319 research outputs found

    Corporate Debt Policy—Pre- and Post-financial Market Reforms: The Case of the Textile Industry of Pakistan

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    The literature provides evidence that the capital structure of a firm is often a combination of several securities; it can arrange (1) Bank loan (2) issue debentures/bonds, (3) issue shares (4) lease financing, or (5) utilise its retained earnings. Eventually number of ideas and theories has been developed to discuss the optimal capital structure. Optimum is the trade-off between the benefit of tax and costs of financial distress; a firm faces due to the borrowed money. Although extensive research work has been done on the capital structure but still it remains one of the unsettled topics in finance. Optimal capital structure has an impact on corporate profits. Debt is considered as the cheapest source of financing due to tax shield, higher the firm’s tax bracket more the debt is advantageous to a firm. The trade off theory states that higher debt is associated with higher profitability. Three reasons support this theory; one debt allow tax shield. Second, more trust is built on profitable companies considering more sustainable and less prone to bankruptcy; hence high profitable companies are able to seek more debt. Third, agency cost, for the profitable firms, lenders/creditors give relaxation in monitoring charges, which reduces the debt cost. This motivates profitable firms to go for more debt

    Assessment approach of production models to commercial pelagic catch and effort data of Indian mackerel (Rastrelliger kanagurta, Cuvier, 1816) in the Arabian Sea

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    Globally, Reference Points (RPs) indicators are usually lifted in the science of fisheries management for the alternative running objectives and tracking the condition of fisheries. The Fox Model (FM) and Logistic Model (LM) in A Stock Production Model Incorporates Covariates (ASPIC) estimated F = 0.062 – 0.132 and F = 0.059 – 0.126 from 2003 to 2018 with F/FMSY showing an increased inclination from 0.628 to 1.346 and 1.027 to 2.179, respectively. Estimated Starting Biomass (B) = 520800 – 263100 MT and B = 541000 – 277000 MT from population trajectory (Non-bootstrapped) sharply decreased to the ratio of biomass to BMSY (B/BMSY) 2.810 – 1.420 and 2.075 – 1.063, respectively. Furthermore, the uncertainties reported in Maximum Sustainable Yield (MSY) (18210 – 15050 MT), FMSY (0.098 – 0.058) and BMSY (185300 – 260700 MT) from FM and LM was also estimated in ASPIC using 0.8 Initial Proportion (IP) of starting Maximum Catch (MC) that was 80 %. According to Target Reference Points (TRPs), CEDA and ASPIC (11000 – 18000 MT and 15000 – 18000 MT) range also indicate overexploitation of the Indian mackerel in the Arabian Sea of Pakistan. Estimated Predicted Yield (PY) of 28841 MT in 2003 and even Recent Catch (RC) of 19421 MT in 2018 is far away from harvested yield values of 31126 and 33658 MT and even MC of 38504 MT, pinpointing this research in a questionable and overexploitation state. Ideally, Fishing Effort (FE) should be reduced at the level of PY which is approximately 12000 fishing vessels (19421 MT) against the current engaged FE of about 19000 fishing vessels (33658 MT) in 2018 for the Indian mackerel fishery in Pakistan. In order to prevent this huge economic loss and to reduce the efforts of fisheries, it is suggested that strict and immediate measures should be followed by the policy makers and law enforcement organizations against the mesh size and illegal nets for this type of commercially important fishery

    Biopsy confirmation of metastatic sites in breast cancer patients:clinical impact and future perspectives

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    Determination of hormone receptor (estrogen receptor and progesterone receptor) and human epidermal growth factor receptor 2 status in the primary tumor is clinically relevant to define breast cancer subtypes, clinical outcome,and the choice of therapy. Retrospective and prospective studies suggest that there is substantial discordance in receptor status between primary and recurrent breast cancer. Despite this evidence and current recommendations,the acquisition of tissue from metastatic deposits is not routine practice. As a consequence, therapeutic decisions for treatment in the metastatic setting are based on the features of the primary tumor. Reasons for this attitude include the invasiveness of the procedure and the unreliable outcome of biopsy, in particular for biopsies of lesions at complex visceral sites. Improvements in interventional radiology techniques mean that most metastatic sites are now accessible by minimally invasive methods, including surgery. In our opinion, since biopsies are diagnostic and changes in biological features between the primary and secondary tumors can occur, the routine biopsy of metastatic disease needs to be performed. In this review, we discuss the rationale for biopsy of suspected breast cancer metastases, review issues and caveats surrounding discordance of biomarker status between primary and metastatic tumors, and provide insights for deciding when to perform biopsy of suspected metastases and which one (s) to biopsy. We also speculate on the future translational implications for biopsy of suspected metastatic lesions in the context of clinical trials and the establishment of bio-banks of biopsy material taken from metastatic sites. We believe that such bio-banks will be important for exploring mechanisms of metastasis. In the future,advances in targeted therapy will depend on the availability of metastatic tissue

    Autism as a disorder of neural information processing: directions for research and targets for therapy

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    The broad variation in phenotypes and severities within autism spectrum disorders suggests the involvement of multiple predisposing factors, interacting in complex ways with normal developmental courses and gradients. Identification of these factors, and the common developmental path into which theyfeed, is hampered bythe large degrees of convergence from causal factors to altered brain development, and divergence from abnormal brain development into altered cognition and behaviour. Genetic, neurochemical, neuroimaging and behavioural findings on autism, as well as studies of normal development and of genetic syndromes that share symptoms with autism, offer hypotheses as to the nature of causal factors and their possible effects on the structure and dynamics of neural systems. Such alterations in neural properties may in turn perturb activity-dependent development, giving rise to a complex behavioural syndrome many steps removed from the root causes. Animal models based on genetic, neurochemical, neurophysiological, and behavioural manipulations offer the possibility of exploring these developmental processes in detail, as do human studies addressing endophenotypes beyond the diagnosis itself

    The Role of T cell PPAR γ in mice with experimental inflammatory bowel disease

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    <p>Abstract</p> <p>Background</p> <p>Peroxisome proliferator-activated receptor γ (PPAR γ) is a nuclear receptor whose activation has been shown to modulate macrophage and T cell-mediated inflammation. The objective of this study was to investigate the mechanisms by which the deletion of PPAR γ in T cells modulates immune cell distribution and colonic gene expression and the severity of experimental IBD.</p> <p>Methods</p> <p>PPAR γ flfl; CD4 Cre<sup>+ </sup>(CD4cre) or Cre- (WT) mice were challenged with 2.5% dextran sodium sulfate in their drinking water for 0, 2, or 7 days. Mice were scored on disease severity both clinically and histopathologically. Flow cytometry was used to assess lymphocyte and macrophage populations in the blood, spleen, and mesenteric lymph nodes (MLN). Global gene expression in colonic mucosa was profiled using Affymetrix microarrays.</p> <p>Results</p> <p>The deficiency of PPAR γ in T cells accelerated the onset of disease and body weight loss. Examination of colon histopathology revealed significantly greater epithelial erosion, leukocyte infiltration, and mucosal thickening in the CD4cre mice on day 7. CD4cre mice had more CD8<sup>+ </sup>T cells than WT mice and fewer CD4<sup>+</sup>FoxP3<sup>+ </sup>regulatory T cells (Treg) and IL10<sup>+</sup>CD4<sup>+ </sup>T cells in blood and MLN, respectively. Transcriptomic profiling revealed around 3000 genes being transcriptionally altered as a result of DSS challenge in CD4cre mice. These included up-regulated mRNA expression of adhesion molecules, proinflammatory cytokines interleukin-6 (IL-6) and IL-1β, and suppressor of cytokine signaling 3 (SOCS-3) on day 7. Gene set enrichment analysis (GSEA) showed that the ribosome and Krebs cycle pathways were downregulated while the apoptosis pathway was upregulated in colons of mice lacking PPAR γ in T cells.</p> <p>Conclusions</p> <p>The expression of PPAR γ in T cells is involved in preventing gut inflammation by regulating colonic expression of adhesion molecules and inflammatory mediators at later stages of disease while favoring the recruitment of Treg to the mucosal inductive sites.</p

    Multi-Level Interactions between the Nuclear Receptor TRα1 and the WNT Effectors β-Catenin/Tcf4 in the Intestinal Epithelium

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    Intestinal homeostasis results from complex cross-regulation of signaling pathways; their alteration induces intestinal tumorigenesis. Previously, we found that the thyroid hormone nuclear receptor TRα1 activates and synergizes with the WNT pathway, inducing crypt cell proliferation and promoting tumorigenesis. Here, we investigated the mechanisms and implications of the cross-regulation between these two pathways in gut tumorigenesis in vivo and in vitro. We analyzed TRα1 and WNT target gene expression in healthy mucosae and tumors from mice overexpressing TRα1 in the intestinal epithelium in a WNT-activated genetic background (vil-TRα1/Apc mice). Interestingly, increased levels of β-catenin/Tcf4 complex in tumors from vil-TRα1/Apc mice blocked TRα1 transcriptional activity. This observation was confirmed in Caco2 cells, in which TRα1 functionality on a luciferase reporter-assay was reduced by the overexpression of β-catenin/Tcf4. Moreover, TRα1 physically interacted with β-catenin/Tcf4 in the nuclei of these cells. Using molecular approaches, we demonstrated that the binding of TRα1 to its DNA target sequences within the tumors was impaired, while it was newly recruited to WNT target genes. In conclusion, our observations strongly suggest that increased β-catenin/Tcf4 levels i) correlated with reduced TRα1 transcriptional activity on its target genes and, ii) were likely responsible for the shift of TRα1 binding on WNT targets. Together, these data suggest a novel mechanism for the tumor-promoting activity of the TRα1 nuclear receptor

    Speed/Accuracy Trade-Off between the Habitual and the Goal-Directed Processes

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    Instrumental responses are hypothesized to be of two kinds: habitual and goal-directed, mediated by the sensorimotor and the associative cortico-basal ganglia circuits, respectively. The existence of the two heterogeneous associative learning mechanisms can be hypothesized to arise from the comparative advantages that they have at different stages of learning. In this paper, we assume that the goal-directed system is behaviourally flexible, but slow in choice selection. The habitual system, in contrast, is fast in responding, but inflexible in adapting its behavioural strategy to new conditions. Based on these assumptions and using the computational theory of reinforcement learning, we propose a normative model for arbitration between the two processes that makes an approximately optimal balance between search-time and accuracy in decision making. Behaviourally, the model can explain experimental evidence on behavioural sensitivity to outcome at the early stages of learning, but insensitivity at the later stages. It also explains that when two choices with equal incentive values are available concurrently, the behaviour remains outcome-sensitive, even after extensive training. Moreover, the model can explain choice reaction time variations during the course of learning, as well as the experimental observation that as the number of choices increases, the reaction time also increases. Neurobiologically, by assuming that phasic and tonic activities of midbrain dopamine neurons carry the reward prediction error and the average reward signals used by the model, respectively, the model predicts that whereas phasic dopamine indirectly affects behaviour through reinforcing stimulus-response associations, tonic dopamine can directly affect behaviour through manipulating the competition between the habitual and the goal-directed systems and thus, affect reaction time

    The androgen receptor can signal through Wnt/β-Catenin in prostate cancer cells as an adaptation mechanism to castration levels of androgens

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    <p>Abstract</p> <p>Background</p> <p>A crucial event in Prostate Cancer progression is the conversion from a hormone-sensitive to a hormone-refractory disease state. Correlating with this transition, androgen receptor (AR) amplification and mutations are often observed in patients failing hormonal ablation therapies. β-Catenin, an essential component of the canonical Wnt signaling pathway, was shown to be a coactivator of the AR signaling in the presence of androgens. However, it is not yet clear what effect the increased levels of the AR could have on the Wnt signaling pathway in these hormone-refractory prostate cells.</p> <p>Results</p> <p>Transient transfections of several human prostate cancer cell lines with the AR and multiple components of the Wnt signaling pathway demonstrate that the AR overexpression can potentiate the transcriptional activities of Wnt/β-Catenin signaling. In addition, the simultaneous activation of the Wnt signaling pathway and overexpression of the AR promote prostate cancer cell growth and transformation at castration levels of androgens. Interestingly, the presence of physiological levels of androgen or other AR agonists inhibits these effects. These observations are consistent with the nuclear co-localization of the AR and β-Catenin shown by immunohistochemistry in human prostate cancer samples. Furthermore, chromatin immunoprecipitation assays showed that Wnt3A can recruit the AR to the promoter regions of Myc and Cyclin D1, which are well-characterized downstream targets of the Wnt signalling pathway. The same assays demonstrated that the AR and β-Catenin can be recruited to the promoter and enhancer regions of a known AR target gene PSA upon Wnt signaling. These results suggest that the AR is promoting Wnt signaling at the chromatin level.</p> <p>Conclusion</p> <p>Our findings suggest that the AR signaling through the Wnt/β-Catenin pathway should be added to the well established functional interactions between both pathways. Moreover, our data show that via this interaction the AR could promote prostate cell malignancy in a ligand-independent manner.</p
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