Search Results (17,513)

Island taxa are frequently susceptible to introduced predators. This susceptibility is thought to be caused by the loss of key ancestral antipredator physiological adaptations during long periods of evolution under reduced predation pressures. Here, we test the hypothesis that island species have reduced locomotor abilities. While locomotor abilities are critical for escaping predation, little is known on how the presence of different types of native predators influences these abilities by maintaining selective pressure. To fill this gap, we documented sprint speed in the Aegean wall lizard (Podarcis erhardii) from the Aegean islands (Greece) with varying levels of predation pressure. We show that lizards from islands where mammalian predators were present sprinted fastest. Lizards sprinted at an intermediate speed where predators other than mammals were present, and lizards sprinted slowest on islands where no predators were present. Longer periods of evolutionary isolation in island environments were also associated with diminished sprinting speeds. These results indicate that lizards from the lowest-predation islands are the most vulnerable and preventing the introduction of invasive predators should be prioritized for these island systems. Full article

I examine how the association between the current period’s budget variance and the subsequent period’s budget is affected by various governmental monitoring mechanisms. Specifically, I consider the following governance and monitoring mechanisms: governance structure, state/city budget-limiting regulations, and voter-initiated monitoring. I find that city budgets ratchet in the top 50 populous cities in the US. I also document evidence of asymmetric ratcheting—the current period’s favorable budget variances result in budget increases in the following year that are larger than the decreases associated with unfavorable variances of the same magnitude. Consistent with the political budget cycle hypothesis that budget pattern alters during pre-election periods, I find the asymmetric ratcheting pattern becomes invisible in times of election, particularly when an incumbent runs for re-election. Given this evidence of the opportunistic budgetary pattern, I hypothesize and find that some monitoring mechanisms mitigate the sensitivity of the subsequent period’s budget with respect to the current period’s budget variance. Full article

Software-defined networking (SDN) is a transformative approach for managing modern network architectures, particularly in Internet-of-Things (IoT) applications. However, ensuring the optimal SDN performance and security often needs a robust sensitivity analysis (SA). To complement existing SA methods, this study proposes a new SA framework that integrates design of experiments (DOE) and machine-learning (ML) techniques. Although existing SA methods have been shown to be effective and scalable, most of these methods have yet to hybridize anomaly detection and classification (ADC) and data augmentation into a single, unified framework. To fill this gap, a targeted application of well-established existing techniques is proposed. This is achieved by hybridizing these existing techniques to undertake a more robust SA of a typified SDN-reliant IoT network. The proposed hybrid framework combines Latin hypercube sampling (LHS)-based DOE and generative adversarial network (GAN)-driven data augmentation to improve SA and support ADC in SDN-reliant IoT networks. Hence, it is called DOE-GAN-SA. In DOE-GAN-SA, LHS is used to ensure uniform parameter sampling, while GAN is used to generate synthetic data to augment data derived from typified real-world SDN-reliant IoT network scenarios. DOE-GAN-SA also employs a classification and regression tree (CART) to validate the GAN-generated synthetic dataset. Through the proposed framework, ADC is implemented, and an artificial neural network (ANN)-driven SA on an SDN-reliant IoT network is carried out. The performance of the SDN-reliant IoT network is analyzed under two conditions: namely, a normal operating scenario and a distributed-denial-of-service (DDoS) flooding attack scenario, using throughput, jitter, and response time as performance metrics. To statistically validate the experimental findings, hypothesis tests are conducted to confirm the significance of all the inferences. The results demonstrate that integrating LHS and GAN significantly enhances SA, enabling the identification of critical SDN parameters affecting the modeled SDN-reliant IoT network performance. Additionally, ADC is also better supported, achieving higher DDoS flooding attack detection accuracy through the incorporation of synthetic network observations that emulate real-time traffic. Overall, this work highlights the potential of hybridizing LHS-based DOE, GAN-driven data augmentation, and ANN-assisted SA for robust network behavioral analysis and characterization in a new hybrid framework. Full article

Introduction: Most audiometers have an in-built “Stenger test” setting. The test is sometimes applied in cases of single-sided deafness as an indicator of malingering. Although textbooks have been written about it, the underlying conditions remain enigmatic. The literature usually points to psychological problems, pointing to the patient as having “nonorganic hearing loss”, “malingering”, “false and exaggerated hearing loss”, “hysterical hearing loss”, or “pseudohypoacusis”. These are all non-objective features without a sound scientific base, and the test tends to blame the patient for providing non-repeatable hearing thresholds. Methods: This opinion piece looks at the literature surrounding the Stenger test and the factors that might cause hearing threshold variability and concludes that the test has a subjective basis that makes it unscientific. In our opinion, we also think it is ethically questionable to blame the patient for malingering when there are non-repeatable findings. In order to make the test scientifically valid, we frame a testable hypothesis: that the Stenger effect could be due to unrecognised contraction of the middle ear muscles in response to stimulation of the contralateral (worse-hearing) ear. That is, we suppose that bilateral contraction impairs thresholds in both the good and poor ear, so the subject can no longer hear a tone in their good ear which they previously could when their audiogram was established monaurally. Thus, we make the case that the subject is not malingering—they genuinely cannot hear the test tones in either ear. Discussion and Conclusions: We believe it is incorrect to blame the patient when the problem may lie with incomplete understanding of how the auditory system functions bilaterally. The test needs to be objectively investigated and perhaps reinterpreted in terms of hearing sensitivity in one ear being reduced by sound levels in the contralateral ear. If this is not possible, we suggest it would be better if the Stenger test were abolished. Full article

High software reliability is essential for safety-critical systems in nuclear power plants. To improve the quality of software following the requirements phase, requirements inspections are conducted to detect defects. Traditional approaches enhance inspection outcomes by employing more effective techniques or by increasing team redundancy. This study investigates an alternative approach: introducing diversity within the inspection team. Inspection technique diversity and inspector background diversity are considered in this paper. We hypothesize that an inspection team in which the inspectors use diverse inspection techniques or have diverse backgrounds will have a better performance in defect detection compared to an inspection team with no diversity. This is because diversity can reduce the number of dependent failures in an inspection team. In this study, a controlled experiment is designed and conducted to examine our hypothesis. In the experiment, research subjects with different backgrounds inspect a software requirements specification using different inspection techniques. The results are collected and analyzed statistically. The experiment shows that using diverse techniques in an inspection team can improve the performance of the inspection team; however, using inspectors with diverse backgrounds will not affect the performance of an inspection team significantly. Full article

Background: Ischemic stroke is a leading cause of morbidity and mortality worldwide. Despite established prevention strategies, many patients present with previously undiagnosed vascular risk factors (URFs) at the time of their first-ever ischemic stroke, suggesting missed opportunities for early detection. In Canada, particularly in Quebec, access to primary care is inconsistent, and a substantial proportion of the population lacks attachment to a family doctor (FD). Objective: This study aimed to determine the prevalence of URFs among patients with first-ever ischemic stroke and to evaluate the relationship between URFs, geographic region, and access to primary care in Quebec, Canada. We hypothesized that patients without an FD would have a higher prevalence of URFs. Methods: We conducted a retrospective chart review of 610 patients admitted with first-ever ischemic stroke to the McGill University Health Center (MUHC) between 2014 and 2017. Data collected included demographics; known and undiagnosed stroke risk factors such as hypertension (HTN), diabetes mellitus (DM), hyperlipidemia (HLD), and atrial fibrillation (AF); FD status; and geographic location based on postal code. Results: Among the 610 patients, 136 (22.3%) had at least one URF. The most common URF was HLD (14.3%), followed by HTN (6.2%), AF (1.6%), and DM (0.1%). Of 609 patients with available data, 146 (23.97%) lacked an FD. Patients without an FD were significantly more likely to have undiagnosed HTN (7.6% vs. 2.1%, p = 0.008). No significant differences were observed for the other URFs. Geographic variation was noted in both URF prevalence and FD access, but regional differences were not statistically significant. Conclusions: Our findings support the hypothesis that a lack of an FD is associated with a higher prevalence of undiagnosed HTN in ischemic stroke patients. Targeted screening and improved access to primary care, particularly in underserved regions, may help to reduce the burden of preventable stroke by facilitating the earlier identification and management of modifiable risk factors. Full article

Cicerbita alpina (L.) Wallroth and Peucedanum ostruthium W.D.J. Koch occur in megaphorb communities in alpine and subalpine areas; both species often share the same habitats. P. ostruthium is used as a spice for spirits, while young shoots of C. alpina are collected in the northeastern regions of Italy as a local delicacy. In the present study, we isolated eleven known coumarins and one chromone from subaerial parts of P. ostruthium; two furanocoumarins were found for the first time in this species. Using UHPLC-HRMS, we analyzed the furanocoumarin content of two P. ostruthium accessions, one commercially purchased and one collected in the wild. These samples were compared to six rootstock samples of Cicerbita alpina collected in the wild. Though the furanocoumarins imperatorin, isoimperatorin, oxypeucedanin, and ostruthol had been reported from C. alpina before, we were not able to detect any of these compounds in our samples of C. alpina. Therefore, and due to the occurrence of both taxa in the same habitat, we assume that the original report of furanocoumarins in C. alpina was based on a mixed collection of C. alpina and P. ostruthium. This hypothesis seems plausible, because furanocoumarins have not been reported from any other taxon of the Cichorieae tribe of the Asteraceae family. Full article

This study proposes an integrated fatigue life assessment methodology to accurately evaluate the time-domain evolution in tubular joint fatigue damage in offshore wind turbine (OWT) jacket structures under long-term combined wind and wave actions. A customized post-processing module was developed via secondary development on the MLife platform, employing a conditional probability distribution model to perform joint probabilistic modeling of measured marine environmental data, thereby establishing a long-term joint wind–wave distribution database. The reconstruction of hotspot stress time histories at the tubular joints was achieved through a hybrid analytical–numerical approach, integrating analytical formulations of nominal stress with a multi-axial stress concentration factor (SCF) matrix. Long-term fatigue damage assessment was implemented using the Palmgren–Miner linear cumulative damage hypothesis, where a weighted summation methodology based on joint wind–wave probability distributions rigorously accounted for the statistical contributions of individual design load cases. An ultimate bearing capacity analysis was also conducted based on S-N fatigue endurance characteristic curves. This research specifically investigates the influence mechanisms of tuned mass dampers (TMDs) on the time-domain-coupled fatigue performance of tubular joints subjected to long-term combined wind and wave loads. Numerical simulations demonstrate that parametrically optimized TMD systems significantly enhance the fatigue life metrics of critical joints in jacket structures. Full article

Chronic wounds are considered a silent epidemic that impact millions of human lives worldwide, causing comorbidities, reducing life quality and expectancy. Diabetic, pressure, and venous ulcers are the three major clinical entities of chronic wounds, in which the presence of a chronicity phenotype and episodes of recurrence remain as contemporary challenges. We are, accordingly, far from a full understanding about the potential endogenous, predisposing factors that may drive both chronicity and recurrence. Decades of academic and financial endeavors have not translated into a pharmacological intervention that may curb these events. These wounds may exhibit the clinical aspect of a torpid granulative response, poor angiogenesis, delayed or abnormal re-epithelialization, and low contraction rates. At the cellular level, chronicity is propelled and distinguished by the triad of interplaying loops of inflammation, oxidative stress, and cellular senescence. Although the proximal molecular drivers of chronicity and their hierarchal debut sequence are a critical research target and pending task, our unifying hypothesis behind chronicity and recurrence is founded on the existence of an epigenetic pathologic code that originates and perpetuates a “chronic wound memory”. In vitro studies suggest that this de novo edited script is sheltered in dermal fibroblasts and keratinocytes and is spreadable and transmissible to descendant cells, dictating abnormal traits even in ideal culture conditions and successive passages. The list of epigenomic alterations and their significance in wound pathology is continuously escalating. The accurate identification of the key epigenetic priming codes of impaired healing, and their selective re-editing, will be remarkably beneficial. Full article

Background and Objectives: Urinary tract infections (UTIs) are a major cause of emergency department (ED) visits and hospital admissions among older adults. Although most seniors present hemodynamically stable, a sizeable fraction deteriorate during hospitalization, and no ED-specific tool exists to identify those at greatest risk. We sought to determine risk factors for in-hospital mortality in this population and to develop a predictive model. Materials and Methods: We analyzed the MIMIC-IV-ED database (2011–2019) and enrolled culture-confirmed UTI patients aged ≥ 65 years who were hemodynamically stable—defined as a systolic blood pressure ≥ 100 mm Hg without vasopressor support. Demographics, comorbidities, triage vital signs, and initial laboratory tests were extracted. Least Absolute Shrinkage and Selection Operator (LASSO) regression with 10-fold cross-validation was performed for variable selection. Discrimination was quantified with the C-statistic, calibration with the Hosmer–Lemeshow test, and clinical utility with decision curve analysis. Internal validation was assessed via 1000-sample bootstrap resampling. Results: Among 1571 eligible encounters (median age 79 years, 33% male), in-hospital mortality was 4.5%. LASSO selected eight variables; six remained significant in multivariable analysis: age, systolic blood pressure, oxygen saturation, white blood cell count, red cell distribution width, and blood urea nitrogen. The predictive nomogram demonstrated a C-statistic of 0.73 (95% CI 0.66–0.79) and outperformed traditional early warning scores. Conclusions: A six-variable nomogram may stratify mortality risk in hemodynamically stable older adults with UTI. Because the model was developed in a single U.S. tertiary-care ED, it remains hypothesis-generating until validated in external, multicenter cohorts to confirm generalizability. Full article

Climate change is elevating temperatures, shifting weather patterns, and increasing frequency and severity of extreme weather events. Despite the urgency with which solutions are needed, relatively few studies comprehensively investigate the effectiveness of alternative flood risk management options under different climate conditions. Specifically, we are interested in a comparison of the effectiveness of resistance, nature-based, and managed retreat strategies. Using an integrated 1D-2D PCSWMM model, this paper presents a comprehensive investigation into the effectiveness of alternative adaptation strategies in reducing flood risks in Eastwick, a community of Philadelphia, PA, subject to fluvial, pluvial, and coastal flood hazards. While addressing the urgent public need to develop local solutions to this community’s flood problems, the research also presents transferable insights into the limitations and opportunities of different flood risk reduction strategies, manifested here by a levee, watershed-scale green stormwater infrastructure (GSI) program, and a land swap. The effectiveness of these options is compared, respectively, under compound climate change conditions, with the spatiotemporal patterns of precipitation and Delaware river tidal conditions based on Tropical Storm Isaias (2020). The hypothesis was that the GSI and managed retreat approaches would be superior to the levee, due to their intrinsic ability to address the compound climate hazards faced by this community. Indeed, the findings illustrate significant differences in the predicted flood extents, depths, and duration of flooding of the various options under both current and future climate scenarios. However, the ideal remedy to flooding in Eastwick is more likely to require an integrated approach, based on more work to evaluate cost-effectiveness, stakeholder preferences, and various logistical factors. The paper concludes with a call for integrating multiple strategies into multifunctional flood risk management. Full article

Incorporating scientific and critical thinking in early childhood education is essential for developing individuals with strong thinking skills. This study assesses the impact of promoting scientific thinking on the development of critical thinking among fifth-graders in central Mexico. We hypothesize that involving students in scientific thinking tasks would further enhance essential thinking skills. The methodology involved longitudinal quasi-experimental design that included a pre-test and post-test, along with a comparison (control) group. Critical thinking was measured using a test that was applied at the start and end of our study to assess four thinking skills: classification, problem-solving, decision-making and logical reasoning. The control group was taught using a standardized methodology, while the experimental group was taught about the structure of the scientific method using a template with characters that guided each step: observation, question, hypothesis, experimentation and conclusions. Students from the critical and scientific thinking experimental group had higher scores on the post-assessment than those of the control group, suggesting that learning through scientific thinking tasks improved their critical thinking skills. Boys’ critical thinking scores were higher than girls’ in both groups, while scientific thinking scores were not associated with gender. We demonstrated that critical thinking improves when children incorporate scientific thinking into their learning abilities. Full article

Side-channel analysis (SCA) poses a persistent threat to cryptographic hardware by exploiting unintended physical leakages. To address the limitations of traditional single-modality SCA methods, we propose a novel multi-modal side-channel analysis framework that targets the recovery of encryption keys by leveraging the imperfections inherent in hardware implementations. The core objective is to extract and classify information-rich segments from power and electromagnetic (EM) signals in order to recover secret keys without profiling or labeling. Our approach introduces a unified pipeline combining joint peak-based segmentation, isometric compression of variable-length trace segments, and multi-modal feature fusion. A key component of the framework is unsupervised clustering, which serves to automatically classify trace segments corresponding to different cryptographic operations (e.g., different key-dependent leakage classes), thereby enabling key byte hypothesis testing and full key reconstruction. Experimental results on an FPGA-based AES-128 implementation demonstrate that our method achieves up to 99.2% clustering accuracy and successfully recovers the entire encryption key using as few as 1–3 traces. Moreover, the proposed approach significantly reduces sample complexity and maintains resilience in low signal-to-noise conditions. These results highlight the practicality of our technique for side-channel vulnerability assessment and its potential to inform the design of more robust cryptographic hardware. Full article

Patients with bowel diseases (inflammatory bowel disease (IBD) in general) tend to seek medical, nursing, and/or physiotherapeutic consultations. Physiotherapists specialized in gastrointestinal (visceral) therapy can help reduce inflammation in patients with ulcerative colitis (UC). In this study, we divided UC patients into three groups according to their age: the youngest (18–35 years old), middle-aged (36–49 years old), and oldest (50–70 years old). Our hypothesis was that gut inflammatory markers (zonulin and fecal calprotectin levels) and microbiota strains would exhibit age-dependent variations in UC patients. We compared differences in zonulin, calprotectin, and vitamin D levels, together with a plethora of microbiota strains, based on age. Calprotectin is a marker of intestinal inflammation and zonulin identifies gut permeability; as IBD is characterized by gastrointestinal inflammation, these are useful markers for diagnosing and monitoring treatment/s in IBD patients, including ulcerative colitis (UC). Dysbiosis can alter the normal balance of intestinal function, and thus, several microbiota strains were compared between different age ranges in UC patients. The results indicated that the middle-aged UC (36–49) patients had the highest endogenous vitamin D levels, as well as lower zonulin and calprotectin levels than the youngest (18–35) and oldest (50–70) UC participants, respectively. The middle-aged group also had lower Enterococcus, E. Coli biovare, and Pseudomonas spp. levels than the youngest UC participants. Meanwhile, the most LPS microbiota producers were found in middle-aged patients. Finally, a higher number of Candida albicans and elevated LPS were found in the oldest UC participants than in the middle-aged (36–49) group. This study was, however, limited by uneven age-group sizes, which may have may limited the power in the youngest cohort. Although altered gut microbiota levels can increase gut inflammation in rodent models of UC, a definitive cause–effect relationship between UC and intestinal microbiota alteration is difficult to demonstrate in humans. Full article

This study is the first to directly compare natural dynamic penumbra shadows with experimentally replicated constant-intensity shadows on photovoltaic modules, providing new insights into the limitations of conventional shadow approximations found in the existing body of knowledge. Neutral density filters were deemed the most appropriate method for replicating a constant-intensity shadow, as they reduce visible light relatively uniformly across the primary silicon wavelength range. Preliminary experiments established the intensity values for each neutral density filter chosen to be able to match with the 29 dynamic penumbra shadows being replicated by both the size of shadow and the averaged intensity. The results revealed that while constant-intensity shadows and dynamic penumbra shadows produced similar overall power loss magnitudes, the constant-intensity shadows consistently led to higher losses, averaging 9.65% more, despite having the same average intensity and shadow size. Regression modelling showed similar curvature trends for both shading types (Adjusted R² = 0.895 for constant-intensity shadows and Adjusted R² = 0.743 for dynamic-intensity shadows), but statistical analyses, including the Mann–Whitney U-test (p = 0.00229), confirmed a significant difference between the power loss output for the two penumbra shadow conditions. Consequently, the null hypothesis was rejected, confirming that the simplified constant-intensity shadows represented in the literature cannot accurately replicate the behaviour of dynamic-intensity penumbra on photovoltaic modules. Full article