18701 research outputs found
Sort by
Metagenomics reveals spatial variation in cyanobacterial composition, function, and biosynthetic potential in the Winam Gulf, Lake Victoria, Kenya
No full textThe Winam Gulf in the Kenyan region of Lake Victoria experiences prolific, year-round cyanobacterial harmful algal blooms (cyanoHABs) which pose threats to human, livestock, and ecosystem health. To our knowledge, there is limited molecular research on the gulf’s cyanoHABs, and thus, the strategies employed for survival and proliferation by toxigenic cyanobacteria in this region remain largely unexplored. Here, we used metagenomics to analyze the Winam Gulf’s cyanobacterial composition, function, and biosynthetic potential. Dolichospermum was the dominant bloom-forming cyanobacterium, co-occurring with Microcystis at most sites. Microcystis and Planktothrix were more abundant in shallow and turbid sites. Metagenome-assembled genomes (MAGs) of Dolichospermum harbored nitrogen fixation genes, suggesting diazotrophy as a potential mechanism supporting the proliferation of Dolichospermum in the nitrogen-limited gulf. Over 300 biosynthetic gene clusters (BGCs) putatively encoding the synthesis of toxins and other secondary metabolites were identified across the gulf, even at sites where there were no visible cyanoHAB events. Almost all BGCs identified had no known synthesis product, indicating a diverse and novel biosynthetic repertoire capable of synthesizing harmful or potentially therapeutic metabolites. Microcystis MAGs contained mcy genes encoding the synthesis of hepatotoxic microcystins which are a concern for drinking water safety. These findings illustrate the spatial variation of bloom-forming cyanobacteria in the Winam Gulf and their available strategies to dominate different ecological niches. This study underscores the need for further use of genomic techniques to elucidate the dynamics and mitigate the potentially harmful effects of cyanoHABs and their associated toxins on human, environmental, and economic health
Experimental Study of Social Signaling through Delayed Plumage Maturation in a Colony-Nesting Seabird
No full textDelayed development is a widespread evolutionary strategy that can reduce competition among highly social animals. Many seabirds exhibit delayed plumage maturation, in which young birds spend years in visually distinct predefinitive plumages before attaining the definitive plumage of adults. Previous work hypothesized that predefinitive plumages may function to reduce aggression towards young, predefinitive seabirds at breeding colonies, an idea known from other lineages of birds as the status signaling hypothesis. We tested this hypothesis with visual stimulus experiments at a breeding colony of American Herring Gulls ( Larus smithsonianus ). We presented painted models of four diYerent plumage classes (first-cycle predefinitive gull plumage, third-cycle predefinitive gull plumage, definitive gull plumage, and a Canada Goose as a control) and measured the aggressive responses of breeding adults at their nests. Breeding gulls responded with significantly less frequent, lower, and slower aggression toward the first-cycle and control plumages compared to the definitive plumage. There were no significant diYerences in response towards the third-cycle plumage. These results oYer support for a status signaling hypothesis, indicating that substantial, mottled brown plumage—as worn by first-cycle gulls—reduces aggression from breeding adults in colonies or foraging flocks. Future research can investigate how immature seabirds—including third-cycle gulls—may combine plumage, posture, and behavior to shift the dynamics of social behavior at breeding colonies
Influence of fibre content, moisture content, and anisotropy on the mechanical properties of direct compounded compression moulded carbon/PA66 and glass/PA6 composites
No full textLong fibre thermoplastic (LFT) materials are employed in a diverse group of engineering applications, and this usage makes it critical to understand how various loading and environmental settings affect the mechanical properties of LFT materials. In this study, the tensile properties of direct-compounded, compression-moulded glass/PA6 with 30% and 45% fibre content and carbon fibre-reinforced thermoplastic (LFT-D) materials were investigated, along with shear properties for glass fibre-reinforced LFTs. Additionally, the tensile and shear properties of glass/PA6 in four different material directions of 0°, 45°, −45°, and 90° were also examined. The results of this study revealed that carbon/PA66(40%) exhibited 67% and 45% higher tensile strength compared to glass/PA6(30%) and glass/PA6(45%), respectively. The behaviour of the glass/PA6 material shifted from brittle to ductile under tension and shear loads when exposed to moisture, regardless of the percentage of fibre content. Notably, the tensile toughness of the glass/PA6 material exhibited a significant increase of up to 230% in specific material configurations from dried to undried samples. The findings of this study will assist in the selection of the optimal LFT material for use in desired loading and environmental conditions and can serve as input for the numerical modelling of these composite materials.Natural Science and Engineering Research Council of CanadaOntario Research Fun
Assessing Driver Comfort and In-Chair Movements in an Automotive Seat with Anti-Fatigue Massage Function
No full textProlonged driving is associated with fatigue and reduced comfort, jeopardizing driver safety. This study proposes an innovative Anti-Fatigue Massage Function (AFMF) system integrated into a driver’s seat to improve subjective comfort and decrease compensatory movements during extended driving due to fatigue. In total, 24 participants (12 males, 12 females) completed two 60 min simulated driving sessions—one with the AFMF activated and one with it deactivated. Subjective comfort was measured every 10 min using a 5-point Likert scale, while objective In-Chair Movements (ICMs) were manually recorded by expert researchers from dual-camera recordings. ART ANOVA revealed that the AFMF-equipped seat significantly enhanced comfort ratings and reduced ICM frequencies compared to the deactivated condition. These findings suggest that the AFMF system can enhance driver well-being and mitigate fatigue-related risks during prolonged driving
Excitation Signal Design for Fast Electrochemical Impedance Spectroscopy in Battery Testing
No full textElectrochemical impedance spectroscopy (EIS) is a widely used technique for analyzing battery dynamics over a broad frequency spectrum. Conventional state-of-the-art EIS methods involve applying a sequence of sinusoidal excitation signals, ranging from very low to very high frequencies, to capture the impedance response of the battery. However, this process is time-consuming, often requiring several hours to complete. Alternatively, approaches using pulse-based excitation have shown promise in reducing test time but often suffer from challenges in handling measurement noise and poor frequency resolution, especially at low frequencies. This work presents an improved rectangular pulse-based impedance characterization technique that enhances low-frequency resolution, increases robustness to noise, and reduces experimental time. This is accomplished through the following three key contributions of this paper: First, it establishes statistical noise properties in the Fourier-transformed signals, enabling effective noise reduction through averaging. Second, it proposes a log-frequency clustering approach to average impedance data, enhancing the accuracy of the impedance spectrum. Third, it presents a systematic pulse design method using the knowledge of the approximate time constants of the system to select the sampling interval, pulse width, and rest duration for reduced test time, improved low-frequency resolution, and enhanced signal-to-noise ratio (SNR). Together, the proposed approach enables faster and more accurate impedance characterization. Simulation analysis and experimental results confirm that the proposed approach enhances spectral resolution at low frequencies, mitigates the impact of noise at high frequencies, and significantly improves the reliability of impedance estimates at a faster measurement time frame
Racial disparities in child welfare: A propensity score matched analysis of Black and White children in Canada
No full textResearch has revealed significant disparities in child welfare (CW) involvement for Black children in Canada. However, the underlying factors contributing to these differences remain poorly understood. Objective: This study aims to identify the factors influencing racial disparities in CW investigations and out-of-home placements, with a focus on understanding the broader structural and institutional drivers shaping CW outcomes for Black children in Canada. Participants and setting: Data were drawn from the 2019 Canadian Incidence Study of Reported Child Abuse and Neglect (CIS-2019). The fully weighted sample included an estimated 134,925 investigations involving White families and 28,415 investigations involving Black families. Methods: A two-stage analytical approach was employed using the weighted and unweighted sample. Propensity score matching (PSM) was used on the unweighted sample to examine racial disparities in out-of-home placement while controlling for case differences. Results: Findings indicate that Black children were investigated for maltreatment at 2.27 times the rate of White children. Out-of-home placement rates were also higher (3.4 vs. 1.9 per 1000; 1.79 times per capita). After matching, Black children remained more likely to be placed in out-of home care, with a rate more than double that of their white counterparts (3.1 % vs. 1.5 %; LR = 0.004, p = 0.004) Conclusion: These findings highlight a compounded effect of bias across Black children's CW trajectories, suggesting a need to address both structural and institutional factors that contribute to disparities in CW investigations and out-of-home placement decisions
Revised efficient and reproducible synthesis of an Fmoc-protected Tn antigen
No full textIn 2021, our team reported a concise synthesis of Thomsen-Nouveau (Tn) antigen, a tumour-associated
O-linked mucin glycopeptide. We have since realized that our characterization of the reported glycoside
was mistaken. Instead of the intended ether-bonded a anomer, the b-anomer containing an ester
glycosidic bond was formed using palladium catalysis and characterised incorrectly as the spectra are
remarkably similar. We demonstrated this conclusively be repeating Danishefky’s synthesis, with some
required modifications of the protocol, of Fmoc-Tn for confirmation. The error is too significant for a
correction as it does affect the conclusions of the work, and the original paper has been retracted,
though its work is included in this manuscript. In this replacement we report a successful synthesis of
the Tn antigen using adjusted glycosylation conditions: a different glycosyl acceptor, N-Fmoc serine
benzyl ester, using TMSOTf as the catalyst. This remains, to the best of our knowledge, the shortest Tn
antigen synthesis reported from galactose, although it provides the Tn antigen now. Furthermore, this
route gives ready access to an essential Tn antigen building block that can be used for large-scale solid
phase peptide synthesis.Banting Research Foundation (Award: 2018-1403)Canada Foundation for Innovation (Award: 37425)Natural Sciences and Engineering Research Council of Canada (Award: 2018-06338, USRA-2017)Government of Ontario (Award: ER18-14-114
Improving academic literacy through an understanding of the role of citations in disciplinary meaning construal
No full textThe Lance: School Year 1989-1990
No full textSchool Year 1989-1990 Vol. 62: no. 1 (1989: Aug. 31) 16p.Vol. 62: no. 2 (1989: Sept. 7) 28p.Vol. 62: no. 3 (1989: Sept. 14) 28p.Vol. 62: no. 4 (1989: Sept. 21) 28p.Vol. 62: no. 5 (1989: Sept. 28) 24p.Vol. 61: no. 6 (1989: Oct. 4) 24p. Really vol. 62Vol. 61: no. 6 (1989: Oct. 12) 20p. Really vol. 62; A second no. 6Vol. 61: no. 7 (1989: Oct. 19) 24p. Really vol. 62Vol. 62: no. 9 (1989: Oct. 26) 28p.Vol. 62: no. 10 (1989: Nov. 2) 16p.Vol. 62: no. 11 (1989: Nov. 9) 20p.Vol. 62: no. 12 (1989: Nov. 16) 24p.Vol. 62: no. 13 (1989: Nov. 23) 16p.Vol. 62: no. 14 (1989: Nov. 30) 40p.Vol. 62: no. 15 (1990: Jan. 11) 20p.Vol. 62: no. 16 (1990: Jan. 18) 24p.Vol. 62: no. 17 (1990: Jan. 25) 28p.Vol. 62: no. 18 (1990: Feb. 1) 24p.Vol. 62: no. 19 (1990: Feb. 8) 24p.Vol. 62: no. 20 (1990: Feb. 15) 24p.Vol. 62: no. 21 (1990: Mar. 1 24p.Vol. 62: no. 22 (1990: Mar. 8) 24p.Vol. 62: no. 23 (1990: Mar. 15) 28p.Vol. 62: no. 24 (1990: Mar. 22) 24p.Vol. 62: no. 25 (1990: Mar. 29) 20p. (1990: Apr. 1) 8p. Penny Saviour SupplementVol. 62: no. 26 (1990: Apr. 5) 20p.Vol. 62: no. 27 (1990: Apr. 12) 32p