Sprouting angiogenesis, the formation of new vessels from preexisting vasculature, is an essential process in the regeneration of new tissues as well as in the development of some diseases like cancer. Although early studies identified chemical signaling as the main driver of this process, many recent studies have shown a strong role of mechanical signals in the formation of new capillaries. Different types of mechanical signals (e.g., external forces, cell traction forces, and blood flow-induced shear forces) have been shown to play distinct roles in the process; however, their interplay remains still largely unknown. During the last decades, mathematical and computational modeling approaches have been developed to investigate and better understand the mechanisms behind mechanically driven angiogenesis. In this manuscript, we review computational models of angiogenesis with a focus on models investigating the role of mechanics on the process. Our aim is not to provide a detailed review on model methodology but to describe what we have learnt from these models. We classify models according to the mechanical signals being investigated and describe how models have looked into their role on the angiogenic process. We show that a better understanding of the mechanobiology of the angiogenic process will require the development of computer models that incorporate the interactions between the multiple mechanical signals and their effect on cellular responses, since they all seem to play a key in sprout patterning. In the end, we describe some of the remaining challenges of computational modeling of angiogenesis and discuss potential avenues for future research.
View lessAflatoxins (AFs), ochratoxin A (OTA), citrinin (CIT), fumonisin B-1 (FB1), zearalenone (ZEN), and deoxynivalenol (DON) are mycotoxins that may contaminate diets, especially in low-income settings, with potentially severe health consequences. This study investigates the exposure of 439 pregnant women in rural Bangladesh to 35 mycotoxins and their corresponding health risks and links their exposure to certain foods and local stimulants. Overall, 447 first-morning urine samples were collected from pregnant women between July 2018 and November 2019. Mycotoxin biomarkers were quantified by DaS-HPLC-MS/MS. Urinary concentration of frequently occurring mycotoxins was used to estimate dietary mycotoxin exposure. Median regression analyses were performed to investigate the association between the consumption of certain foods and local stimulants, and urinary concentration of frequently occurring mycotoxins. Only in 17 of 447 urine samples (4%) were none of the investigated mycotoxins detected. Biomarkers for six major mycotoxins (AFs, CIT, DON, FB1, OTA, and ZEN) were detected in the urine samples. OTA (95%), CIT (61%), and DON (6%) were most frequently detected, with multiple mycotoxins co-occurring in 281/447 (63%) of urine samples. Under the lowest exposure scenario, dietary exposure to OTA, CIT, and DON was of public health concern in 95%, 16%, and 1% of the pregnant women, respectively. Consumption of specific foods and local stimulants-betel nut, betel leaf, and chewing tobacco-were associated with OTA, CIT, and DON urine levels. In conclusion, exposure to multiple mycotoxins during early pregnancy is widespread in this rural community and represents a potential health risk for mothers and their offspring.
View lessBackground: The impact of the prior fixation mode on the treatment outcome of chronic periprosthetic joint infection (PJI) of the hip is unclear. Removal of cemented total hip arthroplasty (THA) is particularly challenging and residual cement might be associated with reinfection. This study seeks to compare the results of two-stage revision for PJI in cemented and cementless THA.
Methods: We reviewed 143 consecutive patients undergoing two-stage revision THA for PJI between 2013 and 2018. Thirty-six patients with a fully cemented (n = 6), hybrid femur (n = 26) or hybrid acetabulum (n = 4) THA (cemented group) were matched 1:2 with a cohort of 72 patients who underwent removal of a cementless THA (cementless group). Groups were matched by sex, age, number of prior surgeries and history of infection treatment. Outcomes included microbiological results, interim re-debridement, reinfection, all-cause revision, and modified Harris hip scores (mHHS). Minimum follow-up was 2 years.
Results: Compared with PJI in cementless THA, patients undergoing removal of cemented THA had increasingly severe femoral bone loss (p = 0.004). Patients in the cemented group had an increased risk for positive cultures during second-stage reimplantation (22% compared to 8%, p = 0.043), higher rates of reinfection (22% compared to 7%, p = 0.021) and all-cause revision (31% compared to 14%, p = 0.039) compared to patients undergoing two-stage revision of cementless THA. Periprosthetic femoral fractures were more frequent in the group of patients with prior cementation (p = .004). Mean mHHS had been 37.5 in the cemented group and 39.1 in the cementless group, and these scores improved significantly in both groups (p < 0.01).
Conclusion: This study shows that chronic infection in cemented THA might be associated with increased bone loss, higher rates of reinfection and all-cause revision following two-stage revision. This should be useful to clinicians counselling patients with hip PJI and can guide treatment and estimated outcomes.
View lessLearning about physical systems from quantum-enhanced experiments can outperform learning from experiments in which only classical memory and processing are available. Whereas quantum advantages have been established for state learning, quantum process learning is less understood. We establish an exponential quantum advantage for learning an unknown n-qubit quantum process . We show that a quantum memory allows to efficiently solve the following tasks: (a) learning the Pauli transfer matrix (PTM) of an arbitrary , (b) predicting expectation values of Pauli-sparse observables measured on the output of an arbitrary upon input of a Pauli-sparse state, and (c) predicting expectation values of arbitrary observables measured on the output of an unknown with sparse PTM upon input of an arbitrary state. With quantum memory, these tasks can be solved using linearly-in-n many copies of the Choi state of . In contrast, any learner without quantum memory requires exponentially-in-n many queries, even when using adaptively designed experiments. In proving this separation, we extend existing shadow tomography bounds from states to channels. Moreover, we combine PTM learning with polynomial interpolation to learn arbitrary Hamiltonians from short-time dynamics. Our results highlight the power of quantum-enhanced experiments for learning highly complex quantum dynamics.
View lessThe transport of individual particles in inhomogeneous environments is complex and exhibits non-Markovian responses. The latter may be quantified by a memory function within the framework of the linear generalised Langevin equation (GLE). Here, we exemplify the implications of steady driving on the memory function of a colloidal model system for Brownian motion in a corrugated potential landscape, specifically, for one-dimensional motion in a sinusoidal potential. To this end, we consider the overdamped limit of the GLE, which is facilitated by separating the memory function into a singular (Markovian) and a regular (non-Markovian) part. Relying on exact solutions for the investigated model, we show that the random force entering the GLE must display a bias far from equilibrium, which corroborates a recent general prediction. Based on data for the mean-square displacement (MSD) obtained from Brownian dynamics simulations, we estimate the memory function for different driving strengths and show that already moderate driving accelerates the decay of the memory function by several orders of magnitude in time. We find that the memory may persist on much longer timescales than expected from the convergence of the MSD to its long-time asymptote. Furthermore, the functional form of the memory function changes from a monotonic decay to a non-monotonic, damped oscillatory behaviour, which can be understood from a competition of confined motion and depinning. Our analysis of the simulation data further reveals a pronounced non-Gaussianity, which questions the Gaussian approximation of the random force entering the GLE.
View lessIn his treatise on arthropod brains, Hans von Alten (1910) focuses on a specific functional group of insects—the flying Hymenoptera—which exhibit a spectrum of lifestyles ranging from solitary to social. His work presents a distinctive comparative neuro-anatomical approach rooted in an eco-evolutionary and eco-behavioral background. We regard his publication as an exceptionally valuable source of information and seek to inspire the research community dedicated to the study of the insect brain to explore its insights further, even after more than 110 years. We have translated and annotated his work, expecting it to engage researchers not just with its remarkable drawings but also with its substantive content and exemplary research strategy. The present text is designed to complement von Alten's publication, situating it within the temporal context of nineteenth-century and early twentieth-century studies, and to draw connections to contemporary perspectives, especially concerning a central brain structure: the mushroom body.
View lessIn this study, we examine the political effects of the breakup of East Prussia into what is today Poland, Russia, and Lithuania. We expect that East Prussian legacies of nationalist and conservative political preferences persist in the respective partitions of Poland, Russia, and Lithuania. We find that there is no pattern of persistence in the Polish partition of former East Prussia, whereas East Prussian persistence appears to be robust in the Lithuanian and Russian partitions. In the context of forced migration, comparative human capital between outgoing refugees (Germans) and incoming settlers (Soviets, Poles) predicts patterns of long-run political development. Hence, higher literacy rates of incoming settlers in the Russian partition (Kaliningrad) predict higher levels of support for conservative and nationalist political parties. The opposite is observed in the Polish partition. The persistence of East Prussian legacies in Eastern Europe relates to settler literacy.
View lessWe show that graphemic variation—at least in some writing systems—can be analysed in terms of grammatical variation given a usage- based probabilistic view of the grammar-graphemics interface. Concretely, we examine a type of noun+verb unit in German, which can be written as one word or two. We argue that the variation in writing is rooted in the units’ ambiguous status in between morphology (one word) and syntax (two words). The major influencing factors are shown to be the semantic relation between the noun and the verb (argument or oblique relation) and the morphosyntactic context. In prototypically nominal contexts, a reinterpretation of the unit as a noun+noun compound is facilitated, which favours spelling as one word, while in prototypically verbal contexts, a syntactic realisation and consequently spelling as two words is preferred. We report the results of two large-scale corpus studies and a controlled production experiment to corroborate our analysis.
View lessDietary fibre is mainly classified according to its chemical characteristics but structure and particle size of fibre-rich feedstuff can also be decisive for digestion and performance. So far, only few studies investigated this in pigs. This experiment aimed to compare coarse and finely ground dried hemp plants and apple pomace regarding performance and ileal and total tract nutrient digestibility of growing pigs. Coarse or finely ground apple pomace or dried hemp plants were added to the diet of 56 nine weeks old growing pigs (DanBred x Duroc), housed in flat decks with each 2 animals. The growing pigs received the experimental diets for three weeks while performance was recorded. Eight pigs per group were sacrificed and digesta and organ tissue sampled. The stomach health was evaluated by visually scoring of the mucosa integrity. Apparent ileal (AID) and total tract digestibility (ATTD) were calculated using titanium dioxide as marker. Statistical analyses were performed using two-way ANOVA (p < 0.05). The highest feed intake (fibre particle size, p = 0.018) and bodyweight gain (fibre particle size, p = 0.018; fibre source x particle size interaction, p = 0.040), was observed in animals fed finely ground apple pomace, while the feed conversion ratio was 8–12% lower in pigs fed finely ground fibre sources (p = 0.012). No differences in stomach mucosa integrity were detected between the groups. The relative pancreas (p = 0.045), stomach (p < 0.001), and jejunum (p = 0.010) weights were higher in animals fed diets containing apple pomace. In contrast, the relative liver, caecum and colon weights were not affected by fibre source or particle size. The AID of protein and amino acids was not affected, while ATTD was increased by fibre source (hemp vs. apple pomace) reducing faecal nitrogen excretion. The AID of calcium was increased when diets contained apple pomace (p < 0.001), while zinc AID and ATTD were enhanced when diets contained dried hemp (p = 0.016; p = 0.016, respectively). Our results suggest that the structure as well as the chemical characteristics should be considered in a future fibre evaluation system in pigs.
View lessThe colours of insects function in intraspecific communication such as sexual signalling, interspecific communication such as protection from predators, and in physiological processes, such as thermoregulation. The expression of melanin-based colours is temperature-dependent and thus likely to be impacted by a changing climate. However, it is unclear how climate change drives changes in body and wing colour may impact insect physiology and their interactions with conspecifics (e.g. mates) or heterospecific (e.g. predators or prey). The aim of this review is to synthesise the current knowledge of the consequences of climate-driven colour change on insects. Here, we discuss the environmental factors that affect insect colours, and then we outline the adaptive mechanisms in terms of phenotypic plasticity and microevolutionary response. Throughout we discuss the impact of climate-related colour change on insect physiology, and interactions with con-and-heterospecifics.
View lessWe discuss the derivation of an effective Hamiltonian for open quantum many-particle systems. The aim is to define an operator that can be used for (molecular) simulations where, through the exchange of energy and matter with the surrounding environment (reservoir), the number of particles, n, becomes a variable of the problem. The Hamiltonian is formally derived from the Von Neumann equation; specifically, we derive an n-hierarchy of equations for the density matrix, rho<^>n , for near equilibrium situations. Such a hierarchy, in case of stationary equilibrium, delivers the standard grand canonical density matrix as it would be expected. We report that a similar Hamiltonian was conjectured, from empirical considerations, in the field of superconductivity. Thus our result also provide a formal basis for this long-standing hypothesis. Finally, an application is discussed for Path Integral simulations of molecular systems.
View lessThe objective of this study was to correlate movement assessed by a pyroelectric infrared sensor system in preweaning dairy calves with lying and standing time assessed by a 3D accelerometer considering the temperature-humidity index (THI). A total of 35 dairy calves (1–7 d of age) were enrolled in the study and 20 calves were included in the final analyses. The lying and standing time of the calves was monitored with a 3D accelerometer (Hobo Pendant G Data Logger, Onset Computer Corporation, USA), which was used as the gold standard reference. The infrared sensor monitoring system (IMS; Calf Monitoring System, Futuro Farming GmbH, Germany) was fixed to the fence of the calf hutch within the calf's reach. Temperature-humidity was monitored with 2 validated THI sensors inside and on outside of each calf hutch. Additionally, one THI sensor was located near the calf hutches. The observation period lasted 14 consecutive days. The average standing time assessed by the 3D accelerometer was 13.4 ± 12.7 (mean ± standard deviation) min/h and the average lying time was 46.6 (±12.7) min/h. The median (25th percentile; 75th percentile) number of movements measured by the IMS was 360 (60; 919) movements per hour. Number of movements per hour measured by the IMS was compared with data obtained with a validated 3D accelerometer. The Pearson correlation coefficient between both standing and lying time and the number of movements was r = 0.85 and r = −0.85, respectively. The Pearson correlation coefficients were only slightly influenced by THI (low THI [<68]: r = 0.86; medium THI [68–72]: r = 0.85; high THI [>72]: r = 0.81). Our data show that the number of movements of dairy calves measured by IMS were highly correlated with the chosen gold standard reference method. High THI slightly affects the measurement accuracy of IMS.
View lessCampanula L. is among the genera with the highest number of endemics in the Caucasus ecoregion. A group of attractive alpine and subalpine perennial rosette plants with short single-flowered stems centred in the Caucasus has been treated as Campanula subg. Scapiflorae or at other ranks, with considerably varying circumscription and classification. Molecular phylogenetic analysis of three plastid DNA regions (trnK/matK, petD, rpl16) of a strongly extended sampling, comprising 23 of the 27 commonly accepted taxa (85%) with 330 accessions built on and guided by the results of our previous study of the group, confirmed the polyphyly of C. subg. Scapiflorae in any of its circumscriptions. The core clade of the group comprises exclusively endemics and near-endemics of the Caucasus and is treated here as C. sect. Tridentatae in a revised circumscription. The phylogenetic relationships of the disparate other elements of the Scapiflorae group are outlined.
View lessLos episodios de violencia de masas salpicaron la ocupación japonesa del Sudeste Asiático entre 1942 y 1945. Aquí examino dos de esos casos: la «purga» de la población china de Singapur tras su captura en febrero de 1942 y las masacres de civiles durante la campaña antiguerrillera en Panay en 1943. Sostengo que estos episodios estaban enraizados en una estrategia militar que posibilitaba el uso de la fuerza como la táctica principal en la gestión de las ocupaciones y que la intermitente escalada de esta estrategia violenta fue contingente a una serie de elementos que condicionaron la toma de decisiones sobre el terreno, facilitando la tolerancia hacia medidas más extremas en la consecución de los objetivos militares.
View lessEn este artículo busco dar cuenta de cómo el proyecto tercermundista adquirió una forma particular de imaginación y discursividad en el gobierno del presidente mexicano Luis Echeverría (1970-1976), la cual se manifestó en la construcción de lo que llamo temporalidades tercermundistas, que fueron proyectadas en el plano de la internacionalización educativa. A partir del análisis del proceso de diversificación de las relaciones exteriores impulsado por el gobierno de Echeverría, propongo que, dada la imposibilidad de una puntual localización geográfica del Tercer Mundo, es posible aproximarse a pensar sobre este proyecto político en términos de temporalidades, tomando como eje el estudio de la multilateralización de las relaciones internacionales de México y su implementación desde el rubro educativo, para intentar posicionar al presidente como líder del Tercer Mundo. En este proceso se conjuntaron nacionalismo e internacionalismo; antiimperialismo y búsqueda de negociación con los países poderosos; imaginación con pragmatismo; así como pasado, presente y futuro. La construcción discursiva de temporalidades tercermundistas derivaba de la revisión selectiva del pasado y el presente mexicanos, para refuncionalizarlos hacia un posible futuro alternativo del proyecto del Tercer Mundo, en el que se buscaba que México tuviera un papel relevante. Mediante este procedimiento, se apuntaba a renovar la legitimidad del régimen, a la par de insertarlo, bajo el mando de Echeverría, en el debate contemporáneo de aquel proyecto, con lo que también se posicionarían intereses gubernamentales y personales, que no necesariamente calzaban del todo con las discusiones más ambiciosas del proyecto tercermundista. Para dar cuenta de ello, analizo fuentes como: esquemas preparativos para la formulación de políticas públicas, documentos producidos estatalmente para la administración pública y otros confidenciales, acuerdos internacionales, discursos, libros de texto, crónicas, entrevistas y películas. El artículo está dividido en cinco secciones, en las que: primero, (1) hago un balance historiográfico y de antecedentes históricos, para situar el estudio; (2) realizo un breve análisis de los planteamientos generales de la política exterior de Luis Echeverría de aproximación al tercermundismo y, en particular, de su relación con Cuba; (3) retomo los documentos relativos a las reformas educativas del sexenio y los textos en los que el secretario de Educación, Víctor Bravo Ahuja, situó al proyecto educativo como parte del Tercer Mundo, inspirado por el modelo educativo cubano; en este mismo apartado examino las reestructuraciones al interior de la SEP, que dieron lugar a la creación de dependencias como Cine Difusión SEP; más adelante, (4) el acercamiento a Cuba se materializó con la visita de Bravo Ahuja a la isla en 1974, por lo que acudo a la fuente cinematográfica que registró la visita en Viaje a Cuba (Bosco Arochi, 1974), así como los acuerdos de colaboración firmados en aquella ocasión; finalmente, (5) a través de algunos proyectos y publicaciones, repaso la proliferación de los proyectos orientados hacia el Tercer Mundo que, al final del sexenio, cohabitaron en México, para interrogarles acerca de las particularidades de sus temporalidades tercermundistas.
View lessThis article examines the emotions-policy nexus within the EU’s foreign policy, specifically focusing on the EU’s human rights sanctions against China and North Korea. By embedding the discussion within an extended framework of analysis that underscores the emotional dimensions of the EU’s foreign policy, the article scrutinizes how policy decisions, unfolding through a series of actions, reactions and third-party responses, shape, and are shaped by, emotional chains via its enabling and constraining mechanisms. While the case study of China illustrates the two mechanisms via exploring the EU-China investment negotiations, human rights sanctions as well as China’s retaliatory measures and the EU’s response, the case of North Korea, using the same sanctions, shows a divergent policy response and absence of emotions albeit within a similar rhetoric. The conclusion ponders over the efficacy of sanctions policies, suggesting that the integration of emotional awareness into policy-making can foster a more holistic approach in international politics.
View lessDue to advances in Artificial Intelligence (AI), computer science education has rapidly started to include topics related to AI along K-12 education. Although this development is timely and important, it is also concerning because the elaboration of the AI field for K-12 is still ongoing. Current efforts may significantly underestimate the role of data, the fundamental component of an AI system. If the goal is to enable students to understand how AI systems work, knowledge of key concepts related to data processing is a prerequisite, as data collection, preparation, and engineering are closely linked to the functionality of AI systems. To advance the field, the following research provides a comprehensive collection of key data-related concepts relevant to K-12 computer science education. These concepts were identified through a theoretical review of the AI field, aligned through a review of AI curricula for school education, evaluated through interviews with domain experts and teachers, and structured hierarchically according to the data lifecycle. Computer science educators can use the elaborated structure as a conceptual guide for designing learning arrangements that aim to enable students to understand how AI systems are created and function.
View lessHaving a concept usually has some epistemic benefits. It might give one means to knowing certain facts, for example. This paper explores the possibility that having a concept can have an epistemic cost. I argue that it typically does, even putting aside our contingent limitations, assuming that there is epistemic value in understanding others from their own perspectives.
The ongoing development of bacterial resistance to antibiotics is a global challenge. Research in that field is thus necessary. Analytical techniques are required for such a purpose. From this perspective, the focus was on atomic absorption spectrometry (AAS). Although it is old, AAS often offers unexpected potential. Of course, this should be exploited. The aim was therefore to demonstrate the versatility of the technique in antibacterial research. This is illustrated by various examples of its practical application. AAS can be used, for example, to confirm the identity of antibacterial compounds, for purity controls, or to quantify the antibiotics in pharmaceutical preparations. The latter allowed analysis without laborious sample preparation and without interference from other excipients. In addition, AAS can help elucidate the mode of action or resistance mechanisms. In this context, quantifying the accumulation of the antibiotic drug in the cell of (resistant) bacteria appears to play an important role. The general application of AAS is not limited to metal-containing drugs, but also enables the determination of some organic chemical antibiotics. Altogether, this perspective presents a range of applications for AAS in antibacterial research, intending to raise awareness of the method and may thus contribute to the fight against resistance.
View lessAlong a climate gradient in the Chilean coastal mountains, we investigated denudation rates using the meteoric cosmogenic nuclide 10Be and its ratio to stable 9Be, and chemical depletion fractions (CDFs) in bulk soil samples. We find that the fraction of 9Be released from bedrock is a sensitive indicator of weathering, similar to CDF. Meteoric 10Be decreases exponentially with depth, reflecting the reactive nature of this tracer. We also measured denudation rates by the well-understood in situ cosmogenic 10Be system on quartz. Assuming that both systems record the same denudation rate we calculated the depositional flux of meteoric 10Be for each study site. The flux agrees to that derived from atmospheric models in the mediterranean and humid areas. In contrast, in the arid and semi-arid areas, the calculated flux agrees with a precipitation-derived flux, indicating delivery of 10Be to be affected by small-scale climatic variations not reflected by current atmospheric models.
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