Quotient method for stabilising a ball-on-a-wheel system – Experimental results

This paper extends the quotient method proposed in [1] and applies it to stabilize a “ball-on-a-wheel” system. The quotient method requires a diffeomorphism to obtain the normal form of the input vector field and uses canonical pro- jection to obtain the quotient. However, the whole process can be done without computing the normal form, which requires defining a quotient generating function and a quotient bracket. This paper presents the steps necessary to apply the quotient method without obtaining the normal form. Furthermore, a Lyapunov function is introduced to prove stability. This paper also presents the experimental implementation of the quotient method to stabilize a ball-on-a-wheel system

Diving into the vertical dimension of elasmobranch movement ecology

Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements

Predictors of Stone-Related Events in Asymptomatic Untreated Intrarenal Calculi

Purpose: There is a lack of data on the natural history of asymptomatic intrarenal calculi. In this study, we investigate stone-related events (SREs) in patients with untreated intrarenal calculi. We also investigate predictive factors for SREs.Methods: All patients found with an asymptomatic intrarenal calculus on CT kidney, ureter, bladder managed conservatively with interval imaging for >= 6 months were included. Patients were evaluated for any SRE. The rate of event according to calculus size, location, and number of calculi was also analyzed. Multivariate logistic regression analysis was performed to determine significant predictors for SREs.Results: In total, 266 renal units from 177 patients met inclusion criteria. The mean stone size was 4.44 mm (range 1-25 mm). Duration of follow-up was 43.78 +/- 26.86 months (range 6-106 months). The overall rate of SREs, including intervention (n = 80) and spontaneous stone passage after ureteral colic (n = 40), was 45.1% (n = 120/266). Stones >5 mm were more likely to lead to an event compared with stones <= 5 mm (odds ratio [OR]: 2.94; p = 0.01). Interpolar stones and stones located in multiple calices were more likely to cause a SRE than lower pole stones (OR: 2.05; p = 0.05 and OR: 2.29; p = 0.03, respectively).Conclusion: In this large series of patients with asymptomatic intrarenal calculi, the incidence of a spontaneous SRE was 45.1% after 41 months. Stone size and stone location were significant predictors for a SRE. Information from this study will enable urologists to accurately risk stratify patients with asymptomatic renal stones

The major genetic determinants of HIV-1 control affect HLA class I peptide presentation.

Infectious and inflammatory diseases have repeatedly shown strong genetic associations within the major histocompatibility complex (MHC); however, the basis for these associations remains elusive. To define host genetic effects on the outcome of a chronic viral infection, we performed genome-wide association analysis in a multiethnic cohort of HIV-1 controllers and progressors, and we analyzed the effects of individual amino acids within the classical human leukocyte antigen (HLA) proteins. We identified >300 genome-wide significant single-nucleotide polymorphisms (SNPs) within the MHC and none elsewhere. Specific amino acids in the HLA-B peptide binding groove, as well as an independent HLA-C effect, explain the SNP associations and reconcile both protective and risk HLA alleles. These results implicate the nature of the HLA-viral peptide interaction as the major factor modulating durable control of HIV infection