Time travel paradoxes, path integrals, and the many worlds interpretation of quantum mechanics

We consider two approaches to evading paradoxes in quantum mechanics with closed timelike curves (CTCs). In a model similar to Politzer's, assuming pure states and using path integrals, we show that the problems of paradoxes and of unitarity violation are related; preserving unitarity avoids paradoxes by modifying the time evolution so that improbable events bewcome certain. Deutsch has argued, using the density matrix, that paradoxes do not occur in the "many worlds interpretation". We find that in this approach account must be taken of the resolution time of the device that detects objects emerging from a wormhole or other time machine. When this is done one finds that this approach is viable only if macroscopic objects traversing a wormhole interact with it so strongly that they are broken into microscopic fragments.Comment: no figure

The use and adherence of oral anticoagulants in Primary Health Care in Catalunya, Spain: A real-world data cohort study

Objective: We aimed to describe sociodemographic, comorbidities, co-medication and risk of thromboembolic events and bleeding in patients with NVAF initiating oral anticoagulants (OAC) for stroke prevention, and to estimate adherence and persistence to OAC. Setting: Primary Health Care (PHC) in the Catalan Health Institute (ICS), Catalunya, Spain. Participants: All NVAF adult patients initiating OAC for stroke prevention in August 2013-December 2015. Methods: Population-based cohort study. Persistence was measured in patients initiating OAC in August 2013-December 2014. Data source: SIDIAP, which captures electronic health records from PHC in the (ICS), covering approximately 5.8 million people. Results: 51,690 NVAF patients initiated OAC; 47,197 (91.3%) were naive to OAC and 32,404 (62.7%) initiated acenocoumarol. Mean age was 72.8 years (SD 12.3) and 49.4% were women. Platelet-aggregation inhibitors were taken by 9105 (17.6%) of the patients. Persistence and adherence were estimated up to the end of follow-up. For 22,075 patients, persistence was higher among the non-naive patients [n = 258 (61.7%)] than among the naive [n = 11,502 (53.1%)]. Adherence was estimated for patients initiating DOAC and it was similar in naive and non-naive patients. Among the naive to DOAC treatment, those starting rivaroxaban showed a highest proportion [(n = 360 (80.1%)] of good adherence at implementation (MPR > 80%) while patients starting dabigatran were less adherent [n=203 (47.8%)]. Conclusions: Acenocoumarol was the most frequently prescribed OAC as first therapy in NVAF patients. Non-naive to DOAC showed better persistence than naive. Rivaroxaban showed higher proportion of adherent patients during the implementation phase than apixaban and dabigatran the lowest. (C) 2020 The Authors. Published by Elsevier Espana, S.L.U

Sciatic nerve movement in the deep gluteal space during hip rotations maneuvers

We hypothesize that the sciatic nerve in the subgluteal space has a specific behavior during internal and external coxofemoral rotation and during isometric contraction of the internal and external rotator muscles of the hip. In 58 healthy volunteers, sciatic nerve behavior was studied by ultrasound during passive internal and external hip rotation movements and during isometric contraction of internal and external rotators. Using MATLAB software, changes in nerve curvature at the beginning and end of each exercise were evaluated for longitudinal catches and axial movement for transverse catches. In the long axis, it was observed that during the passive internal rotation and during the isometric contraction of external rotators, the shape of the curve increased significantly while during the passive external rotation and the isometric contraction of the internal rotators the curvature flattened out. During passive movements in internal rotation, on the short axis, the nerve tended to move laterally and forward, while during external rotation the tendency of the nerve was to move toward a medial and backward position. During the isometric exercises, this displacement was less in the passive movements. Passive movements of hip rotation and isometric contraction of the muscles affect the sciatic nerve in the subgluteal space. Retrotrochanteric pain may be related to both the shear effect of the subgluteus muscles and the endoneural and mechanosensitive aggression to which the sciatic nerve is subjected

Validity of ICD-9 and ICD-10 codes used to identify acute liver injury: a study in three European data sources

This is the peer reviewed version of the following article: Forns, J. [et al.]. Validity of ICD-9 and ICD-10 codes used to identify acute liver injury: a study in three European data sources. "Pharmacoepidemiology and drug safety", 6 Juny 2019, vol. 28, núm. 7, p. 965-975, which has been published in final form at 10.1002/pds.4803. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."Purpose Validating cases of acute liver injury (ALI) in health care data sources is challenging. Previous validation studies reported low positive predictive values (PPVs). Methods Case validation was undertaken in a study conducted from 2009 to 2014 assessing the risk of ALI in antidepressants users in databases in Spain (EpiChron and SIDIAP) and the Danish National Health Registers. Three ALI definitions were evaluated: primary (specific hospital discharge codes), secondary (specific and nonspecific hospital discharge codes), and tertiary (specific and nonspecific hospital and outpatient codes). The validation included review of patient profiles (EpiChron and SIDIAP) and of clinical data from medical records (EpiChron and Denmark). ALI cases were confirmed when liver enzyme values met a definition by an international working group. Results Overall PPVs (95% CIs) for the study ALI definitions were, for the primary ALI definition, 84% (60%-97%) (EpiChron), 60% (26%-88%) (SIDIAP), and 74% (60%-85%) (Denmark); for the secondary ALI definition, 65% (45%-81%) (EpiChron), 40% (19%-64%) (SIDIAP), and 70% (64%-77%) (Denmark); and for the tertiary ALI definition, 25% (18%-34%) (EpiChron), 8% (7%-9%) (SIDIAP), and 47% (42%-52%) (Denmark). The overall PPVs were higher for specific than for nonspecific codes and for hospital discharge than for outpatient codes. The nonspecific code “unspecified jaundice” had high PPVs in Denmark. Conclusions PPVs obtained apply to patients using antidepressants without preexisting liver disease or ALI risk factors. To maximize validity, studies on ALI should prioritize hospital specific discharge codes and should include hospital codes for unspecified jaundice. Case validation is required when ALI outpatient cases are considered.Peer ReviewedPostprint (author's final draft

Changes in membrane fluidity of gilthead seabream Sparus auratus L., 1758 hepatocytes subjected to falling temperatures

We present a study on membrane fluidity dynamics in hepatocytes of gilthead seabream Sparus auratus L., 1758 when exposed to thermal variations. A group of 15 specimens was acclimated to a control physiological temperature (17 ºC) during one week; the fish were then subjected to diminishing temperatures during the following week, reaching 7.5 ºC, and a subgroup was maintained for two weeks, reaching a final temperature of 6 ºC. The temperature drop resulted in an anisotropy change from 0.2205 (r) under control conditions to 0.164 (r) at 7.5 ºC, after one week. No significant differences between this group and the fish later kept at lower temperatures, reaching 6 ºC, were observed after one week; this can be interpreted as a thermal adaptation of the membranes to colder conditions. The adaptive fluidity changes at temperatures of 17, 7.5, and 6 ºC were coin-cident with the observed lessening of Na⁺/K⁺-ATP-ase enzymatic activity as temperatures fell. Therefore, it is possible that after a decrease in water temperature, common in farmed fish under winter conditions, membrane fluidity changes could be correlated with decreasing enzymatic activity in membrane ATP-ases, as an adaptive strategy.Con el fin de estudiar la influencia de la temperatura en la dinámica de la fluidez de las membranas de hepatocitos en dorada Sparus auratus L., 1758, se aclimataron 15 ejemplares a 17 ºC, como temperatura fisiológica de control, durante una semana. Tras la extracción de una muestra, el grupo fue sometido a descenso térmico hasta alcanzar, en una semana, los 7,5 ºC, y se muestrearon de nuevo. Los ejemplares restantes fueron enfriados durante una semana más hasta alcanzar los 6 ºC. La disminución de la temperatura produjo un cambio de anisotropía, que varió de 0,2205 (r) en las condiciones de control, a 0,164 (r) con el descenso a 7,5 ºC de la primera semana, y no se apreciaron diferencias significativas entre este último grupo y los peces mantenidos a bajas temperaturas hasta llegar, otra semana después, a 6 ºC, revelando que las membranas sufrieron una adaptación al descenso térmico. El cambio de fluidez de las membranas adaptadas a las distintas temperaturas (17, 7,5 y 6 ºC) concuerda con los datos obtenidos para la enzima de membrana Na+/K+/-ATP-asa, cuya actividad enzimática también disminuye con el descenso térmico. Por tanto, es verosímil que, después de una disminución brusca de la temperatura del agua, como suele ocurrir en invierno con las condiciones de cultivo de peces, los cambios de la fluidez de la membrana se vean acompañados por una disminución de los valores de la actividad enzimática de las ATP-asas de membrana como resultado de la adaptación a la nueva temperatura.Instituto Español de Oceanografí

The effect of excess dietary manganese on uninfected and Ascaridia galli infected chicks

Abstract The effect of dietary manganese from two different sources on chicks (uninfected and infected with Ascaridia galli) was studied

Looking behind occlusions: A study on amodal segmentation for robust on-tree apple fruit size estimation

The detection and sizing of fruits with computer vision methods is of interest because it provides relevant information to improve the management of orchard farming. However, the presence of partially occluded fruits limits the performance of existing methods, making reliable fruit sizing a challenging task. While previous fruit segmentation works limit segmentation to the visible region of fruits (known as modal segmentation), in this work we propose an amodal segmentation algorithm to predict the complete shape, which includes its visible and occluded regions. To do so, an end-to-end convolutional neural network (CNN) for simultaneous modal and amodal instance segmentation was implemented. The predicted amodal masks were used to estimate the fruit diameters in pixels. Modal masks were used to identify the visible region and measure the distance between the apples and the camera using the depth image. Finally, the fruit diameters in millimetres (mm) were computed by applying the pinhole camera model. The method was developed with a Fuji apple dataset consisting of 3925 RGB-D images acquired at different growth stages with a total of 15,335 annotated apples, and was subsequently tested in a case study to measure the diameter of Elstar apples at different growth stages. Fruit detection results showed an F1-score of 0.86 and the fruit diameter results reported a mean absolute error (MAE) of 4.5 mm and R2 = 0.80 irrespective of fruit visibility. Besides the diameter estimation, modal and amodal masks were used to automatically determine the percentage of visibility of measured apples. This feature was used as a confidence value, improving the diameter estimation to MAE = 2.93 mm and R2 = 0.91 when limiting the size estimation to fruits detected with a visibility higher than 60%. The main advantages of the present methodology are its robustness for measuring partially occluded fruits and the capability to determine the visibility percentage. The main limitation is that depth images were generated by means of photogrammetry methods, which limits the efficiency of data acquisition. To overcome this limitation, future works should consider the use of commercial RGB-D sensors. The code and the dataset used to evaluate the method have been made publicly available at https://github.com/GRAP-UdL-AT/Amodal_Fruit_SizingThis work was partly funded by the Departament de Recerca i Universitats de la Generalitat de Catalunya (grant 2021 LLAV 00088), the Spanish Ministry of Science, Innovation and Universities (grants RTI2018-094222-B-I00 [PAgFRUIT project], PID2021-126648OB-I00 [PAgPROTECT project] and PID2020-117142GB-I00 [DeeLight project] by MCIN/AEI/10.13039/501100011033 and by “ERDF, a way of making Europe”, by the European Union). The work of Jordi Gené Mola was supported by the Spanish Ministry of Universities through a Margarita Salas postdoctoral grant funded by the European Union - NextGenerationEU. We would also like to thank Nufri (especially Santiago Salamero and Oriol Morreres) for their support during data acquisition, and Pieter van Dalfsen and Dirk de Hoog from Wageningen University & Research for additional data collection used in the case study.info:eu-repo/semantics/publishedVersio

Safety of cilostazol in peripheral artery disease: a cohort from a primary healthcare electronic database

Background: Cilostazol has been associated with spontaneous reports of cardiovascular adverse events and serious bleeding. The objective of this study is to determine the relative risk of cardiovascular adverse events or haemorrhages in patients with peripheral artery disease treated with cilostazol in comparison to pentoxifylline users. Methods: Population-based cohort study including all individuals older than 40 who initiated cilostazol or pentoxifylline during 2009–2011 in SIDIAP database. The two treatment groups were matched through propensity score (PS). Results: Nine thousand one hundred twenty-nine patients met inclusion criteria and after PS matching, there were 2905 patients in each group. 76% of patients were men, with similar mean ages in both groups (68.8 for cilostazol and 69.4 for pentoxifylline). There were no differences in bleeding, cerebrovascular and cardiovascular events between both groups. Conclusions: Patients treated with cilostazol were different from those treated with pentoxifylline at baseline, so they were matched through PS. We did not find differences between treatment groups in the incidence of bleeding or cardiovascular and cerebrovascular events. Cilostazol should be used with precaution in elderly polymedicated patients

Statin use and the risk of colorectal cancer in a population-based electronic health records study

There is extensive debate regarding the protective effect of 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors (statins) on colorectal cancer (CRC). We aimed to assess the association between CRC risk and exposure to statins using a large cohort with prescription data. We carried out a case-control study in Catalonia using the System for Development of Primary Care Research (SIDIAP) database that recorded patient diseases history and linked data on reimbursed medication. The study included 25 811 cases with an incident diagnosis of CRC between 2010 and 2015 and 129 117 frequency-matched controls. Subjects were classified as exposed to statins if they had ever been dispensed statins. Analysis considering mean daily defined dose, cumulative duration and type of statin were performed. Overall, 66 372 subjects (43%) were exposed to statins. There was no significant decrease of CRC risk associated to any statin exposure (OR = 0.98; 95% CI: 0.95-1.01). Only in the stratified analysis by location a reduction of risk for rectal cancer was observed associated to statin exposure (OR = 0.87; 95% CI: 0.81-0.92). This study does not support an overall protective effect of statins in CRC, but a protective association with rectal cancer merits further research

Eleven-month longitudinal study of antibodies in SARS-CoV-2 exposed and naïve primary health care workers upon COVID-19 vaccination

We evaluated the kinetics of antibody responses to Two years into the COVID-19 pandemic and 1 year after the start of vaccination rollout, the world faced a peak of cases associated with the highly contagious Omicron variant of concern (VoC) of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) and nucleocapsid (N) antigens over five cross-sectional visits (January-November 2021), and the determinants of pre-booster immunoglobulin levels, in a prospective cohort of vaccinated primary health care workers in Catalonia, Spain. Antibodies against S antigens after a full primary vaccination course, mostly with BNT162b2, decreased steadily over time and were higher in pre-exposed (n = 247) than naive (n = 200) individuals, but seropositivity was maintained at 100% (100% IgG, 95.5% IgA, 30.6% IgM) up to 319 days after the first dose. Antibody binding to variants of concern was highly maintained for IgG compared to wild type but significantly reduced for IgA and IgM, particularly for Beta and Gamma. Factors significantly associated with longer-term antibodies included age, sex, occupation, smoking, adverse reaction to vaccination, levels of pre-vaccination SARS-CoV-2 antibodies, interval between disease onset and vaccination, hospitalization, oxygen supply, post COVID and symptomatology. Earlier morning vaccination hours were associated with higher IgG responses in pre-exposed participants. Symptomatic breakthroughs occurred in 9/447 (2.01%) individuals, all among naive (9/200, 4.5%) and generally boosted antibody responses. Additionally, an increase in IgA and/or IgM seropositivity to variants, and N seroconversion at later time points (6.54%), indicated asymptomatic breakthrough infections, even among pre-exposed. Seropositivity remained highly stable over almost a year after vaccination. However, gradually waning of anti-S IgGs that correlate with neutralizing activity, coupled to evidence of an increase in breakthrough infections during the Delta and Omicron predominance, provides a rationale for booster immunization