Disentangling functional trait variation and covariation in epiphytic lichens along a continent-wide latitudinal gradient.

Characterizing functional trait variation and covariation, and its drivers, is critical to understand the response of species to changing environmental conditions. Evolutionary and environmental factors determine how traits vary among and within species at multiple scales. However, disentangling their relative contribution is challenging and a comprehensive trait-environment framework addressing such questions is missing in lichens. We investigated the variation in nine traits related to photosynthetic performance, water use and nutrient acquisition applying phylogenetic comparative analyses in lichen epiphytic communities on beech across Europe. These poikilohydric organisms offer a valuable model owing to their inherent limitations to buffer contrasting environmental conditions. Photobiont type and growth form captured differences in certain physiological traits whose variation was largely determined by evolutionary processes (i.e. phylogenetic history), although the intraspecific component was non-negligible. Seasonal temperature fluctuations also had an impact on trait variation, while nitrogen content depended on photobiont type rather than nitrogen deposition. The inconsistency of trait covariation among and within species prevented establishing major resource use strategies in lichens. However, we did identify a general pattern related to the water-use strategy. Thus, to robustly unveil lichen responses under different climatic scenarios, it is necessary to incorporate both among and within-species trait variation and covariation.

Building Continuous Time Crystals from Rare Events.

Symmetry-breaking dynamical phase transitions (DPTs) abound in the fluctuations of nonequilibrium systems. Here, we show that the spectral features of a particular class of DPTs exhibit the fingerprints of the recently discovered time-crystal phase of matter. Using Doob's transform as a tool, we provide a mechanism to build classical time-crystal generators from the rare event statistics of some driven diffusive systems. An analysis of the Doob's smart field in terms of the order parameter of the transition then leads to the time-crystal lattice gas (TCLG), a model of driven fluid subject to an external packing field, which presents a clear-cut steady-state phase transition to a time-crystalline phase characterized by a matter density wave, which breaks continuous time-translation symmetry and displays rigidity and long-range spatiotemporal order, as required for a time crystal. A hydrodynamic analysis of the TCLG transition uncovers striking similarities, but also key differences, with the Kuramoto synchronization transition. Possible experimental realizations of the TCLG in colloidal fluids are also discussed.

Order and Symmetry Breaking in the Fluctuations of Driven Systems.

Dynamical phase transitions (DPTs) in the space of trajectories are one of the most intriguing phenomena of nonequilibrium physics, but their nature in realistic high-dimensional systems remains puzzling. Here we observe for the first time a DPT in the current vector statistics of an archetypal two-dimensional (2D) driven diffusive system and characterize its properties using the macroscopic fluctuation theory. The complex interplay among the external field, anisotropy, and vector currents in 2D leads to a rich phase diagram, with different symmetry-broken fluctuation phases separated by lines of first- and second-order DPTs. Remarkably, different types of 1D order in the form of jammed density waves emerge to hinder transport for low-current fluctuations, revealing a connection between rare events and self-organized structures which enhance their probability.

Direct analysis of volatile organic compounds in foods by headspace extraction atmospheric pressure chemical ionisation mass spectrometry.

RATIONALE: The rapid screening of volatile organic compounds (VOCs) by direct analysis has potential applications in the areas of food and flavour science. Currently, the technique of choice for VOC analysis is gas chromatography/mass spectrometry (GC/MS). However, the long chromatographic run times and elaborate sample preparation associated with this technique have led a movement towards direct analysis techniques, such as selected ion flow tube mass spectrometry (SIFT-MS), proton transfer reaction mass spectrometry (PTR-MS) and electronic noses. The work presented here describes the design and construction of a Venturi jet-pump-based modification for a compact mass spectrometer which enables the direct introduction of volatiles for qualitative and quantitative analysis. METHODS: Volatile organic compounds were extracted from the headspace of heated vials into the atmospheric pressure chemical ionization source of a quadrupole mass spectrometer using a Venturi pump. Samples were analysed directly with no prior sample preparation. Principal component analysis (PCA) was used to differentiate between different classes of samples. RESULTS: The interface is shown to be able to routinely detect problem analytes such as fatty acids and biogenic amines without the requirement of a derivatisation step, and is shown to be able to discriminate between four different varieties of cheese with good intra and inter-day reproducibility using an unsupervised PCA model. Quantitative analysis is demonstrated using indole standards with limits of detection and quantification of 0.395 µg/mL and 1.316 µg/mL, respectively. CONCLUSIONS: The described methodology can routinely detect highly reactive analytes such as volatile fatty acids and diamines without the need for a derivatisation step or lengthy chromatographic separations. The capability of the system was demonstrated by discriminating between different varieties of cheese and monitoring the spoilage of meats.

Spectral signatures of symmetry-breaking dynamical phase transitions.

Large deviation theory provides the framework to study the probability of rare fluctuations of time-averaged observables, opening new avenues of research in nonequilibrium physics. Some of the most appealing results within this context are dynamical phase transitions (DPTs), which might occur at the level of trajectories in order to maximize the probability of sustaining a rare event. While macroscopic fluctuation theory has underpinned much recent progress on the understanding of symmetry-breaking DPTs in driven diffusive systems, their microscopic characterization is still challenging. In this work we shed light on the general spectral mechanism giving rise to continuous DPTs not only for driven diffusive systems, but for any jump process in which a discrete Z_{n} symmetry is broken. By means of a symmetry-aided spectral analysis of the Doob-transformed dynamics, we provide the conditions whereby symmetry-breaking DPTs might emerge and how the different dynamical phases arise from the specific structure of the degenerate eigenvectors. In particular, we show explicitly how all symmetry-breaking features are encoded in the subleading eigenvectors of the degenerate subspace. Moreover, by partitioning configuration space into equivalence classes according to a proper order parameter, we achieve a substantial dimensional reduction which allows for the quantitative characterization of the spectral fingerprints of DPTs. We illustrate our predictions in several paradigmatic many-body systems, including (1) the one-dimensional boundary-driven weakly asymmetric exclusion process (WASEP), which exhibits a particle-hole symmetry-breaking DPT for current fluctuations, (2) the three- and four-state Potts model for spin dynamics, which displays discrete rotational symmetry-breaking DPTs for energy fluctuations, and (3) the closed WASEP which presents a continuous symmetry-breaking DPT into a time-crystal phase characterized by a rotating condensate.

Comparison of linear and non-linear decision boundaries to detect feedlot bloat using intensive data collection systems on Angus × Hereford steers.

Ruminal tympany (bloat) has long been an issue for large and small livestock operations. Though improvements in feedlot management practices have reduced its occurrence, it is still highly prevalent and is known to detrimentally affect animal performance, welfare, and in many instances, lead to animal death. Current decision support systems and diet formulation software omit the inclusion of bloat prediction based on animal performance. Here, we aim to predict bloat incidence in implanted and non-implanted feedlot steers from performance data comparing linear (LDB) and non-linear decision boundaries. Eighteen crossbred Angus × Hereford steers: BW (491.13 ± 25.78 kg) and age (12 ± 1 mo) were randomly distributed into implanted and non-implanted treatments. All animals were randomly assigned to one of two pens fit with automated monitoring systems for BW, freshwater intake, and water intake behavior: water intake event visit, no water intake event visit (NWIE), and time spent drinking. DM intake (DMI) was individually recorded from all animals through the Calan Gate system for 135 d (30 d adaptation, 105 d experimental diet). Incidences of bloat were recorded as bloat instances regardless of severity to ensure that early onset detection of bloat was recorded and properly identified in predictive models. Logistic regression with a binomial distribution and a logit link function was utilized to predict the incidences of bloat through LDB. Feature selection and penalization of coefficients were explored through L1 (sum of absolute values) and L2 (sum of squares) penalization to avoid overfitting of models. Additional NLDB and a non-parametric LDB are examined for prediction. Accuracy, specificity, and sensitivity were high for the models reported. No significant differences were observed between LDB and NLDB, with the highest specificity (predicting bloat) value of 0.820 for stepwise feature selection algorithms, and a value of 0.832 for the artificial neural network. Highest accuracy was 0.829 for ridge regression, and 0.847 for the random forest with hyperparameter tuning. DM intake, BW, and NWIE were the three most important variables for the prediction of feedlot bloat showing clear drops in DMI and BW and increases in NWIE when animals bloated. The lack of difference in predictive performance between LDB and NLDB highlights the often-overlooked concept that machine learning algorithms are not always the only/best modeling technique. Additionally, the models reported herein carry acceptable predictive performance for inclusion into management decisions that reduce bloat incidences in feedlot cattle.

Molecular hints of two-step transition to convective flow via streamline percolation.

Convection is a key transport phenomenon important in many different areas, from hydrodynamics and ocean circulation to planetary atmospheres or stellar physics. However, its microscopic understanding still remains challenging. Here we numerically investigate the onset of convective flow in a compressible (non-Oberbeck-Boussinesq) hard disk fluid under a temperature gradient in a gravitational field. We uncover a surprising two-step transition scenario with two different critical temperatures. When the bottom plate temperature reaches a first threshold, convection kicks in (as shown by a structured velocity field) but gravity results in hindered heat transport as compared to the gravity-free case. It is at a second (higher) temperature that a percolation transition of advection zones connecting the hot and cold plates triggers efficient convective heat transport. Interestingly, this picture for the convection instability opens the door to unknown piecewise-continuous solutions to the Navier-Stokes equations.

Comparison of the LMA Supreme™ with the LMA Proseal™ for airway management in patients anaesthetized in prone position.

BACKGROUND: The laryngeal mask airway (LMA) has been successfully used in patients in the prone position either for rescue or elective airway management. The reusable Proseal™ LMA (PLMA) and the single use Supreme™ LMA (SLMA) have been reported to be suitable for this purpose but few comparative data are available. In this study, we compared the clinical use of both devices in adult patients anaesthetized in the prone position. METHODS: One hundred and twenty patients undergoing surgery in the prone position were randomized to receive either the PLMA or the SLMA for airway management. Patients positioned themselves in the prone position and after pre-oxygenation, anaesthesia was induced using a target-controlled i.v. infusion of propofol and remifentanil. All PLMAs and SLMAs were inserted by experienced anaesthetists using a guided and a standard technique respectively. Ease of facemask ventilation, time and number of attempts needed for insertion, quality of ventilation, airway seal pressure, fibreoptic view, and complications were compared. RESULTS: There were no differences between groups in insertion time or first attempt success (100% vs. 98%). The PLMA required fewer manipulations (3% vs. 15%; P=0.02) to achieve effective ventilation and provided a higher seal pressure (mean [sd] 31 [4] vs. 27 [4] cm H2O; P<0.01). The fibrescopic view of the vocal cords was similar, although easier to achieve with the PLMA. The complication rate was low and similar between the groups. Blood was present on masks in 7% vs. 8% and sore throat in 3% vs. 5% of patients with the PLMA and SLMA, respectively. CONCLUSIONS: Airway management in patients anaesthetized in the prone position was efficient with both devices, although the PLMA required fewer manipulations and achieved a higher seal pressure.

[Experience with the proseal laryngeal mask in ventriculoperitoneal shunting]. / Experiencia con el uso de la mascarilla laríngea Proseal en pacientes sometidos a cirugía de derivación ventrículo peritoneal.

OBJECTIVE: To describe the use, utility, safety, and effectiveness of the Proseal laryngeal mask for airway management in patients undergoing ventriculoperitonea shunting. PATIENTS AND METHODS: We retrospectively reviewed the records of all patients in whom the Proseal laryngeal mask was used during ventriculoperitoneal shunting between January 2006 and October 2009. Patient demographic characteristics, airway assessments, type of anesthesia, quality of ventilation, and perioperative complications were recorded. RESULTS: Of the 43 patients included, 8 (18.6%) had at least 1 difficult airway criterion. We were able to insert the Proseal laryngeal mask in all patients. Ventilation was optimal in 39 (91%) patients, with maintenance of end-expiratory carbon dioxide pressures between 35 and 40 mm Hg and airway pressures above 25 cm H2O throughout the procedures. Air leaks developed in 3 cases (7%) when the patient was placed in a lateral-cervical position for surgery; these patients required orotracheal intubation before surgery could begin. Mean duration of surgery was 53 minutes. Awakening occurred without incident in all cases. CONCLUSIONS: The Proseal laryngeal mask is useful for airway management in patients undergoing ventriculoperitoneal shunting. Due to the forced position of the neck, however, it may be necessary to reposition the mask or even proceed to orotracheal intubation in some cases. As is the case for other advanced uses, experience with the device is necessary. Material for managing a difficult airway should be on hand.

Postoperative circuits in patients undergoing elective craniotomy. A narrative review. / Circuitos postoperatorios en los pacientes sometidos a craneotomía programada. Revisión narrativa.

In 2017, the Neurosciences section of the Spanish Society of Anaesthesiology, Critical Care and Pain Therapy published a national survey on postoperative care and treatment circuits in neurosurgery. The survey showed that practices vary widely, depending on the centre, the anaesthesiologist and the pathology of the patient. There is currently no standard postoperative circuit for cranial neurosurgical procedures in Spanish hospitals, and there is sufficient evidence to show that not all patients undergoing elective craniotomy should be routinely admitted to a postsurgical critical care unit. The aim of this study is to perform a narrative review of postoperative circuits in elective craniotomy in order to standardise clinical practice in the light of published studies. For this purpose, we searched MEDLINE (PubMed) to retrieve studies published in the last ten years, up to November 2019, using the keywords neurosurgery and postoperative care, craniotomyand postoperative care.

[Anesthesia considerations for deep-brain stimulation in a patient with type-2 pantothenate kinase deficiency (Hallervorden-Spatz disease)]. / Consideraciones anestésicas en una paciente con déficit de pantotenato cinasa tipo 2 (enfermedad de Hallervorden-Spatz) para estimulación cerebral profunda.

Neurodegeneration associated with pantothenate kinase deficiency is an autosomal recessive condition caused by mutations in the pantothenate kinase 2 gene (PANK2). Clinical characteristics include progressive motor impairment and dementia. Medical treatment is limited and the dystonia tends to be refractory, making stereotactic surgery with placement of deep-brain electrodes an option that is being adopted with greater frequency in these patients. We report the case of a 32-year-old woman with severe dystonia associated with PANK2 protein deficiency. The patient was scheduled for stereotactic bilateral placement of electrodes in the medial globus pallidus, guided by computed tomography and under general anesthesia, to treat the debilitating dystonia and generalized stiffness associated with her condition. Anesthesia was maintained with propofol, rocuronium and remifentanil in perfusion during the intervention, which was uneventful. After the procedure, the patient was transferred to the intensive care unit and sedation was provided with remifentanil to allow slow, gradual emergence from anesthesia. The patient was discharged from hospital after placement of the implanted pulse generator, and subsequent follow-up showed improvement of the dystonia.

[Importance of monitoring neuroendoscopic intracranial pressure during anesthesia for neuroendoscopic surgery: review of 101 cases]. / Importancia de la monitorización de la "presión intracraneal dentro del neuroendoscopio" durante el tratamiento anestésico de la cirugía neuroendoscópica. Experiencia en 101 casos.

OBJECTIVE: The aim of this study was to describe monitoring, anesthetic management, and risk factors for complications in neuroendoscopic surgery. PATIENTS AND METHODS: Patients who underwent neuroendoscopy between 1994 and 2003 under general anesthesia, with monitoring of intracranial pressure from inside the neuroendoscope, were studied retrospectively. In some patients, the blood flow rate in the middle cerebral artery was monitored using transcranial Doppler ultrasound. Information was collected related to surgical procedure and the development of complications. RESULTS: Of 101 patients included in the study, transcranial Doppler ultrasound images were available for 20. In 75 patients neuroendoscopic intracranial pressure exceeded 20 mm Hg. Forty-five percent of the patients with available transcranial Doppler ultrasound images showed episodes of reduced diastolic flow rate in the middle cerebral artery during ventricular irrigation. Hemodynamic instability was associated with higher neuroendoscopic intracranial pressures (P < .05). An increase of more than 30 mm Hg in neuroendoscopic intracranial pressure was associated with more postoperative complications, the most common of which was delayed awakening. Procedures that were more complicated than a simple ventriculostomy were performed in 58% of the cases. Mean (SD) neuroendoscopic intracranial pressures in such cases were higher (50.5 [30.9] mm Hg vs 31.8 [25.1 mm Hg] in the simpler procedures) and the postoperative complication rate was higher (P = .003). CONCLUSIONS: Neuroendoscopic surgery can causes increases in neuroendoscopic intracranial pressure that are associated with disturbances in cerebral blood flow and complications. This situation demonstrates the importance of monitoring intracranial pressure and cerebral blood flow.

Infinite family of universal profiles for heat current statistics in Fourier's law.

Using tools from large deviation theory, we study fluctuations of the heat current in a model of d-dimensional incompressible fluid driven out of equilibrium by a temperature gradient. We find that the most probable temperature fields sustaining atypical values of the global current can be naturally classified in an infinite set of curves, allowing us to exhaustively analyze their topological properties and to define universal profiles onto which all optimal fields collapse. We also compute the statistics of empirical heat current, where we find remarkable logarithmic tails for large current fluctuations orthogonal to the thermal gradient. Finally, we determine explicitly a number of cumulants of the current distribution, finding interesting relations between them.

IgM ANCA in healthy individuals and in patients with ANCA-associated vasculitis.

Low levels of IgM auto-antibodies have been reported in health and disease. IgM anti-neutrophil cytoplasmic antibodies (ANCA) have been reported in patients with ANCA-associated vasculitis (AAV). We sought to investigate if healthy individuals may have IgM ANCA in their sera. The first aim of the study was to determine whether IgM ANCA was present in healthy individuals and in patients with ANCA-associated vasculitis. The second aim was to determine what happens to IgM ANCA levels over time. The third aim was to determine whether bacterial infections affected IgM ANCA levels in non-AAV patients. Sera from healthy individuals and patients with AAV were tested for IgM ANCA by immunofluorescence on fixed neutrophils, immunoprecipitation, Western blot and ELISA. Peripheral blood mononuclear cells were isolated and tested by ELISpot for circulating IgM ANCA B cells. To determine whether infection affected IgM ANCA levels, we studied non-AAV patients with bacterial endocarditis or Staphylococcus aureus bacteraemia and measured IgM ANCA levels over time. IgM ANCA is detectable in both healthy individuals and patients with AAV and the titres decreased with increasing age. Circulating IgM ANCA B cells were identified by ELISpot. In the presence of infection, we could not find a significant change in IgM ANCA levels. We report the presence of low-level specific IgM ANCA in the sera of healthy individuals and in patients with ANCA-associated vasculitis. Bacterial infection did not affect the level of IgM ANCA in this small study.

Expression of metalloproteinases and their tissue inhibitors in inflamed gingival biopsies.

OBJECTIVES: Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) are known to be involved in the periodontal disease process. Results of in vivo MMPs and TIMPs gene expressions in the gingiva, though, are still controversial. In the present study, we compared the gene expression of MMP-1, -2, -9, -13 and TIMP-1, -2 in healthy and inflamed gingiva. METHODS: 38 gingival samples were collected from gingivitis (n = 10), advanced chronic periodontitis (n = 10), generalized aggressive periodontitis (n = 8) and periodontally healthy individuals (n = 10). Total RNA isolated from those samples was subjected to reverse transcription followed by amplification by polymerase chain reaction (RT-PCR). Products were visualized in agarose gels and quantified by optical densitometry. Samples were also processed for gelatin zymography and Western blotting for MMP-2 and MMP-9 in order to assess for post-transcriptional MMP regulation at the protein level. RESULTS: The frequencies and levels of transcripts encoding MMPs and TIMPs were found to be not significantly different among groups (p > 0.05, Fisher's Exact and Kruskall-Wallis tests). There is a trend towards higher MMP-2 and -9 gelatinase activities in the inflamed samples, although not statistically significant. In contrast, zymography and Western blotting studies show that MMP-2 is virtually absent in the chronic periodontitis group. CONCLUSION: These results could reflect a complex regulation of MMPs and TIMPs' gene expression in the course of gingival inflammation. They also reveal a great biological diversity even among individuals with similar periodontal status.

[Neuroanesthetic practice in Catalonia. Results of a survey done on 2003]. / Intervenciones neuroquirúrgicas en Cataluña. Resultados de una encuesta anestésica durante 2003.

INTRODUCTION: Health system planning requires the precise knowledge of the activity performed. We present the neuroanesthesic activity results in Catalonia during 2003. METHODS: A prospective and cross-sectional survey was performed for 14 randomised days during 2003. All hospitals practicing anaesthesia in Catalonia took part in the survey. Data on characteristics of patients, anaesthetic techniques and type of procedure were included. RESULTS: 6909 neuroanesthetic procedures performed in Catalonia in 2003 (95% IC 6022-7847), a 1.28% of total surgical activity. A 74% of procedures were done in the public hospitals and a 26% in private hospitals. Patients mean age was 48 years old (95% IC 45.5-50.6). Scheduled procedures were 79.7%. The most frequent interventions were: Spine surgery 40.1 %; craniotomies for tumour resection 24.1%, for haemorrhage o trauma 7.2% and for aneurysms or AVM surgery 2.3%; ventricular shunts 2.6%. Mean duration of craneotomies for tumour resection was 287 -/+95 min. All patients were distributed postoperatively in a conventional recovery room (55.8 %), in a monitored care unit (19.2%) or in an intensive care unit (24.9 %). Craniotomy patients were admitted to an intensive care unit (41.6%), a monitored care unit (33.7%) or a conventional recovery room (24.7%). CONCLUSIONS: About seven thousand Neurosurgical procedures were performed in Catalonia in 2003, in public (73.6%) and private (26.4%) hospitals. Spine surgery and craniotomies for tumour resection were the most frequently performed interventions. Craniotomy patients were mainly submitted to an ICU or a Monitored care unit.

Structure of the optimal path to a fluctuation.

Macroscopic fluctuations have become an essential tool to understand physics far from equilibrium due to the link between their statistics and nonequilibrium ensembles. The optimal path leading to a fluctuation encodes key information on this problem, shedding light on, e.g., the physics behind the enhanced probability of rare events out of equilibrium, the possibility of dynamic phase transitions, and new symmetries. This makes the understanding of the properties of these optimal paths a central issue. Here we derive a fundamental relation which strongly constrains the architecture of these optimal paths for general d-dimensional nonequilibrium diffusive systems, and implies a nontrivial structure for the dominant current vector fields. Interestingly, this general relation (which encompasses and explains previous results) makes manifest the spatiotemporal nonlocality of the current statistics and the associated optimal trajectories.

IN VIVO AND IN VITRO ANTILEISHMANIAL EFFECTS OF METHANOLIC EXTRACT FROM BARK OF BURSERA APTERA.

BACKGROUND: Cutaneous leishmaniasis lacks effective and well-tolerated treatments. The current therapies mainly rely on antimonial drugs that are inadequate because of their poor efficacy. Traditional medicine offers a complementary alternative for the treatment of various diseases. Additionally, several plants have shown success as anti-leishmanial agents. Therefore, we sought to evaluate the in vitro and in vivo activity of MEBA against Leishmania mexicana. MATERIALS AND METHODS: Methanolic extract of B. aptera was obtained by macetration, after we determined in vitro anti-leishmanial activity of MEBA by MTT assay and the induced apoptosis in promastigotes by flow cytometry. To analyze the in vivo anti-leishmanial activity, we used infected mice that were treated and not treated with MEBA and we determined the levels of cytokines using ELISA. The phytochemical properties were determined by CG-MS and DPPH assay. RESULTS: We determined of LC50 of 0.408 mg/mL of MEBA for in vitro anti-leishmanial activity. MEBA induced apoptosis in promastigotes (15.3% ± 0.86). Treated mice exhibited smaller lesions and contained significantly fewer parasites than did untreated mice; in addition, we found that IFN-γ and TNF-α increased in the sera of MEBA-treated mice. GC-MS analysis showed that podophyllotoxin was the most abundant compound. Evaluation of the activity by DPPH assay demonstrated an SC50 of 11.72 µg/mL. CONCLUSION: Based on the above data, it was concluded that MEBA is a good candidate in the search for new anti-leishmanial agents.