Species-specific responses of Late Quaternary megafauna to climate and humans

Despite decades of research, the roles of climate and humans in driving the dramatic extinctions of large-bodied mammals during the Late Quaternary remain contentious. We use ancient DNA, species distribution models and the human fossil record to elucidate how climate and humans shaped the demographic history of woolly rhinoceros, woolly mammoth, wild horse, reindeer, bison and musk ox. We show that climate has been a major driver of population change over the past 50,000 years. However, each species responds differently to the effects of climatic shifts, habitat redistribution and human encroachment. Although climate change alone can explain the extinction of some species, such as Eurasian musk ox and woolly rhinoceros, a combination of climatic and anthropogenic effects appears to be responsible for the extinction of others, including Eurasian steppe bison and wild horse. We find no genetic signature or any distinctive range dynamics distinguishing extinct from surviving species, underscoring the challenges associated with predicting future responses of extant mammals to climate and human-mediated habitat change.This paper is in the memory of our friend and colleague Dr. Andrei Sher, who was a major contributor of this study. Dr Sher died unexpectedly, but his major contributions to the field of Quaternary science will be remembered and appreciated for many years to come. We are grateful to Dr. Adrian Lister and Dr. Tony Stuart for guides and discussions. Thanks to Tina B. Brandt, Dr. Bryan Hockett and Alice Telka for laboratory help and samples and to L. Malik R. Thrane for his work on the megafauna locality database. Data taken from the Stage 3 project was partly funded by Grant #F/757/A from the Leverhulme Trust, together with a grant from the McDonald Grants and Awards Fund. We acknowledge the Danish National Research Foundation, the Lundbeck Foundation, the Danish Council for Independent Research and the US National Science Foundation for financial suppor

Complex admixture preceded and followed the extinction of wisent in the wild

Retracing complex population processes that precede extreme bottlenecks may be impossible using data from living individuals. The wisent (Bison bonasus), Europe’s largest terrestrial mammal, exemplifies such a population history, having gone extinct in the wild but subsequently restored by captive breeding efforts. Using low coverage genomic data from modern and historical individuals, we investigate population processes occurring before and after this extinction. Analysis of aligned genomes supports the division of wisent into two previously recognized subspecies, but almost half of the genomic alignment contradicts this population history as a result of incomplete lineage sorting and admixture. Admixture between subspecies populations occurred prior to extinction and subsequently during the captive breeding program. Admixture with the Bos cattle lineage is also widespread but results from ancient events rather than recent hybridization with domestics. Our study demonstrates the huge potential of historical genomes for both studying evolutionary histories and for guiding conservation strategies

Assessment of morphological architecture of feet in rock-climbers

It was hypothetically assumed that rock-climbers have normal foot structure. The aim of this study was to assess the structure of all the foot segments. Materials and methods: This study embraced 43 rock-climbers, who had been training for 3 to 7 years. The research group included 17 women and 26 men, aged from 18 to 24 years (mean age – 24.3). The control group consisted of 31 students of the University of Wrocław, aged from 19 to 23 years (mean age – 22.7). Photometric method was used to examine the morphological structure of the feet Results Results of the examinations show that all the rock-climbers had normal structure of the longitudinal arch, while various types of the longitudinal arch structure were observed in the students. The analysis of the transversal arch structure showed that disorders were more frequent in the rock-climbers.Conclusions. 1 Rock-climbing has a beneficial influence on the structure of the longitudinal arch, yet it is the factor facilitating disturbances of the frontal foot segments. 2 Deformations of the transversal arch structure and the toes arrangement do not coexist with the longitudinal platypodia

Spinal cord stimulation in the treatment of chronic pain

Jednym ze sposobów leczenia bólu przewlekłego jest procedura neuromodulacyjna – stymulacja rdzenia kręgowego (spinal cord stimulation SCS). Istnieje wiele teorii wyjaśniających mechanizm jej działania, ale nie jest on ostatecznie poznany. SCS stosuje się między innymi po operacjach neurochirurgicznych w zespołach failed back surgery syndrome i post-laminectomy syndrome. Wskazaniem do stymulacji rdzenia kręgowego jest ból neuropatyczny, który powstaje w wyniku ucisku nerwów (pleksopatie, radikulopatie). Elektrodę umieszcza się w grzbietowej części przestrzeni nadtwardówkowej, na wysokości zależnej od miejsca występowania bólu. Najczęstsze miejsca implantacji generatora zlokalizowane są wzdłuż linii środkowo-pachowej, w górnej części pośladka, w linii pachowej tylnej i powłokach brzucha, tuż poniżej najniższego żebra. Elektroda dodatnia – anoda – hamuje neurony poprzez hiperpolaryzację. Wykorzystując to działanie, programuje się urządzenia stymulujące. SCS jako metoda leczenia bólu przewlekłego daje pacjentom ulgę w bólu, a niektórym stwarza możliwość powrotu do pracy.Neuromodulation is the procedure used for the spinal cord stimulation (SCS). There are many theories explaining its mechanism, however it has not been thoroughly studied. SCS is used e.g. after neurosurgical operations in failed back surgery syndrome as well as post-laminectomy syndrome. An indication for spinal cord stimulation is neuropathic pain occurring as a result of pressure on nerves. An electrode is placed within a dorsal part of the extradural space at the height dependent on the pain location. The most frequent site of generator implantation is located along the midaxillary line, in the upper part of the buttock, in the posterior axillary line and the lining of the stomach just below the lowest rib. The positive electrode – anode – suppresses neurons through hyperpolarization. SCS as a method of chronic pain treatment brings relief to patients, and in some cases it enables them to go back to work

Pharmacokinetic Profile of Spectrum Reduced Nicotine Cigarettes.

INTRODUCTION: Spectrum research cigarettes have been developed with varying nicotine content for use in studies evaluating the effects of a regulatory policy reducing the permissible nicotine content in cigarettes. This study aimed to characterize the nicotine pharmacokinetic profile of Spectrum cigarettes. METHODS: Twelve daily smokers attended four sessions and had blood nicotine, exhaled carbon monoxide, and subjective effects measured before and after smoking either a single cigarette of their preferred brand or high (10.9 mg/cigarette), medium (3.2 mg/cigarette), or low (0.2 mg/cigarette) nicotine content Spectrum research cigarettes, in a double-blind design with order counterbalanced. RESULTS: The boost in blood nicotine concentration was dose-dependent, with a boost of 0.3, 3.9, and 17.3 ng/mL for low-, medium-, and high-nicotine content Spectrum cigarettes. The high dose Spectrum had a similar nicotine boost to the preferred brand cigarettes (19 ng/mL). Subjects took longer puffs on the low nicotine cigarettes, but smoked these cigarettes faster than other cigarette types. High nicotine Spectrum cigarettes reduced the urge to smoke more than other cigarette types. CONCLUSIONS: This study shows that Spectrum research cigarettes produce blood nicotine absorption in a dose-dependent manner, and therefore, are appropriate for use in studies of nicotine reduction in cigarettes. IMPLICATIONS: This is the first study to determine the pharmacokinetic profile of Spectrum reduced nicotine content research cigarettes following an overnight abstinence. These data could provide evidence to regulatory agencies about the effects of reduced nicotine cigarettes when considering regulations on tobacco reduction

Genetic diversity in caribou linked to past and future climate change

Climate-driven range fluctuations during the Pleistocene have continuously reshaped species distribution leading to populations of contrasting genetic diversity. Contemporary climate change is similarly influencing species distribution and population structure, with important consequences for patterns of genetic diversity and species' evolutionary potential1. Yet few studies assess the impacts of global climatic changes on intraspecific genetic variation2, 3, 4, 5. Here, combining analyses of molecular data with time series of predicted species distributions and a model of diffusion through time over the past 21 kyr, we unravel caribou response to past and future climate changes across its entire Holarctic distribution. We found that genetic diversity is geographically structured with two main caribou lineages, one originating from and confined to Northeastern America, the other originating from Euro-Beringia but also currently distributed in western North America. Regions that remained climatically stable over the past 21 kyr maintained a high genetic diversity and are also predicted to experience higher climatic stability under future climate change scenarios. Our interdisciplinary approach, combining genetic data and spatial analyses of climatic stability (applicable to virtually any taxon), represents a significant advance in inferring how climate shapes genetic diversity and impacts genetic structure

Postural control in patients with lumbar disc herniation in the early postoperative period

Chronic spinal disc disease leads to disorders in postural movement coordination. An incorrect asymmetrical movement pattern for the lower limbs loading impairs proprioception and deteriorates postural stability, particularly when the vision is occluded. The standard surgical treatment improves biomechanical conditions in the lumbar spine, reduces pain, yet does it reduce the stability deficit in the upright position? An answer to the latter question would help work out targeted therapy to improve postural stability. We hypothesized that the standard surgical treatment would improve postural stability reflected by decreased sway variability accounting for better use of proprioceptive inputs postoperatively. Thirty-nine patients with lumbar disc herniation participated in the study. Their postural sway was recorded in anterior/posterior and medial/lateral planes with their eyes open or closed (EC) before and after surgery. The variability, range, mean velocity of the recorded time series and the area of the ellipse enclosed by the statokinesiogram were used as measures of postural stability. Preoperatively, EC condition resulted in an increased variability and mean velocity of postural sway, while postoperatively it caused an increase in sway mean velocity and sway area only with no effect on sway variability and range. The comparison of the balance before and after the surgery in the EC condition showed significant decrease in all parameters. In the early postoperative period, the patients recover the ability to control their postural sway in EC within normal limits, however, at the expense of significantly increased frequency of corrective torques. It is probably a transient short-term strategy needed to compensate for the recovery phase when the normal weighting factors for all afferents are being reestablished. We propose that this transient postoperative period may be the best timing of therapeutic intervention targeted at facilitating and reinforcing the acquisition of correct motor patterns

Genetic diversity in caribou linked to past and future climate change

Climate-driven range fluctuations during the Pleistocene have continuously reshaped species distribution leading to populations of contrasting genetic diversity. Contemporary climate change is similarly influencing species distribution and population structure, with important consequences for patterns of genetic diversity and species' evolutionary potential. Yet few studies assess the impacts of global climatic changes on intraspecific genetic variation. Here, combining analyses of molecular data with time series of predicted species distributions and a model of diffusion through time over the past 21 kyr, we unravel caribou response to past and future climate changes across its entire Holarctic distribution. We found that genetic diversity is geographically structured with two main caribou lineages, one originating from and confined to Northeastern America, the other originating from Euro-Beringia but also currently distributed in western North America. Regions that remained climatically stable over the past 21 kyr maintained a high genetic diversity and are also predicted to experience higher climatic stability under future climate change scenarios. Our interdisciplinary approach, combining genetic data and spatial analyses of climatic stability (applicable to virtually any taxon), represents a significant advance in inferring how climate shapes genetic diversity and impacts genetic structure. © 2014 Macmillan Publishers Limited