168 research outputs found
Fish and fisheries in the Sesan River Basin: catchment baseline, fisheries section
The present report was prepared for the Water and Food Challenge Program project āOptimizing the management of a cascade of reservoirs at the catchment levelā (MK3). It constitutes the baseline assessment of fish and fisheries in the Sesan River Basin. The objective of the MK3 project is to contribute knowledge and recommendations so that cascades of reservoirs corresponding to hydropower dams in the Mekong Basin are managed in ways that are more fair and equitable for all water users. This project seeks to understand at the catchment scale the cumulative upstream and downstream consequences of management decisions taken for multiple reservoirs. Revised rules for water storage infrastructure management will in particular take into account fisheries and agricultural potential as well as hydropower ge
Learning curves of minimally invasive donor nephrectomy in a high-volume center: A cohort study of 1895 consecutive living donors
Background
Few studies have investigated the learning curves of minimally invasive donor nephrectomy (MIDN) using the cumulative sum (CUSUM) analysis. In addition, no study has compared the learning curves of the different surgical MIDN techniques in one cohort study using the CUSUM analysis. This study aims to evaluate and compare learning curves for several MIDN using the CUSUM analysis.
Methods
A retrospective review of consecutive donors, who underwent MIDN between 1997 and 2019, was conducted. Three laparoscopic-assisted techniques were applied in our institution and included for analysis: laparoscopic (LDN), hand-assisted retroperitoneoscopic (HARP), and robot-assisted laparoscopic (RADN) donor nephrectomy. The outcomes were compared based on surgeon volume to develop learning curves for the operative time per surgeon.
Results
Out of 1895 MIDN, 1365 (72.0%) were LDN, 427 (22.5%) were HARP, and 103 (5.4%) were RADN. The median operative time and median blood loss were 179 (IQR, 139ā230) minutes and 100 (IQR, 40ā200) mL, respectively. The incidence of major complication was 1.2% with no mortality, and the median hospital stay was three (IQR, 3ā4) days. The CUSUM analysis resulted in learning curves, defined by decreased operative time, of 23 cases in LDN, 45 cases in HARP, and 26 cases in RADN.
Conclusions
Our study shows different learning curves in three MIDN techniques with equal post-operative complications. The LDN and RADN learning curves are shorter than that of the hand-assisted donor nephrectomy. Our observations can be helpful for informing the development of teaching requirements for fellows to be trained in MIDN
Unintentional F doping of the surface of SrTiO3(001) etched in HF acid -- structure and electronic properties
We show that the HF acid etch commonly used to prepare SrTiO3(001) for
heteroepitaxial growth of complex oxides results in a non-negligible level of F
doping within the terminal surface layer of TiO2. Using a combination of x-ray
photoelectron spectroscopy and scanned angle x-ray photoelectron diffraction,
we determine that on average ~13 % of the O anions in the surface layer are
replaced by F, but that F does not occupy O sites in deeper layers. Despite
this perturbation to the surface, the Fermi level remains unpinned, and the
surface-state density, which determines the amount of band bending, is driven
by factors other than F doping. The presence of F at the STO surface is
expected to result in lower electron mobilities at complex oxide
heterojunctions involving STO substrates because of impurity scattering.
Unintentional F doping can be substantially reduced by replacing the HF-etch
step with a boil in deionized water, which in conjunction with an oxygen tube
furnace anneal, leaves the surface flat and TiO2 terminated.Comment: 18 pages, 7 figure
Learning curve of kidney transplantation in a high-volume center: A Cohort study of 1466 consecutive recipients
Background
The purpose of this study was to evaluate surgical outcomes of kidney transplantation (KTX) based on surgeon volume and surgeon experience, and to develop the learning curve model for KTX using the cumulative sum (CUSUM) analysis.
Methods
A retrospective review of 1466 consecutive recipients who underwent KTX between 2010 and 2017 was conducted. In total, 51 surgeons, including certified transplant surgeons, transplant fellows and surgical residents were involved in these procedures using a standardized protocol. Outcomes were compared based on surgeon volume (low [1ā30] versus high [31ā„] volume) and surgeon's type (consultant surgeons, fellows or residents).
Results
Operative time (129 versus 135 min, P
Conclusions
Surgical training in KTX using a standardize protocol can be accomplished with a steep learning curve without compromising perioperative outcomes under the careful selection of surgeons and procedures
Market risk analysis of energy in Vietnam
The purpose of this paper is to evaluate and estimate market risk for the ten major industries in Vietnam. The focus of the empirical analysis is on the energy sector, which has been designated as one of the four key industries, together with services, food, and telecommunications, targeted for economic development by the Vietnam Government through to 2020. The oil and gas industry is a separate energy-related major industry, and it is evaluated separately from energy. The data set is from 2009 to 2017, which is decomposed into two distinct sub-periods after the Global Financial Crisis (GFC), namely the immediate post-GFC (2009ā2011) period and the normal (2012ā2017) period, in order to identify the behavior of market risk for Vietnamās major industries. For the stock market in Vietnam, the website used in this paper provided complete and detailed data for each stock, as classified by industry. Two widely used approaches to measure and analyze risk are used in the empirical analysis, namely Value-at-Risk (VaR) and Conditional Value-at-Risk (CVaR). The empirical findings indicate that Energy and Pharmaceuticals are the least risky industries, whereas oil and gas and securities have the greatest risk. In general, there is strong empirical evidence that the four key industries display relatively low risk. For public policy, the Vietnam Governmentās proactive emphasis on the targeted industries, including energy, to achieve sustainable economic growth and national economic development, seems to be working effectively. This paper presents striking empirical evidence that Vietnamās industries have substantially improved their economic performance over the full sample, moving from relatively higher levels of market risk in the immediate post-GFC period to a lower risk environment in a normal period several years after the end of the calamitous GFC
Maintenance Therapy With Tumor-Treating Fields Plus Temozolomide vs Temozolomide Alone for Glioblastoma: A Randomized Clinical Trial.
IMPORTANCE: Glioblastoma is the most devastating primary malignancy of the central nervous system in adults. Most patients die within 1 to 2 years of diagnosis. Tumor-treating fields (TTFields) are a locoregionally delivered antimitotic treatment that interferes with cell division and organelle assembly.
OBJECTIVE: To evaluate the efficacy and safety of TTFields used in combination with temozolomide maintenance treatment after chemoradiation therapy for patients with glioblastoma.
DESIGN, SETTING, AND PARTICIPANTS: After completion of chemoradiotherapy, patients with glioblastoma were randomized (2:1) to receive maintenance treatment with either TTFields plus temozolomide (nā=ā466) or temozolomide alone (nā=ā229) (median time from diagnosis to randomization, 3.8 months in both groups). The study enrolled 695 of the planned 700 patients between July 2009 and November 2014 at 83 centers in the United States, Canada, Europe, Israel, and South Korea. The trial was terminated based on the results of this planned interim analysis.
INTERVENTIONS: Treatment with TTFields was delivered continuously (>18 hours/day) via 4 transducer arrays placed on the shaved scalp and connected to a portable medical device. Temozolomide (150-200 mg/m2/d) was given for 5 days of each 28-day cycle.
MAIN OUTCOMES AND MEASURES: The primary end point was progression-free survival in the intent-to-treat population (significance threshold of .01) with overall survival in the per-protocol population (nā=ā280) as a powered secondary end point (significance threshold of .006). This prespecified interim analysis was to be conducted on the first 315 patients after at least 18 months of follow-up.
RESULTS: The interim analysis included 210 patients randomized to TTFields plus temozolomide and 105 randomized to temozolomide alone, and was conducted at a median follow-up of 38 months (range, 18-60 months). Median progression-free survival in the intent-to-treat population was 7.1 months (95% CI, 5.9-8.2 months) in the TTFields plus temozolomide group and 4.0 months (95% CI, 3.3-5.2 months) in the temozolomide alone group (hazard ratio [HR], 0.62 [98.7% CI, 0.43-0.89]; Pā=ā.001). Median overall survival in the per-protocol population was 20.5 months (95% CI, 16.7-25.0 months) in the TTFields plus temozolomide group (nā=ā196) and 15.6 months (95% CI, 13.3-19.1 months) in the temozolomide alone group (nā=ā84) (HR, 0.64 [99.4% CI, 0.42-0.98]; Pā=ā.004).
CONCLUSIONS AND RELEVANCE: In this interim analysis of 315 patients with glioblastoma who had completed standard chemoradiation therapy, adding TTFields to maintenance temozolomide chemotherapy significantly prolonged progression-free and overall survival.
TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00916409
Instability, Intermixing and Electronic Structure at the Epitaxial LaAlO3/SrTiO3(001) Heterojunction
The question of stability against diffusional mixing at the prototypical
LaAlO3/SrTiO3(001) interface is explored using a multi-faceted experimental and
theoretical approach. We combine analytical methods with a range of
sensitivities to elemental concentrations and spatial separations to
investigate interfaces grown using on-axis pulsed laser deposition. We also
employ computational modeling based on the density function theory as well as
classical force fields to explore the energetic stability of a wide variety of
intermixed atomic configurations relative to the idealized, atomically abrupt
model. Statistical analysis of the calculated energies for the various
configurations is used to elucidate the relative thermodynamic stability of
intermixed and abrupt configurations. We find that on both experimental and
theoretical fronts, the tendency toward intermixing is very strong. We have
also measured and calculated key electronic properties such as the presence of
electric fields and the value of the valence band discontinuity at the
interface. We find no measurable electric field in either the LaAlO3 or SrTiO3,
and that the valence band offset is near zero, partitioning the band
discontinuity almost entirely to the conduction band edge. Moreover, we find
that it is not possible to account for these electronic properties
theoretically without including extensive intermixing in our physical model of
the interface. The atomic configurations which give the greatest electrostatic
stability are those that eliminate the interface dipole by intermixing, calling
into question the conventional explanation for conductivity at this interface -
electronic reconstruction. Rather, evidence is presented for La indiffusion and
doping of the SrTiO3 below the interface as being the cause of the observed
conductivity
Minimally invasive versus open pancreatoduodenectomy (LEOPARD-2): Study protocol for a randomized controlled trial
Background: Data from observational studies suggest that minimally invasive pancreatoduodenectomy (MIPD) is superior to open pancreatoduodenectomy regarding intraoperative blood loss, postoperative morbidity, and length of hospital stay, without increasing total costs. However, several case-matched studies failed to demonstrate superiority of MIPD, and large registry studies from the USA even suggested increased mortality for MIPDs performed in low-volume (< 10 MIPDs annually) centers. Randomized controlled multicenter trials are lacking but clearly required. We hypothesize that time to functional recovery is shorter after MIPD compared with open pancreatoduodenectomy, even in an enhanced recovery setting. Methods/design: LEOPARD-2 is a randomized controlled, parallel-group, patient-blinded, multicenter, phase 2/3, superiority trial in centers that completed the Dutch Pancreatic Cancer Group LAELAPS-2 training program for laparoscopic pancreatoduodenectomy or LAELAPS-3 training program for robot-assisted pancreatoduodenectomy and have performed ā„ 20 MIPDs. A total of 136 patients with symptomatic benign, premalignant, or malignant disease will be randomly assigned to undergo minimally invasive or open pancreatoduodenectomy in an enhan
PROMISING THE DREAM: changing destination image of London through the effect of website place
Drawing on theories of place identity and social identity, this study aims to fill a gap in place identity studies regarding the effect of a place website on the destination image of customers/visitors/tourists. The research addresses three questions: (1) what are the main impacts of touristsā attitude on place identity and the place website, (2) what are the factors that influence destination image, and (3) what are the main impacts of a favorable destination image? The favorability of a destination image is reflected by the extent to which visitors positively regard that place website. Results reveal the importance of the destination image in enhancing the intention to revisit and recommend. Also, visitorsā satisfaction impacts on their intention to revisit and recommend the place. Significant implications for place managers and researchers are highlighted
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