Border Collision Bifurcations in a Generalized Model of Population Dynamics

We analyze the dynamics of a generalized discrete time population model of a two-stage species with recruitment and capture. This generalization, which is inspired by other approaches and real data that one can find in literature, consists in considering no restriction for the value of the two key parameters appearing in the model, that is, the natural death rate and the mortality rate due to fishing activity. In the more general case the feasibility of the system has been preserved by posing opportune formulas for the piecewise map defining the model. The resulting two-dimensional nonlinear map is not smooth, though continuous, as its definition changes as any border is crossed in the phase plane. Hence, techniques from the mathematical theory of piecewise smooth dynamical systems must be applied to show that, due to the existence of borders, abrupt changes in the dynamic behavior of population sizes and multistability emerge. The main novelty of the present contribution with respect to the previous ones is that, while using real data, richer dynamics are produced, such as fluctuations and multistability. Such new evidences are of great interest in biology since new strategies to preserve the survival of the species can be suggested

Health system response during the european refugee crisis : policy and practice analysis in four Italian regions

The decentralization of the provision of health services at the subnational level produces variations in healthcare offered to asylum seekers (ASs) across the different Italian regions, even if they are entitled to healthcare through the national health service. The present study aims to map the healthcare path and regional policies for ASs upon arrival and identify challenges and best practices. This is a multicentric, qualitative study of migrant health policies and practices at the regional level within four Italian regions. For the analysis, a dedicated tool for the systematic comparison of policies and practices was developed. The collection and analysis of data demonstrated the presence of many items of international recommendations, even if many gaps exist and differences between regions remain. The analysis of practices permitted the identification of three models of care and access. Some aspects identified are as follows: fragmentation and barriers to access; a weakness in or lack of a governance system, with the presence of many actors involved; variability in the response between territories. The inclusion of ASs in healthcare services requires intersectoral actions, involving healthcare sectors and other actors within local social structures, in order to add value to local resources and practices, reinforce networks and contribute to social integration

Buccal mucosa is a promising graft in Peyronie's disease surgery. Our experience and a brief literature review on autologous grafting materials

AIM: Peyronie's Disease (PD) is an under reported acquired benign condition that, at the moment, is not curable with medical therapy. Surgery represent the gold standard of treatment. Surgical approaches are several and they consist in "plication techniques" or plaque incision/excision with grafting of resulting albuginea defect. Among grafting procedures, albuginea defect substitution with autologous materials demonstrated over the years not inferior results respect to heterologous grafts. Buccal mucosa graft (BMG) is not usually emphasized in many review articles and clinical series are yet limited. METHODS: We present our experience with seventeen plaque incision procedures and BMG in surgical correction of complex penile curvatures due to PD performed in a period of 30 months. Our analyses was focused on buccal mucosa graft characteristics as major determinant of the surgical success. We also conducted a brief literature review on autologous grafting materials used in reconstructive penile surgery for PD. RESULTS: Our cosmetics and functional results consists in a 100% of functional penile straightening with no relapses and 5,8% of de novo erectile dysfunction. Mean age was 56.4 years, mean follow-up of 22.5 (6-36) months. No complications graft related were observed. Operative time was 115.3 minutes in mean. Over 94% of patients referred they were "really much better" and "much better" satisfied based on PGI-I questionnaire administrated at the last follow- up visit. CONCLUSION: BMG is revealing as an optimal choice for reconstructive surgery in PD. Anatomical characteristics consisting in the great elasticity, the quick integration time and the easy harvesting technique lead to high cosmetics and functional success rate, without omitting economical and invasiveness aspects

Multiband optical variability of 3C 279 on diverse time-scales

We have monitored the flat spectrum radio quasar, 3C 279, in the optical B, V, R, and I passbands from 2018 February to 2018 July for 24 nights, with a total of 716 frames, to study flux, colour, and spectral variability on diverse time-scales. 3C 279 was observed using seven different telescopes: two in India, two in Argentina, two in Bulgaria, and one in Turkey to understand the nature of the source in optical regime. The source was found to be active during the whole monitoring period and displayed significant flux variations in B, V, R, and I passbands. Variability amplitudes on intraday basis varied from 5.20 to 17.9 per cent. A close inspection of variability patterns during our observation cycle reveals simultaneity among optical emissions from all passbands. During the complete monitoring period, progressive increase in the amplitude of variability with frequency was detected for our target. The amplitudes of variability in B, V, R, and I passbands have been estimated to be 177 per cent, 172 per cent, 171 per cent, and 158 per cent, respectively. Using the structure function technique, we found intraday time-scales ranging from ∼23 min to about 115 min. We also studied colour–magnitude relationship and found indications of mild bluer-when-brighter trend on shorter time-scales. Spectral indices ranged from 2.3 to 3.0 with no clear trend on long-term basis. We have also generated spectral energy distributions for 3C 279 in optical B, V, R, and I passbands for 17 nights. Finally, possible emission mechanisms causing variability in blazars are discussed briefly.Fil: Agarwal, Aditi. Indian Institute of Astrophysics; IndiaFil: Cellone, Sergio Aldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Andruchow, Ileana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas; ArgentinaFil: Mammana, Luis Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Singh, Mridweeka. Aryabhatta Research Institute of Observational Sciences; IndiaFil: Anupama, G. C.. Indian Institute of Astrophysics; IndiaFil: Mihov, B.. Bulgarian Academy of Sciences; BulgariaFil: Raj, Ashish. Indian Institute of Astrophysics; IndiaFil: Slavcheva Mihova, L.. Bulgarian Academy of Sciences; BulgariaFil: Özdönmez, Aykut. Tübİtak National Observatory; TurquíaFil: Ege, Ergün. Istanbul University; Turquí

Diagnostic value of plasma p-tau181, NfL, and GFAP in a clinical setting cohort of prevalent neurodegenerative dementias

Background: Increasing evidence supports the use of plasma biomarkers of neurodegeneration and neuroinflammation to screen and diagnose patients with dementia. However, confirmatory studies are required to demonstrate their usefulness in the clinical setting. Methods: We evaluated plasma and cerebrospinal fluid (CSF) samples from consecutive patients with frontotemporal dementia (FTD) (n = 59), progressive supranuclear palsy (PSP) (n = 31), corticobasal syndrome (CBS) (n = 29), dementia with Lewy bodies (DLB) (n = 49), Alzheimer disease (AD) (n = 97), and suspected non-AD physiopathology (n = 51), as well as plasma samples from 60 healthy controls (HC). We measured neurofilament light chain (NfL), phospho-tau181 (p-tau181), and glial fibrillary acid protein (GFAP) using Simoa (all plasma biomarkers and CSF GFAP), CLEIA (CSF p-tau181), and ELISA (CSF NfL) assays. Additionally, we stratified patients according to the A/T/N classification scheme and the CSF α-synuclein real-time quaking-induced conversion assay (RT-QuIC) results. Results: We found good correlations between CSF and plasma biomarkers for NfL (rho = 0.668, p < 0.001) and p-tau181 (rho = 0.619, p < 0.001). Plasma NfL was significantly higher in disease groups than in HC and showed a greater increase in FTD than in AD [44.9 (28.1–68.6) vs. 21.9 (17.0–27.9) pg/ml, p < 0.001]. Conversely, plasma p-tau181 and GFAP levels were significantly higher in AD than in FTD [3.2 (2.4–4.3) vs. 1.1 (0.7–1.6) pg/ml, p < 0.001; 404.7 (279.7–503.0) vs. 198.2 (143.9–316.8) pg/ml, p < 0.001]. GFAP also allowed discriminating disease groups from HC. In the distinction between FTD and AD, plasma p-tau181 showed better accuracy (AUC 0.964) than NfL (AUC 0.791) and GFAP (AUC 0.818). In DLB and CBS, CSF amyloid positive (A+) subjects had higher plasma p-tau181 and GFAP levels than A− individuals. CSF RT-QuIC showed positive α-synuclein seeding activity in 96% DLB and 15% AD patients with no differences in plasma biomarker levels in those stratified by RT-QuIC result. Conclusions: In a single-center clinical cohort, we confirm the high diagnostic value of plasma p-tau181 for distinguishing FTD from AD and plasma NfL for discriminating degenerative dementias from HC. Plasma GFAP alone differentiates AD from FTD and neurodegenerative dementias from HC but with lower accuracy than p-tau181 and NfL. In CBS and DLB, plasma p-tau181 and GFAP levels are significantly influenced by beta-amyloid pathology

The first observed stellar occultations by the irregular satellite Phoebe (Saturn IX) and improved rotational period

peer reviewedWe report six stellar occultations by Phoebe (Saturn IX), an irregular satellite of Saturn, obtained between mid-2017 and mid-2019. The 2017 July 6 event was the first stellar occultation by an irregular satellite ever observed. The occultation chords were compared to a 3D shape model of the satellite obtained from Cassini observations. The rotation period available in the literature led to a sub-observer point at the moment of the observed occultations where the chords could not fit the 3D model. A procedure was developed to identify the correct sub-observer longitude. It allowed us to obtain the rotation period with improved precision compared to the currently known value from literature. We show that the difference between the observed and the predicted sub-observer longitude suggests two possible solutions for the rotation period. By comparing these values with recently observed rotational light curves and single- chord stellar occultations, we can identify the best solution for Phoebe's rotational period as 9.27365 ± 0.00002 h. From the stellar occultations, we also obtained six geocentric astrometric positions in the ICRS as realized by the Gaia DR2 with uncertainties at the 1-mas level

Multi-band behaviour of the TeV blazar PG 1553+113 in optical range on diverse timescales. Flux and spectral variations

Context. The TeV BL Lac object PG1553+113 is one of the primary candidates for a binary supermassive black hole system.Aims. We study the flux and spectral variability of PG1553+113 on intra-night to long-term timescales using (i) BVRI data collected over 76 nights from January 2016 to August 2019 involving nine optical telescopes and (ii) historical VR data (including ours) obtained for the period from 2005 to 2019.Methods. We analysed the light curves using various statistical tests, fitting and cross-correlation techniques, and methods for the search for periodicity. We examined the colour-magnitude diagrams before and after the corresponding light curves were corrected for the long-term variations.Results. Our intra-night monitoring, supplemented with literature data, result in a low duty cycle of ∼(10?18)%. In April 2019, we recorded a flare, which marks the brightest state of PG1553+113 for the period from 2005 to 2019: R ≃ 13.2mag. This flare is found to show a clockwise spectral hysteresis loop on its VR colour-magnitude diagram and a time lag in the sense that the V-band variations lead the R-band ones.We obtain estimates of the radius, the magnetic field strength, and the electron energy that characterize the emission region related to the flare.We find a median period of (2.21±0.04) years using the historical light curves. In addition, we detect a secondary period of about 210 days using the historical light curves corrected for the long-term variations. We briefly discuss the possible origin of this period.Fil: Agarwal, A.. Indian Institute Of Astrophysics; India. Raman Research Institute; IndiaFil: Mihov, B.. Institute Of Astronomy And Nao; BulgariaFil: Andruchow, Ileana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Cellone, Sergio Aldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Anupama, G. C.. Indian Institute Of Astrophysics; IndiaFil: Agrawal, V.. Embibe; IndiaFil: Zola, S.. Jagiellonian University; PoloniaFil: Slavcheva Mihova, L.. Institute Of Astronomy And Nao; BulgariaFil: Özdönmez, A.. Ataturk University; TurquíaFil: Ege, E.. Istanbul University; TurquíaFil: Raj, A.. University Enclave; IndiaFil: Mammana, Luis Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Zibecchi, Lorena Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Fernandez Lajus, Eduardo Eusebio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; Argentin

Multi-band behaviour of the TeV blazar PG 1553+113 in optical range on diverse timescales. Flux and spectral variations

Context. The TeV BL Lac object PG1553+113 is one of the primary candidates for a binary supermassive black hole system.Aims. We study the flux and spectral variability of PG1553+113 on intra-night to long-term timescales using (i) BVRI data collected over 76 nights from January 2016 to August 2019 involving nine optical telescopes and (ii) historical VR data (including ours) obtained for the period from 2005 to 2019.Methods. We analysed the light curves using various statistical tests, fitting and cross-correlation techniques, and methods for the search for periodicity. We examined the colour-magnitude diagrams before and after the corresponding light curves were corrected for the long-term variations.Results. Our intra-night monitoring, supplemented with literature data, result in a low duty cycle of ∼(10?18)%. In April 2019, we recorded a flare, which marks the brightest state of PG1553+113 for the period from 2005 to 2019: R ≃ 13.2mag. This flare is found to show a clockwise spectral hysteresis loop on its VR colour-magnitude diagram and a time lag in the sense that the V-band variations lead the R-band ones.We obtain estimates of the radius, the magnetic field strength, and the electron energy that characterize the emission region related to the flare.We find a median period of (2.21±0.04) years using the historical light curves. In addition, we detect a secondary period of about 210 days using the historical light curves corrected for the long-term variations. We briefly discuss the possible origin of this period.Fil: Agarwal, A.. Indian Institute Of Astrophysics; India. Raman Research Institute; IndiaFil: Mihov, B.. Institute Of Astronomy And Nao; BulgariaFil: Andruchow, Ileana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Cellone, Sergio Aldo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Anupama, G. C.. Indian Institute Of Astrophysics; IndiaFil: Agrawal, V.. Embibe; IndiaFil: Zola, S.. Jagiellonian University; PoloniaFil: Slavcheva Mihova, L.. Institute Of Astronomy And Nao; BulgariaFil: Özdönmez, A.. Ataturk University; TurquíaFil: Ege, E.. Istanbul University; TurquíaFil: Raj, A.. University Enclave; IndiaFil: Mammana, Luis Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; ArgentinaFil: Zibecchi, Lorena Cecilia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; ArgentinaFil: Fernandez Lajus, Eduardo Eusebio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Astrofísica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias Astronómicas y Geofísicas. Instituto de Astrofísica La Plata; Argentin