In this paper we consider a fixed-effects stochastic frontier model. That is, we have panel data, fixed individual (firm) effects, and the usual stochastic frontier analysis (SFA) composed error.
...Maximum likelihood estimation (MLE) of this model has been considered by Greene (2005a,b). It is subject to the “incidental parameters problem”, that is, to possible inconsistency due to the number of parameters growing with the number of firms. In the linear regression model with normal errors, it is known that the MLE of the regression coefficients is consistent, and the inconsistency due to the incidental parameters problem applies only to the error variance. Greene’s simulations suggest that the same is true in the fixed effects SFA model.
In this paper we take a somewhat different approach. We consider MLE based only on the joint density of the deviations from means. In the linear regression model with normal errors, this estimator is the same as the full MLE for the regression coefficients, but it yields a consistent estimator of the error variance. For the SFA model, the MLE based on the deviations from means is not the same as the full MLE, and it has the advantage of not being subject to the incidental parameters problem.
The derivation of the joint density of the deviations from means is made possible by results in the statistical literature on the closed skew normal family of distributions. These results may be of independent interest to researchers in this area.
Simulations indicate that our within MLE estimator performs quite well in finite samples.
We also present an empirical example.
Lung cancer in East Asia is characterized by a high percentage of never-smokers, early onset and predominant EGFR mutations. To illuminate the molecular phenotype of this demographically distinct ...disease, we performed a deep comprehensive proteogenomic study on a prospectively collected cohort in Taiwan, representing early stage, predominantly female, non-smoking lung adenocarcinoma. Integrated genomic, proteomic, and phosphoproteomic analysis delineated the demographically distinct molecular attributes and hallmarks of tumor progression. Mutational signature analysis revealed age- and gender-related mutagenesis mechanisms, characterized by high prevalence of APOBEC mutational signature in younger females and over-representation of environmental carcinogen-like mutational signatures in older females. A proteomics-informed classification distinguished the clinical characteristics of early stage patients with EGFR mutations. Furthermore, integrated protein network analysis revealed the cellular remodeling underpinning clinical trajectories and nominated candidate biomarkers for patient stratification and therapeutic intervention. This multi-omic molecular architecture may help develop strategies for management of early stage never-smoker lung adenocarcinoma.
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•First deep proteogenomic landscape of non-smoking lung adenocarcinoma in East Asia•Identified age, sex-related endogenous, and environmental carcinogen mutagenic processes•Proteome-informed classification distinguished clinical features within early stages•Protein networks identified tumorigenesis hallmarks, biomarkers, and druggable targets
Deep proteogenomic landscape of early stage lung adenocarcinoma in a cohort of mostly non-smokers reveals unique drivers and biomarkers, as well as gender-associated mutagenesis.
Traditional panel stochastic frontier models do not distinguish between unobserved individual heterogeneity and inefficiency. They thus force all time-invariant individual heterogeneity into the ...estimated inefficiency.
Greene (2005) proposes a true fixed-effect stochastic frontier model which, in theory, may be biased by the incidental parameters problem. The problem usually cannot be dealt with by model transformations owing to the nonlinearity of the stochastic frontier model. In this paper, we propose a class of panel stochastic frontier models which create an exception. We show that first-difference and within-transformation can be analytically performed on this model to remove the fixed individual effects, and thus the estimator is immune to the incidental parameters problem. Consistency of the estimator is obtained by either
N
→
∞
or
T
→
∞
, which is an attractive property for empirical researchers.
Background
Basal cell carcinoma (BCC), the most common skin cancer in humans, requires early detection. Dermoscopy enhances diagnostic accuracy through a noninvasive approach. Pigmented BCC (pBCC) is ...characterized by distinctive dermoscopic features, including the presence of pigmented globules or nests. While dermoscopic features of large pBCC (size >6 mm) have been extensively studied, limited data are available on small pBCC (size ≤6 mm) and its relationship with tumor progression.
Methods
Dermoscopic images of histologically proven pBCCs were collected between 2014 and 2022 at Hualien Tzu Chi Hospital. Each image was analyzed for patterns of pigmentation, vasculature, and epidermal and dermal structures. Statistical analysis was performed to compare the differences according to the size and the trend during tumor progression.
Results
In total, 135 pBCCs (48 small and 87 large) were included. Pigment structures were present in all cases. Short fine telangiectasia and small erosions constituted over 85% of the cases, showing no significant distinction between small and large pBCCs, nor any specific pattern correlating with tumor enlargement. The number of arborizing vessels, ulcerations, and shiny white structures showed an increasing trend associated with size progression. Arborizing vessels appeared when tumor size exceeded 6 mm.
Conclusions
This study provides a dynamic interpretation of the dermoscopic features of pBCC according to size enlargement. Short fine telangiectasia and small erosions are highly important features for the early diagnosis of small pBCCs. Arborizing vessels, ulceration, and shiny white structures are more frequent in large pBCCs, and they increase in association with tumor progression.
This study aimed to evaluate the risk of ischemic stroke (IS) in hormone therapy (HT) with oral conjugated equine estrogen (CEE) and estradiol (E2) in postmenopausal women in Taiwan. A retrospective ...cohort study was conducted using the Taiwan National Health Insurance Research Database, a population-based healthcare claims dataset. Eligible women, aged 40-65 years, who received HT with E2 and CEE orally were enrolled. The primary outcome was IS. Propensity score matching with menopausal age and comorbidities was used. Cox proportional hazard regression models were used to calculate the incidence and hazard ratios (HRs) for IS. The mean menopausal ages of the E2 and CEE groups were 50.31 ± 4.99 and 50.45 ± 5.31 years, respectively. After adjusting for age and comorbidities, the incidence of IS was 1.17-fold higher in the women treated with CEE than in those treated with E2 (4.24 vs. 3.61/1000 person-years), with an adjusted HR (aHR) of 1.23 (95% confidence interval CI 1.05-1.44). Moreover, HT with CEE initiated within 5 years of menopause had a higher HR than E2 (aHR = 1.20; 95% CI 1.02-1.42). In conclusion, HT with oral CEE might be associated with a higher risk of IS than E2 in postmenopausal Taiwanese women. The use of HT with CEE should be cautioned with the risk of IS.
This study investigated the oncological and functional outcomes of robot-assisted radical prostatectomy (RaRP) in high-risk and very high-risk prostate cancer patients.
One hundred localized prostate ...cancer patients receiving RaRP from August 2015 to December 2020 were retrospectively enrolled. According to NCCN risk classification, patients were classified into two groups, below high-risk group, and high-risk/very high-risk group, to analyze continence outcome within postoperative year one and biochemical recurrence-free survival.
The mean age of the cohort was 69.7 ± 7.4 years with a median follow-up of 26.4 (range 3.3-71.3) months. Among them, 53%, and 47% patients were below high-risk group, and high-risk/very high-risk group, respectively. The median biochemical recurrence-free survival of the entire cohort was 53.1 months. The high-risk/very high-risk group without adjuvant treatment had significantly worse biochemical recurrence-free survival than the high-risk/very high-risk group with adjuvant treatment (19.6 vs. 60.5 months, p = 0.029). Rates of postoperative stress urinary incontinence at 1 week, 1 month, and 12 months were 50.7%, 43.7%, and 8.5%, respectively. High-risk/very high-risk patients had significantly higher rates of stress urinary incontinence at postoperative week 1 (75.8% vs. 28.9%) and month 1 (63.6% vs. 26.3%) than the below high-risk group (both p < 0.01). Rates of stress urinary incontinence after RaRP did not differ between two groups from postoperative 3 months to 12 months. The factor of high-risk / very high-risk group was a predictor of immediate but not for long-term postoperative stress urinary incontinence.
High-risk and very high-risk prostate cancer patients receiving a combination of RaRP and adjuvant treatment had comparable biochemical recurrence-free survival to below high-risk prostate cancer patients. The high-risk/very high-risk factor impeded early but not long-term postoperative recovery of continence. RaRP can be considered a safe and feasible option for high-risk and very high-risk prostate cancer patients.
Myopic anisometropia (anisomyopia) is a specific type of refractive error that may cause fusion impairment, asthenopia, and aniseikonia. It is sometimes severe enough to reduce the quality of life. ...Several studies have investigated the treatment effects of orthokeratology (Ortho-K) and topical atropine on anisomyopia control. However, no study has compared these two interventions simultaneously until now. The cohort of this retrospective study included 124 children with anisomyopia who were treated with binocular Ortho-K lenses, 0.01% atropine, or 0.05% atropine. After a 2-year follow-up, the inter-eye difference in axial length (AL) significantly decreased in the Ortho-K group (P = 0.015) and remained stable in the two atropine groups. When comparing the myopia control effect, the use of Ortho-K lenses resulted in an obviously smaller change in AL than the use of 0.01% and 0.05% atropine (P < 0.01). Ortho-K treatment may reduce the degree of anisomyopia and stabilise the progression of myopia. Hence, Ortho-K might be a better choice for anisomyopic children.
Several studies reported the efficacy of orthokeratology for myopia control. Somehow, there is limited publication with follow-up longer than 3 years. This study aims to research whether overnight ...orthokeratology influences the progression rate of the manifest refractive error of myopic children in a longer follow-up period (up to 12 years). And if changes in progression rate are found, to investigate the relationship between refractive changes and different baseline factors, including refraction error, wearing age and lens replacement frequency. In addition, this study collects long-term safety profile of overnight orthokeratology.
This is a retrospective study of sixty-six school-age children who received overnight orthokeratology correction between January 1998 and December 2013. Thirty-six subjects whose baseline age and refractive error matched with those in the orthokeratology group were selected to form control group. These subjects were followed up at least for 12 months. Manifest refractions, cycloplegic refractions, uncorrected and best-corrected visual acuities, power vector of astigmatism, corneal curvature, and lens replacement frequency were obtained for analysis.
Data of 203 eyes were derived from 66 orthokeratology subjects (31 males and 35 females) and 36 control subjects (22 males and 14 females) enrolled in this study. Their wearing ages ranged from 7 years to 16 years (mean ± SE, 11.72 ± 0.18 years). The follow-up time ranged from 1 year to 13 years (mean ± SE, 6.32 ± 0.15 years). At baseline, their myopia ranged from -0.5 D to -8.0 D (mean ± SE, -3.70 ± 0.12 D), and astigmatism ranged from 0 D to -3.0 D (mean ± SE, -0.55 ± 0.05 D). Comparing with control group, orthokeratology group had a significantly (p < 0.001) lower trend of refractive error change during the follow-up periods. According to the analysis results of GEE model, greater power of astigmatism was found to be associated with increased change of refractive error during follow-up years.
Overnight orthokeratology was effective in slowing myopia progression over a twelve-year follow-up period and demonstrated a clinically acceptable safety profile. Initial higher astigmatism power was found to be associated with increased change of refractive error during follow-up years.
Denosumab and zoledronic acid are both effective and easily administrable injectable anti‐osteoporotic medications for postmenopausal women. This study investigated the treatment efficacy of these ...agents in older male patients with low a bone mass and history of fragility fracture. A cohort of 175 male patients receiving continuous zoledronic acid treatment and a cohort of 366 male patients receiving continuous denosumab treatment at our medical center between 2015 and 2020 were included, and we analyzed the efficacy of treatment by the improvement in bone mineral density (BMD) and the new‐onset low‐energy fracture rate after 5 years of continuous medication. BMD significantly improved after 5 years of medication, and >90% of patients were satisfied with their treatment medication. BMD improved more with denosumab than with zoledronic acid, especially in patients with T‐scores higher than −2.5. Smoking, alcohol abuse, diabetes, and inflammatory polyarthritis were associated with poor improvements in BMD. The incidence rate of new fragile fracture was 4.4% and old age was significantly associated with the incidence rate of new fracture. In summary, our study revealed that denosumab and zoledronic acid both significantly increased BMD among older male patients with high fragility fracture rates over a 5‐year follow‐up period. Early medical treatment and lifestyle adjustment were crucial for improving quality of life.
A shock wave, which carries energy and can propagate through a medium, is a type of continuous transmitted sonic wave with a frequency of 16 Hz–20 MHz. It is accompanied by processes involving rapid ...energy transformations. The energy associated with shock waves has been harnessed and used for various applications in medical science. High‐energy extracorporeal shock wave therapy is the most successful application of shock waves, and has been used to disintegrate urolithiasis for 30 years. At lower energy levels, however, shock waves have enhanced expression of vascular endothelial growth factor, endothelial nitric oxide synthase, proliferating cell nuclear antigen, chemoattractant factors and recruitment of progenitor cells; shock waves have also improved tissue regeneration. Low‐energy shock wave therapy has been used clinically with musculoskeletal disorders, ischemic cardiovascular disorders and erectile dysfunction, through the mechanisms of neovascularization, anti‐inflammation and tissue regeneration. Furthermore, low‐energy shock waves have been proposed to temporarily increase tissue permeability and facilitate intravesical drug delivery. The present review article provides information on the basics of shock wave physics, mechanisms of action on the biological system and potential applications in functional urology.
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