17 research outputs found
A new species of Arrhopalites (Collembola, Symphypleona, Arrhopalitidae) from a cave on the Central East Iberian Peninsula
A new species of Collembola, Arrhopalites miravetensis, sp. nov., is described, from a karstic cave in the “Desierto de las Palmas”
Nature Park, CastellĂłn, Spain. The new species can be distinguished from all other species in the genus by the combination
of the following characters: 2+2 pigmented eyes, rod-like anal appendage with two, relatively long, basal projections, small teeth
present in both mucro edges and visible only from posterior view, winged circumanal setae, and no spines on the head. The new
species belongs to the A. pygmaeus-group s. str. This species could be a troglophile species as the most of Arrhopalites, although
there are too troglobite species
Decoupling of component and ensemble density feedbacks in birds and mammals
A component density feedback represents the effect of change in population size on single demographic rates, whereas an ensemble density feedback captures that effect on the overall growth rate of a population. Given that a population's growth rate is a synthesis of the interplay of all demographic rates operating in a population, we test the hypothesis that the strength of ensemble density feedback must augment with increasing strength of component density feedback, using long-term censuses of population size, fertility, and survival rates of 109 bird and mammal populations (97 species). We found that compensatory and depensatory component feedbacks were common (each detected in 50% of the demographic rates). However, component feedback strength only explained <10% of the variation in ensemble feedback strength. To explain why, we illustrate the different sources of decoupling between component and ensemble feedbacks. We argue that the management of anthropogenic impacts on populations using component feedbacks alone is ill-advised, just as managing on the basis of ensemble feedbacks without a mechanistic understanding of the contributions made by its components and environmental variability can lead to suboptimal decisions.Salvador Herrando-Perez, Steven Delean, Barry W. Brook, and Corey J. A. Bradsha
Density dependence: An ecological Tower of Babel
The concept of density dependence represents the effect of changing population size on demographic rates and captures the demographic role of social and trophic mechanisms (e.g. competition, cooperation, parasitism or predation). Ecologists have coined more than 60 terms to denote different statistical and semantic properties of this concept, resulting in a formidable lexicon of synonymies and polysemies. We have examined the vocabulary of density dependence used in the modern ecological literature from the foundational lexicon developed by Smith, Allee, Haldane, Neave and Varley. A few simple rules suffice to abate terminological inconsistency and to enhance the biological meaning of this important concept. Correct citation of original references by ecologists and research journals could ameliorate terminological standards in our discipline and avoid linguistic confusion of mathematically and theoretically complex patterns.Salvador Herrando-PĂ©rez, Steven Delean, Barry W. Brook, Corey J. A. Bradsha
Water deprivation drives intraspecific variability in lizard heat tolerance
Quantifying intraspecific variation in heat tolerance is critical to understand how species respond to climate change. In a previous study, we recorded variability in critical thermal maxima (CTmax) by 3 degrees C among populations of small Iberian lizard species, which could substantially influence predictions of climate-driven activity restriction. Here, we undertake experiments to examine whether we could reproduce similar levels of heat-tolerance variability in response to water deficit. We hypothesized that deprivation of drinking water should increase variability in CTmax between populations more than deprivation of food under the theoretical expectation that the variation of the more limiting resource must trigger stronger variation in physiological performance. We measured CTmax after manipulating availability of live prey and drinking water in two populations of an arid and a mesic lizard species from the Iberian Peninsula. We quantified a mean CTmax across all studied lizards of 44.2 degrees C +/- 0.2 SE for the arid species and 41.7 degrees C +/- 0.3 SE for the mesic species. Using multimodel inference, we found that water deprivation (combined with food supply) caused population differences in CTmax by 3 to 4 degrees C which were two to three times wider than population differences due to food deprivation (combined with water supply) or to food and water provision. To highlight the need for more thermo-hydroregulatory research, we examined bias in research effort towards thermal versus hydric environmental effects on heat tolerance through a systematic literature review. We show that environmental temperature has been used five times more frequently than precipitation in ecological studies of heat tolerance of terrestrial species. Studies linking thermal tolerance of ectotherms to the interplay of air temperature and water availability are needed in the face of projected increases in aridity and drought in the 21st century, because the balance of body temperature and water resources are functionally interlinked
Watch and wait after neoadjuvant treatment in rectal cancer: comparison of outcomes in patients with and without a complete response at first reassessment in the International Watch & Wait Database (IWWD)
Background: In rectal cancer, watch and wait for patients with a cCR after neoadjuvant treatment has an established evidence base. However, there is a lack of consensus on the definition and management of a near-cCR. This study aimed to compare outcomes in patients who achieved a cCR at first reassessment versus later reassessment.
Methods: This registry study included patients from the International Watch & Wait Database. Patients were categorized as having a cCR at first reassessment or at later reassessment (that is near-cCR at first reassessment) based on MRI and endoscopy. Organ preservation, distant metastasis-free survival, and overall survival rates were calculated. Subgroup analyses were done for near-cCR groups based on the response evaluation according to modality.
Results: A total of 1010 patients were identified. At first reassessment, 608 patients had a cCR; 402 had a cCR at later reassessment. Median follow-up was 2.6 years for patients with a cCR at first reassessment and 2.9 years for those with a cCR at later reassessment. The 2-year organ preservation rate was 77.8 (95 per cent c.i. 74.2 to 81.5) and 79.3 (75.1 to 83.7) per cent respectively (P = 0.499). Similarly, no differences were found between groups in distant metastasis-free survival or overall survival rate. Subgroup analyses showed a higher organ preservation rate in the group with a near-cCR categorized exclusively by MRI.
Conclusion: Oncological outcomes for patients with a cCR at later reassessment are no worse than those of patients with a cCR at first reassessment.info:eu-repo/semantics/publishedVersio
The impact of hip fracture on health-related quality of life and activities of daily living: the SPARE-HIP prospective cohort study
Gap in secondary fracture prevention (but not in primary prevention of infection and thrombosis) following a hip fracture: the spare-hip prospective cohort
We assessed the proportion of patients on anti-osteoporosis treatment/s during a hospital admission for a hip fracture, and at 1- and 4-month follow-up. For comparison, we also report on anti-thrombotic and antibiotic therapies at these same times