ASSESSING ECONOMIC RESILIENCE OF THE NORTH AMERICAN ELECTRICITY MARKET UNDER DIFFERENT PRICE SHOCKS TO NATURAL GAS

After wide adoption of hydraulic fracking and renewable energy in the late 2000s, North America has seen a large influx of low-cost natural gas and increased renewable energy capacity, both becoming main sources of electricity generation. The electricity market's reliance on natural gas increases its exposure to volatile natural gas prices. This paper investigates the economic resilience of the North American electricity market due to four different natural gas price shocks and renewable energy policies. Under these price shock scenarios, the electricity market’s resilience is measured the time required to recover the deviation from total system cost incurred by electricity market players relative to the business-as-usual scenario. Using the North American Electricity Model (NANELM), a partial equilibrium model that describes the behavior of electricity producers and transmission operators, we can measure the resilience and observe the behavior of generators and transmission operators. Although the electricity market reacts differently in all four price shock scenarios, they show that the market is under-prepared for sudden changes in natural gas prices and current infrastructure prevents recovery back to the business-as-usual electricity prices

DEVELOPMENT OF A FINITE ELEMENT TOOL FOR STRESS ANALYSIS OF A SURGICALLY ALTERED FEMUR

This paper reports the development of a tool for analyzing stresses in a surgically altered femur. The three-dimensional FE model incorporates a novel approach to implementing orthotropic and heterogeneous bone properties and non-uniform distributed loading. The model contains cortical, cancellous, and subchondral bone incorporating experimentally determined mechanical properties to characterize the anisotropy and heterogeneity of the bone. Ligaments and muscles of the joint are represented to more fully describe the loading condition. Use of the tool is demonstrated for an anterior cruciate ligament (ACL) reconstruction with button-type fixation and the knee joint at full extension. The stresses at the tunnel aperture on the femoral cortex produced from the fixation were noticeable for low levels of loading. Forces from the ligaments and muscles had only slight influence on the stresses at the aperture. Repeated compression of the femoral cortex at these stress levels may cause microdamage to the cortex eventually resulting in fatigue failure

Distinctive Mechanisms and Patterns of Exudative Versus Tractional Intraretinal Cystoid Spaces as Seen With Multimodal Imaging.

PurposeTo determine clear-cut distinctions between tractional and exudative intraretinal cystoid spaces subtypes.DesignRetrospective, multicenter, observational case series.MethodsA cohort of patients diagnosed with intraretinal cystoid spaces and imaged with optical coherence tomography (OCT), fluorescein angiography (FA), blue fundus autofluorescence (BFAF), en face OCT, and OCT angiography (OCT-A) was included in the study. All images were qualitatively and quantitatively evaluated.ResultsIn this study were included 72 eyes of 69 patients. Exudative intraretinal cystoid spaces (36/72 eyes, 50%) displayed a "petaloid" morphology as seen with en face OCT, FA, and BFAF. Tractional intraretinal cystoid spaces (24/72 eyes, 33.3%), displayed a radial "spoke-wheel" en face OCT pattern. There was no leakage with FA and BFAF did not reveal specific patterns. Eyes with full-thickness macular hole (FTMH, 12/72 eyes, 16.7%) displayed a "sunflower" en face OCT appearance. FTMH showed OCT, OCT-A, and BFAF features of both exudative and tractional cystoid spaces, but without any FA leakage. Inner nuclear layer (INL) thickness was significantly lower in tractional cystoid spaces (P < .001). There were a greater number of INL cystoid spaces in both the exudative and FTMH subgroups (P = .001). The surface area of INL cystoid spaces was significantly lower in the tractional subgroup (P < .001). There was a significant reduction of the microvascular density in eyes with exudative vs tractional (P = .002) and FTMH (P < .001) subgroups.ConclusionsExudative and tractional intraretinal cystoid spaces displayed characteristic multimodal imaging features and they may represent 2 different pathologic conditions with equally different clinical implications

Evaluation of the Choroid in Eyes With Retinitis Pigmentosa and Cystoid Macular Edema

Purpose: To study the anatomical choroidal features associated with the presence of cystoid macular edema (CME) in eyes with retinitis pigmentosa (RP). Methods: A total of 159 eyes (from 159 patients) with a diagnosis of RP were enrolled in this retrospective cross-sectional case-control study and divided into two groups based on the presence (67 eyes) or absence (92 eyes) of CME. Retinal and choroidal features were evaluated on spectral domain optical coherence tomography including central macular thickness (CMT) and subfoveal choroidal thickness (CT). Total choroidal area (TCA), choroidal luminal area (LA), and choroidal stromal area (SA) were measured and the choroidal vascularity index (CVI) was calculated in all study eyes. Results: Average age was 49.2 ± 14.9 and 47.1 ± 15.5 years (P = 0.40) and logMAR Snellen visual acuity (VA) was 0.4 ± 0.6 (median 0.3, 20/40) and 0.2 ± 0.4 (median 0.1, 20/25) in the RP groups with and without CME, respectively (P = 0.05). Mean CMT was 334.1 ± 93.5 and 252.6 ± 47.6 μm in the RP groups with and without CME, respectively (P < 0.001). The subfoveal CT was significantly increased in the RP group with versus without CME (294.2 ± 110.9 μm vs. 198.1 ± 75.5 μm, respectively, P < 0.001). In patients with CME, the CVI was lower (P < 0.001) and the TCA, LA, and SA were all significantly higher (P < 0.001). Conclusions: In patients with CME associated with RP, the choroid exhibited significantly greater subfoveal thickening and decreased CVI. The choroid may be an important factor to consider in the etiology of CME in patients with RP

Malaysian herbs as feeding attractants and enhancers for the giant freshwater prawn (Macrobrachium rosenbergii) and the whiteleg shrimp (Litopenaeus vannamei)

Feeding attractiveness of 21 fresh herbs was examined for the giant freshwater prawn (Macrobrachium rosenbergii) and the whiteleg shrimp (Litopenaeus vannamei) at different growth stages in tanks. The feeding attractant and enhancement were assessed by behavioural observations of the test animals in response to pelleted feeds incorporated with the herbal extracts in different concentrations. For M. rosenbergii, peppermint (Mentha piperita) and dokudami (Houttuynia cordata) were the most attractive herbs at all stages, and garlic (Allium sativum) strongly attracting to the juveniles but only weekly to the adults, postlarvae and larvae. Peppermint significantly enhanced feeding of M. rosenbergii at all stages except for the larvae. Garlic was a significant feeding enhancer for M. rosenbergii juveniles and postlarvae. The inclusion of the herbal extract at high concentrations had a negative effect on the feeding. As far as L. vannamei is concerned, the red chilli (Capsicum annuum) was the best feeding attractant and ginger (Zingiber officinale) and peppermint were moderate attractants for adults and juveniles. While galangal (Alpinia galangal), ginger and yellow onion (Allium cepa sp.) enhanced feeding in L. vannamei adults, but red chilli, garlic and peppermint did not enhance feeding. Evidently, the strong feeding attractants were not necessarily effective feeding enhancers. The incorporation of several herb extracts at higher concentrations caused a negative effect on the feeding of the test animals. This could be due to the presence of feeding deterrents in the herb such as saponins which are known to lower food palatability in insect, decapod crustaceans and fishes. More long-term work is warranted to determine if inclusion of feeding enhancing herbs in artificial feed promotes growth performance of the shrimp

Tactile emoticons: Conveying social emotions and intentions with manual and robotic tactile feedback during social media communications

Touch offers important non-verbal possibilities for socioaffective communication. Yet most digital communications lack capabilities regarding exchanging affective tactile messages (tactile emoticons). Additionally, previous studies on tactile emoticons have not capitalised on knowledge about the affective effects of certain mechanoreceptors in the human skin, e.g., the C-Tactile (CT) system. Here, we examined whether gentle manual stroking delivered in velocities known to optimally activate the CT system (defined as 'tactile emoticons'), during lab-simulated social media communications could convey increased feelings of social support and other prosocial intentions compared to (1) either stroking touch at CT sub-optimal velocities, or (2) standard visual emoticons. Participants (N = 36) felt more social intent with CT-optimal compared to sub-optimal velocities, or visual emoticons. In a second, preregistered study (N = 52), we investigated whether combining visual emoticons with tactile emoticons, this time delivered at CT-optimal velocities by a soft robotic device, could enhance the perception of prosocial intentions and affect participants' physiological measures (e.g., skin conductance rate) in comparison to visual emoticons alone. Visuotactile emoticons conveyed more social intent overall and in anxious participants affected physiological measures more than visual emoticons. The results suggest that emotional social media communications can be meaningfully enhanced by tactile emoticons. [Abstract copyright: Copyright: © 2024 Saramandi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

The psychophysiological effects of Tai-chi and exercise in residential Schizophrenic patients: a 3-arm randomized controlled trial

BACKGROUND: Patients with schizophrenia are characterized by high prevalence rates and chronicity that often leads to long-term institutionalization. Under the traditional medical model, treatment usually emphasizes the management of psychotic symptoms through medication, even though anti-psychotic drugs are associated with severe side effects, which can diminish patients’ physical and psychological well-being. Tai-chi, a mind-body exercise rooted in Eastern health philosophy, emphasizes the motor coordination and relaxation. With these potential benefits, a randomized controlled trial (RCT) is planned to investigate the effects of Tai-chi intervention on the cognitive and motor deficits characteristic of patients with schizophrenia. METHODS/DESIGN: A 3-arm RCT with waitlist control design will be used in this study. One hundred and fifty three participants will be randomized into (i) Tai-chi, (ii) exercise or (iii) waitlist control groups. Participants in both the Tai-chi and exercise groups will receive 12-weeks of specific intervention, in addition to the standard medication and care received by the waitlist control group. The exercise group will serve as a comparison, to delineate any unique benefits of Tai-chi that are independent of moderate aerobic exercise. All three groups will undergo three assessment phases: (i) at baseline, (ii) at 12 weeks (post-intervention), and (iii) at 24 weeks (maintenance). All participants will be assessed in terms of symptom management, motor coordination, memory, daily living function, and stress levels based on self-perceived responses and a physiological marker. DISCUSSION: Based on a promising pilot study conducted prior to this RCT, subjects in the Tai-chi intervention group are expected to be protected against deterioration of motor coordination and interpersonal functioning. They are also expected to have better symptoms management and lower stress level than the other treatment groups. TRIAL REGISTRATION: The trail has been registered in the Clinical Trials Center of the University of Hong Kong (HKCTR-1453)