROUND: The stock dynamics of harvested wood products (HWPs) are a relevant component of anthropogenic carbon cycles. Generally, HWP stock increases are treated as carbon removals from the atmosphere, while stock decreases are considered emissions. Among the different approaches suggested by the Intergovernmental Panel on Climate Change (IPCC) for accounting HWPs in national greenhouse gas inventories, the production approach has been established as the common approach under the Kyoto Protocol and Paris Agreement. However, the 24th session of the Conference of the Parties to the United Nations Framework Convention on Climate Change decided that alternative approaches can also be used. The IPCC has published guidelines for estimating HWP carbon stocks and default parameters for the various approaches in the 2006 Guidelines, 2013 Guidance, and 2019 Refinement. Although there are significant differences among the default methods in the three IPCC guidelines, no studies have systematically quantified or compared the results from the different guidelines on a global scale. This study quantifies the HWP stock dynamics and corresponding carbon removals/emissions under each approach based on the default methods presented in each guideline for 235 individual countries/regions. RESULTS: We identified relatively good consistency in carbon stocks/removals between the stock-change and the atmospheric flow approaches at a global level. Under both approaches, the methodological and parameter updates in the 2019 Refinement (e.g., considered HWPs, starting year for carbon stocks, and conversion factors) resulted in one-third reduction in carbon removals compared to the 2006 Guidelines. The production approach leads to a systematic underestimation of global carbon stocks and removals because it confines accounting to products derived from domestic harvests and uses the share of domestic feedstock for accounting. The 2013 Guidance and the 2019 Refinement reduce the estimated global carbon removals under the production approach by 15% and 45% (2018), respectively, compared to the 2006 Guidelines. CONCLUSIONS: Gradual refinements in the IPCC default methods have a considerably higher impact on global estimates of HWP carbon stocks and removals than the differences in accounting approaches. The methodological improvements in the 2019 Refinement halve the global HWP carbon removals estimated in the former version, the 2006 Guidelines.