Current Account And Financial Account: Push Or Finance?

The purpose of this paper is to empirically investigate the causality pattern between current account (CA) with the components in financial account (FA) for the four crisis-affected Asian countries of Indonesia, Korea, the Philippines and Thailand. The sample periods are divided into two non-overlapping sub-periods namely; pre-crisis (1987Q1 – 1996Q4) and post-crisis (1997Q1 –2006Q4). Empirical results clearly suggest that CA Granger causes FA in these countries for the two sampling periods. Observations imply that causality patterns differ for each of the FA components with CA

Plant genetic diversity affects multiple trophic levels and trophic interactions

: Intraspecific genetic diversity is an important component of biodiversity. A substantial body of evidence has demonstrated positive effects of plant genetic diversity on plant performance. However, it has remained unclear whether plant genetic diversity generally increases plant performance by reducing the pressure of plant antagonists across trophic levels for different plant life forms, ecosystems and climatic zones. Here, we analyse 4702 effect sizes reported in 413 studies that consider effects of plant genetic diversity on trophic groups and their interactions. We found that that increasing plant genetic diversity decreased the performance of plant antagonists including invertebrate herbivores, weeds, plant-feeding nematodes and plant diseases, while increasing the performance of plants and natural enemies of herbivores. Structural equation modelling indicated that plant genetic diversity increased plant performance partly by reducing plant antagonist pressure. These results reveal that plant genetic diversity often influences multiple trophic levels in ways that enhance natural pest control in managed ecosystems and consumer control of plants in natural ecosystems for sustainable plant production

Dosimetric superiority of IMRT with jaw tracking technique for whole esophagus and T-shaped field radiotherapy in advanced esophageal cancer.

PURPOSE:For whole esophagus and T-shaped field radiotherapy using intensity modulated radiotherapy (IMRT) technique in advanced esophageal cancer, lower absorbed doses to lung and heart remains a challenge. The aim of this study was to investigate the dosimetric superiority in IMRT plans with jaw tracking technique for whole esophagus radiotherapy. METHODS AND MATERIALS:Thirty-two patients with esophageal cancer were subjected to IMRT treatment plans using Eclipse treatment planning system. For every patient, four different plans were generated with six gantry angles: six large fields IMRT plans with fixed jaw (6F-IMRT), six large fields IMRT plans with jaw tracking technique (6F-IMRT-T), twelve small fields IMRT plans with fixed jaw (12F-IMRT), and twelve small fields IMRT plans with jaw tracking technique (12F-IMRT-T). Dosimetric evaluation was assessed for all plans. RESULTS:For every technique, there were no differences in planning target volume (PTV) coverage and conformity. 6F-IMRT-T plans could significantly reduce lung irradiation with 7.9% (P<0.001) reduction in V5lung and 2.5% (P<0.001) reduction in V20 lung respectively compared to 6F-IMRT plans. 12F-IMRT-T plans resulted in superior plans compared to 12-IMRT plans with a reduction of 2.9% (P<0.001) in V5lung and 0.9% (P<0.001) in V20 lung, respectively. For heart irradiation, 6F-IMRT-T and 12F-IMRT-T plans were slightly superior to 6F-IMRT and 12-IMRT plans respectively with a reduction of 1.1 Gy and 0.5 Gy in the respective mean doses. CONCLUSIONS:By the use of jaw tracking technique, the IMRT plans resulted in further lung and heart sparing compared to fixed jaw plans for radiotherapy in esophageal cancer

Planning Study of Flattening Filter Free Beams for Volumetric Modulated Arc Therapy in Squamous Cell Carcinoma of the Scalp

<div><p>Purpose</p><p>Flattening filter free (FFF) beams show the potential for a higher dose rate and lower peripheral dose. We investigated the planning study of FFF beams with their role for volumetric modulated arc therapy (VMAT) in squamous cell carcinoma of the scalp.</p><p>Methods and Materials</p><p>One patient with squamous cell carcinoma which had involvement of entire scalp was subjected to VMAT using TrueBeam linear accelerator. As it was a rare skin malignancy, CT data of 7 patients with brain tumors were also included in this study, and their entire scalps were outlined as target volumes. Three VMAT plans were employed with RapidArc form: two half-field full-arcs VMAT using 6 MV standard beams (HFF-VMAT-FF), eight half-field quarter-arcs VMAT using 6 MV standard beams (HFQ-VMAT-FF), and HFQ-VMAT using FFF beams (HFQ-VMAT-FFF). Prescribed dose was 25×2 Gy (50 Gy). Plan quality and efficiency were assessed for all plans.</p><p>Results</p><p>There were no statistically significant differences among the three VMAT plans in target volume coverage, conformity, and homogeneity. For HFQ-VMAT-FF plans, there was a significant decrease by 12.6% in the mean dose to the brain compared with HFF-VMAT-FF. By the use of FFF beams, the mean dose to brain in HFQ-VMAT-FFF plans was further decreased by 7.4% compared with HFQ-VMAT-FF. Beam delivery times were similar for each technique.</p><p>Conclusions</p><p>The HFQ-VMAT-FF plans showed the superiority in dose distributions compared with HFF-VMAT-FF. HFQ-VMAT-FFF plans might provide further normal tissue sparing, particularly in the brain, showing their potential for radiation therapy in squamous cell carcinoma of the scalp.</p></div

Robustness of VMAT to setup errors in postmastectomy radiotherapy of left-sided breast cancer: Impact of bolus thickness.

BackgroundVolumetric modulated arc therapy (VMAT) with varied bolus thicknesses has been employed in postmastectomy radiotherapy (PMRT) of breast cancer to improve superficial target coverage. However, impact of bolus thickness on plan robustness remains unclear.MethodsThe study enrolled ten patients with left-sided breast cancer who received radiotherapy using VMAT with 5 mm and 10 mm bolus (VMAT-5B and VMAT-10B). Inter-fractional setup errors were simulated by introducing a 3 mm shift to isocenter of the original plans in the anterior-posterior, left-right, and inferior-superior directions. The plans (perturbed plans) were recalculated without changing other parameters. Dose volume histograms (DVH) were collected for plan evaluation. Absolute dose differences in DVH endpoints for the clinical target volume (CTV), heart, and left lung between the perturbed plans and the original ones were used for robustness analysis.ResultsVMAT-10B showed better target coverage, while VMAT-5B was superior in organs-at-risk (OARs) sparing. As expected, small setup errors of 3 mm could induce dose fluctuations in CTV and OARs. The differences in CTV were small in VMAT-5B, with a maximum difference of -1.05 Gy for the posterior shifts. For VMAT-10B, isocenter shifts in the posterior and right directions significantly decreased CTV coverage. The differences were -1.69 Gy, -1.48 Gy and -1.99 Gy, -1.69 Gy for ΔD95% and ΔD98%, respectively. Regarding the OARs, only isocenter shifts in the posterior, right, and inferior directions increased dose to the left lung and the heart. Differences in VMAT-10B were milder than those in VMAT-5B. Specifically, mean heart dose were increased by 0.42 Gy (range 0.10 ~ 0.95 Gy) and 0.20 Gy (range -0.11 ~ 0.72 Gy), and mean dose for the left lung were increased by 1.02 Gy (range 0.79 ~ 1.18 Gy) and 0.68 Gy (range 0.47 ~ 0.84 Gy) in VMAT-5B and VMAT-10B, respectively. High-dose volumes in the organs were increased by approximate 0 ~ 2 and 1 ~ 3 percentage points, respectively. Nevertheless, most of the dosimetric parameters in the perturbed plans were still clinically acceptable.ConclusionsVMAT-5B appears to be more robust to 3 mm setup errors than VMAT-10B. VMAT-5B also resulted in better OARs sparing with acceptable target coverage and dose homogeneity. Therefore 5 mm bolus is recommended for PMRT of left-sided breast cancer using VMAT

Isodose distributions for one patient with squamous cell carcinoma in axial, coronal, and sagittal planes.

<p>(A) HFF-VMAT-FF: two half-field full-arcs VMAT with conventional flattened (FF) beam; (B) HFQ-VMAT-FF: eight half-field quarter-arcs VMAT with FF beam; (C) HFQ-VMAT-FFF: eight half-field quarter-arcs VMAT with flattening filter free (FFF) beam.</p

Dosimetric parameters of PTV for treatment plans created with different planning techniques.

<p><i>Abbreviations:</i> HFF-VMAT-FF = two half-field full-arcs VMAT with conventional flattened (FF) beam; HFQ-VMAT-FF = eight half-field quarter-arcs VMAT with FF beam; HFQ-VMAT-FFF = eight half-field quarter-arcs VMAT with flattening filter free (FFF) beam; CI = conformity index; HI = homogeneity index.</p><p>* <i>P</i> value corresponds to the paired <i>t</i> test: a = HFF-VMAT-FF vs HFQ-VMAT-FF, b = HFQ-VMAT-FF vs HFQ-VMAT-FFF.</p><p>Dosimetric parameters of PTV for treatment plans created with different planning techniques.</p

The mean doses of organs at risk, MU, beam-on time, and mean dose rate (MDR) for treatment plans created with different planning techniques.

<p><i>Abbreviations:</i> HFF-VMAT-FF = two half-field full-arcs VMAT with conventional flattened (FF) beam; HFQ-VMAT-FF = eight half-field quarter-arcs VMAT with FF beam; HFQ-VMAT-FFF = eight half-field quarter-arcs VMAT with flattening filter free (FFF) beam.</p><p>* Body: it is the region of the CT which was scanned.</p><p>* <i>P</i> value corresponds to the paired <i>t</i> test: a = HFF-VMAT-FF vs HFQ-VMAT-FF, b = HFQ-VMAT-FF vs HFQ-VMAT-FFF.</p><p>The mean doses of organs at risk, MU, beam-on time, and mean dose rate (MDR) for treatment plans created with different planning techniques.</p

Planning Study of Flattening Filter Free Beams for Volumetric Modulated Arc Therapy in Squamous Cell Carcinoma of the Scalp - Figure 1

<p><b>Delineated planning target volume (PTV) for squamous cell carcinoma of the scalp (A), and two different beam setups in VMAT plans:</b> (B) Two 360° arcs were used with half-field beam. (C) Eight half-field quarter-arcs (90°) were used in VMAT plan.</p

Planning Study of Flattening Filter Free Beams for Volumetric Modulated Arc Therapy in Squamous Cell Carcinoma of the Scalp - Figure 4

<p><b>Dose-volume histogram (DVH) comparison for the PTV and brain with different planning techniques:</b> (a) HFF-VMAT-FF: two half-field full-arcs VMAT with conventional flattened (FF) beam; (b) HFQ-VMAT-FF: eight half-field quarter-arcs VMAT with FF beam; (c) HFQ-VMAT-FFF: eight half-field quarter-arcs VMAT with flattening filter free (FFF) beam.</p