Coordinated Movements Prevent Jamming in an Emperor Penguin Huddle

For Emperor penguins (Aptenodytes forsteri), huddling is the key to survival during the Antarctic winter. Penguins in a huddle are packed so tightly that individual movements become impossible, reminiscent of a jamming transition in compacted colloids. It is crucial, however, that the huddle structure is continuously reorganized to give each penguin a chance to spend sufficient time inside the huddle, compared with time spent on the periphery. Here we show that Emperor penguins move collectively in a highly coordinated manner to ensure mobility while at the same time keeping the huddle packed. Every 30–60 seconds, all penguins make small steps that travel as a wave through the entire huddle. Over time, these small movements lead to large-scale reorganization of the huddle. Our data show that the dynamics of penguin huddling is governed by intermittency and approach to kinetic arrest in striking analogy with inert non-equilibrium systems, including soft glasses and colloids

Multi-scale Inference of Interaction Rules in Animal Groups Using Bayesian Model Selection

Inference of interaction rules of animals moving in groups usually relies on an analysis of large scale system behaviour. Models are tuned through repeated simulation until they match the observed behaviour. More recent work has used the fine scale motions of animals to validate and fit the rules of interaction of animals in groups. Here, we use a Bayesian methodology to compare a variety of models to the collective motion of glass prawns (Paratya australiensis). We show that these exhibit a stereotypical ‘phase transition’, whereby an increase in density leads to the onset of collective motion in one direction. We fit models to this data, which range from: a mean-field model where all prawns interact globally; to a spatial Markovian model where prawns are self-propelled particles influenced only by the current positions and directions of their neighbours; up to non-Markovian models where prawns have ‘memory’ of previous interactions, integrating their experiences over time when deciding to change behaviour. We show that the mean-field model fits the large scale behaviour of the system, but does not capture fine scale rules of interaction, which are primarily mediated by physical contact. Conversely, the Markovian self-propelled particle model captures the fine scale rules of interaction but fails to reproduce global dynamics. The most sophisticated model, the non-Markovian model, provides a good match to the data at both the fine scale and in terms of reproducing global dynamics. We conclude that prawns' movements are influenced by not just the current direction of nearby conspecifics, but also those encountered in the recent past. Given the simplicity of prawns as a study system our research suggests that self-propelled particle models of collective motion should, if they are to be realistic at multiple biological scales, include memory of previous interactions and other non-Markovian effects

Effect of Lactoferrin on Clinical Outcomes of Hospitalized Patients with COVID-19: The LAC Randomized Clinical Trial

As lactoferrin is a nutritional supplement with proven antiviral and immunomodulatory abilities, it may be used to improve the clinical course of COVID-19. The clinical efficacy and safety of bovine lactoferrin were evaluated in the LAC randomized double-blind placebo-controlled trial. A total of 218 hospitalized adult patients with moderate-to-severe COVID-19 were randomized to receive 800 mg/die oral bovine lactoferrin (n = 113) or placebo (n = 105), both given in combination with standard COVID-19 therapy. No differences in lactoferrin vs. placebo were observed in the primary outcomes: the proportion of death or intensive care unit admission (risk ratio of 1.06 (95% CI 0.63–1.79)) or proportion of discharge or National Early Warning Score 2 (NEWS2) ≤ 2 within 14 days from enrollment (RR of 0.85 (95% CI 0.70–1.04)). Lactoferrin showed an excellent safety and tolerability profile. Even though bovine lactoferrin is safe and tolerable, our results do not support its use in hospitalized patients with moderate-to-severe COVID-19

A new automatic video multitracking system able to follow a large school.

peer reviewedThe study of shoaling behaviours is tackled by scientists by three approaches: the field, laboratory and computer modelling approach. The field studies are complicated and permit rarely an analysis of individual positions. The third approach, consisting of development of mathematic models, is artificial. It requires a comparison with empiric results to validate and to determine the explications’ degree of each model. Thanks to the developments of digital imaging techniques, the laboratory studies on fish are able to measure the behavioural parameters with precision, impossible to realize with manual recording. Multitracking systems are rare and of recent development. These are insufficient to study the real size of shoals, often composed of hundreds of .shes. We have developed a new system of multitracking thanks to collaboration with the G.R.A.S.P. The G.R.A.S.P. has before realised other multitracking systems to follow some hundreds physical objects. Our video multitracking system is able to detect and to track more than a hundred unmarked fishes by gray scaling technique during some minutes. It permits an analysis as well at the group level as at the individual level. The multitraking program is able to attribute a number at each fish and to follow each one during the whole duration of the track. Our system permits the analysis of the movement of each individual, even if the trajectories of two fishes cross each other. It is possible thanks to the theoretical estimation of trajectory of each fish, compared with the real trajectory (analysis with feedback). The human eye is always necessary to detect the errors in identification but reediting is possible. However, if the fishes don’t move too rapidly, a rate of 25 images /s gives very good results, without too much visual expertise from the experimenter. If the fishes are too fast (i.e. escape response), it is better to use a high speed camera

Trastuzumab-related cardiotoxicity in patients with nonlimiting cardiac comorbidity

Background: Significant and symptomatic cardiac comorbidity is a contraindication to adjuvant trastuzumab in breast cancer patients. However, some patients with asymptomatic, nonlimiting cardiac comorbidity and normal baseline left ventricular ejection fraction (LVEF) receive adjuvant trastuzumab in the clinical practice. We sought to describe the tolerability of trastuzumab in these patients. Patients and Methods: Retrospective analysis of patients with baseline asymptomatic, nonlimiting cardiac comorbidity receiving adjuvant trastuzumab at six Institutions between July 2007 and January 2016. Results: Thirty-seven patients with HER2-positive, surgery treated breast cancer at high risk of relapse were studied. Median age was 64 years (range 36-82), median baseline LVEF 61% (range 50%-85%). Thirteen patients (35%) received trastuzumab with adjuvant anthracycline and taxane-based regimens, 19 (51%) with taxane-based, three (8%) with off-label vinorelbine and two (5%) with off-label endocrine therapy. Most frequent cardiac comorbidities were ischemic heart disease (35%), valvular disease (30%), atrial fibrillation (19%), and conduction disorders (14%). Nine patients (24.3%) experienced a cardiac event: congestive heart failure (one patient, 3%), asymptomatic LVEF reduction (six patients, 16%), and rhythm disturbances (two patients, 5%). Trastuzumab had to be discontinued either permanently (five patients, 14%) or temporarily (two patients, 5%). At the time of last follow-up visit, all patients showed LVEF within normal limits, except one who had experienced a symptomatic cardiac event (LVEF value at last follow-up 46%). Conclusions: Caution is needed in patients with significant ongoing cardiovascular risk factors, but when adjuvant trastuzumab is deemed beneficial on breast cancer outcomes, nonlimiting cardiac comorbidity should not preclude treatment