18 research outputs found
A survey of cardinalfish (Apogonidae) of Antsiranana Bay, northern Madagascar
The cardinalfish of Antsiranana Bay, northern Madagascar, were surveyed over an 11 month period by underwater census employing a simple search pattern using self-contained underwater breathing apparatus. Over this period 15 species were observed including one species not previously recorded in Madagascar, Siphamia versicolor. Whilst some species were ubiquitous across sites within the bay others appeared only as single records. Cardinalfish communities were compared between sites within the bay using PRIMER 6 (Plymouth Routines In Multivariate Ecological Research) and on a national scale against existing records. Overall the species richness of cardinalfish in Antsiranana Bay is less than that observed in other regions of Madagascar. The reasons behind these regional variations include oceanic currents, temperature, depth, disturbance and sedimentation, a recognised threat to Madagascarâs marine communities. This final point was reaffirmed by comparison of cardinalfish communities between sites within the bay which revealed little variation in species composition between sites, with the exception of highly-sedimented sites in the north-east of the bay that had a significantly different cardinalfish fauna to the rest. As a family that relies on the complexity of the coral reef for shelter, and exhibit high site fidelity, examination of cardinalfish communities may provide a measure of the health of a regionâs reef. RĂSUMĂ Lâinventaire des poissons de la famille des Apogonidae de la baie dâAntsiranana, dans le Nord de Madagascar a Ă©tĂ© rĂ©alisĂ© au cours dâune pĂ©riode de 11 mois sous forme dâun recensement sous-marin utilisant un modĂšle de recherche simple en plongĂ©e en scaphandre autonome. Au cours de cette pĂ©riode, 15 espĂšces ont Ă©tĂ© observĂ©es, dont une espĂšce qui nâĂ©tait pas encore connue de Madagascar, Siphamia versicolor. Alors que certaines espĂšces Ă©taient omniprĂ©sentes dans tous les sites de la baie, dâautres nâont Ă©tĂ© relevĂ©es quâune seule fois. Les communautĂ©s dâApogonidae ont Ă©tĂ© comparĂ©es entre les sites de la baie Ă lâaide de PRIMER 6 (Plymouth Routines in Multivariate Ecological Research) et avec dâautres donnĂ©es existantes Ă lâĂ©chelle nationale. Dans lâensemble, la richesse en espĂšces dâApogonidae dans la baie dâAntsiranana est infĂ©rieure Ă celle observĂ©e dans dâautres rĂ©gions de Madagascar. Les raisons de ces variations rĂ©gionales peuvent ĂȘtre expliquĂ©es par les diffĂ©rences relevĂ©es sur les courants ocĂ©aniques, la tempĂ©rature, la profondeur, les perturbations et la sĂ©dimentation, cette derniĂšre Ă©tant une menace reconnue pour les communautĂ©s marines de Madagascar. La sĂ©dimentation est ressortie dans la comparaison des communautĂ©s dâApogonidae entre les sites de la baie qui a rĂ©vĂ©lĂ© peu de variation dans la composition des espĂšces entre les sites, si ce nâest que les sites prĂ©sentant une sĂ©dimentation importante dans le Nord-est de la baie abritaient une faune diffĂ©rente des autres sites. Les Apogonidae ont besoin de trouver refuge dans la barriĂšre de corail pour sâabriter et montrent ainsi une fidĂ©litĂ© Ă©levĂ©e aux sites ; lâĂ©tude des communautĂ©s dâApogonidae peut ainsi constituer une mesure de lâĂ©tat des rĂ©cifs dâune rĂ©gion donnĂ©e
Establishment of a community managed marine reserve in the Bay of Ranobe, southwest Madagascar
The Bay of Ranobe, in southwest Madagascar, once noted for its high biodiversity and fish abundance, is under increasing pressure from overfishing, pollution, sedimentation and tourism. The declining health of the coral reef is reflected in fishery productivity and survey data on biological diversity. Sustainable conservation requires the engagement of all interested parties and the integration of their needs into resource management. The British NGO ReefDoctor has adopted this approach in establishing the first community-protected site in the Bay of Ranobe, the Massif des Roses. This is a large coral patch with a high percentage of live coral cover (38%) and important fish diversity compared to other sites surveyed in the lagoon. Since 25 May 2007 it has been legally recognised as a community managed marine reserve under temporary protection where fishing is banned. Tourists must now pay an entry fee to visit the site, with the proceeds contributing to the funding of community projects. In conjunction with the protection of this site, ReefDoctor has worked with local people, regional and local government, tour operators and hotels, and conservation organisations to set up âFIMIHARAâ, an association representative of local people responsible for the management of this site and the development of sustainable conservation initiatives in the Bay of Ranobe. This paper explains the approach taken by ReefDoctor, by setting up and working with FIMIHARA, to protect the Massif des Roses site and develop other conservation initiatives and community projects in the Bay of Ranobe. RĂSUMĂ La baie de Ranobe, au sud-ouest de Madagascar, autrefois remarquable pour sa biodiversitĂ© et lâabondance de la pĂȘche, est de plus en plus menacĂ©e par la surpĂȘche, la sĂ©dimentation, la pollution et le tourisme. Le dĂ©clin de lâĂ©tat de santĂ© du rĂ©cif corallien se reflĂšte dans la diminution de la productivitĂ© des pĂȘcheries et dans les suivis de la biodiversitĂ© marine. La situation est Ă prĂ©sent critique car les ressources marines associĂ©es au rĂ©cif assurent la subsistance des populations cĂŽtiĂšres vivant le long de la baie. Nous considĂ©rons ici quâune protection pĂ©renne nĂ©cessite un engagement concret de toutes les parties prenantes - en particulier des communautĂ©s locales - et que leurs besoins soient intĂ©grĂ©s dans la gestion des ressources. LâONG ReefDoctor a mis en oeuvre cette approche lors de la crĂ©ation de la premiĂšre rĂ©serve marine dans la baie de Ranobe gĂ©rĂ©e par la communautĂ© locale, le Massif des Roses. Cette rĂ©serve est constituĂ©e dâun grand massif de corail largement couvert de coraux et abritant une importante diversitĂ© de poissons par rapport au reste du lagon. Depuis le 25 mai 2007, ce site est lĂ©galement reconnu comme rĂ©serve marine communautaire avec un statut de protection temporaire ; la pĂȘche et les pratiques destructrices associĂ©es au tourisme y sont interdites. De plus, les touristes doivent dĂ©sormais payer un droit dâentrĂ©e pour visiter le site, qui contribue au financement de projets communautaires. En parallĂšle avec la protection du site, ReefDoctor a travaillĂ© avec les communautĂ©s locales, les responsables nationaux et rĂ©gionaux du gouvernement, les opĂ©rateurs touristiques et diverses organisations de protection de la nature pour crĂ©er lâassociation FIMIHARA, reprĂ©sentative de la population locale. Cette association, qui a un statut lĂ©gal depuis le 11 avril 2007, a pour but dâamĂ©liorer la qualitĂ© de vie de ceux qui vivent le long de la baie de Ranobe et de mettre en oeuvre des projets de conservation des ressources marines et terrestres dans la rĂ©gion de la baie de Ranobe. La crĂ©ation de la rĂ©serve marine communautaire du Massif des Roses a rapidement connu le succĂšs qui sâest traduit par la vente de plus dâun millier de tickets, mais lâassociation FIMIHARA doit encore faire face Ă de nombreux dĂ©fis. Lâobjectif principal de lâassociation Ă long terme est de dĂ©velopper son indĂ©pendance par rapport Ă lâONG ReefDoctor et sa capacitĂ© Ă gĂ©rer indĂ©pendamment les ressources marines de la baie de Ranobe dont les communautĂ©s locales dĂ©pendent pour leur survie
Factors influencing terrestriality in primates of the Americas and Madagascar
Among mammals, the order Primates is exceptional in having a high taxonomic richness in which the taxa are arboreal, semiterrestrial, or terrestrial. Although habitual terrestriality is pervasive among the apes and African and Asian monkeys (catarrhines), it is largely absent among monkeys of the Americas (platyrrhines), as well as galagos, lemurs, and lorises (strepsirrhines), which are mostly arboreal. Numerous ecological drivers and species-specific factors are suggested to set the conditions for an evolutionary shift from arboreality to terrestriality, and current environmental conditions may provide analogous scenarios to those transitional periods. Therefore, we investigated predominantly arboreal, diurnal primate genera from the Americas and Madagascar that lack fully terrestrial taxa, to determine whether ecological drivers (habitat canopy cover, predation risk, maximum temperature, precipitation, primate species richness, human population density, and distance to roads) or species-specific traits (bodymass, group size, and degree of frugivory) associate with increased terrestriality. We collated 150,961 observation hours across 2,227 months from 47 species at 20 sites in Madagascar and 48 sites in the Americas. Multiple factors were associated with ground use in these otherwise arboreal species, including increased temperature, a decrease in canopy cover, a dietary shift away from frugivory, and larger group size. These factors mostly explain intraspecific differences in terrestriality. As humanity modifies habitats and causes climate change, our results suggest that species already inhabiting hot, sparsely canopied sites, and exhibiting more generalized diets, are more likely to shift toward greater ground use
Factors influencing terrestriality in primates of the Americas and Madagascar
Among mammals, the order Primates is exceptional in having a high taxonomic richness in which the taxa are arboreal, semiterrestrial, or terrestrial. Although habitual terrestriality is pervasive among the apes and African and Asian monkeys (catarrhines), it is largely absent among monkeys of the Americas (platyrrhines), as well as galagos, lemurs, and lorises (strepsirrhines), which are mostly arboreal. Numerous ecological drivers and species-specific factors are suggested to set the conditions for an evolutionary shift from arboreality to terrestriality, and current environmental conditions may provide analogous scenarios to those transitional periods. Therefore, we investigated predominantly arboreal, diurnal primate genera from the Americas and Madagascar that lack fully terrestrial taxa, to determine whether ecological drivers (habitat canopy cover, predation risk, maximum temperature, precipitation, primate species richness, human population density, and distance to roads) or species-specific traits (body mass, group size, and degree of frugivory) associate with increased terrestriality. We collated 150,961 observation hours across 2,227 months from 47 species at 20 sites in Madagascar and 48 sites in the Americas. Multiple factors were associated with ground use in these otherwise arboreal species, including increased temperature, a decrease in canopy cover, a dietary shift away from frugivory, and larger group size. These factors mostly explain intraspecific differences in terrestriality. As humanity modifies habitats and causes climate change, our results suggest that species already inhabiting hot, sparsely canopied sites, and exhibiting more generalized diets, are more likely to shift toward greater ground use
Effect of angiotensin-converting enzyme inhibitor and angiotensin receptor blocker initiation on organ support-free days in patients hospitalized with COVID-19
IMPORTANCE Overactivation of the renin-angiotensin system (RAS) may contribute to poor clinical outcomes in patients with COVID-19.
Objective To determine whether angiotensin-converting enzyme (ACE) inhibitor or angiotensin receptor blocker (ARB) initiation improves outcomes in patients hospitalized for COVID-19.
DESIGN, SETTING, AND PARTICIPANTS In an ongoing, adaptive platform randomized clinical trial, 721 critically ill and 58 nonâcritically ill hospitalized adults were randomized to receive an RAS inhibitor or control between March 16, 2021, and February 25, 2022, at 69 sites in 7 countries (final follow-up on June 1, 2022).
INTERVENTIONS Patients were randomized to receive open-label initiation of an ACE inhibitor (nâ=â257), ARB (nâ=â248), ARB in combination with DMX-200 (a chemokine receptor-2 inhibitor; nâ=â10), or no RAS inhibitor (control; nâ=â264) for up to 10 days.
MAIN OUTCOMES AND MEASURES The primary outcome was organ supportâfree days, a composite of hospital survival and days alive without cardiovascular or respiratory organ support through 21 days. The primary analysis was a bayesian cumulative logistic model. Odds ratios (ORs) greater than 1 represent improved outcomes.
RESULTS On February 25, 2022, enrollment was discontinued due to safety concerns. Among 679 critically ill patients with available primary outcome data, the median age was 56 years and 239 participants (35.2%) were women. Median (IQR) organ supportâfree days among critically ill patients was 10 (â1 to 16) in the ACE inhibitor group (nâ=â231), 8 (â1 to 17) in the ARB group (nâ=â217), and 12 (0 to 17) in the control group (nâ=â231) (median adjusted odds ratios of 0.77 [95% bayesian credible interval, 0.58-1.06] for improvement for ACE inhibitor and 0.76 [95% credible interval, 0.56-1.05] for ARB compared with control). The posterior probabilities that ACE inhibitors and ARBs worsened organ supportâfree days compared with control were 94.9% and 95.4%, respectively. Hospital survival occurred in 166 of 231 critically ill participants (71.9%) in the ACE inhibitor group, 152 of 217 (70.0%) in the ARB group, and 182 of 231 (78.8%) in the control group (posterior probabilities that ACE inhibitor and ARB worsened hospital survival compared with control were 95.3% and 98.1%, respectively).
CONCLUSIONS AND RELEVANCE In this trial, among critically ill adults with COVID-19, initiation of an ACE inhibitor or ARB did not improve, and likely worsened, clinical outcomes.
TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT0273570
A test of whether selection maintains isochores using sites polymorphic for Alu and L1 elements
No description supplie
Analysis of the phylogenetic distribution of isochores in vertebrates and a test of the thermal stability hypothesis
Warm-blooded vertebrates show large-scale variation in G + C content along their chromosomes, a pattern which appears to be largely absent from cold-blooded vertebrates. However, compositional variation in poikilotherms has generally been studied by ultracentrifugation rather than sequence analysis. In this paper, we investigate the compositional properties of coding sequences from a broad range of vertebrate poikilotherms using DNA sequence analysis. We find that on average poikilotherms have lower third-codon position GC contents (GC3) than homeotherms but that some poikilotherms have higher mean GC3 values. We find that most poikilotherms have lower variation in GC3 than homeotherms but that there is a correlation between GC12 and GC3 for some species, indicating that there is systematic variation in base composition across their genomes. We also demonstrate that the GC3 of genes in the zebrafish, Danio rerio, is correlated with that in humans, suggesting that vertebrates share a basic isochore structure. However, we find no correlation between either the mean GC3 or the standard deviation in GC3 and body temperature
Why are young and old repetitive elements distributed differently in the human genome?
Alu elements are not distributed homogeneously throughout the human genome: old elements are preferentially found in the GC-rich parts of the genome, while young Alus are more often found in the GC-poor parts of the genome. The process giving rise to this differential distribution remains poorly understood. Here we investigate whether this pattern could be due to a preferential degradation of Alu elements integrated in GC-poor regions by small indel mutations. We aligned 5.1 Mb of human and chimpanzee sequences and examined whether the rate of insertion and deletion inside Alu elements differed according to the base composition surrounding them. We found that Alu elements are not preferentially degraded in GC-poor regions by indel events. We also looked at whether very young L1 elements show the same change in distribution compared to older ones. This analysis indicated that L1 elements also show a shift in their distribution, although we could not assess it as precisely as for Alu elements. We propose that the differential distribution of Alu elements is likely to be due to a change in their pattern of insertion or their probability of fixation through evolutionary time
An investigation of the variation in the transition bias among various animal mitochondrial DNA
The transition : transversion ratio (ts / tv) is known to be very high in human mitochondrial DNA, but we have little information about this ratio in other species. Here we investigate the transition bias in animal mitochondrial DNA using single nucleotide polymorphism data at four-fold degenerate sites. We investigate this pattern of polymorphism in the cytochrome b gene (cyt-b) in 70 species using a total of 1823 mutations. We show that most species show a bias towards transitions but that the ratio varies significantly between species. There is little evidence for variation within orders or genera and between closely related species such as the great apes. The majority of the variation appears to be at a higher phylogenetic levels: between orders and classes. We test whether the variation in ts / tv ratio could be due to variation in the metabolic rate by considering whether the ratio is correlated to base composition. We find no evidence that the metabolic rate affects the ts / tv ratio. We also investigate the relative frequencies of C to T or T to C (C Âż T) mutations and A to G or G to A (A Âż G) mutations. We show that overall they occur at significantly different frequencies, and that there is significant variation in their relative frequency between species and between classes. We find no evidence in support of the hypothesis that this variation could be due to different metabolic rates