Anion emission from water molecules colliding with positive ions: Identification of binary and many-body processes

It is shown that negative ions are ejected from gas-phase water molecules when bombarded with positive ions at keV energies typical of solar-wind velocities. This finding is relevant for studies of planetary and cometary atmospheres, as well as for radiolysis and radiobiology. Emission of both H- and heavier (O- and OH-) anions, with a larger yield for H-, was observed in 6.6-keV 16O+ + H2O collisions. The ex-perimental setup allowed separate identification of anions formed in collisions with many-body dynamics from those created in hard, binary collisions. Most of the ani-ons are emitted with low kinetic energy due to many-body processes. Model calcu-lations show that both nucleus-nucleus interactions and electronic excitations con-tribute to the observed large anion emission yield.Comment: 5 pages, 4 figure

Dielectronic Recombination of Ground-State and Metastable Li+ Ions

Dielectronic recombination has been investigated for Delta-n = 1 resonances of ground-state Li+(1s^2) and for Delta-n = 0 resonances of metastable Li+(1s2s ^3S). The ground-state spectrum shows three prominent transitions between 53 and 64 eV, while the metastable spectrum exhibits many transitions with energies < 3.2 eV. Reasonably good agreement of R-matrix, LS coupling calculations with the measured recombination rate coefficient is obtained. The time dependence of the recombination rate yields a radiative lifetime of 52.2 +- 5.0 s for the 2 ^3S level of Li+.Comment: Submitted to Phys. Rev. A; REVTeX, 4 pages, 3 figure

Phenoconversion from probable rapid eye movement sleep behavior disorder to mild cognitive impairment to dementia in a population-based sample

© 2017 The Authors Introduction Rapid eye movement sleep behavior disorder (RBD) is strongly associated with synucleinopathies. In 2012, we reported an increased risk of mild cognitive impairment (MCI) and Parkinson disease (PD) in cognitively normal Olmsted County, Minnesota, residents, aged 70 to 89 years with probable RBD. Here, we examine their progression to dementia and other neurodegenerative phenotypes. Methods Fifteen participants with RBD who were diagnosed with either MCI or PD were longitudinally followed, and their subsequent clinical courses were reviewed. Results Over 6.4 ± 2.9 years, six of the 14 participants with MCI developed additional neurodegenerative signs, five of whom had Lewy body disease features. Four of them progressed to dementia at a mean age 84.8 ± 4.9 years, three of whom met the criteria for probable dementia with Lewy bodies. One subject with PD developed MCI, but not dementia. Discussion Our findings from the population-based sample of Olmsted County, Minnesota, residents suggest that a substantial number of RBD patients tend to develop overt synucleinopathy features over time, and RBD patients who develop MCI and subsequent dementia have clinical features most consistent with dementia with Lewy bodies

Influence Of Wind Turbines On Mammalian Occupancy Patterns

Wind energy is among the most rapidly growing energy industries in the United States, with support for development coming from both state and federal governments. While the industry depicts an environmentally friendly image, the addition of infrastructure associated with wind farms alters landscapes in novel ways. Numerous studies have documented impacts wind turbines have on bird and bat mortality; however, far less attention has been directed towards responses of non-volant, terrestrial organisms. Mammalian mesocarnivores are model organisms to assess the alteration of communities surrounding wind turbines as they respond to addition of turbines and human activity, addition and improvement of roadways, and increases in turbine-induced carrion. In September 2011, I established a yearlong study surrounding the Central Plains Wind Facility in western Kansas to document patterns associated with the occupancy of terrestrial mammals within turbine and turbine-free habitats. I placed 34 scent-baited trail cameras among turbine and control habitats, with a randomly placed subset along roadways. Detection histories during 28-day survey periods and habitat covariates were analyzed with PRESENCE 5.5. Canis latrans and Vulpes velox were the most abundant mesocarnivores detected. Canis latrans had a higher probability of occupancy at the control area, while V. velox had higher probabilities of occupancy at the turbine area. Detection probabilities were impacted strongly by mean precipitation as well as between field and roadway locations for V. velox. Vulpes velox detection probabilities were conditional on C. latrans presence and detection, although the two species occupied sites independently

Sex-based differences in anti-predator response of crickets to chemical cues of a mammalian predator

Anti-predator behaviors like vigilance or hiding come at the expense of other fitness increasing behaviors such as foraging. To compensate for this trade-off, prey assess predation risk and modify the frequency of anti-predator behaviors according to the likelihood of the threat. In this study, we tested the ability of house crickets (Acheta domesticus) to indirectly assess predation risk via odors from a mammalian predator, Elliot\u27s short-tailed shrew (Blarina hylophaga). As natural differences in encounter rates and predation risk differs between sexes, we tested if male and female crickets perceive similar rates of predation risk from the presence of shrew odor measured via anti-predator behavioral response. Crickets were placed in enclosed, cardboard-lined chambers either treated with shrew odor or control, along with a food source. Time until foraging was measured for each individual and compared across treatment and sex. We found that in the presence of shrew odor, female crickets delayed foraging while males showed no response. These results suggest adult crickets can use chemical cues to detect mammalian predators. Furthermore, we demonstrate that female crickets associate greater predation risk from shrew predators than do male crickets, which are more stationary yet acoustically conspicuous. As predation risk potentially differs drastically for each sex, changes to the operational sex ratios of wild cricket populations could be influenced by the identity of the predator community

Dogs, Death, and Dietary Breadth: Insights into the Macroecology and Macroevolution of Canidae

The size, shape, and stability of a species’ dietary niche can both influence and reflect a variety of biological patterns, including species interactions, extinction risk, and ecosystem function. This is particularly apparent when dietary changes manifest at ecosystem and clade scales to profoundly affect macroecological and macroevolutionary trajectories. However, many studies exploring interactions, extinction, and ecosystem function rarely take into account dietary breadth across broad temporal and spatial scales, despite the fact that many ecological processes unfold over temporal and spatial scales that are beyond the scope of traditional ecology. This dissertation addresses this gap by testing the hypothesized drivers of two macroecological and macroevolutionary patterns using dietary niche breadth reconstructed from historical and paleontological canid specimens. Canid predators represent a model system for exploring broad patterns of ecology and evolution given their strong interspecific interactions coupled with a historical legacy of human-driven exterminations resulting in novel community dynamics. Additionally, North American canids offer a rich and diverse fossil history complete with iterative patterns of extinction and radiation used to describe macroevolutionary theory. I quantified dietary niche breadth for western North American canids via stable isotope analysis (SIA) and dental microwear texture analysis (DMTA) and applied these techniques across the spatial and temporal extent of canid distributions. Across space, I explored how mesopredator release has altered the dietary niche breadth of coyotes following the historical extirpation of gray wolves from the Pacific Northwest. Through time, I utilized the 33 million years of evolutionary history preserved in the North American canid fossil record to test the hypothesized link between dietary breadth and the ultimate extinction of canid lineages. In order to make more complete use of fossil, historical, and modern museum collections, which can contain fragmentary specimens, I also developed a novel approach to DMTA, devised to increase sample sizes while not biasing reconstructed dietary behaviors. I demonstrated that multiple facets along the cheek teeth in canids yield comparable microwear signals regardless of molar type or bite force (chapter 2). Thus scans from multiple molars can be combined to increase sample sizes among taxa with limited material. Looking across a latitudinal gradient along Western North America, I found that coyotes sympatric with wolves have reduced dietary niche breadth compared with coyotes sympatric with wolves. Furthermore, DMTA and SIA independently suggest released coyotes increased dietary plasticity following a reduction in scavenging behavior, previously facilitated by wolves (chapter 3). Extinction risk has been hypothesized to be positively correlated with dietary specialization, known as the macroevolutionary ratchet. The fossil record of canids has revealed iterative ratchets as multiple clades evolved towards hypercarnivory followed by rapid lineage extinctions. Morphological traits previously used to describe the macroevolutionary ratchet in canid evolution, however, are unable to capture the dietary breadth of a species. I found morphological traits were inferior to DMTA parameters at explaining extinction risk. Counter to expectations, I observed a positive correlation between specialization and lineage duration and that specialization was not correlated with traditionally-used dietary categories, suggesting that overspecialization in diet alone did not drive iterative extinctions in canids. Outcomes of this dissertation offer direct hypotheses for management officials dealing with proliferating mesopredators and trophic restructuring today. Additionally, my temporal analysis advances our fundamental understanding of macroevolutionary ratchets, and will enable future community-level studies of how species interactions influenced past evolutionary trajectories

Adjuvant hyperthermic intraperitoneal chemotherapy (HIPEC) in patients with colon cancer at high risk of peritoneal carcinomatosis; the COLOPEC randomized multicentre trial

Background: The peritoneum is the second most common site of recurrence in colorectal cancer. Early detection of peritoneal carcinomatosis (PC) by imaging is difficult. Patients eventually presenting with clinically apparent PC have a poor prognosis. Median survival is only about five months if untreated and the benefit of palliative systemic chemotherapy is limited. Only a quarter of patients are eligible for curative treatment, consisting of cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CR/HIPEC). However, the effectiveness depends highly on the extent of disease and the treatment is associated with a considerable complication rate. Methods/Design: The aim of this study is to determine the effectiveness of adjuvant HIPEC in preventing the development of PC in patients with colon cancer at high risk of peritoneal recurrence. This study will be performed in the nine Dutch HIPEC centres, starting in April 2015. Eligible for inclusion are patients who underwent curative resection for T4 or intra-abdominally perforated cM0 stage colon cancer. After resection of the primary tumour, 176 patients will be randomized to adjuvant HIPEC followed by routine adjuvant systemic chemotherapy in the experimental arm, or to systemic chemotherapy only in the control arm. Adjuvant HIPEC will be performed simultaneously or shortly after the primary resection. Oxaliplatin will be used as chemotherapeutic agent, for 30 min at 42-43 °C. Just before HIPEC, 5-fluorouracil and leucovorin will be administered intravenously. Primary endpoint is peritoneal disease-free survival at 18 months. Diagnostic laparoscopy will be performed routinely after 18 months postoperatively in both arms of the study in patients without evidence of disease based on routine follow-up using CT imaging and CEA. Discussion: Adjuvant HIPEC is assumed to reduce the expected 25 % absolute risk of PC in patients with T4 or perforated colon cancer to a risk of 10 %. This reduction is likely to translate into a prolonged overall survival. Trial registration number: NCT02231086 (Clinicaltrials.gov)

Impact of hospital volume on survival in patients with locally advanced colon cancer – A Dutch population-based study

Aim: Locally advanced colon cancer (LACC) often necessitates complex prognosis-determining treatment. This study investigated the impact of hospital volume on short- and long-term outcomes following surgery for LACC. Method: Data involving all patients with LACC categorized as clinical T4 and/or N2, between 2015 and 2019 in the Netherlands, were extracted from the Netherlands Cancer Registry. Hospitals were stratified into low volume (1–19 LACC resections per year), medium volume (20–29 LACC resections per year) and high volume (≥30 LACC resections per year). Data were analysed using Kaplan–Meier curves, logistic regression analysis and Cox-regression models. Results: A total of 49 298 patients were diagnosed with colon cancer, of whom 9206 (18.7%) had locally advanced disease. Of these 9206 patients, resection was performed in 8537 with a median age of 71 (interquartile range: 63–78) years. Patients were more likely to undergo laparoscopic procedures in high-volume hospitals than in low-volume hospitals (OR = 1.28, 95% CI: 1.12–1.46). No risk differences in anastomotic leakage or postoperative 90-day mortality were observed according to hospital volume. Five-year overall survival rates were comparable among high-, medium- and low-volume hospitals (58.7% vs. 58.0% vs. 60.0%, p = 0.62). Hospital volume was not associated with overall survival in multivariable analysis. Independent predictors of worse overall survival included older age, higher American Society of Anaesthesiologists score, emergency/urgent setting, anastomotic leakage, higher pTNM status, involved resection margins and no adjuvant chemotherapy.Conclusion: Despite the complexity of surgical treatment, hospital volume was not associated with survival in LACC. Hospital volume might be an imperfect surrogate for quality assessment.</p