3,187 research outputs found
The Einstein-Hilbert action of the space of holomorphic maps from S^2 to CP^k
Let be the space of degree holomorphic
maps from a compact Riemann surface to . In the case
and , the metric on was
computed exactly by Speight. In this paper, the Ricci curvature tensor and the
scalar curvature on are determined explicitly for
. An exact direct computation of the Einstein-Hilbert action with
respect to the metric on is made and shown to
coincide with a formula conjectured by Baptista.Comment: 12 pages - updated versio
Two Weeks of Ischemic Conditioning Improves Walking Speed and Reduces Neuromuscular Fatigability in Chronic Stroke Survivors
This pilot study examined whether ischemic conditioning (IC), a noninvasive, cost-effective, and easy-to-administer intervention, could improve gait speed and paretic leg muscle function in stroke survivors. We hypothesized that 2 wk of IC training would increase self-selected walking speed, increase paretic muscle strength, and reduce neuromuscular fatigability in chronic stroke survivors. Twenty-two chronic stroke survivors received either IC or IC Sham on their paretic leg every other day for 2 wk (7 total sessions). IC involved 5-min bouts of ischemia, repeated five times, using a cuff inflated to 225 mmHg on the paretic thigh. For IC Sham, the cuff inflation pressure was 10 mmHg. Self-selected walking speed was assessed using the 10-m walk test, and paretic leg knee extensor strength and fatigability were assessed using a Biodex dynamometer. Self-selected walking speed increased in the IC group (0.86 ± 0.21 m/s pretest vs. 1.04 ± 0.22 m/s posttest, means ± SD; P\u3c 0.001) but not in the IC Sham group (0.92 ± 0.47 m/s pretest vs. 0.96 ± 0.46 m/s posttest; P= 0.25). Paretic leg maximum voluntary contractions were unchanged in both groups (103 ± 57 N·m pre-IC vs. 109 ± 65 N·m post-IC; 103 ± 59 N·m pre-IC Sham vs. 108 ± 67 N·m post-IC Sham; P = 0.81); however, participants in the IC group maintained a submaximal isometric contraction longer than participants in the IC Sham group (278 ± 163 s pre-IC vs. 496 ± 313 s post-IC, P = 0.004; 397 ± 203 s pre-IC Sham vs. 355 ± 195 s post-IC Sham; P = 0.46). The results from this pilot study thus indicate that IC training has the potential to improve walking speed and paretic muscle fatigue resistance poststroke
Transorbital transnasal endoscopic combined approach to the anterior and middle skull base: a laboratory investigation
Orbital approaches provide significant trajectory to the skull base and are used with differently designed pathways. The aim of this study is to investigate the feasibility of a combined transorbital and transnasal approach to the anterior and middle cranial fossa. Cadaveric dissection of five silicon-injected heads was used. A total of 10 bilateral transorbital approaches and 5 extended endonasal approaches were performed. Identification of surgical landmarks, main anatomical structures, feasibility of a combined approach and reconstruction of the superior orbital defect were examined. Rod lens endoscope (with 0° and 45° lenses) and endoscopic instruments were used to complete the dissection. The transorbital approach showed good versatility and provides the surgeon with a direct route to the anterior and middle cranial fossa. The transorbital avascular plane showed no conflict with major nerves or vessels. Large exposure area from crista galli to the third ventricle was demonstrated with significant control of different neurovascular structures. A combined transorbital transnasal approach provides considerable value in terms of extent of exposure and free hand movement of the two surgeons, and allows better visualisation and control of the ventral skull base, thus overcoming the current surgical limits of a single approach. Combination of these two minimally invasive approaches should reduce overall morbidity. Clinical trials are needed to evaluate the virtual applications of this approach
The efficacy and safety of prokinetic agents in critically ill patients receiving enteral nutrition: a systematic review and meta-analysis of randomized trials.
BACKGROUND: Intolerance to enteral nutrition is common in critically ill adults, and may result in significant morbidity including ileus, abdominal distension, vomiting and potential aspiration events. Prokinetic agents are prescribed to improve gastric emptying. However, the efficacy and safety of these agents in critically ill patients is not well-defined. Therefore, we conducted a systematic review and meta-analysis to determine the efficacy and safety of prokinetic agents in critically ill patients. METHODS: We searched MEDLINE, EMBASE, and Cochrane Library from inception up to January 2016. Eligible studies included randomized controlled trials (RCTs) of critically ill adults assigned to receive a prokinetic agent or placebo, and that reported relevant clinical outcomes. Two independent reviewers screened potentially eligible articles, selected eligible studies, and abstracted pertinent data. We calculated pooled relative risk (RR) for dichotomous outcomes and mean difference for continuous outcomes, with the corresponding 95 % confidence interval (CI). We assessed risk of bias using Cochrane risk of bias tool, and the quality of evidence using grading of recommendations assessment, development, and evaluation (GRADE) methodology. RESULTS: Thirteen RCTs (enrolling 1341 patients) met our inclusion criteria. Prokinetic agents significantly reduced feeding intolerance (RR 0.73, 95 % CI 0.55, 0.97; P = 0.03; moderate certainty), which translated to 17.3 % (95 % CI 5, 26.8 %) absolute reduction in feeding intolerance. Prokinetics also reduced the risk of developing high gastric residual volumes (RR 0.69; 95 % CI 0.52, 0.91; P = 0.009; moderate quality) and increased the success of post-pyloric feeding tube placement (RR 1.60, 95 % CI 1.17, 2.21; P = 0.004; moderate quality). There was no significant improvement in the risk of vomiting, diarrhea, intensive care unit (ICU) length of stay or mortality. Prokinetic agents also did not significantly increase the rate of diarrhea. CONCLUSION: There is moderate-quality evidence that prokinetic agents reduce feeding intolerance in critically ill patients compared to placebo or no intervention. However, the impact on other clinical outcomes such as pneumonia, mortality, and ICU length of stay is unclear
Prevalence of Anxiety and Depression Among Respiratory Therapy Professionals in The Western Region of Saudi Arabia
Background: Anxiety and depression are prevalent concerns among psychologists, psychiatric professionals, and behavioral scientists across the world. Anxiety is defined as worry-filled thoughts and a pervasive sense of impending doom. It is a broad concern about what will or might occur in the future. Depression is a debilitating disorder, leading to higher death rates and a significant decline in the quality of life. It is characterized by persistent feelings of sadness, emptiness, and lack of happiness. Therefore, anxiety and depression could have a detrimental effect on the well-being and productivity of respiratory therapists. Purpose: The purpose of this study is to investigate the prevalence and severity of anxiety and depression among respiratory therapists employed by public and private hospitals in the western region of Saudi Arabia. Methods: A cross-sectional study was conducted between September 5 and October 7, 2023. The Hospital Anxiety and Depression Scale (HADS) was distributed electronically to respiratory therapists\u27 email addresses through direct collaboration with RT department heads. Data were collected from RT professionals in both public and private hospitals by using a non-probability convenience sampling technique. The data analysis and statistical description provided by the participants were displayed as means, standard deviations, frequencies, and percentages. A one-way ANOVA test was used to determine the significant differences in HADS scores among categorical groups. Results: A total of 307 responses were received from RTs working in the western region of Saudi Arabia. The majority of them were from public hospitals (74.3%) and (25.7%) from private hospitals. The study findings showed that the prevalence of anxiety and depression among RT professionals in the western of SA were found to be 38.8% and 37.5%, respectively. In addition, HADS scores were significantly higher among RT professionals who were female, current smokers, divorced, or widowed. However, HADS showed that anxiety was significantly higher among RT professionals with clinical experience between 1-4 years as well. Conclusion: Anxiety and depression were common psychological disorders among respiratory therapists in the western region of Saudi Arabia. Higher odds of anxiety and depression were significantly found among females, staff with clinical experience between 1 and 4 years, smokers, and divorced/widowed staff. Further studies are required to investigate the prevalence of depression and anxiety among RTs in all regions of Saudi Arabia
A Multimodality Hybrid Gamma-Optical Camera for Intraoperative Imaging
The development of low profile gamma-ray detectors has encouraged the production of small field of view (SFOV) hand-held imaging devices for use at the patient bedside and in operating theatres. Early development of these SFOV cameras was focussed on a single modality-gamma ray imaging. Recently, a hybrid system-gamma plus optical imaging-has been developed. This combination of optical and gamma cameras enables high spatial resolution multi-modal imaging, giving a superimposed scintigraphic and optical image. Hybrid imaging offers new possibilities for assisting clinicians and surgeons in localising the site of uptake in procedures such as sentinel node detection. The hybrid camera concept can be extended to a multimodal detector design which can offer stereoscopic images, depth estimation of gamma-emitting sources, and simultaneous gamma and fluorescence imaging. Recent improvements to the hybrid camera have been used to produce dual-modality images in both laboratory simulations and in the clinic. Hybrid imaging of a patient who underwent thyroid scintigraphy is reported. In addition, we present data which shows that the hybrid camera concept can be extended to estimate the position and depth of radionuclide distribution within an object and also report the first combined gamma and Near-Infrared (NIR) fluorescence images.Peer-reviewedPublisher Versio
Underuse of Pragmatic Markers among Non-native English Speakers: Causes and Suggestions for Interventions
Pragmatic markers (PMs)—those optional markers used in conversations to facilitate communication—have been gaining attention among researchers in the field of pragmatics in the past three decades or so. Proper use of PMs contributes to the success of any interaction in real-life conversations. However, they are often underused by non-native English speakers (NNSs). This paper critically reviews the existing research literature to investigate the causes of the underuse of PMs among NNSs, focusing on linguistic and extralinguistic factors that might contribute to the limited use of PMs. The findings of this study show that the distinctive nature of pragmatic development in the first and second languages, lack of instructions on PMs, limited exposure to the target language, and the NNSs\u27 level of proficiency are the main linguistic issues that arise during pragmatic development. Gender and age, as non-linguistic factors, also limit the use of PMs. These findings suggest that linguistic and extralinguistic factors constrain the use of PMs in NNSs’ speech. Based on the findings, suggestions for interventions are offered for language educators to better integrate PM use in ESL/EFL teaching
Simulations of events for the LUX-ZEPLIN (LZ) dark matter experiment
The LUX-ZEPLIN dark matter search aims to achieve a sensitivity to the WIMP-nucleon spin-independent cross-section down to (1–2)×10−12 pb at a WIMP mass of 40 GeV/c2. This paper describes the simulations framework that, along with radioactivity measurements, was used to support this projection, and also to provide mock data for validating reconstruction and analysis software. Of particular note are the event generators, which allow us to model the background radiation, and the detector response physics used in the production of raw signals, which can be converted into digitized waveforms similar to data from the operational detector. Inclusion of the detector response allows us to process simulated data using the same analysis routines as developed to process the experimental data
0E2FA: Zero Effort Two-Factor Authentication
Smart devices (mobile devices, laptops, tablets, etc.) can receive signals from different radio frequency devices that are within range. As these devices move between networks (e.g., Wi-Fi hotspots, cellphone towers, etc.), they receive broadcast messages from access points, some of which can be used to collect useful information. This information can be utilized in a variety of ways, such as to establish a connection, to share information, to locate devices, and to identify users, which is central to this dissertation. The principal benefit of a broadcast message is that smart devices can read and process the embedded information without first being connected to the corresponding network. Moreover, broadcast messages can be received only within the range of the wireless access point that sends the broadcast, thus inherently limiting access to only those devices in close physical proximity, which may facilitate many applications that are dependent on proximity. In our research, we utilize data contained in these broadcast messages to implement a two-factor authentication (2FA) system that, unlike existing methods, does not require any extra effort on the part of the users of the system. By determining if two devices are in the same physical location and sufficiently close to each other, we can ensure that they belong to the same user. This system depends on something that a user knows, something that a user owns, and—a significant contribution of this work—something that is in the user’s environment
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