Sperm whale foraging behaviour: a predicted model based on 3D movement and acoustic data from Dtags

High-resolution sound and movement recording tags (e.g. Dtags, Acousonde tags, Atags) offer unprecedented views of the fine-scale foraging behaviour of cetaceans, especially those that use sound to forage, such as the sperm whale (Physeter macrocephalus). However, access to these tags is difficult and expensive, limiting studies of sperm whale foraging behaviour to small sample sizes and short time periods, preventing inferences at the population level. The development of accurate foraging indices from relatively inexpensive time-depth recorder (TDR) data would allow obtaining data from a larger number of individuals, and capitalizing on datasets already available, providing long-term analyses of foraging activity. In this study, data from high-resolution acoustic and movement recording tags from 8 sperm whales was used to build predictive models of the number of buzzes (i.e, indicative of prey capture attempts (PCA)) for dive segments of different lengths, using dive metrics calculated from timedepth data only. The number of buzzes per dive segments of 180s and 300s was best predicted by the average depth, depth variance, vertical velocity variance and number of wiggles. Model performance was best for 180s segments, accurately predicting the number of buzzes in 63% of the segments used to construct the model and in 58% of the segments for new individuals. Predictive accuracy reached 81%, when only presence or absence of buzzes in segments was assessed. These results demonstrate the feasibility of finding a reliable index of sperm whale foraging activity for time-depth data, when combining different dive metrics. This index estimates the number of buzzes over short dive segments (of 180s), enabling investigating and quantifying PCAs at very finescales. Finally, this work contributes to leverage the potential of time-depth data for studying the foraging ecology of sperm whales and the capacity of applying this approach to a wide range of cetacean species.O cachalote (Physeter macrocephalus) é um dos mais conhecidos predadores marinhos, passando mais da metade da sua vida abaixo dos 500m de profundidade, onde se alimenta principalmente de lulas meso e bentopelágicas, embora também possam consumir outros cefalópodes, peixes profundos e invertebrados. Apresenta uma distribuição mundial e pode ser encontrado no arquipélago dos Açores durante todo o ano, perto da costa, razão pela qual os Açores foram uma das regiões baleeiras mais importantes. O som desempenha um papel fundamental na vida dos cachalotes. Eles produzem sons enquanto estão a socializar e na procura e captura de alimento. Foram identificados pelo menos quatro tipos de cliques (cliques usuais, “buzzes”, codas e “slow clicks”), dos quais os cliques usuais e os “buzzes” estão envolvidos no comportamento de alimentação. Os cliques usuais têm níveis sonoros elevados e são altamente direcionais, servindo como um biosonar para navegar pelo ambiente e eco-localizar presas. Os “buzzes”, consistem em cliques de alta frequência e baixa amplitude, produzidos em intervalos rápidos. Por esta razão, têm um alcance mais curto do que os cliques usuais, fornecendo uma resolução mais alta e, portanto, informações mais detalhadas sobre o seu ambiente próximo e presas. A observação direta é uma das ferramentas mais poderosas para estudar o comportamento animal, não obstante, no caso dos cachalotes é altamente limitada, consequência dos longos períodos que passam em profundidade. Por este motivo, os estudos sobre o comportamento do cachalote, e de outros predadores marinhos de mergulho profundo, dependem da utilização de diferentes ferramentas que permitem obter informações sobre o seu comportamento subaquático. Os hidrofones e as marcas colocadas em animais estão entre as ferramentas mais importantes para estudos sobre o comportamento dos cetáceos, permitindo o registo contínuo de sons produzidos debaixo de água e o seguimento, também contínuo, de movimento e outras variáveis de mergulho. A incorporação de hidrofones em marcas para colocação em animais, como as marcas acústicas digitais (“Dtags”), marcas “Acousonde” ou “A-tags” revolucionou o estudo do comportamento dos cetáceos. Estas marcas fornecem dados de movimento tridimensional e acústicos de alta resolução, simultaneamente registando informação sobre o comportamento do animal, possibilitando, por exemplo, a compreensão de como os cachalotes usam o som durante a alimentação. Estudos baseados na análise de dados de “Dtags” revelaram que a presença de picos de velocidade na parte mais profunda do mergulho e movimentos rápidos da mandíbula estavam relacionados com a produção de “buzzes”. Consequentemente, foi sugerido que os “buzzes” são emitidos durante a fase terminal de captura de presas, a fim de obter informação de alta resolução sobre o alvo. Desde então, a produção de cliques tem sido usada como um indicador de esforço de alimentação e a produção de “buzzes”, considerada como o melhor indicador de tentativa de captura de presas. Não obstante, o acesso a estas marcas de alta resolução acústica e movimento é extremamente difícil e caro, limitando o estudo do comportamento de alimentação do cachalote a amostras pequenas e curtos períodos de tempo. Por esta razão, o desenvolvimento de um índice de esforço de alimentação exato, a partir de dados de mergulho 2D de dados de tempo-profundidade como os “time-depth recorders” (TDR), permitiria capitalizar um conjunto de dados de mergulho já disponíveis, analisando séries temporais de atividade de alimentação e avaliando alterações ligadas a mudanças climáticas ou antropogénicas. No presente estudo, dados de alta resolução com informação acústica de oito cachalotes marcados com “Dtags” no arquipélago dos Açores foram usados para construir um modelo preditivo do número de “buzzes”, baseado exclusivamente em dados profundidade-tempo e com resolução máxima de 1m de profundidade, correspondendo, portanto, às capacidades de registo de um TDR. O número total de “buzzes” por segmento foi modelado a partir de um conjunto de variáveis que descrevem a média e variabilidade de profundidade, tempo passado na fase profunda do mergulho, velocidade vertical, aceleração vertical e número de excursões verticais, usando um modelo linear generalizado misto (GLMM), com o indivíduo como um efeito aleatório. De um total de 816 “buzzes” analisados, 95% apresentaram uma duração de 2 a 14 segundos. Portanto, inicialmente os mergulhos foram divididos em segmentos de curta duração. Porém, as primeiras análises demonstraram fracas capacidades preditivas e finalmente optou-se por usar segmentos de 180s e 300s. Os melhores modelos de número de buzzes por segmento de 180s e 300s incluíram a profundidade média, a variância de profundidade, a variância da velocidade vertical e o número de “wiggles” por segmento. Os segmentos de mergulho com “buzzes” apresentaram uma maior profundidade média, menor variância de profundidade, maior variância de velocidade e maior presença de “wiggles”, sendo a profundidade média a métrica mais relevante do modelo. Estes resultados confirmam que os “buzzes” ocorrem nas partes profundas do mergulho e sugerem que as várias tentativas de captura podem ocorrer numa extensão de profundidade limitada, demonstrado pela pequena variação de profundidade, maior variação de velocidade e presença de “wiggles”. O desempenho do modelo foi melhor para segmentos de 180s, resultando em deteções corretas do número de “buzzes” em 63% dos segmentos usados para construir o modelo e em 58% dos segmentos para novos indivíduos usados para testar o modelo. Assim mesmo, o modelo resultou em 81% de deteções corretas quando avaliada apenas a presença ou ausência de “buzzes” nos segmentos. Apesar do nosso modelo ter algumas deficiências preditivas, os resultados preditivos são similares àqueles obtidos com modelos desenvolvidos anteriormente, para prever tentativas de captura de presas em conjuntos de dados 2D de baixa resolução em outras espécies. Porém, ao contrário desses modelos que previram tentativas de captura de presas na escala de mergulho ou, na melhor das hipóteses, em escalas de 30 minutos e de uma hora, o modelo desenvolvido neste estudo previu tentativas de captura de presas a cada 3 minutos. Este é o primeiro estudo a desenvolver um modelo que prevê o número de tentativas de captura de presas e, consequentemente, o esforço de alimentação em cachalotes a partir de perfis de mergulho 2D. O presente método poderá ser aplicado a conjuntos de dados de profundidade de tempo já disponíveis, a fim de conduzir análises retrospetivas do comportamento de alimentação. Porém, o aumento do tamanho da amostra e uma análise de dados mais detalhada permitiria obter previsões mais precisas. Finalmente, a presente abordagem de estimativa de alimentação é baseada na previsão do número de “buzzes” e, portanto, poderia ser potencialmente aplicada a uma série de espécies de odontocetes, potencialmente permitindo estimativas mais precisas do esforço de alimentação, do que os índices grosseiros e gerais tipicamente derivados de perfis de mergulho 2D

Predictive model of sperm whale prey capture attempts from time-depth data

Funding: Research was supported by the Portuguese Science & Technology Foundation (FCT), the Azorean Science & Technology Fund (FRCT), and the EU through research projects WATCH IT-Acores-01-0145-FEDER-000057, FCT-IF/00943/2013/CP1199/CT0001, META-FA_06_2017_017, and SUMMER-H2020 GA 817806, co-funded by FEDER, COMPETE, QREN, POPH, ESF, PO AZORES 2020, Portuguese Ministry for Science and Education, and individual contracts/grants to CO (WATCH IT-Acores-01-0145-FEDER-000057, 3/SRMCT/DRAM/2019 under RAGES-SUB/ENV.C.2-GA 110661, and INTERTAGUA-MAC2/1.1a/385), SPJ (SUMMER-H2020 GA 817806), IC (FCT-IP Project UIDP/05634/2020). PJW is funded by RANNÍS Icelandic Research Fund grant 207081. RP and MAS are co-financed by AZORES2020, through the EU Fund 01-0145-FEDER-000140 “MarAZ Researchers: Consolidate a body of researchers in Marine Sciences in the Azores”. Okeanos is funded by FCT (UIDB/05634/2020) and by the Regional Government of the Azores through the initiative to support the Research Centers of the University of the Azores (M1.1.A/REEQ.CIENTÍFICO UI&D/2021/010).Background High-resolution sound and movement recording tags offer unprecedented insights into the fine-scale foraging behaviour of cetaceans, especially echolocating odontocetes, enabling the estimation of a series of foraging metrics. However, these tags are expensive, making them inaccessible to most researchers. Time-Depth Recorders (TDRs), which have been widely used to study diving and foraging behaviour of marine mammals, offer a more affordable alternative. Unfortunately, data collected by TDRs are bi-dimensional (time and depth only), so quantifying foraging effort from those data is challenging. Methods A predictive model of the foraging effort of sperm whales (Physeter macrocephalus) was developed to identify prey capture attempts (PCAs) from time-depth data. Data from high-resolution acoustic and movement recording tags deployed on 12 sperm whales were downsampled to 1 Hz to match the typical TDR sampling resolution and used to predict the number of buzzes (i.e., rapid series of echolocation clicks indicative of PCAs). Generalized linear mixed models were built for dive segments of different durations (30, 60, 180 and 300 s) using multiple dive metrics as potential predictors of PCAs. Results Average depth, variance of depth and variance of vertical velocity were the best predictors of the number of buzzes. Sensitivity analysis showed that models with segments of 180 s had the best overall predictive performance, with a good area under the curve value (0.78 ± 0.05), high sensitivity (0.93 ± 0.06) and high specificity (0.64 ± 0.14). Models using 180 s segments had a small difference between observed and predicted number of buzzes per dive, with a median of 4 buzzes, representing a difference in predicted buzzes of 30%. Conclusions These results demonstrate that it is possible to obtain a fine-scale, accurate index of sperm whale PCAs from time-depth data alone. This work helps leveraging the potential of time-depth data for studying the foraging ecology of sperm whales and the possibility of applying this approach to a wide range of echolocating cetaceans. The development of accurate foraging indices from low-cost, easily accessible TDR data would contribute to democratize this type of research, promote long-term studies of various species in several locations, and enable analyses of historical datasets to investigate changes in cetacean foraging activity.Publisher PDFPeer reviewe

Treatment with tocilizumab or corticosteroids for COVID-19 patients with hyperinflammatory state: a multicentre cohort study (SAM-COVID-19)

Objectives: The objective of this study was to estimate the association between tocilizumab or corticosteroids and the risk of intubation or death in patients with coronavirus disease 19 (COVID-19) with a hyperinflammatory state according to clinical and laboratory parameters. Methods: A cohort study was performed in 60 Spanish hospitals including 778 patients with COVID-19 and clinical and laboratory data indicative of a hyperinflammatory state. Treatment was mainly with tocilizumab, an intermediate-high dose of corticosteroids (IHDC), a pulse dose of corticosteroids (PDC), combination therapy, or no treatment. Primary outcome was intubation or death; follow-up was 21 days. Propensity score-adjusted estimations using Cox regression (logistic regression if needed) were calculated. Propensity scores were used as confounders, matching variables and for the inverse probability of treatment weights (IPTWs). Results: In all, 88, 117, 78 and 151 patients treated with tocilizumab, IHDC, PDC, and combination therapy, respectively, were compared with 344 untreated patients. The primary endpoint occurred in 10 (11.4%), 27 (23.1%), 12 (15.4%), 40 (25.6%) and 69 (21.1%), respectively. The IPTW-based hazard ratios (odds ratio for combination therapy) for the primary endpoint were 0.32 (95%CI 0.22-0.47; p < 0.001) for tocilizumab, 0.82 (0.71-1.30; p 0.82) for IHDC, 0.61 (0.43-0.86; p 0.006) for PDC, and 1.17 (0.86-1.58; p 0.30) for combination therapy. Other applications of the propensity score provided similar results, but were not significant for PDC. Tocilizumab was also associated with lower hazard of death alone in IPTW analysis (0.07; 0.02-0.17; p < 0.001). Conclusions: Tocilizumab might be useful in COVID-19 patients with a hyperinflammatory state and should be prioritized for randomized trials in this situatio

A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)

Meeting abstrac

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

The original version of this article unfortunately contained a mistake

Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat

Unique genetic profile of sporadic colorectal cancer liver metastasis versus primary tumors as defined by high-density single-nucleotide polymorphism arrays

Most genetic studies in colorectal carcinomas have focused on those abnormalities that are acquired by primary tumors, particularly in the transition from adenoma to carcinoma, whereas few studies have compared the genetic abnormalities of primary versus paired metastatic samples. In this study, we used high-density 500K single-nucleotide polymorphism arrays to map the overall genetic changes present in liver metastases (n20) from untreated colorectal carcinoma patients studied at diagnosis versus their paired primary tumors (n20). MLH1, MSH2 and MSH6 gene expression was measured in parallel by immunohistochemistry. Overall, metastatic tumors systematically contained those genetic abnormalities observed in the primary tumor sample from the same subject. However, liver metastases from many cases (up to 8 out of 20) showed acquisition of genetic aberrations that were not found in their paired primary tumors. These new metastatic aberrations mainly consisted of (1) an increased frequency of genetic lesions of chromosomes that have been associated with metastatic colorectal carcinoma (1p, 7p, 8q, 13q, 17p, 18q, 20q) and, more interestingly, (2) acquisition of new chromosomal abnormalities (eg, losses of chromosomes 4 and 10q and gains of chromosomes 5p and 6p). These genetic changes acquired by metastatic tumors may be associated with either the metastatic process and/or adaption of metastatic cells to the liver microenvironment. Further studies in larger series of patients are necessary to dissect the specific role of each of the altered genes and chromosomal regions in the metastatic spread of colorectal tumors. © 2012 USCAP, Inc. All rights reserved.This work has been partially supported by grants from the Consejería de Sanidad, Junta de Castilla y León, Valladolid, Spain (SAN191/SA09/06, SAN673/SA39/08 and SAN/103/2011), Fundación Memoria de Don Samuel Solórzano Barruso, Salamanca, Spain, Caja de Burgos (Obra Social), Burgos, Spain, Grupo Excelencia de Castilla y León (GR37) and the RTICC from the Instituto de Salud Carlos III (ISCIII), Ministerio de Sanidad y Consumo, Madrid, Spain (RD06/0020/0035-FEDER). JM Sayagués and M González are supported by grants (CP05/00321 and FI08/00721, respectively) from the ISCIII, Ministerio de Ciencia e Innovación, Madrid, Spain.Peer Reviewe

Vectorized nanodelivery systems for ischemic stroke: a concept and a need

Abstract Neurological diseases of diverse aetiologies have significant effects on the quality of life of patients. The limited self-repairing capacity of the brain is considered to be the origin of the irreversible and progressive nature of many neurological diseases. Therefore, neuroprotection is an important goal shared by many clinical neurologists and neuroscientists. In this review, we discuss the main obstacles that have prevented the implementation of experimental neuroprotective strategies in humans and propose alternative avenues for the use of neuroprotection as a feasible therapeutic approach. Special attention is devoted to nanotechnology, which is a new approach for developing highly specific and localized biomedical solutions for the study of the multiple mechanisms involved in stroke. Nanotechnology is contributing to personalized neuroprotection by allowing us to identify mechanisms, determine optimal therapeutic windows, and protect patients from brain damage. In summary, multiple aspects of these new players in biomedicine should be considered in future in vivo and in vitro studies with the aim of improving their applicability to clinical studies