199 research outputs found
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Shallow-Water Habitats as Sources of Fallback Foods for Hominins
Underground storage organs (USOs) have been proposed as critical fallback foods for early hominins in savanna, but there has been little discussion as to which habitats would have been important sources of USOs. USOs consumed by hominins could have included both underwater and underground storage organs, i.e., from both aquatic and terrestrial habitats. Shallow aquatic habitats tend to offer high plant growth rates, high USO densities, and relatively continuous USO availability throughout the year. Baboons in the Okavango delta use aquatic USOs as a fallback food, and aquatic or semiaquatic USOs support high-density human populations in various parts of the world. As expected given fossilization requisites, the African early- to mid-Pleistocene shows an association of Homo and Paranthropus fossils with shallow-water and flooded habitats where high densities of plant-bearing USOs are likely to have occurred. Given that early hominins in the tropics lived in relatively dry habitats, while others occupied temperate latitudes, ripe, fleshy fruits of the type preferred by African apes would not normally have been available year round. We therefore suggest that water-associated USOs were likely to have been key fallback foods, and that dry-season access to aquatic habitats would have been an important predictor of hominin home range quality. This study differs from traditional savanna chimpanzee models of hominin origins by proposing that access to aquatic habitats was a necessary condition for adaptation to savanna habitats. It also raises the possibility that harvesting efficiency in shallow water promoted adaptations for habitual bipedality in early hominins.Human Evolutionary Biolog
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Testosterone related to age and life-history stages in male baboons and geladas
AbstractDespite significant advances in our knowledge of how testosterone mediates life-history trade-offs, this research has primarily focused on seasonal taxa. We know comparatively little about the relationship between testosterone and life-history stages for non-seasonally breeding species. Here we examine testosterone profiles across the life span of males from three non-seasonally breeding primates: yellow baboons (Papio cynocephalus or P. hamadryas cynocephalus), chacma baboons (Papio ursinus or P. h. ursinus), and geladas (Theropithecus gelada). First, we predict that testosterone profiles will track the reproductive profiles of each taxon across their respective breeding years. Second, we evaluate age-related changes in testosterone to determine whether several life-history transitions are associated with these changes. Subjects include males (>2.5Â years) from wild populations of each taxon from whom we had fecal samples for hormone determination. Although testosterone profiles across taxa were broadly similar, considerable variability was found in the timing of two major changes: (1) the attainment of adult levels of testosterone and (2) the decline in testosterone after the period of maximum production. Attainment of adult testosterone levels was delayed by 1Â year in chacmas compared with yellows and geladas. With respect to the decline in testosterone, geladas and chacmas exhibited a significant drop after 3Â years of maximum production, while yellows declined so gradually that no significant annual drop was ever detected. For both yellows and chacmas, increases in testosterone production preceded elevations in social dominance rank. We discuss these differences in the context of ecological and behavioral differences exhibited by these taxa
Mobility related physical and functional losses due to aging and disease - a motivation for lower limb exoskeletons
Background: Physical and functional losses due to aging and diseases decrease human mobility, independence, and quality of life. This study is aimed at summarizing and quantifying these losses in order to motivate solutions to overcome them with a special focus on the possibilities by using lower limb exoskeletons.
Methods: A narrative literature review was performed to determine a broad range of mobility-related physical and functional measures that are affected by aging and selected cardiovascular, respiratory, musculoskeletal, and neurological diseases.
Results: The study identified that decreases in limb maximum muscle force and power (33% and 49%, respectively, 25–75 yrs) and in maximum oxygen consumption (40%, 20–80 yrs) occur for older adults compared to young adults. Reaction times more than double (18–90 yrs) and losses in the visual, vestibular, and somatosensory systems were reported. Additionally, we found decreases in steps per day (75%, 60–85 yrs), maximum walking speed (24% 25–75 yrs), and maximum six-minute and self-selected walking speed (38% and 21%, respectively, 20–85 yrs), while we found increases in the number of falls relative to the number of steps per day (800%), injuries due to falls (472%, 30–90 yrs) and deaths caused by fall (4000%, 65–90 yrs). Measures were identified to be worse for individuals with
impaired mobility. Additional detrimental effects identified for them were the loss of upright standing and locomotion, freezing in movement, joint stress, pain, and changes in gait patterns.
Discussion: This review shows that aging and chronic conditions result in wide-ranging losses in physical and sensory capabilities. While the impact of these losses are relatively modest for level walking, they become limiting during more demanding tasks such as walking on inclined ground, climbing stairs, or walking over longer periods, and especially when coupled with a debilitating disease. As the physical and functional parameters are closely related, we believe that lost functional capabilities can be indirectly improved by training of the physical capabilities. However, assistive devices can supplement the lost functional capabilities directly by compensating for losses with propulsion, weight support, and balance support.
Conclusions: Exoskeletons are a new generation of assistive devices that have the potential to provide both, training capabilities and functional compensation, to enhance human mobility
Correction to: Mobility related physical and functional losses due to aging and disease - a motivation for lower limb exoskeletons
The original article contains an error in Fig. 3f whereby data is erroneously extrapolated beyond 80 years of age; this also affects statements made elsewhere in the article.
Thus, the correct version of Fig. 3f can be viewed ahead and should be considered in place of the original Fig. 3f; furthermore, the following amendments to affected statements should also be considered
Impact of Coronary Anatomy and Stenting Technique on Long-Term Outcome After Drug-Eluting Stent Implantation for Unprotected Left Main Coronary Artery Disease
ObjectivesThis study sought to evaluate the impact of anatomic and procedural variables on the outcome of the unprotected left main coronary artery (uLMCA) itself after drug-eluting stent (DES) implantation.BackgroundThere is a controversial debate regarding when and how to perform percutaneous coronary intervention (PCI) for an uLMCA stenosis.MethodsThis analysis is based on a randomized study of 607 patients undergoing PCI for uLMCA, randomized 1:1 to receive paclitaxel- or sirolimus-eluting stents. We evaluated the impact of the SYNTAX score, uLMCA anatomy, and stenting technique on in-stent restenosis (ISR), target lesion revascularization (TLR), and the 3-year outcomes.ResultsThe 3-year cardiac mortality rate was 5.8%; 235 (39%) patients had a true bifurcation lesion (TBL), and the median SYNTAX score was 27. TBL was associated with a higher need for multiple stents (72% vs. 37%, p < 0.001). TBL was a significant predictor of ISR (23% vs. 14%, p = 0.008) and for TLR (18% vs. 9%, p < 0.001). The need for multiple stents was a predictor of ISR (22% vs. 13%, p = 0.005) and for TLR (16% vs. 9%, p = 0.005). Culotte stenting showed better results compared with T-stenting for ISR (21% vs. 56%, p = 0.02) and for TLR (15% vs. 56%, p < 0.001). We observed a significant association between uLMCA-TLR and SYNTAX scores (9.2% for scores ≤22, 14.9% for scores 23 to 32, and 13.0% for scores ≥33, p = 0.008).ConclusionsPCI of uLMCA lesions with DES is safe and effective out to 3 years. TBL and multiple stents were independent predictors for ISR. In the multivariate analysis, independent predictors for TLR were TBL, age, and EuroSCORE (European System for Cardiac Operative Risk Evaluation). (Drug-Eluting-Stents for Unprotected Left Main Stem Disease [ISAR-LEFT-MAIN]; NCT00133237
Impact of Age and Body Site on Adult Female Skin Surface pH
Background: pH is known as an important parameter in epidermal barrier function and homeostasis. Aim: The impact of age and body site on skin surface pH (pH(SS)) of women was evaluated in vivo. Methods: Time domain dual lifetime referencing with luminescent sensor foils was used for pH(SS) measurements. pH(SS) was measured on the forehead, the temple, and the volar forearm of adult females (n = 97, 52.87 +/- 18.58 years, 20-97 years). Every single measurement contained 2,500 pH values due to the luminescence imaging technique used. Results: pH(SS) slightly increases with age on all three investigated body sites. There are no significant differences in pH(SS) between the three investigated body sites. Conclusion: Adult pH(SS) on the forehead, the temple and the volar forearm increases slightly with age. This knowledge is crucial for adapting medical skin care products. Copyright (C) 2012 S. Karger AG, Base
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