36 research outputs found
Effect of annealing on mechanical properties and thermal stability of ZrCu/O nanocomposite amorphous films synthetized by pulsed laser deposition
Binary ZrCu nanocomposite amorphous films are synthetized by pulsed laser deposition (PLD) under vacuum (2 Ă 10â3 Pa) and 10 Pa He pressure, leading to fully amorphous compact and nanogranular morphologies, respectively. Then, post-thermal annealing treatments are carried out to explore thermal stability and crystallization phenomena together with the evolution of mechanical properties. Compact films exhibit larger thermal stability with partial crystallization phenomena starting at 420 °C, still to be completed at 550 °C, while nanogranular films exhibit early-stage crystallization at 300 °C and completed at 485 °C. The microstructural differences are related to a distinct evolution of mechanical properties and residual stress, with compact TFMGs showing the highest values of Youngâs modulus (157 GPa), hardness (12 GPa), strain rate sensitivity (0.096), and local residual stress (+691 MPa) upon annealing at 550 °C, while nanogranular films reach the maximum values of mechanical properties at 485 °C followed by relaxation at higher temperatures due to complete crystallization. We show that PLD in combination with post-thermal annealing can generate different families of amorphous films with varying nanoscale morphologies, resulting in tunable mechanical properties and thermal stability, which can thus be used for designing novel film configurations for different fields of application
Genomic characteristics of Staphylococcus aureus strains associated with high within-herd prevalence of intramammary infections in dairy cows
Staphylococcus aureus is one of the most important causes of mastitis in dairy cattle. Based on previous research, Staph. aureus genotypes with different pathogenic and contagious properties can cause intramammary infection (IMI) and coexist in the same herd. Our study aimed to compare Staph. aureus strains from herds that differed in IMI prevalence using different molecular approaches such as ribosomal spacer (RS)-PCR, multilocus sequence typing (MLST), spa typing, ribotyping, pulsed-field gel electrophoresis (PFGE), and multiplex PCR. For this purpose, 31 dairy herds with Staph. aureus IMI were selected, and 16 of these were chosen for a comparison study: the 8 high-prevalence (HP) herds had Staph. aureus IMI prevalence >28% and the 8 low-prevalence (LP) herds had an IMI prevalence <4%. A total of 650 isolates of Staph. aureus from mammary quarters of all positive cows were genotyped with RS-PCR, a technique based on amplification of a portion of the intergenic spacer 16S-23S rRNA, and a subset of 54 strains was also analyzed by multiplex PCR, ribotyping, PFGE, MLST, and spa typing. The RS-PCR analysis revealed 12 different profiles. Staphylococcus aureus strains isolated from 5 out of 8 HP herds showed a profile identical to the genotype B (GTB), described in previous studies as being strongly associated with high within-herd prevalence of Staph. aureus mastitis and the presence of the genes coding for enterotoxins sea, sed, and sej, a long x-region of spa gene, and 3 lukE fragments. Moreover, all strains isolated in the HP herds possessed genes coding for staphylococcal enterotoxins. In LP herds, a limited number of strains of 6 genotypes, different from those isolated in HP herds, were identified and GTB was not found. Within these genotypes, 4 strains were positive for the mecA gene. Preliminary results and comparison with other genotyping methods confirmed that genotyping by RS-PCR is an accurate, rapid, and inexpensive tool for future field studies on Staph. aureus mastitis strains and generates clinically relevant results
Assessing the cost of global biodiversity and conservation knowledge
Knowledge products comprise assessments of authoritative information supported by
standards, governance, quality control, data, tools, and capacity building mechanisms.
Considerable resources are dedicated to developing and maintaining knowledge
products for biodiversity conservation, and they are widely used to inform policy and
advise decision makers and practitioners. However, the financial cost of delivering this
information is largely undocumented. We evaluated the costs and funding sources for
developing and maintaining four global biodiversity and conservation knowledge
products: The IUCN Red List of Threatened Species, the IUCN Red List of
Ecosystems, Protected Planet, and the World Database of Key Biodiversity Areas.
These are secondary data sets, built on primary data collected by extensive networks
of expert contributors worldwide. We estimate that US116-204
million), plus 293 person-years of volunteer time (range: 278-308 person-years) valued
at US12-16 million), were invested in these four knowledge
products between 1979 and 2013. More than half of this financing was provided
through philanthropy, and nearly three-quarters was spent on personnel costs. The
estimated annual cost of maintaining data and platforms for three of these knowledge
products (excluding the IUCN Red List of Ecosystems for which annual costs were not
possible to estimate for 2013 ) is US6.2-6.7 million).
We estimated that an additional US12 million. These costs
are much lower than those to maintain many other, similarly important, global
knowledge products. Ensuring that biodiversity and conservation knowledge products
are sufficiently up to date, comprehensive and accurate is fundamental to inform
decision-making for biodiversity conservation and sustainable development. Thus, the
development and implementation of plans for sustainable long-term financing for them
is critical
Synergies between the key biodiversity area and systematic conservation planning approaches
Systematic conservation planning and Key Biodiversity Areas (KBAs) are the two most widely used approaches for identifying important sites for biodiversity. However, there is limited advice for conservation policy makers and practitioners on when and how they should be combined. Here we provide such guidance, using insights from the recently developed Global Standard for the Identification of KBAs and the language of decision science to review and clarify their similarities and differences. We argue the two approaches are broadly similar, with both setting transparent environmental objectives and specifying actions. There is however greater contrast in the data used and actions involved, as the KBA approach uses biodiversity data alone and identifies sites for monitoring and vigilance actions at a minimum, whereas systematic conservation planning combines biodiversity and implementationârelevant data to guide management actions. This difference means there is much scope for combining approaches, so conservation planners should use KBA data in their analyses, setting contextâspecific targets for each KBA type, and planners and donors should use systematic conservation planning techniques when prioritizing between KBAs for management action. In doing so, they will benefit conservation policy, practice and research by building on the collaborations formed through the KBA Standard's development
Meeting the Aichi targets: Pushing for zero extinction conservation
Effective protection of the ~19,000 IUCN-listed threatened species has never been more pressing. Ensuring the survival of the most vulnerable and irreplaceable taxa and places, such as those identified by the Alliance for Zero Extinction (AZE) species and their associated sites (AZEs&s), is an excellent opportunity to achieve the Aichi 2020 Targets T11 (protected areas) and T12 (preventing species extinctions). AZE taxa have small, single-site populations that are especially vulnerable to human-induced extinctions, particularly for the many amphibians. We show that AZEs&s can be protected feasibly and cost-effectively, but action is urgent. We argue that the Alliance, whose initial main aim was to identify AZEs&s, must be followed up by a second-generation initiative that directs and co-ordinates AZE conservation activities on the ground. The prominent role of zoos, conservation NGOs and governmental institutions provides a combination of all-encompassing knowhow that can, if properly steered, maximize the long-term survival of AZEs&s
The impact of natural resource use on bird and reptile communities within multiple-use protected areas: evidence from sub-arid southern Madagascar
Multiple-use protected areas, in which sustainable levels of extractive livelihood activities are permitted, play an increasingly important role in the global protected area estate, and are expected to rise in prevalence. However, we know little about their effectiveness at conserving biodiversity. We surveyed bird and reptile communities in three areas across a forest disturbance gradient resulting from charcoal production and shifting cultivation within a multiple-use protected area in Madagascarâs sub-arid spiny forest. We scored individual species using a Conservation Value Index (CVI; a simple metric based on rarity, threat and distinctiveness), and estimated the total conservation value of each treatment by calculating the sum of frequency-weighted CVI scores across all present species. Bird and reptile community responses to forest disturbance were idiosyncratic. Bird richness was greatest in the moderate-disturbance treatment, but the low-disturbance treatment had the superior conservation value due to higher frequencies of locally-endemic species. Reptile richness was the same in low- and moderate-disturbance treatments, but the conservation value of the latter was greater. The high-disturbance areas had lowest richness and conservation value for both groups. For birds, increasing disturbance levels were accompanied by community turnover from high-value to low-value species, a pattern highlighted by CVI that is masked by assessing species richness alone. Although some endemic species appear to be resilient to degradation, multiple-use protected areas in Madagascar may lose biodiversity since most endemic species are forest-dependent. Stricter protected area models may be more appropriate in areas where much of the high-value biodiversity is sensitive to habitat degradation