2,416 research outputs found
Evolutionary Assembly of the Neotropical Montane Avifauna
Three fundamental processes are thought to underlie biodiversity patterns: speciation, dispersal, and extinction. Biodiversity patterns in species-rich tropical mountains vary along horizontal (barriers), and vertical (elevation) dimensions. In this dissertation, I set out to explore the interplay between historical and ecological mechanisms hypothesized to shape diversification of Neotropical cloud forest birds. In the second chapter, I conducted comparative analyses using species-specific ecological traits, and 3,175 mtDNA sequences collected across the range of 45 co-distributed birds. First, I found that niche breadth, dispersal ability, and clade age influence lineage diversity (population differentiation). In particular, species that are old, poor dispersers, and specialized to narrow elevational zones, accumulate greater lineage diversity with time. These results are consistent with predictions of the time-for-speciation effect, Janzen’s climatic zonation model, and niche conservatism. Second, I found weak support for simultaneous divergence between multiple population-pairs separated by the same barriers, suggesting temporal idiosyncrasies in differentiation. In the third chapter, I explored geographic patterns of evolutionary assembly using the same dataset. Overall, birds that presently co-occur in the same mountain range represent avian groups that originated in disjunct geographic areas (e.g., Southern Andes, Northern Andes, or Central American mountains), and subsequently occupied the entire Neotropical montane region. In the fourth chapter, I conducted a more in-depth investigation of the role niche breadth and elevational distribution on multi-species divergence. Using 2,475 mtDNA sequences, I estimated genetic divergence between population pairs (287 comparisons) divided by three major Andean barriers: the North Peruvian Low, the Táchira Depression, and the Motilones Pass. I found that genetic divergences were not randomly distributed with respect to minimum elevation (i.e., elevational distribution) and elevational amplitude (i.e., niche breadth). Elevation specialists (i.e., birds with narrow amplitudes) and the upper limits of elevational distributions (i.e., high minimum elevations) exhibited deeper genetic divergences. These results support the hypothesis of greater genetic divergence with increasing elevational distribution and decreasing niche breadth. In summary, my dissertation suggests that the present-day assemblages of Neotropical montane birds resulted from localized speciation in isolation and subsequent colonization. The effect of physical barriers is modulated by niche specialization along elevational gradients, dispersal ability, and time
Barriers and Solutions to Advance Care Planning among Homeless-Experienced Older Adults.
Background/Objectives: Older homeless-experienced adults have low rates of advance care planning (ACP) engagement despite high rates of morbidity and mortality. To inform intervention development, we examined potential barriers and solutions to ACP engagement. Design: Cross-sectional qualitative study. Setting: We recruited adults who were homeless in the prior three years and ≥50 years of age in the San Francisco Bay Area, and recruited clinical stakeholders from a national meeting of homeless providers. We analyzed qualitative data using thematic analysis. Measurements: We conducted semistructured interviews with homeless-experienced older adults (n = 20) and focus groups with clinical stakeholders (n = 24) about perceived barriers and solutions to ACP engagement. Results: Participants considered ACP important, reflecting on deaths of people in their networks who had died. Participant-identified barriers to ACP included poor ACP knowledge, lack of familial ties and social isolation, competing priorities, avoidance and lack of readiness, fatalism and mistrust, and lack of ACP training for clinical and nonclinical staff. They identified solutions that included framing ACP as a way to provide meaning and assert choice, providing easy-to-read written documents focused on the populations' unique needs, tailoring content and delivery, initiating ACP in nonclinical settings, such as permanent supportive housing, and providing incentives. Conclusions: Both older homeless-experienced adults and clinical stakeholders believe that ACP is important, but acknowledge multiple barriers that impede engagement. By focusing on potential solutions, including capitalizing on opportunities outside of health care settings, focusing on the period after housing, and tailoring content, there are opportunities to improve ACP uptake
Reaching the millennium development goals : Mauritania should care
Mauritania is a resource-rich developing country. As many other African nations, it will not reach most of the Millennium Development Goals, unless the authorities commit to accelerating progress. To succeed by 2015, the government needs to: mobilize additional financial resources, introduce policy changes at the sector level, and strengthen the links between strategic objectives and the budget. Adopting the Millennium Development Goals as the overarching development framework will keep policy-makers focused on concrete results and help them avoid the so-called"natural resource curse."This paper calculates the total cost of the Millennium Development Goals and financing gap (on aggregate and for each goal); recommends changes in domestic sector policies; and proposes ways to integrate the Millennium Development Goals into the budget process. Over 2008-2015, the total cost of reaching the goals in Mauritania and the resulting financing gap stand at, respectively, around 9 and 3 percent of non-oil gross domestic product on average per year. Education is the most expensive goal in absolute terms, but the individual financing gaps are widest for poverty reduction and improving maternal health. On the policy side, sector strategies need to be aligned with the goals and resources allocated more than proportionally to the disadvantaged groups, mainly at the local level.Population Policies,Health Monitoring&Evaluation,Rural Poverty Reduction,Health Systems Development&Reform,
Effects of experimental tail shortening on the phenotypic condition of barn swallows Hirundo rustica: Implications for tail-length evolution
Some studies have suggested that tail streamers in the barn swallow Hirundo rustica may have been elongated 10-12 mm by sexual selection, but according to other studies, the length of these feathers is at the aerodynamic optimum or very close to it. To shed light on this issue, outermost tail feathers were experimentally shortened in male and female barn swallows by 1, 11 or 21 mm. Changes in four physiological parameters commonly used to estimate phenotypic condition in birds (weight, erythrocyte sedimentation rate, blood leukocyte concentration and heterophil/lymphocyte ratio) were checked one month later. Health improved (blood leukocyte concentration decreased) in the group of birds with tails shortened by 11 mm (both males and females), but body condition deteriorated (weight decreased) compared to the other two experimental groups. There was no significant effect of tail-length manipulation on the other two physiological parameters. These contradictory results suggest trade-offs between components of phenotypic condition. Possible negative relationships between condition-related traits imply that using one or very few physiological parameters to estimate phenotypic condition might not be appropriate. The most plausible explanation for the turning point in phenotypic condition when streamers were shortened by 11 mm is that these feathers are 7-15 mm longer than the aerodynamic optimum in both sexes. Therefore, our results are consistent with the hypothesis that tail streamers have been elongated 10-12 mm by sexual selection. This conclusion disagrees with a previous study on the effect of experimental tail shortening on haematocrit, but the complexity of interpreting changes in haematocrit might account for this discrepancy. © 2014 The Authors.The study was funded by the Andalusian Regional Government (Acc. Coord. 2001) and by the Spanish Ministry of Science and Technology and the European Regional Development Fund (projects BOS2001-1717 and CGL2008-00137/BOS).Peer Reviewe
Rampant polyphyly indicates cryptic diversity in a clade of Neotropical flycatchers (Aves: Tyrannidae)
Polyphyletic arrangements in DNA phylogenies are often indicators of cryptic species diversity masked by erroneous taxonomic treatments that are frequently based on morphological data. Although mitochondrial (mt)DNA polyphyly is detected relatively rarely in phylogenetic studies, it has recently been found in a variety of tyrant-flycatcher (Tyrannidae) groups. In the present study, we provide a DNA phylogeny for a mitochondrial and a nuclear locus with a complete species sampling in Zimmerius flycatchers, showing that the genus is characterized by multiple mtDNA polyphyly. Based on phylogenetic and life-history information, we suggest the elevation of a number of taxa to species status, leading to a doubling of Zimmerius species-level diversity compared to taxonomic treatments conducted before 2001. © 2013 The Linnean Society of London
Pericytes and vascular smooth muscle cells in central nervous system arteriovenous malformations.
Previously considered passive support cells, mural cells-pericytes and vascular smooth muscle cells-have started to garner more attention in disease research, as more subclassifications, based on morphology, gene expression, and function, have been discovered. Central nervous system (CNS) arteriovenous malformations (AVMs) represent a neurovascular disorder in which mural cells have been shown to be affected, both in animal models and in human patients. To study consequences to mural cells in the context of AVMs, various animal models have been developed to mimic and predict human AVM pathologies. A key takeaway from recently published work is that AVMs and mural cells are heterogeneous in their molecular, cellular, and functional characteristics. In this review, we summarize the observed perturbations to mural cells in human CNS AVM samples and CNS AVM animal models, and we discuss various potential mechanisms relating mural cell pathologies to AVMs.This work was supported by the Ohio University
Neuroscience Program Confocal Graduate Assistantship and
College of Arts and Sciences Graduate Student Research Fund
grant to SN; ISCIII and FEDER European institutions through
Fondo de Investigación en Salud (FIS) project PI21/
01844 to AL; NIH R15 NS111376 to CN; and 2020-T1/BMD19985 mod.1 grant funded by “Atracción de Talento Investigador”
call from Comunidad de Madrid to HC The CNIC is supported by
the Instituto de Salud Carlos III (ISCIII), the Ministerio de Ciencia
e Innovación (MCIN) and the Pro CNIC Foundation, and is a
Severo Ochoa Center of Excellence (grant CEX 2020-001041-S
funded by MICIN/AEI/10.13039/501100011033).S
Pterygosomatid mites from Cuba, with the description of a new species of Bertrandiella (Acari: Prostigmata: Pterygosomatidae)
AbstractBertrandiella griseldae, new species is described based on specimens found on the gecko Tarentola americana. Additionally, the female of Geckobiella javieri is described for the first time, new data for larvae and deutonymphs are presented, and a summary of the leg chaetotaxy for Geckobia tarentolae is reported. A taxonomic identification key for the mite species of Pterygosomatidae ectoparasitic on lizards from Cuba is also provided
The logistic decision making in management accounting with genetic algoritms and fuzzy sets
The logistics problems in business environments deal with assignation from a number of sources to a number of destinations. Each source offers amounts of goods, while each destination demands quantities of these goods. The object is to find the cheapest transporting schedule that satisfies the demand without violating supply restraints. In this paper we propose to use Fuzzy Sets to represents the previsional information related to costs, demands and other variables. Moreover, we suggest including the problem of shortest route for the distribution vehicles. Finally, to solve this complex problem we propose to use a Genetic Algorithm with a Fuzzy Fitness Function
Antagonistic effect of Trichoderma harzianum VSL291 on phytopathogenic fungi isolated from cocoa (Theobroma cacao L.) fruits
In this study we evaluated the antagonism in vitro of Trichoderma harzianum strain VSL291 against 18 pathogens of cocoa fruits in dual culture. T. harzianum VSL291 inhibited the growth of the phytopathogenic fungi tested between 10.54 and 85.43%. The mycoparasitism of Moniliophthora roreri by T. harzianum VSL291 was studied by light and scanning electron microscopy. T. harzianum VSL291 hyphae grew in parallel with the hyphae of M. roreri and in some places these were united with the hyphae of the cocoa pathogen through small structures like apresorious that tangled in the pathogenic fungus preventing its growth. T. harzianum VSL291 produced lytic enzymes: β-1,3-glucanases, chitinases, proteases, xylanases and lipases, when grown in minimal medium, with fungal cell walls as the sole carbon source. The highest proteolytic activities detected in T. harzianum VSL291 broth with M. roreri, Penicillium expansum and Byssochlamys spectabilis cell walls appear to be associated with increased activities of β-1,3 glucanases, chitinases, lipases, proteases and xylanases and biocontrol index derived from the experiments of confrontation. These results suggest that proteolytic enzymes according to their degree of induction could participate in the antagonistic effect of T. harzianum VSL291 against the fungi tested.Key words: Antagonism, Trichoderma harzianum, mycoparasitism, phytopathogenic fung
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