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We investigate how externalities and cooperation affect nations' efforts to counter transnational terrorism activities. Our model captures three factors whose interplay determines counterterrorism (CT) efforts and terrorist activity: the size of the spillover effect, the degree of internalization of the externality, and whether nations' CT efforts have an asymmetric or symmetric effect on the security of other nations. In our symmetric model, preemptive CT efforts and terrorist activities decrease with the size of the externality regardless of the degree of cooperation between nations. In our asymmetric model, as the externality of the "smaller" nation increases, the "larger" nations reduce their efforts, and the smaller nation reacts by increasing its own efforts. We also investigate coalition stability and show that (a) in the preemptive case, the full coalition is not stable and partial coalitions are stable for sufficiently small externalities; and (b) in the defensive, symmetric case, only the full coalition is stable.

Hydrogels of spatially controlled physicochemical properties are appealing platforms for tissue engineering and drug delivery. In this study, core-shell silk fibroin (SF) hydrogels of spatially controlled conformation were developed. The core-shell structure in the hydrogels was formed by means of soaking the preformed (enzymatically crosslinked) random coil SF hydrogels in methanol. When increasing the methanol treatment time from 1 to 10 minutes, the thickness of the shell layer can be tuned from about 200 to around 850 µm as measured in wet status. After lyophilization of the rehydrated core-shell hydrogels, the shell layer displayed compact morphology and the core layer presented porous structure, when observed by scanning electron microscopy. The conformation of the hydrogels was evaluated by Fourier transform infrared spectroscopy in wet status. The results revealed that the shell layer possessed dominant β-sheet conformation and the core layer maintained mainly random coil conformation. Enzymatic degradation data showed that the shell layers presented superior stability to the core layer. The mechanical analysis displayed that the compressive modulus of the core-shell hydrogels ranged from around 25 kPa to about 1.1 MPa by increasing the immersion time in methanol. When incorporated with albumin, the core-shell SF hydrogels demonstrated slower and more controllable release profiles compared with the non-treated hydrogel. These core-shell SF hydrogels of highly tuned properties are useful systems as drug delivery system and may be applied as cartilage substitute. ; This study was funded by the Portuguese Foundation for Science and Technology (FCT) projects Tissue2Tissue (PTDC/CTM/105703/2008) and OsteoCart (PTDC/CTM-BPC/115977/2009), as well as the European Union's FP7 Programme under grant agreement no. REGPOT-CT2012-316331-POLARIS. Le-Ping Yan was awarded a FCT PhD scholarship (SFRH/BD/ 64717/2009). The FCT distinctions attributed to J.M. Oliveira and A.L. Oliveira under the Investigador FCT program ...

Abstract Context. Tree hollows are a key habitat resource for hollow-nesting species, including the northern Australian Gouldian finch (Erythrura gouldiae). Certain fire and disturbance regimes limit tree hollow availability in the northern Australian savannas. Aims. This study investigated the influence of fire regime and vegetation structure on the density of tree hollows at Gouldian finch breeding sites. Methods. Fire scars were mapped across breeding sites by using LANDSAT images. Vegetation plots within sites were spatially stratified according to three fire-regime attributes, namely, fire frequency, late dry-season wildfire frequency and time since the last fire. Tree hollow and vegetation structural attributes were measured at each vegetation plot. We modelled the relationship among hollow density, fire and vegetation attributes by using general linear mixed models with site as the random factor. Key results. We found that the highest tree-hollow density was found at plots with high eucalypt tree density and cover and with the lowest frequency of late dry-season wildfires (<1 wildfire over 5 years). Tree-hollow density declined after >2 years without fire. Hollow density was not directly related to total fire frequency. Conclusions. This study adds to previous work on grass seed resources in highlighting the importance of fire in Gouldian finch ecology. This study particularly highlighted the importance of reducing the impacts of high-intensity late dry-season wildfires because of their negative impacts on tree-hollow density, which is a key resource for breeding Gouldian finches. Implications. We recommend the use of a network of interconnected annual patchy early dry-season prescribed burns for protecting Gouldian breeding habitat from threat of high-intensity wildfires. We do NOT recommend fire exclusion from Gouldian finch breeding habitats. This is because fire risks to hollow-bearing trees, and grass seed resources, increase with the long-term accumulation of savanna litter fuels in the absence of fire.

© 2018 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/BY-NC-ND/4.0/) ; Interleukin 7 (IL-7) and its receptor (IL-7R, a heterodimer of IL-7Rα and γc) are essential for normal lymphoid development. In their absence, severe combined immunodeficiency occurs. By contrast, excessive IL-7/IL-7R-mediated signaling can drive lymphoid leukemia development, disease acceleration and resistance to chemotherapy. IL-7 and IL-7R activate three main pathways: STAT5, PI3K/Akt/mTOR and MEK/Erk, ultimately leading to the promotion of leukemia cell viability, cell cycle progression and growth. However, the contribution of each of these pathways towards particular functional outcomes is still not completely known and appears to differ between normal and malignant states. For example, IL-7 upregulates Bcl-2 in a PI3K/Akt/mTOR-dependent and STAT5-independent manner in T-ALL cells. This is a 'symmetric image' of what apparently happens in normal lymphoid cells, where PI3K/Akt/mTOR does not impact on Bcl-2 and regulates proliferation rather than survival. In this review, we provide an updated summary of the knowledge on IL-7/IL-7R-mediated signaling in the context of cancer, focusing mainly on T-cell acute lymphoblastic leukemia, where this axis has been more extensively studied. ; Publication costs were supported by LISBOA-01-0145-FEDER-007391, project cofunded by FEDER, through POR Lisboa2020 Programa Operacional Regional de Lisboa, PORTUGAL 2020, and Fundação para a Ciência e a Tecnologia (FCT, Portugal). The research work in JTB's lab related to the present review was supported by the grants FAPESP/20015/2014 and PTDC/MEC-HEM/31588/2017, from FCT; and by the consolidator grant ERC CoG-648455 from the European Research Council, under the European Union's Horizon 2020 research and innovation programme. JTB is an FCT investigator (consolidator). MLO is a LisbonBioMed PhD student and received a fellowship from FCT. PA received a PhD fellowship from ...

LAQUEUR, Thomas Walter. Inventando o sexo: corpo e gênero dos gregos a Freud. Trad. Vera Whately. Rio de Janeiro: Relume Dumará, 2001. 313 p.

Macro/micro porous silk/nano-sized calcium phosphate scaffolds (SC16) with bioactive and superior physicochemical properties have been recently developed. In this study, we aim at evaluating the new bone formation ability of the SC 16 scaffolds in vivo, using silk fibroin scaffolds (S16) as control. The CaP distribution profile in the scaffolds was characterized by Micro-Computed Tomography. The in vitro mineralization behavior was examined by immersion in Simulated Body Fluid solution from 1 to 14 days. The long-term hydration degree and weight loss ratio of the scaffolds were evaluated by immersion in an Isotonic Saline Solution from 1 month to 1 year. In vivo osteogenesis properties of the scaffolds were screened by implantation into the rat femur defects for 3 weeks. The results showed that the CaP phase distributed homogeneously in the SC16 scaffolds. Mineralization was only observed in SC16 scaffolds, and both scaffolds gradually degraded with time. The staining of the explants showed that new bone formation with higher density was observed in the SC16 scaffolds as compared to S16 scaffolds, guiding the growth of new bone directly onto its surface. These results demonstrated that the SC16 hybrid scaffolds are osteoconductive and can be good candidates for bone tissue engineering as promoted superior de novo bone formation. ; This study was supported by the Portuguese Foundation for Science and Technology (FCT) projects OsteoCart (PTDC/CTM-BPC/115977/2009) and Tissue2Tissue (PTDC/CTM/105703/2008). Research leading to these results has received funding from the European Union's Seventh Framework Programme (FP7/2007-2013) under grant agreement no REGPOT-CT2012-316331-POLARIS. Le-Ping Yan is an FCT PhD scholarship holder ...