► Data on crop productivity after biochar application to soils quantitatively analysed. ► Grand mean effect is 10% increase in crop productivity. ► Large variation in data allows limited but useful ...insights in causative mechanisms. ► Auxiliary, temporal and spatial data is not currently sufficiently representative. ► Strategic research and full reporting on statistics and auxiliary data are needed.
Increased crop yield is a commonly reported benefit of adding biochar to soils. However, experimental results are variable and dependent on the experimental set-up, soil properties and conditions, while causative mechanisms are yet to be fully elucidated. A statistical meta-analysis was undertaken with the aim of evaluating the relationship between biochar and crop productivity (either yield or above-ground biomass). Results showed an overall small, but statistically significant, benefit of biochar application to soils on crop productivity, with a grand mean increase of 10%. However, the mean results for each analysis performed within the meta-analysis covered a wide range (from −28% to 39%). The greatest (positive) effects with regard to soil analyses were seen in acidic (14%) and neutral pH soils (13%), and in soils with a coarse (10%) or medium texture (13%). This suggests that two of the main mechanisms for yield increase may be a liming effect and an improved water holding capacity of the soil, along with improved crop nutrient availability. The greatest positive result was seen in biochar applications at a rate of 100
t
ha
−1 (39%). Of the biochar feedstocks considered and in relation to crop productivity, poultry litter showed the strongest (significant) positive effect (28%), in contrast to biosolids, which were the only feedstock showing a statistically significant negative effect (−28%). However, many auxiliary data sets (i.e. information concerning co-variables) are incomplete and the full range of relevant soil types, as well as environmental and management conditions are yet to be investigated. Furthermore, only short-term studies limited to periods of 1 to 2 years are currently available. This paper highlights the need for a strategic research effort, to allow elucidation of mechanisms, differentiated by environmental and management factors and to include studies over longer time frames.
Explainable models of credit losses Bastos, João A.; Matos, Sara M.
European journal of operational research,
08/2022, Letnik:
301, Številka:
1
Journal Article
Recenzirano
Odprti dostop
•Predictions of LGD given by a black-box model are explained in terms of the inputs.•Banks do not have to sacrifice accuracy for transparency to comply with Basel II.•XAI may contribute to the ...stability of the financial system and ensure fairness.•Black-box and glass-box models disagree on the most important determinants of LGD.•The relative seniority of the debt is the most important variable for the black-box.
Credit risk management is an area where regulators expect banks to have transparent and auditable risk models, which would preclude the use of more accurate black-box models. Furthermore, the opaqueness of these models may hide unknown biases that may lead to unfair lending decisions. In this study, we show that banks do not have to sacrifice prediction accuracy at the cost of model transparency to be compliant with regulatory requirements. We illustrate this by showing that the predictions of credit losses given by a black-box model can be easily explained in terms of their inputs. Because black-box models are better at uncovering complex patterns in the data, banks should consider the determinants of credit losses suggested by these models in lending decisions and pricing of credit exposures.
With the advent of the new Basel Capital Accord, banking organizations are invited to estimate credit risk capital requirements using an internal ratings based approach. In order to be compliant with ...this approach, institutions must estimate the loss-given-default, the fraction of the credit exposure that is lost if the borrower defaults. This study evaluates the ability of a parametric fractional response regression and a nonparametric regression tree model to forecast bank loan credit losses. The out-of-sample predictive ability of these models is evaluated at several recovery horizons after the default event. The out-of-time predictive ability is also estimated for a recovery horizon of 1 year. The performance of the models is benchmarked against recovery estimates given by historical averages. The results suggest that regression trees are an interesting alternative to parametric models in modeling and forecasting loss-given-default.
Osteosarcoma is one of the most common metastatic bone cancers, which results in significant morbidity and mortality. Unfolding of effectual therapeutic strategies against osteosarcoma is impeded ...because of the absence of adequate animal models, which can truly recapitulate disease biology of humans. Tissue engineering provides an opportunity to develop physiologically relevant, reproducible, and tunable in vitro platforms to investigate the interactions of osteosarcoma cells with its microenvironment. Adipose-derived stem cells (ASCs) are detected adjacent to osteosarcoma masses and are considered to have protumor effects. Hence, the present study focuses on investigating the role of reactive ASCs in formation of spheroids of osteosarcoma cells (Saos 2) within a three-dimensional (3D) niche, which is created using gellan gum (GG)–silk fibroin. By modifying the blending ratio of GG–silk, the optimum stiffness of the resultant hydrogels such as GG and GG75: S25 is obtained for cancer spheroid formation. This work indicates that the co-existence of cancer and stem cells can form a spheroid, the hallmark of cancer, only in particular microenvironment stiffness. The incorporation of fibrillar silk fibroin within the hydrophilic network of GG in GG75: S25 spongy-like hydrogels closely mimics the stiffness of commercially established cancer biomaterials (e.g., Matrigel, HyStem). The GG75: S25 hydrogel maintains the metabolically active construct for a longer time with elevated expression of osteopontin, osteocalcin, RUNX 2, and bone sialoprotein genes, the biomarkers of osteosarcoma, compared to GG. The GG75: S25 construct also exhibits intense alkaline phosphatase expression in immunohistochemistry compared to GG, indicating itspotentiality to serve as biomimetic niche to model osteosarcoma. Taken together, the GG–silk fibroin-blended spongy-like hydrogel is envisioned as an alternative low-cost platform for 3D cancer modeling.
This paper reports a dynamic causal modeling study of electrocorticographic (ECoG) data that addresses functional asymmetries between forward and backward connections in the visual cortical ...hierarchy. Specifically, we ask whether forward connections employ gamma-band frequencies, while backward connections preferentially use lower (beta-band) frequencies. We addressed this question by modeling empirical cross spectra using a neural mass model equipped with superficial and deep pyramidal cell populations—that model the source of forward and backward connections, respectively. This enabled us to reconstruct the transfer functions and associated spectra of specific subpopulations within cortical sources. We first established that Bayesian model comparison was able to discriminate between forward and backward connections, defined in terms of their cells of origin. We then confirmed that model selection was able to identify extrastriate (V4) sources as being hierarchically higher than early visual (V1) sources. Finally, an examination of the auto spectra and transfer functions associated with superficial and deep pyramidal cells confirmed that forward connections employed predominantly higher (gamma) frequencies, while backward connections were mediated by lower (alpha/beta) frequencies. We discuss these findings in relation to current views about alpha, beta, and gamma oscillations and predictive coding in the brain.
•We briefly review evidence for canonical microcircuits (CMC) and predictive coding.•This evidence is incorporated into a novel Dynamic Causal Model (DCM).•We model observed cross-spectral densities from monkey visual cortex (V1 and V4).•We establish the face and predictive validity of this new DCM.•Gamma rhythms subserve feedforward, and alpha/beta rhythms feedback influences.
Both the aging of the population and the increase in noncommunicable diseases may influence the progression and outcomes culminating in death, changing the evolution of ischemic heart diseases (IHDs) ...and their associated causes. Using the multiple causes of death method could help understand the magnitude of these relationships and enable better targeting of investments in health.
To evaluate the mortality from IHD in Brazil between 2006 and 2020 using the method of multiple causes and identify differences in the distribution pattern of IHD mortality by sex and geographic region.
Based on information extracted from death certificates (DCs) obtained from the database of the Department of Informatics of the Unified Health System (DATASUS), we used the multiple causes method to analyze the causes of death associated with IHD when IHD was defined as the underlying cause of death (UC) and the causes of death listed as the UC when IHD was recorded in any other lines of the DC, from 2006 to 2020, in Brazil. Subsequently, the proportion of these causes of death and differences between sexes and geographic regions were evaluated, with statistical relevance analyzed using the chi-square test, and the dependence between factors illustrated using stacked bar charts and small-world network graphs.
When IHD was listed as the UC of death, the most frequent associated causes of death were, in descending order of frequency, acute myocardial infarction (AMI), arterial hypertension (AH), chronic ischemic heart disease (CHID), heart failure (HF), and diabetes mellitus (DM). When IHD was mentioned in any line of the DC, the most frequent UCs of death were AMI followed by DM, CIHD, chronic obstructive pulmonary disease (COPD), stroke, dyslipidemia, and, in the year 2020, COVID-19. The most frequent cause of death in women were DM as the UC and associated cause of death, AH as the UC, and CIHD and Alzheimer's disease as associated causes of death, while the most frequent causes of death in men were substance dependence as the UC and associated cause of death, and cancer as an associated cause of death. The most frequent causes of death were DM and stroke in the North and Northeast, dyslipidemia and obesity in the Midwest, Alzheimer's disease in the South and Southeast, and atherosclerotic heart disease (AHD) and COPD in the South.
Several diseases - including AMI, AH, CIHD, HF, and DM - were the most frequent associated causes of death when IHD was recorded as the UC. In contrast, AMI, DM, CIHD, COPD, and stroke were the most frequent UCs when IHD was listed as an associated cause of death. The degree of these associations varied between sexes and geographic regions.
The role of extended pelvic lymph node dissection (EPLND) in the surgical management of prostate cancer (PCa) patients remains controversial, mainly because of a lack of randomized controlled trials ...(RCTs).
To determine whether EPLND has better oncological outcomes than limited PLND (LPLND.
This was a prospective, single-center phase 3 trial in patients with intermediate- or high-risk clinically localized PCa.
Randomization (1:1) to LPLND (obturator nodes) or EPLND (obturator, external iliac, internal iliac, common iliac, and presacral nodes) bilaterally.
The primary endpoint was biochemical recurrence–free survival (BRFS). Secondary outcomes were metastasis-free survival (MFS), cancer-specific survival (CSS), and histopathological findings. The trial was designed to show a minimal 15% advantage in 5-yr BRFS by EPLND.
In total, 300 patients were randomized from May 2012 to December 2016 (150 LPLND and 150 EPLND). The median BRFS was 61.4 mo in the LPLND group and not reached in the EPLND group (hazard ratio HR 0.91, 95% confidence interval CI 0.63–1.32; p = 0.6). Median MFS was not reached in either group (HR 0.57, 95% CI 0.17–1.8; p = 0.3). CSS data were not available because no patient died from PCa before the cutoff date. In exploratory subgroup analysis, patients with preoperative biopsy International Society of Urological Pathology (ISUP) grade groups 3–5 who were allocated to EPLND had better BRFS (HR 0.33, 95% CI 0.14–0.74, interaction p = 0.007). The short follow-up and surgeon heterogeneity are limitations to this study.
This RCT confirms that EPLND provides better pathological staging, while differences in early oncological outcomes were not demonstrated. Our subgroup analysis suggests a potential BCRFS benefit in patients diagnosed with ISUP grade groups 3–5; however, these findings should be considered hypothesis-generating and further RCTs with larger cohorts and longer follow up are necessary to better define the role of EPLND during RP.
In this study, we investigated early outcomes in prostate cancer patients undergoing prostatectomy according to the anatomic extent of lymph node resection. We found that extended removal of lymph nodes did not reduce biochemical recurrence of prostate cancer in the expected range.
In this randomized clinical trial that included 300 patients, we were unable to demonstrate an early difference in biochemical recurrence between extended and limited pelvic lymph node dissection among men undergoing radical prostatectomy for intermediate- and high-risk localized prostate cancer.
Prostate cancer is a highly heterogeneous disease, with remarkably different prognosis across all stages. Increased circulating tumor cell (CTC) count (≥ 5) using the CellSearch assay has been ...identified as one of the markers that can be used to predict survival, with added value beyond currently available prognostic factors. Recently, androgen receptor splice variant 7 (AR-V7) detection has been associated with worse outcomes for patients with castration-resistant prostate cancer (CRPC) treated with novel androgen receptor-signaling (ARS) inhibitors such as abiraterone and enzalutamide but not taxane chemotherapies. Areas covered: In this manuscript, the authors review the available biomarkers in CRPC and discuss emerging data on the value of CTC-derived AR-V7 status to assess prognosis and its potential role to guide treatment selection for patients with advanced prostate cancer. Expert commentary: Current evidence supports AR-V7 status as a prognostic biomarker and also as a potential predictive biomarker for patients with mCRPC. The authors expect that the incorporation of AR-V7 status and other biomarkers (e.g. AR mutations) in the sequential assessment of patients with advanced prostate cancer will lead to a more rational use of available and future therapies, with significant improvements in outcomes for our patients.
The chronic unpredictable stress (CUS) paradigm is extensively used in preclinical research. However, CUS exhibits translational inconsistencies, some of them resulting from the use of adult rodents, ...despite the evidence that vulnerability for many psychiatric disorders accumulates during early life. Here, we assessed the validity of the CUS model by including ethologically-relevant paradigms in juvenile rats. Thus, socially-isolated (SI) rats were submitted to CUS and compared with SI (experiment 1) and group-housed controls (experiment 1 and 2). We found that lower body-weight gain and hyperlocomotion, instead of sucrose consumption and preference, were the best parameters to monitor the progression of CUS, which also affected gene expression and neurotransmitter contents associated with that CUS-related phenotype. The behavioural characterisation after CUS placed locomotion and exploratory activity as the best stress predictors. By employing the exploratory factor analysis, we reduced each behavioural paradigm to few latent variables which clustered into two general domains that strongly predicted the CUS condition: (1) hyper-responsivity to novelty and mild threats, and (2) anxiety/depressive-like response. Altogether, the analyses of observable and latent variables indicate that early-life stress impairs the arousal-inhibition system leading to augmented and persistent responses towards novel, rewarding, and mildly-threatening stimuli, accompanied by lower body-weight gain.
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