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Carbon dioxide removal from the atmosphere (CDR)-also known as 'negative emissions'-features prominently in most 2 °C scenarios and has been under increased scrutiny by scientists, citizens, and policymakers. Critics argue that 'negative emission technologies' (NETs) are insufficiently mature to rely on them for climate stabilization. Some even argue that 2 °C is no longer feasible or might have unacceptable social and environmental costs. Nonetheless, the Paris Agreement endorsed an aspirational goal of limiting global warming to even lower levels, arguing that climate impacts-especially for vulnerable nations such as small island states-will be unacceptably severe in a 2 °C world. While there are few pathways to 2 °C that do not rely on negative emissions, 1.5 °C scenarios are barely conceivable without them. Building on previous assessments of NETs, we identify some urgent research needs to provide a more complete picture for reaching ambitious climate targets, and the role that NETs can play in reaching them.

This paper examines a flashing liquid regime that takes place at very high ratios of injection to discharge pressures in flow restrictions. Typically, the flashing phenomenon has been observed in laboratory experiments where a liquid flows through a short nozzle into a low-pressure chamber at a pressure value considerably lower than the liquid saturation pressure at the injection temperature. By using two visualization techniques, the schlieren and the back-lighting methods, it was possible to identify some compressible phenomena associated with the liquid flashing process from the nozzle exit section. The schlieren method was used to capture the image of a shock-wave structure surrounding a liquid core from which the phase change takes place, and the optical technique allowed us to observe the central liquid core itself. The work corroborates previous physical descriptions of flashing liquid jets to explain an observed choking behaviour as well as the presence of shock waves. According to the present analysis, flashing takes place on the surface of the liquid core through an evaporation wave process, which results from a sudden liquid evaporation in a discontinuous process. Downstream of the evaporation discontinuity, the two-phase flow reaches very high velocities, up to the local sonic speed that typically occurs at high expansion conditions, as inferred from experiments and the physical model. That sonic state is also a point of maximum mass flow rate and it is known as the Chapman–Jouguet condition. The freshly sonic two-phase flow expands freely to increasing supersonic velocities and eventually terminates the expansion process through a shock-wave structure. This paper presents experimental results at several test conditions with iso-octane.

This work investigates the effect of flow rate variation on mass transfer and on the development of Escherichia coli biofilms on a flow cell reactor under turbulent flow conditions. Computational fluid dynamics (CFD) was used to assess the applicability of this reactor for the simulation of industrial and biomedical biofilms and the numerical results were validated by streak photography. Two flow rates of 374 and 242 L h −1 (corresponding to Reynolds numbers of 6,720 and 4,350) were tested and wall shear stresses between 0.183 and 0.511 Pa were predicted in the flow cell reactor. External mass transfer coefficients of 1.38 × 10 −5 and 9.64 × 10 −6  m s −1 were obtained for the higher and lower flow rates, respectively. Biofilm formation was favored at the lowest flow rate because shear stress effects were more important than mass transfer limitations. This flow cell reactor generates wall shear stresses that are similar to those found in some industrial and biomedical settings, thus it is likely that the results obtained on this work can be used in the development of biofilm control strategies in both scenarios.

A fabrication method is developed to produce a microfluidic device to test cell adhesion to polymeric materials. The process is able to produce channels with walls of any spin coatable polymer. The method is a modification of the existing poly-dimethylsiloxane soft lithography method and, therefore, it is compatible with sealing methods and equipment of most microfluidic laboratories. The molds are produced by xurography, simplifying the fabrication in laboratories without sophisticated equipment for photolithography. The fabrication method is tested by determining the effective differences in bacterial adhesion in five different materials. These materials have different surface hydrophobicities and charges. The major drawback of the method is the location of the region of interest in a lowered surface. It is demonstrated by bacterial adhesion experiments that this drawback has a negligible effect on adhesion. The flow in the device was characterized by computational fluid dynamics and it was shown that shear stress in the region of interest can be calculated by numerical methods and by an analytical equation for rectangular channels. The device is therefore validated for adhesion tests.

Recent energy scenarios, dealing with Climate Change mitigation with the purpose to limit warming up to 2°C or less by 2100, report high biomass energy participation in the primary global energy portfolio. By 2017, global biomass contributed with 52.3 EJ and average annual growth rate, in the last four yrs was 2.23%. However, the recent bioenergy growth rate must increase to meet CO2 concentration pathways aligned with the mitigation scenarios. This paper describes a bioenergy deployment strategy, based on liquid fuel and electricity joint production from sugar cane used for light duty vehicles. The pathway relies on 1st generation ethanol production, and steam power cogeneration from sugar cane waste supplemented by planted forest. Both technologies are commercial, and when used in conjunction with Biomass Energy Capture and Storage (BECCS) from sugar fermentation CO2, reach negative CO2e emissions. This yields a significant volume of GHGs abatement to contribute for the Paris Agreement. Exploring an area of 80 million hectares, from which 60 Mha is dedicated for sugar cane and 20 Mha for fast growing trees, it is possible to move a fleet of 1 billion plug-in hybrid light duty vehicles through the combination of ethanol and bioelectricity. The cost of ethanol and bioelectricity to consumers is lower than the cost of gasoline used in conventional cars and the net balance of GHGs emissions is lower than for electric vehicles.

We examined the histology of testes of 134 capybaras (Hydrochoerus hydrochaeris) and the relationship among mass of testes, body mass, and the ratio of seminiferous tubules to interstitial tissue. The capybara had a low gonadosomatic index (0.14% of body weight, epididymides included) and one of the highest known proportion of nonspermatogenic tissue (72% interstitial tissue) among mammals. Seminiferous tubules in testes of capybaras developed earlier than interstitial tissue. Older adults had testes with larger volumes of interstitial tissue and narrower diameters of seminiferous tubules than younger adults.

IntroductionVaccination coverage levels of the National Immunisation Program (PNI) in Brazil ranges from 80% to 95%, suggesting that parental acceptance of these vaccines is high. In 2014, HPV vaccine was introduced in the PNI. We conducted a survey to estimate parental acceptance of HPV vaccine and its determinants.MethodsThis was a random digit calling telephone survey performed in seven large cities from all five regions in Brazil. Eligible parents had to have one or more child less than 18 years old. We selected at least 100 subjects in each city. A standardised questionnaire was used to collect sociodemographic informationa and data on knowledge, attitudes and practices related to HPV vaccine, cervical cancer and HPV. Trained personnel conducted the interviews that lasted on average 20 min.ResultsOverall 826 parents were included in the survey (73% response rate). Parental acceptance for vaccinating against HPV was similarly high for female or male children, 92.8% and 91.7%, respectively. It did not change significantly among the cities studied (range 86.3%–95.5%). Parents’s main reasons to give the HPV vaccine to their children were: “Vaccines are good/important”(85.6%), “Prevents cervical cancer”(6.6%), and “Vaccine is in the PNI”(3.3%). Only 0.7% reported “Prevents genital warts”. Among parents with girls eligible for HPV vaccination (10–14 years old) under the PNI (n=291), 71.4% had their daughters vaccinated.ConclusionParental acceptance of HPV vaccine is high (92%%), but a lower percentage results in actual vaccination. Moreover, the main reason to vaccinate is based on a vague assumption (“vaccines are good/important”). Only few parents reported that HPV vaccination prevents cervical cancer. Parents whose vaccine acceptance is ill founded and based on poor knowledge are more vulnerable to change their mind when challenged by stress related mass reactions to HPV vaccine reported by the media or when facing false arguments against vaccination by anti-vax reports.

Because of its fossil abundance and exceptional preservation, the Romualdo Formation of the Santana Group has become a famous lithostratigraphic unit of the Araripe Basin. In the past decades, much research has been conducted on the vertebrates of this unit, especially fish and pterosaurs, based mainly on museum collections. Despite the importance of these fossil finds, no stratigraphic information is known about them, because until recently, locals have collected most of the fossils. Here we present the results of the third controlled excavation of these layers. The data from all fossils collected confirm a faunal succession of fish biota. In the upper and most fossiliferous layer, the faunal composition shows a pattern of fish distribution never observed before, indicating that previous categories (abundance versus diversity) do not include the total diversity of fish populations. Pterosaur remains were recorded for the first time in the field, contradicting the general idea that these volant reptiles are common in the Romualdo strata. The specimen was attributed to the clade Anhangueridae because the proportional length of the first wing phalanx is less than twice the length of the wing metacarpal. The controlled excavation showed that the pterosaur assemblages from this formation probably occur in clusters. The known abundance of pterosaurs in the Romualdo Formation has been biased by just a few sites of fossil extraction, and these reptiles do not appear to have been as widespread or abundant as previously thought.