46 research outputs found
Lubricating Bacteria Model for Branching growth of Bacterial Colonies
Various bacterial strains (e.g. strains belonging to the genera Bacillus,
Paenibacillus, Serratia and Salmonella) exhibit colonial branching patterns
during growth on poor semi-solid substrates. These patterns reflect the
bacterial cooperative self-organization. Central part of the cooperation is the
collective formation of lubricant on top of the agar which enables the bacteria
to swim. Hence it provides the colony means to advance towards the food. One
method of modeling the colonial development is via coupled reaction-diffusion
equations which describe the time evolution of the bacterial density and the
concentrations of the relevant chemical fields. This idea has been pursued by a
number of groups. Here we present an additional model which specifically
includes an evolution equation for the lubricant excreted by the bacteria. We
show that when the diffusion of the fluid is governed by nonlinear diffusion
coefficient branching patterns evolves. We study the effect of the rates of
emission and decomposition of the lubricant fluid on the observed patterns. The
results are compared with experimental observations. We also include fields of
chemotactic agents and food chemotaxis and conclude that these features are
needed in order to explain the observations.Comment: 1 latex file, 16 jpeg files, submitted to Phys. Rev.
Protocol to develop a core outcome set in incisional hernia surgery : the HarMoNY Project
Incisional hernia has an incidence of up to 20% following laparotomy and is associated with significant morbidity and impairment of quality of life. A variety of surgical strategies including techniques and mesh types are available to manage patients with incisional hernia. Previous works have reported significant heterogeneity in outcome reporting for abdominal wall herniae, including ventral and inguinal hernia. This is coupled with under-reporting of important clinical and patient-reported outcomes. The lack of standardisation in outcome reporting contributes to reporting bias, hinders evidence synthesis and adequate data comparison between studies. This project aims to develop a core outcome set (COS) of clinically important, patient-oriented outcomes to be used to guide reporting of future research in incisional hernia. This project has been designed as an international, multicentre, mixed-methods project. Phase I will be a systematic review of current literature to examine the current clinical and patient-reported outcomes for incisional hernia and abdominal wall reconstruction. Phase II will identify the outcomes of importance to all key stakeholders through in depth qualitative interviews. Phase III will achieve consensus on outcomes of most importance and for inclusion into a COS through a Delphi process. Phase IV will achieve consensus on the outcomes that should be included in a final COS. The adoption of this COS into clinical and academic practice will be endorsed by the American, British and European Hernia Societies. Its utilisation in future clinical research will enable appropriate data synthesis and comparison and will enable better clinical interpretation and application of the current evidence base. This study has been registered with the Core Outcome Measures in Effectiveness Trials initiative. CRD42018090084
Global overview of the management of acute cholecystitis during the COVID-19 pandemic (CHOLECOVID study)
Background: This study provides a global overview of the management of patients with acute cholecystitis during the initial phase of the COVID-19 pandemic. Methods: CHOLECOVID is an international, multicentre, observational comparative study of patients admitted to hospital with acute cholecystitis during the COVID-19 pandemic. Data on management were collected for a 2-month study interval coincident with the WHO declaration of the SARS-CoV-2 pandemic and compared with an equivalent pre-pandemic time interval. Mediation analysis examined the influence of SARS-COV-2 infection on 30-day mortality. Results: This study collected data on 9783 patients with acute cholecystitis admitted to 247 hospitals across the world. The pandemic was associated with reduced availability of surgical workforce and operating facilities globally, a significant shift to worse severity of disease, and increased use of conservative management. There was a reduction (both absolute and proportionate) in the number of patients undergoing cholecystectomy from 3095 patients (56.2 per cent) pre-pandemic to 1998 patients (46.2 per cent) during the pandemic but there was no difference in 30-day all-cause mortality after cholecystectomy comparing the pre-pandemic interval with the pandemic (13 patients (0.4 per cent) pre-pandemic to 13 patients (0.6 per cent) pandemic; P = 0.355). In mediation analysis, an admission with acute cholecystitis during the pandemic was associated with a non-significant increased risk of death (OR 1.29, 95 per cent c.i. 0.93 to 1.79, P = 0.121). Conclusion: CHOLECOVID provides a unique overview of the treatment of patients with cholecystitis across the globe during the first months of the SARS-CoV-2 pandemic. The study highlights the need for system resilience in retention of elective surgical activity. Cholecystectomy was associated with a low risk of mortality and deferral of treatment results in an increase in avoidable morbidity that represents the non-COVID cost of this pandemic
CropPol: a dynamic, open and global database on crop pollination
Seventy five percent of the world's food crops benefit from insect pollination. Hence, there has been increased interest in how global change drivers impact this critical ecosystem service. Because standardized data on crop pollination are rarely available, we are limited in our capacity to understand the variation in pollination benefits to crop yield, as well as to anticipate changes in this service, develop predictions, and inform management actions. Here, we present CropPol, a dynamic, open and global database on crop pollination. It contains measurements recorded from 202 crop studies, covering 3,394 field observations, 2,552 yield measurements (i.e. berry weight, number of fruits and kg per hectare, among others), and 47,752 insect records from 48 commercial crops distributed around the globe. CropPol comprises 32 of the 87 leading global crops and commodities that are pollinator dependent. Malus domestica is the most represented crop (32 studies), followed by Brassica napus (22 studies), Vaccinium corymbosum (13 studies), and Citrullus lanatus (12 studies). The most abundant pollinator guilds recorded are honey bees (34.22% counts), bumblebees (19.19%), flies other than Syrphidae and Bombyliidae (13.18%), other wild bees (13.13%), beetles (10.97%), Syrphidae (4.87%), and Bombyliidae (0.05%). Locations comprise 34 countries distributed among Europe (76 studies), Northern America (60), Latin America and the Caribbean (29), Asia (20), Oceania (10), and Africa (7). Sampling spans three decades and is concentrated on 2001-05 (21 studies), 2006-10 (40), 2011-15 (88), and 2016-20 (50). This is the most comprehensive open global data set on measurements of crop flower visitors, crop pollinators and pollination to date, and we encourage researchers to add more datasets to this database in the future. This data set is released for non-commercial use only. Credits should be given to this paper (i.e., proper citation), and the products generated with this database should be shared under the same license terms (CC BY-NC-SA). This article is protected by copyright. All rights reserved
Impact of COVID-19 on cardiovascular testing in the United States versus the rest of the world
Objectives: This study sought to quantify and compare the decline in volumes of cardiovascular procedures between the United States and non-US institutions during the early phase of the coronavirus disease-2019 (COVID-19) pandemic.
Background: The COVID-19 pandemic has disrupted the care of many non-COVID-19 illnesses. Reductions in diagnostic cardiovascular testing around the world have led to concerns over the implications of reduced testing for cardiovascular disease (CVD) morbidity and mortality.
Methods: Data were submitted to the INCAPS-COVID (International Atomic Energy Agency Non-Invasive Cardiology Protocols Study of COVID-19), a multinational registry comprising 909 institutions in 108 countries (including 155 facilities in 40 U.S. states), assessing the impact of the COVID-19 pandemic on volumes of diagnostic cardiovascular procedures. Data were obtained for April 2020 and compared with volumes of baseline procedures from March 2019. We compared laboratory characteristics, practices, and procedure volumes between U.S. and non-U.S. facilities and between U.S. geographic regions and identified factors associated with volume reduction in the United States.
Results: Reductions in the volumes of procedures in the United States were similar to those in non-U.S. facilities (68% vs. 63%, respectively; p = 0.237), although U.S. facilities reported greater reductions in invasive coronary angiography (69% vs. 53%, respectively; p < 0.001). Significantly more U.S. facilities reported increased use of telehealth and patient screening measures than non-U.S. facilities, such as temperature checks, symptom screenings, and COVID-19 testing. Reductions in volumes of procedures differed between U.S. regions, with larger declines observed in the Northeast (76%) and Midwest (74%) than in the South (62%) and West (44%). Prevalence of COVID-19, staff redeployments, outpatient centers, and urban centers were associated with greater reductions in volume in U.S. facilities in a multivariable analysis.
Conclusions: We observed marked reductions in U.S. cardiovascular testing in the early phase of the pandemic and significant variability between U.S. regions. The association between reductions of volumes and COVID-19 prevalence in the United States highlighted the need for proactive efforts to maintain access to cardiovascular testing in areas most affected by outbreaks of COVID-19 infection
The PREDICTS database: a global database of how local terrestrial biodiversity responds to human impacts
Biodiversity continues to decline in the face of increasing anthropogenic pressures
such as habitat destruction, exploitation, pollution and introduction of
alien species. Existing global databases of speciesâ threat status or population
time series are dominated by charismatic species. The collation of datasets with
broad taxonomic and biogeographic extents, and that support computation of
a range of biodiversity indicators, is necessary to enable better understanding of
historical declines and to project â and avert â future declines. We describe and
assess a new database of more than 1.6 million samples from 78 countries representing
over 28,000 species, collated from existing spatial comparisons of
local-scale biodiversity exposed to different intensities and types of anthropogenic
pressures, from terrestrial sites around the world. The database contains
measurements taken in 208 (of 814) ecoregions, 13 (of 14) biomes, 25 (of 35)
biodiversity hotspots and 16 (of 17) megadiverse countries. The database contains
more than 1% of the total number of all species described, and more than
1% of the described species within many taxonomic groups â including flowering
plants, gymnosperms, birds, mammals, reptiles, amphibians, beetles, lepidopterans
and hymenopterans. The dataset, which is still being added to, is
therefore already considerably larger and more representative than those used
by previous quantitative models of biodiversity trends and responses. The database
is being assembled as part of the PREDICTS project (Projecting Responses
of Ecological Diversity In Changing Terrestrial Systems â www.predicts.org.uk).
We make site-level summary data available alongside this article. The full database
will be publicly available in 2015
Differential branching fractions and isospin asymmetries of B â K (*) ÎŒ + ÎŒ â decays
The isospin asymmetries of and
decays and the partial branching fractions of the , and decays are measured as
functions of the dimuon mass squared, . The data used correspond to an
integrated luminosity of 3fb from proton-proton collisions collected
with the LHCb detector at centre-of-mass energies of 7TeV and 8TeV in
2011 and 2012, respectively. The isospin asymmetries are both consistent with
the Standard Model expectations. The three measured branching fractions, while
individually consistent, all favour lower values than their respective Standard
Model predictions.Comment: 25 pages, 4 figures, 7 tables, fix typ