20 research outputs found

    Darwin's Manufactory Hypothesis Is Confirmed and Predicts the Extinction Risk of Extant Birds

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    In the Origin of Species Darwin hypothesized that the “manufactory” of species operates at different rates in different lineages and that the richness of taxonomic units is autocorrelated across levels of the taxonomic hierarchy. We confirm the manufactory hypothesis using a database of all the world's extant avian subspecies, species and genera. The hypothesis is confirmed both in correlations across all genera and in paired comparisons controlling for phylogeny. We also find that the modern risk of extinction, as measured by “Red List” classifications, differs across the different categories of genera identified by Darwin. Specifically, species in “manufactory” genera are less likely to be threatened, endangered or recently extinct than are “weak manufactory” genera. Therefore, although Darwin used his hypothesis to investigate past evolutionary processes, we find that the hypothesis also foreshadows future changes to the evolutionary tree

    Systematic Review of Potential Health Risks Posed by Pharmaceutical, Occupational and Consumer Exposures to Metallic and Nanoscale Aluminum, Aluminum Oxides, Aluminum Hydroxide and Its Soluble Salts

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    Aluminum (Al) is a ubiquitous substance encountered both naturally (as the third most abundant element) and intentionally (used in water, foods, pharmaceuticals, and vaccines); it is also present in ambient and occupational airborne particulates. Existing data underscore the importance of Al physical and chemical forms in relation to its uptake, accumulation, and systemic bioavailability. The present review represents a systematic examination of the peer-reviewed literature on the adverse health effects of Al materials published since a previous critical evaluation compiled by Krewski et al. (2007). Challenges encountered in carrying out the present review reflected the experimental use of different physical and chemical Al forms, different routes of administration, and different target organs in relation to the magnitude, frequency, and duration of exposure. Wide variations in diet can result in Al intakes that are often higher than the World Health Organization provisional tolerable weekly intake (PTWI), which is based on studies with Al citrate. Comparing daily dietary Al exposures on the basis of “total Al”assumes that gastrointestinal bioavailability for all dietary Al forms is equivalent to that for Al citrate, an approach that requires validation. Current occupational exposure limits (OELs) for identical Al substances vary as much as 15-fold. The toxicity of different Al forms depends in large measure on their physical behavior and relative solubility in water. The toxicity of soluble Al forms depends upon the delivered dose of Al+ 3 to target tissues. Trivalent Al reacts with water to produce bidentate superoxide coordination spheres [Al(O2)(H2O4)+ 2 and Al(H2O)6 + 3] that after complexation with O2‱−, generate Al superoxides [Al(O2‱)](H2O5)]+ 2. Semireduced AlO2‱ radicals deplete mitochondrial Fe and promote generation of H2O2, O2 ‱ − and OH‱. Thus, it is the Al+ 3-induced formation of oxygen radicals that accounts for the oxidative damage that leads to intrinsic apoptosis. In contrast, the toxicity of the insoluble Al oxides depends primarily on their behavior as particulates. Aluminum has been held responsible for human morbidity and mortality, but there is no consistent and convincing evidence to associate the Al found in food and drinking water at the doses and chemical forms presently consumed by people living in North America and Western Europe with increased risk for Alzheimer\u27s disease (AD). Neither is there clear evidence to show use of Al-containing underarm antiperspirants or cosmetics increases the risk of AD or breast cancer. Metallic Al, its oxides, and common Al salts have not been shown to be either genotoxic or carcinogenic. Aluminum exposures during neonatal and pediatric parenteral nutrition (PN) can impair bone mineralization and delay neurological development. Adverse effects to vaccines with Al adjuvants have occurred; however, recent controlled trials found that the immunologic response to certain vaccines with Al adjuvants was no greater, and in some cases less than, that after identical vaccination without Al adjuvants. The scientific literature on the adverse health effects of Al is extensive. Health risk assessments for Al must take into account individual co-factors (e.g., age, renal function, diet, gastric pH). Conclusions from the current review point to the need for refinement of the PTWI, reduction of Al contamination in PN solutions, justification for routine addition of Al to vaccines, and harmonization of OELs for Al substances

    Establishment of a coastal fish in the Azores : recent colonisation or suddenexpansion of an ancient relict population?

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    The processes and time scales associated with ocean-wide changes in the distribution of marinespecies have intrigued biologists since Darwin’s earliest insights into biogeography. The Azores, amid-Atlantic volcanic archipelago located more than 1000 km off the European continental shelf,offers ideal opportunities to investigate phylogeographic colonization scenarios. The benthopelagicsparid fish known as the common two-banded seabream (Diplodus vulgaris) is now relativelycommon along the coastline of the Azores archipelago, but was virtually absent prior to the 1990s.We employed a multiple genetic marker approach to test whether the successful establishment of theAzorean population derives from a recent colonization from western continental/island populationsor from the demographic explosion of an ancient relict population.Results from nuclear and mtDNA sequences show that all Atlantic and Mediterranean populationsbelong to the same phylogroup, though microsatellite data indicate significant genetic divergencebetween the Azorean sample and all other locations, as well as among Macaronesian, westernIberian and Mediterranean regions. The results from Approximate Bayesian Computation indicatethat D. vulgaris has likely inhabited the Azores for approximately 40 (95% C.I.: 5.5─83.6) to 52(95% C.I.; 6.32─89.0) generations, corresponding to roughly 80-150 years, which suggests nearcontemporary colonisation, followed by a more recent demographic expansion which could havebeen facilitated by changing climate conditions. Moreover, the lack of previous records of thisspecies over the past century, together with the absence of lineage separation and the presence ofrelatively few private alleles, do not exclude the possibility of an even more recent colonisationevent

    Sex Differences in Poisonings Among Older Adults: An Analysis of the Toxicology Investigators Consortium (ToxIC) Registry, 2010 to 2016.

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    PURPOSE: Adults aged \u3e65 years are susceptible to intentional and unintentional poisoning, with contributing factors that include polypharmacy, comorbidity, susceptibility to medication error, and gaps in research. Although toxicologists are often tasked with managing and preventing poisoning among older adults, little is known about sex differences in these poisonings. The aim of this study was to review sex differences in poisonings among older adults managed at the bedside by medical toxicologists. METHODS: All case subjects aged \u3e65 years in the Toxicology Investigators Consortium (ToxIC) registry between January 2010 and December 2016 were reviewed. Data included reasons for exposure and consultation, exposure agents and routes, presenting clinical findings, and treatment provided. Cases missing age, sex, or primary reason for toxicology consultation data were excluded. We used χ FINDINGS: Among 51,441 total registry cases, 542 (1.05%) were excluded because of missing data. Among the remaining 50,899 cases, 2930 (5.8%) were included for age \u3e65 years; 52.3% of older adults were female. Race was missing or unknown for 49.2% of cases. Adverse drug reactions were more commonly encountered in female subjects than in their male counterparts (9.6% vs 6.4%; P = 0.001). No statistically significant sex differences were observed for total numbers of intentional, unintentional pharmaceutical, and nonpharmaceutical exposures. The most common medications involved were cardiovascular (16.8%) and analgesics/opioids (14.8%). Female subjects were more likely than male subjects to be evaluated by a toxicologist for cardiovascular medications (18.7% vs 14.7%; P = 0.004) and analgesics/opioids (17.6% vs 11.8%; P \u3c 0.001). Male subjects were more likely than female subjects to be evaluated for ethanol toxicity (7.4% vs 1%; P \u3c 0.001) and for envenomations (4.2% vs 1.8%; P \u3c 0.001). The most common route of exposure was oral ingestion (81.3%). Signs/symptoms were noted in 54.8% of cases, with the most common abnormal vital sign being bradycardia (17.2%). Pharmacologic support was the most common intervention and was more common in male subjects than in female subjects (17.7% vs 12.3%; P \u3c 0.001). Deaths were reported in 38 female subjects (2.45%) and 46 male subjects (3.34%); there was no statistically significant difference in death rate according to sex (P = 0.148). IMPLICATIONS: Older female adults were more commonly evaluated by a medical toxicologist for an adverse drug reaction than older male adults. Female patients were more likely than male patients to be evaluated for poisoning related to analgesic/opioids and cardiovascular medications, and older male patients more frequently received pharmacologic support than older female patients. No significant sex differences were observed in numbers of toxicology consultations for intentional, unintentional pharmaceutical, and nonpharmaceutical exposures

    Electro-Tactile Stimulation Enhances Cochlear Implant Speech Recognition in Noise

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    For cochlear implant users, combined electro-acoustic stimulation (EAS) significantly improves the performance. However, there are many more users who do not have any functional residual acoustic hearing at low frequencies. Because tactile sensation also operates in the same low frequencies (<500 Hz) as the acoustic hearing in EAS, we propose electro-tactile stimulation (ETS) to improve cochlear implant performance. In ten cochlear implant users, a tactile aid was applied to the index finger that converted voice fundamental frequency into tactile vibrations. Speech recognition in noise was compared for cochlear implants alone and for the bimodal ETS condition. On average, ETS improved speech reception thresholds by 2.2 dB over cochlear implants alone. Nine of the ten subjects showed a positive ETS effect ranging from 0.3 to 7.0 dB, which was similar to the amount of the previously-reported EAS benefit. The comparable results indicate similar neural mechanisms that underlie both the ETS and EAS effects. The positive results suggest that the complementary auditory and tactile modes also be used to enhance performance for normal hearing listeners and automatic speech recognition for machines

    Freshwater Molluscs as Indicators of Bioavailability and Toxicity of Metals in Surface-Water Systems

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