Effect of hydro-climate variation on biofilm dynamics and its impact in intertidal environments

Shallow tidal environments are very productive ecosystems but are sensitive to environmental changes and sea level rise. Bio-morphodynamic control of these environments is therefore a crucial consideration; however, the effect of small-scale biological activity on large-scale cohesive sediment dynamics like tidal basins and estuaries is still largely unquantified. This study advances our understanding by assessing the influence of biotic and abiotic factors on biologically cohesive sediment transport and morphology. An idealised benthic biofilm model is incorporated in a 1D morphodynamic model of tide-dominated channels. This study investigates the effect of a range of environmental and biological conditions on biofilm growth and their feedback on the morphological evolution of the entire intertidal channel. By carrying out a sensitivity analysis of the bio-morphodynamic model, parameters like (i) hydrodynamic disturbances, (ii) seasonality, (iii) biofilm growth rate, (iv) temperature variation and (v) bio-cohesivity of the sediment are systematically changed. Results reveal that key parameters such as growth rate and temperature strongly influence the development of biofilm and are key determinants of equilibrium biofilm configuration and development under a range of disturbance periodicities and intensities. Long-term simulations of intertidal channel development demonstrate that the hydrodynamic disturbances induced by tides play a key role in shaping the morphology of the bed and that the presence of surface biofilm increases the time to reach morphological equilibrium. In locations characterised by low hydrodynamic forces, the biofilm grows and stabilises the bed, inhibiting the transport of coarse sediment (medium and fine sand). These findings suggest biofilm presence in channel beds results in intertidal channels that have significantly different characteristics in terms of morphology and stratigraphy compared abiotic sediments. It is concluded that inclusion of bio-cohesion in morphodynamic models is essential to predict estuary development and mitigate coastal erosion.</p

NEW GASOLINE PASSENGER CAR ENGINE OIL PERFORMANCE CATEGORY

U budućnosti će motori biti osmišljeni na način da više štede gorivo i da budu ekološki prihvatljiviji, što s jedne strane potiču važeći propisi, a s druge strane zahtjevi kupaca. Međunarodni odbor za standardizaciju i odobravanje motornih ulja ILSAC (International Lubricant Standardization and Approval Committee), kojega sačinjavaju Sjevernoameričko udruženje proizvođača motora EMA (Engine Manufacturer’s Association) i Japansko udruženje proizvođača automobila JAMA (Japanese Automobile Manufacturer’s Association), bio je sastavljen kako bi se razvili minimalni standardi radnih karakteristika maziva koja će proizvođačima vozila i motora omogućiti veću uštedu goriva, smanjiti emisije štetnih plinova, produljiti vijek trajanja i poboljšati pouzdanost njihovih vozila i motora. Važeća specifikacija ulja ILSAC GF-4, uvedena je u srpnju 2004. Rad na sljedećoj specifikaciji, GF-5, započeo je 2005., a plan je da bude završen na vrijeme za komercijalno uvođenje GF-5 ulja u zadnjem kvartalu 2010. za modele vozila koji će izaći 2011. godine. U odnosu na GF-4, postoje tri osnovna područja poboljšanja primjenskih svojstava za GF-5 ulja: (1) ušteda goriva i trajnost uštede goriva, (2) kompatibilnost sa sustavom obrade ispušnih plinova i (3) sveukupna robusnost ulja. Želja za većom uštedom goriva je djelomice potaknuta propisima američke vlade koja traži da CAFÉ (Corporate Average Fuel Economy) dosegne 35 milja po galonu (14,9 km/l ili 6,7 l/100km) do 2020. godine. Trenutačni CAFÉ zahtjev iznosi 27,5 milja po galonu (11,7 km/l ili 8,5 l/100km). Pored važećih propisa, rekordne cijene goriva potakle su potražnju kupaca prema vozilima s manjom potrošnjom goriva. Specifikacija ILSAC GF-5 uključuje novi motorni test pomoću kojeg će se ocijeniti sposobnost motornog ulja da smanji potrošnju goriva. Kako bi se osigurala usklađenost emisije ispušnih plinova tijekom vijeka trajanja vozila, Agencija za zaštitu okoliša EPA (Environmental Protection Agency) je postavila granicu od 10 godina/120 000 milja (194 000 km) vijeka trajanja u kojem vozilo mora ostati unutar ograničenja emisije ispušnih plinova. Osim toga, obavezno korištenje ugrađenog sustava rada motora OBD (On-Board Diagnostic) omogućuje da vozila ne prelaze ograničenja i nastave ispravno raditi tijekom svog vijeka korištenja. Izgaranjem motornog ulja u motorima dolazi do stvaranja taloga koji mogu dovesti do neispravnosti sustava obrade ispušnih plinova. Stoga, osim što sprječava trošenje motora, kompatibilnost motornog ulja sa sustavima obrade ispušnih plinova je važno primjensko svojstvo ulja. Specifikacija ILSAC GF-5 će uključivati kemijska ograničenja koja osiguravaju poboljšanu kompatibilnost sa sustavima obrade ispušnih plinova. Poboljšanja u konstrukciji vozila i motora, kao i povećani troškovi kupnje odrazili su se na smanjenje potrebe zamjene vozila, a kao rezultat toga prosječan vijek trajanja vozila se na mnogim tržištima produljio. Robusnost ulja igra vodeću ulogu u produljenju vijeka trajanja motora. Specifikacija ILSAC GF-5 će uključivati motorne testove i granice primjenskih svojstava kako bi osigurala prikladnu robusnost motornog ulja koje će produljiti vijek trajanja motora. U radu se daje pregled svega onoga što je potaklo stvaranje ILSAC GF-5 specifikacije motornih ulja i raspravlja se o ispitivanjima i ograničenjima primjenskih svojstava koja su ustanovljena kako bi ta specifikacija zadovoljila zahtjeve industrije.Future engine designs will be more fuel efficient and environmentally friendly. These are being driven by government regulations and mandates as well as consumer demand. The International Lubricant Standardization and Approval Committee (ILSAC), which is comprised of the North America Engine Manufacturer’s Association (EMA) as well as the Japanese Automobile Manufacturer’s Association (JAMA), was formed to develop minimum performance standards for lubricants which enable vehicle and engine manufacturers to increase fuel economy, reduce emissions, and improve durability and reliability of their vehicles and engines. The current performance category of ILSAC oil, GF-4, was introduced in July 2004. Work on the next generation oil, GF-5, began in 2005 and is scheduled to be completed in time for a commercial introduction of GF-5 oil during the 4th quarter of 2010 in time for 2011 model year vehicles. Relative to GF-4, there are three primary performance areas of GF-5 that have been identified for improvement: (1) Fuel economy and fuel economy durability, (2) Emissions system compatibility, and (3) Overall oil robustness. The desire for fuel economy improvements are being driven in part by U.S. government regulations requiring Corporate Average Fuel Economy (CAFÉ) to reach 35 miles per gallon by 2020. The current CAFÉ requirement is 27.5 miles per gallon. In addition to government mandates, record fuel prices have driven consumer demand and focus towards improved fuel economy. The ILSAC GF-5 category will include a new lab engine test which will assess the ability of engine oils with respect to fuel economy performance. In order to assure emissions compliance during the life of the vehicle, the Environmental Protection Agency (EPA) has established a 10 year/120,000 mile (194,000 km) useful life in which the vehicle must remain within certain emissions limits. In addition, the mandated use of On-Board Diagnostic (OBD) systems assure the vehicles do not exceed certain limits and continue to operate properly during their useful life. A certain amount of engine oil is burned in engines and ash forming compounds can lead to fouling of exhaust emissions systems. Therefore, besides protecting the engine from wear, compatibility of engine oil with exhaust emissions systems is an important performance parameter. The ILSAC GF-5 category will include a test and chemical limits that help assure improved emissions system compatibility. Improvements in vehicle and engine design, as well as increased purchase costs, have resulted in customers extending trade-in cycles and, as a result, the average vehicle age has increased in many markets. Oil robustness plays a major role in extended engine life. The ILSAC GF-5 category will include engine tests and performance targets to assure proper engine oil robustness to allow extended engine durability. In this presentation, we will provide an overview of the drivers for the ILSAC GF-5 engine oil category and also discuss the performance tests and li-mits that are being established to assure the category meets the industry objectives

AVERT2(a very early rehabilitation trial, a very effective reproductive trigger): retrospective observational analysis of the number of babies born to trial staff

Objective: To report the number of participants needed to recruit per baby born to trial staff during AVERT, a large international trial on acute stroke, and to describe trial management consequences. Design: Retrospective observational analysis. Setting: 56 acute stroke hospitals in eight countries. Participants: 1074 trial physiotherapists, nurses, and other clinicians. Outcome measures: Number of babies born during trial recruitment per trial participant recruited. Results: With 198 site recruitment years and 2104 patients recruited during AVERT, 120 babies were born to trial staff. Births led to an estimated 10% loss in time to achieve recruitment. Parental leave was linked to six trial site closures. The number of participants needed to recruit per baby born was 17.5 (95% confidence interval 14.7 to 21.0); additional trial costs associated with each birth were estimated at 5736 Australian dollars on average. Conclusion: The staff absences registered in AVERT owing to parental leave led to delayed trial recruitment and increased costs, and should be considered by trial investigators when planning research and estimating budgets. However, the celebration of new life became a highlight of the annual AVERT collaborators’ meetings and helped maintain a cohesive collaborative group

Time-resolved Neutron-gamma-ray Data Acquisition for in Situ Subsurface Planetary Geochemistry

The current gamma-ray/neutron instrumentation development effort at NASA Goddard Space Flight Center aims to extend the use of active pulsed neutron interrogation techniques to probe the subsurface elemental composition of planetary bodies in situ. Previous NASA planetary science missions, that used neutron and/or gamma-ray spectroscopy instruments, have relied on neutrons produced from galactic cosmic rays. One of the distinguishing features of this effort is the inclusion of a high intensity 14.1 MeV pulsed neutron generator synchronized with a custom data acquisition system to time each event relative to the pulse. With usually only one opportunity to collect data, it is difficult to set a priori time-gating windows to obtain the best possible results. Acquiring time-tagged, event-by-event data from nuclear induced reactions provides raw data sets containing channel/energy, and event time for each gamma ray or neutron detected. The resulting data set can be plotted as a function of time or energy using optimized analysis windows after the data are acquired. Time windows can now be chosen to produce energy spectra that yield the most statistically significant and accurate elemental composition results that can be derived from the complete data set. The advantages of post-processing gamma-ray time-tagged event-by-event data in experimental tests using our prototype instrument will be demonstrated

The care of patients with Duchenne, Becker and other muscular dystrophies in the COVID-19 pandemic

The corona virus disease 2019 (COVID-19) pandemic has resulted in the reorganization of healthcare settings affecting clinical care delivery to patients with Duchenne and Becker muscular dystrophy (DBMD) as well as other inherited muscular dystrophies. The magnitude of the impact of this public health emergency on the care of patients with DBMD is unclear as they are suspected of having an increased risk for severe manifestations of COVID-19. In this paper, the authors discuss their consensus recommendations pertaining to care of these patients during the pandemic. We address issues surrounding corticosteroid and exon skipping treatments, cardiac medications, hydroxychloroquine use, emergency/respiratory care, rehabilitation management, and the conduct of clinical trials. We highlight the importance of collaborative treatment decisions between the patient, family, and health care provider, considering any geographic or institution-specific policies and precautions for COVID-19. We advocate for continuing multidisciplinary care for these patients using telehealth

Current- and Wave-Generated Bedforms on Mixed Sand–Clay Intertidal Flats:A New Bedform Phase Diagram and Implications for Bed Roughness and Preservation Potential

The effect of bedforms on frictional roughness felt by the overlying flow is crucial to the regional modelling of estuaries and coastal seas. Bedforms are also a key marker of palaeoenvironments. Experiments have shown that even modest biotic and abiotic cohesion in sand inhibits bedform formation, modifies bedform size, and slows bedform development, but this has rarely been tested in nature. The present study used a comprehensive dataset recorded over a complete spring–neap cycle on an intertidal flat to investigate bedform dynamics controlled by a wide range of wave and current conditions, including the effects of wave–current angle and bed cohesion. A detailed picture of different bedform types and their relationship to the flow, be they equilibrium, non-equilibrium, or relict, was produced, and captured in a phase diagram that integrates wave-dominated, current-dominated, and combined wave–current bedforms. This bedform phase diagram incorporates a substantially wider range of flow conditions than previous phase diagrams, including bedforms related to near-orthogonal wave–current angles, such as ladderback ripples. Comparison with laboratory-derived bedform phase diagrams indicates that washed-out ripples, lunate interference ripples and upper-stage plane beds replace the subaqueous dune field; such bedform distributions may be a key characteristic of intertidal flats. The field data also provide a means of predicting the dimensions of these bedforms, which can be transferred to other areas and grain sizes. We show that an equation for the prediction of equilibrium bedform size is sufficient to predict the roughness, even though the bedforms are highly variable in character and only in equilibrium with the flow for approximately half the time. Whilst the effect of cohesive clay is limited under more active spring conditions, clay does play a role in reducing the bedform dimensions under more quiescent neap conditions. We also investigated which combinations of waves, currents, and bed clay contents in the intertidal zone have the highest potential for bedform preservation in the geological record. This shows that combined wave–current bedforms have the lowest preservation potential and equilibrium current ripples have the highest preservation potential, even in the presence of moderate and storm waves. Hence, the absence of wave ripples and combined-flow bedforms and their primary stratification in sedimentary successions cannot be taken as evidence that waves were absent at the time of deposition

Design considerations in a clinical trial of a cognitive behavioural intervention for the management of low back pain in primary care : Back Skills Training Trial

Background Low back pain (LBP) is a major public health problem. Risk factors for the development and persistence of LBP include physical and psychological factors. However, most research activity has focused on physical solutions including manipulation, exercise training and activity promotion. Methods/Design This randomised controlled trial will establish the clinical and cost-effectiveness of a group programme, based on cognitive behavioural principles, for the management of sub-acute and chronic LBP in primary care. Our primary outcomes are disease specific measures of pain and function. Secondary outcomes include back beliefs, generic health related quality of life and resource use. All outcomes are measured over 12 months. Participants randomised to the intervention arm are invited to attend up to six weekly sessions each of 90 minutes; each group has 6–8 participants. A parallel qualitative study will aid the evaluation of the intervention. Discussion In this paper we describe the rationale and design of a randomised evaluation of a group based cognitive behavioural intervention for low back pain

The role of biophysical cohesion on subaqueous bed form size

Biologically active, fine-grained sediment forms abundant sedimentary deposits on Earth's surface, and mixed mud-sand dominates many coasts, deltas, and estuaries. Our predictions of sediment transport and bed roughness in these environments presently rely on empirically based bed form predictors that are based exclusively on biologically inactive cohesionless silt, sand, and gravel. This approach underpins many paleoenvironmental reconstructions of sedimentary successions, which rely on analysis of cross-stratification and bounding surfaces produced by migrating bed forms. Here we present controlled laboratory experiments that identify and quantify the influence of physical and biological cohesion on equilibrium bed form morphology. The results show the profound influence of biological cohesion on bed form size and identify how cohesive bonding mechanisms in different sediment mixtures govern the relationships. The findings highlight that existing bed form predictors require reformulation for combined biophysical cohesive effects in order to improve morphodynamic model predictions and to enhance the interpretations of these environments in the geological record