The sterile insect technique (SIT) is an environmentally safe and proven technology to suppress wild populations. To further advance its utility, a novel CRISPR-based technology termed precision ...guided SIT (pgSIT) is described. PgSIT mechanistically relies on a dominant genetic technology that enables simultaneous sexing and sterilization, facilitating the release of eggs into the environment ensuring only sterile adult males emerge. Importantly, for field applications, the release of eggs will eliminate burdens of manually sexing and sterilizing males, thereby reducing overall effort and increasing scalability. Here, to demonstrate efficacy, we systematically engineer multiple pgSIT systems in Drosophila which consistently give rise to 100% sterile males. Importantly, we demonstrate that pgSIT-generated sterile males are fit and competitive. Using mathematical models, we predict pgSIT will induce substantially greater population suppression than can be achieved by currently-available self-limiting suppression technologies. Taken together, pgSIT offers to potentially transform our ability to control insect agricultural pests and disease vectors.
The demand for hydrogen over the coming decade is expected to grow for both traditional uses (ammonia, methanol, refinery) and running fuel cells. At least in the near future, this thirst for ...hydrogen will be quenched primarily through the reforming of fossil fuels. However, reforming fossil fuels emits huge amounts of carbon dioxide. One approach to reduce carbon dioxide emissions, which is considered first in this review, is to apply reforming methods to alternative renewable materials. Such materials might be derived from plant crops, agricultural residues, woody biomass, etc. Clean biomass is a proven source of renewable energy that is already used for generating heat, electricity, and liquid transportation fuels. Clean biomass and biomass-derived precursors such as ethanol and sugars are appropriate precursors for producing hydrogen through different conversion strategies. Virtually no net greenhouse gas emissions result because a natural cycle is maintained, in which carbon is extracted from the atmosphere during plant growth and released during hydrogen production. The second option explored here is hydrogen production from water splitting by means of the photons in the visible spectrum. The sun provides silent and precious energy that is distributed fairly evenly all over the earth. However, its tremendous potential as a clean, safe and economical energy source cannot be exploited unless it is accumulated or converted into more useful forms of energy. Finally, this review discusses the use of semiconductors, more specifically CdS and CdS-based semiconductors, which are able to absorb photons in the visible region of the spectrum. The energy stored within a semiconductor as electronic energy (electrons and holes) can be used to split water molecules by simultaneous reactions into H2 and O2. This conversion of solar energy into a clean fuel (H2) is perhaps the greatest challenge for scientists in the 21st century.
This study seeks to highlight the key role played by an entrepreneurship education (EE) program on entrepreneurial competencies and intention of secondary students in order to confirm (or disconfirm) ...conventional wisdom that entrepreneurial education increases the intention to start a business. We used a pretest-posttest quasi-experimental design. The results confirm our hypotheses; the students in the "experimental" group increased their competencies and intention toward self-employment, whereas students in the "control" group did not. The findings contribute to the theories of planned behavior, and to the literature of EE itself, by revealing the effect of specific benefits for the students derived from the EE program.
•Pulsed photoacoustic technique allowed to determine the production rate of NPs.•Pulsed photoacoustic technique allows to determine the Ag concentration in colloids.•The nanoparticles production rate ...drops quickly during the first laser pulses.•Nanoparticles production rate is almost constant after few hundreds of laser shots.•Photoacoustic signal amplitude was proportional to fluence on the target surface.
The pulsed photoacoustic (PA) technique was used to study the synthesis by laser ablation of silver nanoparticles (Ag-NPs) in ethanol. PA technique allowed to determine the production rate per laser pulse and concentration of synthesized Ag-NPs. The samples were produced by using a pulsed Nd:YAG laser with 1064nm of wavelength and 7ns of pulse duration. The laser pulse energy varied from 10 to 100mJ. Transmission electron microscopy micrographs demonstrated that the obtained nanoparticles were spherical with an average size close to 10nm. The absorption spectra of the colloids showed a plasmon absorption peak around 400nm. The PA analyses showed a significant reduction of the production rate of Ag-NPs during the first hundreds of laser pulses. For a higher number of pulses this rate was kept almost constant. Finally, we found that the root mean square (RMS) value of the PA signal was proportional to the laser pulse fluence on the target surface. Thus PA technique was useful to monitor the ablation process.
Managing agricultural landscapes to support biodiversity conservation requires profound structural changes worldwide. Often, discussions are centered on management at the field level. However, a wide ...and growing body of evidence calls for zooming out and targeting agricultural policies, research, and interventions at the landscape level to halt and reverse the decline in biodiversity, increase biodiversity-mediated ecosystem services in agricultural landscapes, and improve the resilience and adaptability of these ecosystems. We conducted the most comprehensive assessment to date on landscape complexity effects on nondomesticated terrestrial biodiversity through a meta-analysis of 1,134 effect sizes from 157 peer-reviewed articles. Increasing landscape complexity through changes in composition, configuration, or heterogeneity significatively and positively affects biodiversity. More complex landscapes host more biodiversity (richness, abundance, and evenness) with potential benefits to sustainable agricultural production and conservation, and effects are likely underestimated. The few articles that assessed the combined contribution of linear (e.g., hedgerows) and areal (e.g., woodlots) elements resulted in a near-doubling of the effect sizes (i.e., biodiversity level) compared to the dominant number of studies measuring these elements separately. Similarly, positive effects on biodiversity are stronger in articles monitoring biodiversity for at least 2 y compared to the dominant 1-y monitoring efforts. Besides, positive and stronger effects exist when monitoring occurs in nonoverlapping landscapes, highlighting the need for long-term and robustly designed monitoring efforts. Living in harmony with nature will require shifting paradigms toward valuing and promoting multifunctional agriculture at the farm and landscape levels with a research agenda that untangles complex agricultural landscapes’ contributions to people and nature under current and future conditions.
Graphene is a single-atom thick, two-dimensional sheet of hexagonally arranged carbon atoms isolated from its three-dimensional parent material, graphite. Related materials include few-layer-graphene ...(FLG), ultrathin graphite, graphene oxide (GO), reduced graphene oxide (rGO), and graphene nanosheets (GNS). This review proposes a systematic nomenclature for this set of Graphene-Family Nanomaterials (GFNs) and discusses specific materials properties relevant for biomolecular and cellular interactions. We discuss several unique modes of interaction between GFNs and nucleic acids, lipid bilayers, and conjugated small molecule drugs and dyes. Some GFNs are produced as dry powders using thermal exfoliation, and in these cases, inhalation is a likely route of human exposure. Some GFNs have aerodynamic sizes that can lead to inhalation and substantial deposition in the human respiratory tract, which may impair lung defense and clearance leading to the formation of granulomas and lung fibrosis. The limited literature on in vitro toxicity suggests that GFNs can be either benign or toxic to cells, and it is hypothesized that the biological response will vary across the material family depending on layer number, lateral size, stiffness, hydrophobicity, surface functionalization, and dose. Generation of reactive oxygen species (ROS) in target cells is a potential mechanism for toxicity, although the extremely high hydrophobic surface area of some GFNs may also lead to significant interactions with membrane lipids leading to direct physical toxicity or adsorption of biological molecules leading to indirect toxicity. Limited in vivo studies demonstrate systemic biodistribution and biopersistence of GFNs following intravenous delivery. Similar to other smooth, continuous, biopersistent implants or foreign bodies, GFNs have the potential to induce foreign body tumors. Long-term adverse health impacts must be considered in the design of GFNs for drug delivery, tissue engineering, and fluorescence-based biomolecular sensing. Future research is needed to explore fundamental biological responses to GFNs including systematic assessment of the physical and chemical material properties related to toxicity. Complete materials characterization and mechanistic toxicity studies are essential for safer design and manufacturing of GFNs in order to optimize biological applications with minimal risks for environmental health and safety.
As Africa-wide malaria prevalence declines, an understanding of human movement patterns is essential to inform how best to target interventions. We fitted movement models to trip data from surveys ...conducted at 3-5 sites throughout each of Mali, Burkina Faso, Zambia and Tanzania. Two models were compared in terms of their ability to predict the observed movement patterns - a gravity model, in which movement rates between pairs of locations increase with population size and decrease with distance, and a radiation model, in which travelers are cumulatively "absorbed" as they move outwards from their origin of travel. The gravity model provided a better fit to the data overall and for travel to large populations, while the radiation model provided a better fit for nearby populations. One strength of the data set was that trips could be categorized according to traveler group - namely, women traveling with children in all survey countries and youth workers in Mali. For gravity models fitted to data specific to these groups, youth workers were found to have a higher travel frequency to large population centers, and women traveling with children a lower frequency. These models may help predict the spatial transmission of malaria parasites and inform strategies to control their spread.
While tumor-tissue remains the ‘gold standard’ for genetic analysis in cancer patients, it is challenged with the advent of circulating cell-free tumor DNA (ctDNA) analysis from blood samples. Here, ...we broaden our previous study on the clinical validation of plasma DNA in metastatic colorectal cancer patients, by evaluating its clinical utility under standard management care.
Concordance and data turnaround-time of ctDNA when compared with tumor-tissue analysis were studied in a real-time blinded prospective multicenter clinical study (n = 140 metastatic colorectal patients). Results are presented according to STARD criteria and were discussed in regard with clinical outcomes of patients.
Much more mutations were found by ctDNA analysis: 59%, 11.8% and 14.4% of the patients were found KRAS, NRAS and BRAF mutant by ctDNA analysis instead of 44%, 8.8% and 7.2% by tumor-tissue analysis. Median tumor-tissue data turnaround-time was 16 days while 2 days for ctDNA analysis. Discordant samples analysis revealed that use of biopsy, long delay between tumor-tissue and blood collection and resection of the tumor at time of blood draw, tumor site, or type of tissue analyzed seem to affect concordance. Altogether, the clinical data with respect to the anti-epidermal growth factor receptor response (RAS status) and the prognosis (BRAF status) of those discordant patients do not appear contradictory to the mutational status as determined by plasma analysis. Lastly, we present the first distribution profile of the RAS and BRAF hotspot mutations as determined by ctDNA analysis (n = 119), revealing a high proportion of patients with multiple mutations (45% of the population and up to 5 mutations) and only 24% of WT scored patients for both genes. Mutation profile as determined from ctDNA analysis with using various detection thresholds highlights the importance of the test sensitivity.
Our study showed that ctDNA could replace tumor-tissue analysis, and also clinical utility of ctDNA analysis by considerably reducing data turnaround time.
•Hotel cancellation forecasts using optimised artificial intelligence techniques.•Primary PNR booking data to forecast hotel cancellations.•Identification of guests likely to cancel a hotel booking.
...Cancellations are a key aspect of hotel revenue management because of their impact on room reservation systems. In fact, very little is known about the reasons that lead customers to cancel, or how it can be avoided. The aim of this paper is to propose a means of enabling the forecasting of hotel booking cancellations using only 13 independent variables, a reduced number in comparison with related research in the area, which in addition coincide with those that are most often requested by customers when they place a reservation. For this matter, machine-learning techniques, among other artificial neural networks optimised with genetic algorithms were applied achieving a cancellation rate of up to 98%. The proposed methodology allows us not only to know about cancellation rates, but also to identify which customer is likely to cancel. This approach would mean organisations could strengthen their action protocols regarding tourist arrivals.
In this paper glycerol steam reforming over Ni catalysts supported on bare CeO
2 and Al
2O
3, and CeO
2-promoted Al
2O
3 to produce H
2 was studied. The catalytic activity results for the NiAl5Ce and ...NiAl10Ce catalysts showed that the incorporation of low ceria loadings enhances the activity of the NiAl catalyst prepared using a similar composition to the commercial Ni/Al
2O
3 catalysts. The catalyst surface characterization revealed that the good behaviour of the NiAl5Ce and the NiAl10Ce catalysts depends on the stabilization of Ni° particles which is promoted by the formation of nickel–ceria interactions. The increase of ceria content reduced the capacity of the NiAl20Ce catalyst to convert intermediate oxygenated hydrocarbons into H
2.
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