Universality class of the special adsorption point of two-dimensional lattice polymers.

In recent work [Rodrigues et al., Phys. Rev. E 100, 022121 (2019)10.1103/PhysRevE.100.022121], evidence was found that the surface adsorption transition of interacting self-avoiding trails (ISATs) placed on the square lattice displays a nonuniversal behavior at the special adsorption point (SAP) where the collapsing polymers adsorb. In fact, different surface exponents ϕ^{(s)} and 1/δ^{(s)} were found at the SAP depending on whether the surface orientation is horizontal (HS) or diagonal (DS). Here, we revisit these systems and study other ones, through extensive Monte Carlo simulations, considering much longer trails than previous works. Importantly, we demonstrate that the different exponents observed in the reference above are due to the presence of a surface-attached-globule (SAG) phase in the DS system, which changes the multicritical nature of the SAP and is absent in the HS case. By considering a modified horizontal surface (mHS), on which the trails are forbidden from having two consecutive steps, resembling the DS situation, a stable SAG phase is found in the phase diagram, and both DS and mHS systems present similar 1/δ^{(s)} exponents at the SAP, namely, 1/δ^{(s)}≈0.44, whereas 1/δ^{(s)}≈0.34 in the HS case. Intriguingly, while ϕ^{(s)}≈1/δ^{(s)} is found for the DS and HS scenarios, as expected, in the mHS case ϕ^{(s)} is about 10% smaller than 1/δ^{(s)}. These results strongly indicate that at least two universality classes exist for the SAPs of adsorbing ISATs on the square lattice

Moesin orchestrates the reorganisation of the actin cortex and shape changes during mitotic progression in an epithelium

Animal cells endure dramatic actin-dependent changes in shape as they progress through mitosis – they round up at mitotic entry, elongate at anaphase and split into two at cytokinesis. In this thesis I explore the role of Moesin, an actin-membrane crosslinker and the sole ERM protein expressed in Drosophila, in orchestrating rearrangements of the actin cortex and morphological changes in epithelial cells undergoing mitosis. To perform my studies I used the fly notum and sensory organ precursor (SOP) cells therein as a model system. In this thesis I show that Moesin is required for the stabilisation of the actomyosin cortex at metaphase. This mechanism is dependent upon phosphorylation of Moesin by the Slik kinase, which activates the ERM protein. Reduced levels of Moesin or Slik lead to myosin-II-driven cortical instabilities. Cortical stabilisation in mitotic SOP cells ensures the efficient accumulation of fate determinants at the plasma membrane. At mitotic exit, a pool of active, phosphorylated Moesin is lost from the cell poles, thereby triggering polar relaxation and initiating anaphase cell elongation. These two events precede furrow formation, are independent of centrosome or astral microtubules-derived signals, and are induced by proximity of the segregating chromosomes to the cell poles. I show that a pool of kinetochore-localised PP1-87B phosphatase and its regulatory subunit Sds22 inactivate cortical Moesin and elicit the dismantling of the actomyosin cortex at mid-anaphase. Cells with reduced amounts of PP1-87B or Sds22 fail to clear Moesin and actin from the anaphase poles. Importantly, these defects in polar relaxation are mimicked by the expression of a constitutively active form of Moesin in fly tissues. Finally, I demonstrate that delocalisation of PP1/Sds22 from the kinetochores via KNL1 depletion abolishes polar blebbing at anaphase and impairs cell elongation. My work shows how the dynamic regulation of Moesin activation and localisation controls shape changes in cells undergoing mitosis. Moreover, it sheds light on a novel mechanism of polar relaxation at anaphase, in which a kinetochore-derived signal instructs the cell cortex to become polarised, thereby initiating cytokinesis

Kinetochore-localized PP1-Sds22 couples chromosome segregation to polar relaxation

Cell division requires the precise coordination of chromosome segregation and cytokinesis. This coordination is achieved by the recruitment of an actomyosin regulator, Ect2, to overlapping microtubules at the centre of the elongating anaphase spindle. Ect2 then signals to the overlying cortex to promote the assembly and constriction of an actomyosin ring between segregating chromosomes. Here, by studying division in proliferating Drosophila and human cells, we demonstrate the existence of a second, parallel signalling pathway, which triggers the relaxation of the polar cell cortex at mid anaphase. This is independent of furrow formation, centrosomes and microtubules and, instead, depends on PP1 phosphatase and its regulatory subunit Sds22 (refs 2, 3). As separating chromosomes move towards the polar cortex at mid anaphase, kinetochore-localized PP1-Sds22 helps to break cortical symmetry by inducing the dephosphorylation and inactivation of ezrin/radixin/moesin proteins at cell poles. This promotes local softening of the cortex, facilitating anaphase elongation and orderly cell division. In summary, this identifies a conserved kinetochore-based phosphatase signal and substrate, which function together to link anaphase chromosome movements to cortical polarization, thereby coupling chromosome segregation to cell division

Adsorption of interacting self-avoiding trails in two dimensions

We investigate the surface adsorption transition of interacting self-avoiding square lattice trails onto a straight boundary line. The character of this adsorption transition depends on the strength of the bulk interaction, which induces a collapse transition of the trails from a swollen to a collapsed phase, separated by a critical state. If the trail is in the critical state, the universality class of the adsorption transition changes; this is known as the special adsorption point. Using flatPERM, a stochastic growth Monte Carlo algorithm, we simulate the adsorption of self-avoiding interacting trails on the square lattice using three different boundary scenarios which differ with respect to the orientation of the boundary and the type of surface interaction. We confirm the expected phase diagram, showing swollen, collapsed, and adsorbed phases in all three scenarios, and confirm universality of the normal adsorption transition at low values of the bulk interaction strength. Intriguingly, we cannot confirm universality of the special adsorption transition. We find different values for the exponents; the most likely explanation is that this is due to the presence of strong corrections to scaling at this point.Comment: 10 pages, 8 figure

Multi-level Autonomic Business Process Management

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-642-38484-4_14Nowadays, business processes are becoming increasingly complex and heterogeneous. Autonomic Computing principles can reduce this complexity by autonomously managing the software systems and the running processes, their states and evolution. Business Processes that are able to be self-managed are referred to as Autonomic Business Processes (ABP). However, a key challenge is to keep the models of such ABP understandable and expressive in increasingly complex scenarios. This paper discusses the design aspects of an autonomic business process management system able to self-manage processes based on operational adaptation. The goal is to minimize human intervention during the process definition and execution phases. This novel approach, named MABUP, provides four well-defined levels of abstraction to express business and operational knowledge and to guide the management activity; namely, Organizational Level, Technological Level, Operational Level and Service Level. A real example is used to illustrate our proposal.Research supported by CAPES, CNPQ and Spanish Ministry of Science and Innovation.Oliveira, K.; Castro, J.; España Cubillo, S.; Pastor López, O. (2013). Multi-level Autonomic Business Process Management. En Enterprise, Business-Process and Information Systems Modeling. Springer. 184-198. doi:10.1007/978-3-642-38484-4_14S184198España, S., González, A., Pastor, Ó.: Communication Analysis: A Requirements Engineering Method for Information Systems. In: van Eck, P., Gordijn, J., Wieringa, R. (eds.) CAiSE 2009. LNCS, vol. 5565, pp. 530–545. Springer, Heidelberg (2009)Ganek, A.G., Corbi, T.A.: The dawning of the autonomic computing era. IBM Systems Journal 42(1), 5–18 (2003)Gonzalez, A., et al.: Unity criteria for Business Process Modelling. In: Third International Conference on Research Challenges in Information Science, RCIS 2009, pp. 155–164 (2009)Greenwood, D., Rimassa, G.: Autonomic Goal-Oriented Business Process Management. Management, 43 (2007)Haupt, T., et al.: Autonomic execution of computational workflows. In: 2011 Federated Conference on Computer Science and Information Systems, FedCSIS, pp. 965–972 (2011)Kephart, J.O., Chess, D.M.: The vision of autonomic computing. IEEE (2003)Lee, K., et al.: Workflow adaptation as an autonomic computing problem. In: Proceedings of the 2nd Workshop on Workflows in Support of Large-Scale Science, New York, NY, USA, pp. 29–34 (2007)Mosincat, A., Binder, W.: Transparent Runtime Adaptability for BPEL Processes. In: Bouguettaya, A., Krueger, I., Margaria, T. (eds.) ICSOC 2008. LNCS, vol. 5364, pp. 241–255. Springer, Heidelberg (2008)Oliveira, K., et al.: Towards Autonomic Business Process Models. In: International Conference on Software Engineering and Knowledge, SEKE 2012, San Francisco, California, USA (2012)Rahman, M., et al.: A taxonomy and survey on autonomic management of applications in grid computing environments. Concurr. Comput.: Pract. Exper. 23(16), 1990–2019 (2011)Reijers, H.A., Mendling, J.: Modularity in process models: Review and effects. In: Dumas, M., Reichert, M., Shan, M.-C. (eds.) BPM 2008. LNCS, vol. 5240, pp. 20–35. Springer, Heidelberg (2008)Rodrigues Nt., J.A., Monteiro Jr., P.C.L., de O. Sampaio, J., de Souza, J.M., Zimbrão, G.: Autonomic Business Processes Scalable Architecture. In: ter Hofstede, A.H.M., Benatallah, B., Paik, H.-Y. (eds.) BPM Workshops 2007. LNCS, vol. 4928, pp. 78–83. Springer, Heidelberg (2008)Strohmaier, M., Yu, E.: Towards autonomic workflow management systems. ACM Press (2006)Terres, L.D., et al.: Selection of Business Process for Autonomic Automation. In: 2010 14th IEEE International Enterprise Distributed Object Computing Conference, pp. 237–246 (October 2010)Tretola, G., Zimeo, E.: Autonomic internet-scale workflows. In: Proceedings of the 3rd International Workshop on Monitoring, Adaptation and Beyond, New York, NY, USA, pp. 48–56 (2010)Vedam, H., Venkatasubramanian, V.: A wavelet theory-based adaptive trend analysis system for process monitoring and diagnosis. In: Proceedings of the 1997 American Control Conference, vol. 1, pp. 309–313 (June 1997)Wang, Y., Mylopoulos, J.: Self-Repair through Reconfiguration: A Requirements Engineering Approach. In: 2009 IEEE/ACM International Conference on Automated Software Engineering, pp. 257–268 (November 2009)Yu, T., Lin, K.: Adaptive algorithms for finding replacement services in autonomic distributed business processes. In: Proceedings Autonomous Decentralized Systems, ISADS 2005, pp. 427–434 (2005

PP1-mediated moesin dephosphorylation couples polar relaxation to mitotic exit.

Animal cells undergo dramatic actin-dependent changes in shape as they progress through mitosis; they round up upon mitotic entry and elongate during chromosome segregation before dividing into two [1-3]. Moesin, the sole Drosophila ERM-family protein [4], plays a critical role in this process, through the construction of a stiff, rounded metaphase cortex [5-7]. At mitotic exit, this rigid cortex must be dismantled to allow for anaphase elongation and cytokinesis through the loss of the active pool of phospho-Thr559moesin from cell poles. Here, in an RNA interference (RNAi) screen for phosphatases involved in the temporal and spatial control of moesin, we identify PP1-87B RNAi as having elevated p-moesin levels and reduced cortical compliance. In mitosis, RNAi-induced depletion of PP1-87B or depletion of a conserved noncatalytic PP1 phosphatase subunit Sds22 leads to defects in p-moesin clearance from cell poles at anaphase, a delay in anaphase elongation, together with defects in bipolar anaphase relaxation and cytokinesis. Importantly, similar cortical defects are seen at anaphase following the expression of a constitutively active, phosphomimetic version of moesin. These data reveal a new role for the PP1-87B/Sds22 phosphatase, an important regulator of the metaphase-anaphase transition, in coupling moesin-dependent cell shape changes to mitotic exit

The economic burden of tuberculosis and latent tuberculosis in people living with HIV in Brazil: a cost study from the patient perspective.

OBJECTIVE: The objective of this study was to evaluate the direct and indirect costs of tuberculosis (TB) (active and latent TB [LTB]) and HIV co-infection from the patient perspective. STUDY DESIGN: Costing study conducted alongside a pragmatic clinical trial. METHODS: The study was conducted in Brazil in a referral service for HIV/AIDS. We applied a standardised questionnaire to collect data about out-of-pocket expenses and indirect cost. The questionnaire was applied at every patient's appointment in the referral service after TB or LTB diagnosis. We followed all patients' pathways during the prediagnosis period and treatment period. For patients on sickness benefit due to TB/HIV, income loss was calculated as the difference between an employee's wages forgone and the sickness benefit received. The monetary value of the time loss was calculated based on the Brazilian minimum wage/2015. RESULTS: Among 239 people living with HIV recruited in the first year of the trial, 31 patients were included into the costing study, 26 patients who were diagnosed and treated for TB/HIV and five patients who were diagnosed and treated for LTB/HIV. TB/HIV patients incurred higher total costs than LTB/HIV (US$1,429 vs US$ 166). The main cost component for TB/HIV was indirect costs, especially income loss (US$ 749). CONCLUSIONS: Public health policies may address ways to prevent high patients' costs through the introduction of more accurate algorithms for TB diagnosis to prevent delays in the diagnosis and treatment