Independent from muscle power and balance performance, a creatinine clearance below 65ml/min is a significant and independent risk factor for falls and fall-related fractures in elderly men and women diagnosed with osteoporosis

Summary: We assessed in a cross-sectional study in elderly men and women with osteoporosis, the association between the creatinine clearance (CrCl) and the performance in different balance and muscle power and function tests and found that a decreasing creatinine clearance was significantly associated with lower balance and muscle power. Introduction: To determine if a creatinine clearance of <65ml/min is significantly associated with decreasing muscle power and balance and an increased risk for falls and fractures. Methods: We assessed in a cross-sectional-study in 1781 German osteoporotic patients, the association between the CrCl, the physical performance, and the number of falls and fractures. Results: Controlling for age, gender, BMI, and osteoporosis treatment (fracture analysis only), a decreasing CrCl was associated with lower physical performance in the timed-up-and-go test (corr −0.2337, P < 0.0001), chair-rising test (corr −0.1706, P < 0.001), and tandem-stand test (corr 0.2193, P < 0.0001), and a CrCl of <65ml/min was associated with a significantly higher risk for falls (47.7% vs. 36.2%, P = 0.0008) and fall-related fractures (33.1% vs. 22.9%, P = 0.0003) compared with a CrCl of ≥65ml/min. Conclusions: In this study, we found a significant gender-independent correlation between decreasing CrCl and lower performance in balance and muscle power tests. Reduced muscle power and balance may therefore be involved in the low creatinine clearance associated increased risk for falls and fall-related fractures. Furthermore, we found that a CrCl <65ml/min., independent from the performance in muscle power, muscle function, and balance tests, is a significant risk factor for falls and fracture

Prospective Study of Bowel Movement, Laxative Use, and Risk of Colorectal Cancer among Women

The authors prospectively examined the association between bowel movement frequency, laxative use, and the risk of colorectal cancer in 84, 577 women of the Nurses' Health Study living in the United States, 36-61 years of age and free of cancer in 1982. Between 1984 and 1996, 611 incident cases of colorectal cancer were documented. After controlling for age, body mass index, fiber intake, postmenopausal status and hormone use, physical activity, and use of laxatives, the relative risks associated with having bowel movements every third day or less, compared with those with bowel movements once daily, were 0.94 (95% confidence interval (Cl): 0.69, 1.28) for colorectal cancer, 0.88 (95% Cl: 0.62, 1.26) for colon cancer, and 1.18 (95% Cl: 0.63, 2.20) for rectal cancer. Compared with women who never used laxatives, the multivariate relative risks associated with weekly to daily laxative use were 1.00 (95% Cl: 0.72, 1.40) for colorectal cancer, 1.09 (95% Cl: 0.76, 1.57) for colon cancer, and 0.68 (95% Cl: 0.29, 1.57) for rectal cancer. These findings do not support an association between infrequent bowel movement, laxative use, and risk of colorectal cancer and indicate that simple questions directed at bowel movement frequency are unlikely to enhance our ability to predict colorectal cancer risk. Am J Epidemiol2000; 151: 958-6

Spider Movement, UV Reflectance and Size, but Not Spider Crypsis, Affect the Response of Honeybees to Australian Crab Spiders

According to the crypsis hypothesis, the ability of female crab spiders to change body colour and match the colour of flowers has been selected because flower visitors are less likely to detect spiders that match the colour of the flowers used as hunting platform. However, recent findings suggest that spider crypsis plays a minor role in predator detection and some studies even showed that pollinators can become attracted to flowers harbouring Australian crab spider when the UV contrast between spider and flower increases. Here we studied the response of Apis mellifera honeybees to the presence of white or yellow Thomisus spectabilis Australian crab spiders sitting on Bidens alba inflorescences and also the response of honeybees to crab spiders that we made easily detectable painting blue their forelimbs or abdomen. To account for the visual systems of crab spider's prey, we measured the reflectance properties of the spiders and inflorescences used for the experiments. We found that honeybees did not respond to the degree of matching between spiders and inflorescences (either chromatic or achromatic contrast): they responded similarly to white and yellow spiders, to control and painted spiders. However spider UV reflection, spider size and spider movement determined honeybee behaviour: the probability that honeybees landed on spider-harbouring inflorescences was greatest when the spiders were large and had high UV reflectance or when spiders were small and reflected little UV, and honeybees were more likely to reject inflorescences if spiders moved as the bee approached the inflorescence. Our study suggests that only the large, but not the small Australian crab spiders deceive their preys by reflecting UV light, and highlights the importance of other cues that elicited an anti-predator response in honeybees

Specialized Learning in Antlions (Neuroptera: Myrmeleontidae), Pit-Digging Predators, Shortens Vulnerable Larval Stage

Unique in the insect world for their extremely sedentary predatory behavior, pit-dwelling larval antlions dig pits, and then sit at the bottom and wait, sometimes for months, for prey to fall inside. This sedentary predation strategy, combined with their seemingly innate ability to detect approaching prey, make antlions unlikely candidates for learning. That is, although scientists have demonstrated that many species of insects possess the capacity to learn, each of these species, which together represent multiple families from every major insect order, utilizes this ability as a means of navigating the environment, using learned cues to guide an active search for food and hosts, or to avoid noxious events. Nonetheless, we demonstrate not only that sedentary antlions can learn, but also, more importantly, that learning provides an important fitness benefit, namely decreasing the time to pupate, a benefit not yet demonstrated in any other species. Compared to a control group in which an environmental cue was presented randomly vis-à-vis daily prey arrival, antlions given the opportunity to associate the cue with prey were able to make more efficient use of prey and pupate significantly sooner, thus shortening their long, highly vulnerable larval stage. Whereas “median survival time,” the point at which half of the animals in each group had pupated, was 46 days for antlions receiving the Learning treatment, that point never was reached in antlions receiving the Random treatment, even by the end of the experiment on Day 70. In addition, we demonstrate a novel manifestation of antlions' learned response to cues predicting prey arrival, behavior that does not match the typical “learning curve” but which is well-adapted to their sedentary predation strategy. Finally, we suggest that what has long appeared to be instinctive predatory behavior is likely to be highly modified and shaped by learning

Merging of long-term memories in an insect

© 2015 Elsevier Ltd All rights reserved.Research on comparative cognition has largely focused on successes and failures of animals to solve certain cognitive tasks, but in humans, memory errors can be more complex than simple failures to retrieve information [1, 2]. The existence of various types of "false memories," in which individuals remember events that they have never actually encountered, are now well established in humans [3, 4]. We hypothesize that such systematic memory errors may be widespread in animals whose natural lifestyle involves the processing and recollection of memories for multiple stimuli [5]. We predict that memory traces for various stimuli may "merge," such that features acquired in distinct bouts of training are combined in an animal's mind, so that stimuli that have never been viewed before, but are a combination of the features presented in training, may be chosen during recall. We tested this using bumblebees, Bombus terrestris. When individuals were first trained to a solid single-colored stimulus followed by a black and white (b/w)-patterned stimulus, a subsequent preference for the last entrained stimulus was found in both short-term- and long-term-memory tests. However, when bees were first trained to b/w-patterned stimuli followed by solid single-colored stimuli and were tested in long-term-memory tests 1 or 3 days later, they only initially preferred the most recently rewarded stimulus, and then switched their preference to stimuli that combined features from the previous color and pattern stimuli. The observed merging of long-term memories is thus similar to the memory conjunction error found in humans [6].K.H. was supported by a PhD studentship provided by the National Environmental Research Council (NE/H525089/1), and L.C. is supported by a Royal Society Wolfson Research Merit Award (WM130106)

Bumblebees exhibit the memory spacing effect

Associative learning is key to how bees recognize and return to rewarding floral resources. It thus plays a major role in pollinator floral constancy and plant gene flow. Honeybees are the primary model for pollinator associative learning, but bumblebees play an important ecological role in a wider range of habitats, and their associative learning abilities are less well understood. We assayed learning with the proboscis extension reflex (PER), using a novel method for restraining bees (capsules) designed to improve bumblebee learning. We present the first results demonstrating that bumblebees exhibit the memory spacing effect. They improve their associative learning of odor and nectar reward by exhibiting increased memory acquisition, a component of long-term memory formation, when the time interval between rewarding trials is increased. Bombus impatiens forager memory acquisition (average discrimination index values) improved by 129% and 65% at inter-trial intervals (ITI) of 5 and 3 min, respectively, as compared to an ITI of 1 min. Memory acquisition rate also increased with increasing ITI. Encapsulation significantly increases olfactory memory acquisition. Ten times more foragers exhibited at least one PER response during training in capsules as compared to traditional PER harnesses. Thus, a novel conditioning assay, encapsulation, enabled us to improve bumblebee-learning acquisition and demonstrate that spaced learning results in better memory consolidation. Such spaced learning likely plays a role in forming long-term memories of rewarding floral resources

Aversive Learning in Honeybees Revealed by the Olfactory Conditioning of the Sting Extension Reflex

Invertebrates have contributed greatly to our understanding of associative learning because they allow learning protocols to be combined with experimental access to the nervous system. The honeybee Apis mellifera constitutes a standard model for the study of appetitive learning and memory since it was shown, almost a century ago, that bees learn to associate different sensory cues with a reward of sugar solution. However, up to now, no study has explored aversive learning in bees in such a way that simultaneous access to its neural bases is granted. Using odorants paired with electric shocks, we conditioned the sting extension reflex, which is exhibited by harnessed bees when subjected to a noxious stimulation. We show that this response can be conditioned so that bees learn to extend their sting in response to the odorant previously punished. Bees also learn to extend the proboscis to one odorant paired with sugar solution and the sting to a different odorant paired with electric shock, thus showing that they can master both appetitive and aversive associations simultaneously. Responding to the appropriate odorant with the appropriate response is possible because two different biogenic amines, octopamine and dopamine subserve appetitive and aversive reinforcement, respectively. While octopamine has been previously shown to substitute for appetitive reinforcement, we demonstrate that blocking of dopaminergic, but not octopaminergic, receptors suppresses aversive learning. Therefore, aversive learning in honeybees can now be accessed both at the behavioral and neural levels, thus opening new research avenues for understanding basic mechanisms of learning and memory

Effects of resistance and functional-skills training on habitual activity and constipation among older adults living in long-term care facilities: a randomized controlled trial

BACKGROUND: Large-scale RCTs comparing different types of exercise training in institutionalised older people are scarce, especially regarding effects on habitual physical activity and constipation. This study investigated the effects of different training protocols on habitual physical activity and constipation of older adults living in long-term care facilities. METHODS: A randomized controlled trial with 157 participants, aged 64 to 94 years, who were randomly assigned to 1) resistance training; 2) all-round functional-skills training; 3) both; or 4) an 'educational' control condition. Habitual physical activity was assessed with a physical activity questionnaire and accelerometers. Constipation was assessed by a questionnaire. Measurements were performed at baseline and after six months of training. RESULTS: At baseline the median time spent sitting was 8.2 hr/d, the median time spent on activity of at least moderate intensity was 32 min/d. At baseline, about 22% of the subjects were diagnosed with constipation and 23% were taking laxatives. There were no between-group differences for changes in habitual physical activity or constipation over 6-months. CONCLUSION: Six months of moderate intensity exercise training neither enhances habitual physical activity nor affects complaints of constipation among older people living in long-term care facilities