37 research outputs found
Natural Disasters, Investor Attention, and Non-Fundamental Green Asset Demand
This study examines how the occurrence of natural disasters in the U.S. influences investor interest in green assets and actual investments, focusing on inflows into green ETFs as a proxy for non-fundamental demand. Event study analyses demonstrate both increases in investor interest in eco-friendly investments (proxied by Google searches) and inflows into green ETFs following disasters, driven by the period following the 2015 Paris Agreement. The additional inflows average about USD 4.3 million in the week directly following disasters, compared to average inflows of around USD 1.1 million in the non-disaster reference window. Importantly, both effects disappear when other attention-grabbing events, such as terrorist attacks or mass shootings, occur simultaneously with disasters. Analysis of climate change coverage across U.S. media suggests that media attention devoted to climate change concerns drives the documented shifts in investor behavior towards green investments. Furthermore, analysis of flows in brown ETFs (e.g., the oil and gas sector) reveals analogous disinvestments in the wake of disasters, but notably, only in the absence of concurrent distracting events
Psychological Responses Prior to a Strenuous Task Involving an Injured Joint
Injuries are an inherent risk of sport participation. Roughly 68% of athletes experience an athletic injury during their college career, with over half being injuries to the lower extremity (Hootman, Dick & Agel, 2007). While much attention has been given to the physical effects of an injury, the psychological ramifications can also affect an athlete’s recovery from injury. According to Quinn & Fallon (2008), an athlete can physically recover from an injury however they may not attain a complete psychological recovery. An athlete’s performance can be affected negatively if they return to sport participation without recovering psychologically from their injury, which can also lead to a risk of re-injury or receiving additional injuries (Quinn & Fallon, 2008). Two variables related to psychological recovery include re-establishment of confidence and a decrease in fear of re-injury (Magyar & Duda, 2000; Walker & Heaney, 2013). Additionally, an athlete may feel reluctance to perform skills that require the site of injury to be used which affects subsequent performance. An athlete’s fear of re-injury can negatively affect athletes’ performance by undermining an athlete’s confidence in obtaining their pre-injury sport performance (Arden, Taylor, Feller & Webster, 2012). The purpose of this study was to determine how psychological responses to injury, namely sport resumption confidence, fear of re-injury, and injury perception change throughout the rehabilitation process. These variables were examined in relation to performing a strenuous isokinetic dynamometer task on an injured joint (e.g., knee, ankle). Participants (N=21; 62% female) completed psychometrically sound measures designed to assess confidence, fear and injury perception across three groups of athletes: healthy (n = 9), injured (n = 6), and rehabilitated (n = 6). All subjects were told they would be completing a maximal isokinetic contraction task on the lower extremity that had been injured before completing the survey. Only healthy and rehabilitated athletes actually performed the task at the completion of the survey. ANOVA was utilized to compare group differences on study variables. There was a significant difference between groups with regard to fear (healthy=1.62 ± 0.03; injured=4.09 ± 0.10; rehabilitated=3.17 ± 0.61; p \u3c .05) and confidence (healthy=5.82 ± 0.68; injured=2.99 ± 0.06; rehabilitated=4.06 ± 0.58; p \u3c .01) where healthy athletes reported the highest confidence and lowest fear across groups. Additionally, injured athletes reported the lowest confidence and highest fear across groups. There were no group differences found with regard to injury perception (healthy=0.00 ± 0.00; injured=1.01 ± 0.41; rehabilitated=0.07 ± 0.09). This study extends the current sport injury research base by identifying changes in key psychological variables across the healthy-injured-rehabilitated continuum of the collegiate sport experience
Perthes Syndrome associated with intramedullary spinal cord hemorrhage in a 4-year-old child: a case report
Comparative evaluation of diode laser versus argon laser photocoagulation in patients with central serous retinopathy: A pilot, randomized controlled trial [ISRCTN84128484]
BACKGROUND: To evaluate the efficacy of diode laser photocoagulation in patients with central serous retinopathy (CSR) and to compare it with the effects of argon green laser. METHODS: Thirty patients with type 1 unilateral CSR were enrolled and evaluated on parameters like best corrected visual acuity (BCVA), direct and indirect ophthalmoscopy, amsler grid for recording scotoma and metamorphopsia, contrast sensitivity using Cambridge low contrast gratings and fluorescein angiography to determine the site of leakage. Patients were randomly assigned into 2 groups according to the statistical random table using sequence generation. In Group 1 (n = 15), diode laser (810 nm) photocoagulation was performed at the site of leakage while in Group 2 (n = 15), eyes were treated with argon green laser (514 nm) using the same laser parameters. Patients were followed up at 4, 8 and 12 weeks after laser. RESULTS: The mean BCVA in group 1 improved from a pre-laser decimal value of 0.29 ± 0.14 to 0.84 ± 0.23 at 4 weeks and 1.06 ± 0.09 at 12 weeks following laser. In group 2, the same improved from 0.32 ± 0.16 to 0.67 ± 0.18 at 4 weeks and 0.98 ± 0.14 at 12 weeks following laser. The improvement in BCVA was significantly better in group 1 (p < 0.0001) at 4 weeks. At 4 weeks following laser, all the patients in group1 were free of scotoma while 6 patients in group 2 had residual scotoma (p < 0.05). The mean contrast sensitivity in group 1 improved from pre-laser value of 98.4 ± 24.77 to 231.33 ± 48.97 at 4 weeks and 306.00 ± 46.57 at 12 weeks following laser. In group 2, the same improved from 130.66 ± 31.95 to 190.66 ± 23.44 at 4 weeks and 215.33 ± 23.25 at 12 weeks. On comparative evaluation, a significantly better (p < 0.001) improvement was noted in group 1. CONCLUSION: Diode laser may be a better alternative to argon green laser whenever laser treatment becomes indicated in patients with central serous retinopathy in terms of faster visual rehabilitation and better contrast sensitivity. In addition, diode laser also has the well-recognized ergonomic and economic advantages
Effects of Long Acting Methylphenidate on Ghrelin Levels in Male Children with Attention Deficit Hyperactivity Disorder: An Open Label Trial
Optimization Based Evaluation of Grating Interferometric Phase Stepping Series and Analysis of Mechanical Setup Instabilities
The diffraction contrast modalities accessible by X-ray grating interferometers are not imaged directly but have to be inferred from sine-like signal variations occurring in a series of images acquired at varying relative positions of the interferometer’s gratings. The absolute spatial translations involved in the acquisition of these phase stepping series usually lie in the range of only a few hundred nanometers, wherefore positioning errors as small as 10 nm will already translate into signal uncertainties of 1–10% in the final images if not accounted for. Classically, the relative grating positions in the phase stepping series are considered input parameters to the analysis and are, for the Fast Fourier Transform that is typically employed, required to be equidistantly distributed over multiples of the gratings’ period. In the following, a fast converging optimization scheme is presented simultaneously determining the phase stepping curves’ parameters as well as the actually performed motions of the stepped grating, including also erroneous rotational motions which are commonly neglected. While the correction of solely the translational errors along the stepping direction is found to be sufficient with regard to the reduction of image artifacts, the possibility to also detect minute rotations about all axes proves to be a valuable tool for system calibration and monitoring. The simplicity of the provided algorithm, in particular when only considering translational errors, makes it well suitable as a standard evaluation procedure also for large image series
Using measurements of the spatial SNR to optimize phase contrast X-ray imaging
X-ray phase contrast imaging is a measurement task which is challenging to optimize, because many physical effects determine signal and noise. If we describe the detail visibility by the spatial signal to noise ratio, SNR(u), we can optimize an imaging setup by maximizing its SNR(u). We propose a measurement method for the spatial SNR which is suitable for this purpose. It consists of measuring a series of images from which the spatial SNR is calculated. This allows a convenient and exact optimization of the SNR that does not rely on theoretical simplifications and is not specific to X-ray imaging. We demonstrate the measurement method for the example of choosing the optimal geometrical magnification for cone-beam inline X-ray phase contrast. Additionally, we propose the use of a known signal reconstruction method - the Wiener Deconvolution - to improve the detail visibility by post-processing images within the limits given by the measured SNR(u). As the SNR(u) give s the degree of this improvement, we derive a measure for the effective spatial resolution from the SNR(u)
Hybrid setup for micro- and nano-computed tomography in the hard X-ray range
With increasing miniaturization in industry and medical technology, non-destructive testing techniques are an area of ever-increasing importance. In this framework, X-ray microscopy offers an efficient tool for the analysis, understanding, and quality assurance of microscopic samples, in particular as it allows reconstructing three-dimensional data sets of the whole sample’s volume via computed tomography (CT). The following article describes a compact X-ray microscope in the hard X-ray regime around 9 keV, based on a highly brilliant liquid-metal-jet source. In comparison to commercially available instruments, it is a hybrid that works in two different modes. The first one is a micro-CT mode without optics, which uses a high-resolution detector to allow scans of samples in the millimeter range with a resolution of 1 μm. The second mode is a microscope, which contains an X-ray optical element to magnify the sample and allows resolving 150 nm features. Changing between the modes is possible without moving the sample. Thus, the instrument represents an important step towards establishing high-resolution laboratory-based multi-mode X-ray microscopy as a standard investigation method
Laboratory source based full-field x-ray microscopy at 9 keV
In the past decade, hard x-ray transmission microscopy experienced tremendous developments. With the availability of efficient Fresnel zone plates, even set-ups utilizing laboratory sources were developed [1]. In order to improve the performance of these x-ray microscopes, novel approaches to fabricate optical elements [2] and brighter x-ray tubes [3] are promising candidates. We are currently building a laboratory transmission x-ray microscope for 9.25 keV, using an electron impact liquid-metal-jet anode source. Up to now, the further elements of our setup are: a polycapillary condenser, a tungsten zone plate, and a scintillator which is optically coupled to a CMOS camera. However, further variations in terms of optical elements are intended. Here we present the current status of our work, as well as first experimental results