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Cephalopods are important prey in the diet of top predators, such as marine mammals and seabirds. However, detailed information on their trophic relationships in the Patagonian marine ecosystem is scarce, including those cephalopod species with commercial interest. The aims of this study were to evaluate the composition of the cephalopod component in the diet of Otaria byronia and determine the habitat use and trophic levels of their main cephalopod prey by measuring the stable isotopic signature of cephalopod beaks. Between May 2005 and February 2009, fresh faecal samples were collected from two sea lions rookeries in San Matias Gulf. Cephalopods occurred in 39.4% of the 1112 samples collected during the whole period of study. The dominant prey species was Octopus tehuelchus, which occurred in 45.8% of scats containing cephalopod remains, and represented 58.7% in terms of numerical abundance and 52.0% in mass of cephalopods consumed. The second species most consumed was the myopsid Doryteuthis gahi. The significant higher δ15N values of O. tehuelchus beaks in comparison with those of D. gahi showed that these two species have different trophic levels while occupying similar habitat (δ13C values) in neritic waters of the Patagonian shelf.
Objectives: It is unclear whether the primary motor cortex (PMC) is involved in the mental simulation of movement [i.e., motor imagery (MI)]. The present study aimed to clarify PMC involvement using a highly novel adaptation of the hand laterality task (HLT). Methods: Participants were administered single-pulse transcranial magnetic stimulation (TMS) to the hand area of the left PMC (hPMC) at either 50 ms, 400 ms, or 650 ms post stimulus presentation. Motor-evoked potentials (MEPs) were recorded from the right first dorsal interosseous via electromyography. To avoid the confound of gross motor response, participant response (indicating left or right hand) was recorded via eye tracking. Participants were 22 healthy adults (18 to 36 years), 16 whose behavioral profile on the HLT was consistent with the use of a MI strategy (MI users). Results: hPMC excitability increased significantly during HLT performance for MI users, evidenced by significantly larger right hand MEPs following single-pulse TMS 50 ms, 400 ms, and 650 ms post stimulus presentation relative to baseline. Subsequent analysis showed that hPMC excitability was greater for more complex simulated hand movements, where hand MEPs at 50 ms were larger for biomechanically awkward movements (i.e., hands requiring lateral rotation) compared to simpler movements (i.e., hands requiring medial rotation). Conclusions: These findings provide support for the modulation of PMC excitability during the HLT attributable to MI, and may indicate a role for the PMC during MI. (JINS, 2017, 23, 185–193)
We obtained new HST/STIS long-slit spectra and WFPC2 imagery of the planetary nebula NGC 7009 in order to obtain high spatial resolution of the intrinsic flux ratio [O III] 4364/5008, which is a well-known diagnostic for electron temperature (Te). Our primary purpose was to quantify Te variations across the nebula. We address whether the observational data support the possibility that the [fractional] mean-square Te variation (t2) (Peimbert 1967) in NGC 7009 may be as large as ~0.1. Such large values are required to reconcile the “abundance dichotomy” by Te variations alone. The abundance dichotomy (discussed by Liu at greater length elsewhere in this volume) refers to the significantly higher heavy element abundances derived from optical recombination lines (e.g., a factor of ~5 for NGC 7009, Liu et al. 1995) compared with the corresponding values deduced from collisionally-excited lines.
In the recent years new techniques are expanding visual binary star astronomy into previously inaccessible regimes of angular resolution and accuracy of measurements regarding the astrometric and astrophysical parameters of their components. New techniques and algorithms are providing enhanced sensitivity to low mass companions and the determination of photometric properties of the components of close visual binaries. The potential now exists for significantly narrowing, if not eliminating entirely, the historic gap separating spectroscopic from visual binaries. Advances in closely related fields as in precision radial velocity measurement and enhanced accuracy of parallax determination from ground and space based observatories will place demands upon double star astronomy that have been absent for half a century. Today double and multiple star astronomy is perhaps closer to fulfilling its true potential than it has ever been, entering a fundamentally important area of modern astrophysics.
Zeta Cancri is a multiple system in which the well-observed orbit is an inner, or close one. Three-body coupling effects are an order of magnitude more significant for the close orbit in a hierarchical system, and they must be included. An exact numerical integration is very easy and requires no approximations. Inclusion of these effects improves the residuals for this system.
The Darwin region in northern Australia has experienced rapid population growth in recent years, and with it, an increased incidence of melioidosis. Previous studies in Darwin have associated the environmental presence of Burkholderia pseudomallei, the causative agent of melioidosis, with anthropogenic land usage and proximity to animals. In our study, we estimated the occurrence of B. pseudomallei and Burkholderia spp. relatives in faecal matter of wildlife, livestock and domestic animals in the Darwin region. A total of 357 faecal samples were collected and bacteria isolated through culture and direct DNA extraction after enrichment in selective media. Identification of B. pseudomallei, B. ubonensis, and other Burkholderia spp. was carried out using TTS1, Bu550, and recA BUR3–BUR4 quantitative PCR assays, respectively. B. pseudomallei was detected in seven faecal samples from wallabies and a chicken. B. cepacia complex spp. and Pandoraea spp. were cultured from wallaby faecal samples, and B. cenocepacia and B. cepacia were also isolated from livestock animals. Various bacteria isolated in this study represent opportunistic human pathogens, raising the possibility that faecal shedding contributes to the expanding geographical distribution of not just B. pseudomallei but other Burkholderiaceae that can cause human disease.
We have assembled a new sample of some of the most FIR-luminous galaxies in the Universe and have imaged them in 1.1 mm dust emission and measured their redshifts 1 < z < 4 via CO emission lines using the 32-m Large Millimeter Telescope / Gran Telescopio Milimétrico (LMT/GTM). Our sample of 31 submm galaxies (SMGs), culled from the Planck and Herschel all-sky surveys, includes 14 of the 21 most luminous galaxies known, with LFIR > 1014L⊙ and SFR > 104M⊙/yr. These extreme inferred luminosities – and multiple / extended 1.1 mm images – imply that most or all are strongly gravitationally lensed, with typical magnification μ ~ 10 × . The gravitational lensing provides two significant benefits: (1) it boosts the S/N, and (2) it allows investigation of star formation and gas processes on sub-kpc scales.
Due to its favourable properties, in particular, low permeability and swelling capacity, bentonite has been favoured as an engineered-barrier and backfill material for the geological storage of radioactive waste. To ensure its safe long-term performance it is important to understand any changes in these properties when the material is subject to heat-emitting waste. As such, this study investigates the hydraulic response of bentonite under multi-step thermal loading subject to a constant-volume boundary condition, to represent a barrier system used in a crystalline or other hard-rock host rock. The experimental set up allows continuous measurement of the hydraulic and mechanical responses during each phase of the thermal cycle. After the initial hydration of the bentonite, the temperature was raised in 20°C increments from 20 to 80°C followed by a final step to reach 120°C. Each temperature was held constant for at least 7–10 days to allow the hydraulic transients to equilibrate. The data suggest that the permeability of bentonite appears to be sensitive to changes in temperature which may extend beyond those explained by simple changes in water viscosity. However, permeability may be boundary-condition dependent and this should be considered when designing experiments or applying these results to other repository host rocks. Either way, the magnitude of the change in permeability observed in this study is minor and its impact on the hydraulic performance of the barrier is negligible.
We describe two cases of infant botulism due to Clostridium butyricum producing botulinum type E neurotoxin (BoNT/E) and a previously unreported environmental source. The infants presented at age 11 days with poor feeding and lethargy, hypotonia, dilated pupils and absent reflexes. Faecal samples were positive for C. butyricum BoNT/E. The infants recovered after treatment including botulism immune globulin intravenous (BIG-IV). C. butyricum BoNT/E was isolated from water from tanks housing pet ‘yellow-bellied’ terrapins (Trachemys scripta scripta): in case A the terrapins were in the infant's home; in case B a relative fed the terrapin prior to holding and feeding the infant when both visited another relative. C. butyricum isolates from the infants and the respective terrapin tank waters were indistinguishable by molecular typing. Review of a case of C. butyricum BoNT/E botulism in the UK found that there was a pet terrapin where the infant was living. It is concluded that the C. butyricum-producing BoNT type E in these cases of infant botulism most likely originated from pet terrapins. These findings reinforce public health advice that reptiles, including terrapins, are not suitable pets for children aged <5 years, and highlight the importance of hand washing after handling these pets.
The significance of the potential impacts of microbial activity on the transport properties of host rocks for geological repositories is an area of active research. Most recent work has focused on granitic environments. This paper describes pilot studies investigating changes in transport properties that are produced by microbial activity in sedimentary rock environments in northern Japan. For the first time, these short experiments (39 days maximum) have shown that the denitrifying bacteria, Pseudomonas denitrificans, can survive and thrive when injected into flow-through column experiments containing fractured diatomaceous mudstone and synthetic groundwater under pressurized conditions. Although there were few significant changes in the fluid chemistry, changes in the permeability of the biotic column, which can be explained by the observed biofilm formation, were quantitatively monitored. These same methodologies could also be adapted to obtain information from cores originating from a variety of geological environments including oil reservoirs, aquifers and toxic waste disposal sites to provide an understanding of the impact of microbial activity on the transport of a range of solutes, such as groundwater contaminants and gases (e.g. injected carbon dioxide).
Background: Elevated plasma homocysteine concentrations have been associated with both cognitive impairment and dementia. However, it is unclear whether some cognitive domains are more affected than others, or if this relationship is independent of B12 and folate levels, which can also affect cognition. We examined the relationship between plasma homocysteine and cognitive decline in an older hypertensive population.
Methods: 182 older people (mean age 80 years) with hypertension and without dementia, were studied at one center participating in the Study on COgnition and Prognosis in the Elderly (SCOPE). Annual cognitive assessments were performed using a computerized assessment battery and executive function tests, over a 3–5 year period (mean 44 months). Individual rates of decline on five cognitive domains were calculated for each patient. End of study plasma homocysteine, folate and B12 concentrations were measured. The relationship between homocysteine levels and cognitive decline was studied using multivariate regression models, and by comparing high versus low homocysteine quartile groups.
Results: Higher homocysteine showed an independent association with greater cognitive decline in three domains: speed of cognition (β = −27.33, p = 0.001), episodic memory (β = −1.25, p = 0.02) and executive function (β = −0.05, p = 0.04). The association with executive function was no longer significant after inclusion of folate in the regression model (β = −0.032, p = 0.22). Change in working memory and attention were not associated with plasma homocysteine, folate or B12. High homocysteine was associated with greater decline with a Cohen's d effect size of approximately 0.7 compared to low homocysteine.
Conclusions: In a population of older hypertensive patients, higher plasma homocysteine was associated with cognitive decline.
A precipitation process has been developed to prepare precursor powders which can be calcined and sintered to form high critical temperature superconductors such as YBa2Cu3O7−x. Precursor powders are prepared using a continuous precipitation system in which a solution containing highly soluble salts of the desired metal cations is rapidly and completely mixed with a solution containing precipitating anions such as hydroxide and carbonate ions. The resulting amorphous powder can be calcined to form sub-micron particles of desired superconducting phases which are useful in preparing inks for the ink-jet printing of superconducting interconnects. The powders can be redissolved in organic solvents to form solutions which can be used in spin or dip coating substrates with thin superconducting films. Finally, the powders have been used to prepare bulk ceramics which exhibit the highest reported critical currents of any chem-prep ceramics. Bulk samples prepared from chloride doped precursors exhibit large, oriented grains and extensive flux pinning.
The effect of varying single mode fiber fabrication factors such as core and clad dopant concentrations, deposition conditions, and draw parameters on the recovery of the nuclear radiation-induced attenuation at 1.3 μm has been studied. Statistically significant correlations of core factors have been established with a 24 experimental design, and separate one-dimensional experiments revealed the effect of clad [Ge] and [F].
To evaluate factors related to a gradual rise in sternal surgical site infection (SSI) rates.
Retrospective cohort study.
A 608-bed, tertiary care teaching hospital.
All patients who underwent coronary artery bypass graft (CABG) from January 2000 through September 2004.
Of 3,578 patients who underwent CABG, 144 (4%) had sternal SSI. There was an increase in infection rate, with a marked reduction in the number of operations per year. The percentage of patients with peripheral vascular disease increased from 12% to 24.3% (P < .001), and the percentage with congestive heart failure increased from 17% to 22% (P < .001). Between 2002 and 2004, the mean duration of surgery increased from 233 to 290 minutes (P < .001), the percentage of patients with a National Nosocomial Infections Surveillance System (NNIS) risk index of 2 increased from 14.3% to 38% (P < .001), and the percentage of patients with a postoperative stay in the intensive care unit of greater than 72 hours increased from 29% to 40.6% (P < .001). Multivariate analysis showed diabetes mellitus, peripheral vascular disease, obesity, duration of surgery, and postoperative stay in the intensive care unit of greater than 72 hours to be independently associated with infection.
An increase in infection in the CABG population not associated with an outbreak may be a reflection of a change in the severity of illness. Preoperative, intraoperative, and postoperative markers for increased infection risk may be used, in addition to the NNIS risk index, to assess the patient population risk.
We demonstrate analytically that cross-sectional variation in the effects of events, i.e., in true abnormal returns, necessarily produces event-induced variance increases, biasing popular tests for mean abnormal returns in short-horizon event studies. We show that unexplained cross-sectional variation in true abnormal returns plausibly produces nonproportional heteroskedasticity in cross-sectional regressions, biasing coefficient standard errors for both ordinary and weighted least squares. Simulations highlight the resulting biases, the necessity of using tests robust to cross-sectional variation, and the power of robust tests, including regression-based tests for nonzero mean abnormal returns, which may increase power by conditioning on relevant explanatory variables.
The Fourier-Kelvin Stellar Interferometer (FKSI) is a mission concept for a spacecraft-borne imaging and nulling interferometer for the near to mid-infrared spectral region. FKSI is a scientific and technological pathfinder to the Darwin and Terrestrial Planet Finder (TPF) missions and will be a high angular resolution system complementary to the James Webb Space Telescope (JWST). There are four key scientific issues the FKSI mission is designed to address. These are: 1.) characterization of the atmospheres of the known extra-solar giant planets, 2.) assay of the morphology of debris disks to look for resonant structures characteristic of the presence of extrasolar planets, 3.) study of circumstellar material around a variety of stellar types to better understand their evolutionary state, and in the case of young stellar systems, their planet forming potential, and 4.) measurement of detailed structures inside active galactic nuclei. We report results of simulation studies of the imaging capabilities of the FKSI, current progress on our nulling testbed, results from control system and residual jitter analysis, and selection of hollow waveguide fibers for wavefront cleanup.
Diagnosis of herbicide injury can be complex because of the large number and interaction of factors leading to herbicide injury. Computer-based expert systems have great potential to assist users, particularly nonexperts, in accurate diagnosis of herbicide injury. Rule-based and case-based reasoning are the most widely used forms of expert systems, and each system has strengths and limitations. Approaches that integrate rule-based and case-based reasoning may augment the positive aspects of the two reasoning methods and simultaneously minimize their negative aspects. The Herbicide Injury Diagnostic Expert System (HIDES) integrates rule-based and case-based reasoning and uses field-specific information, injury symptoms, herbicide use history, and herbicide information to diagnose crop injury from herbicides. The HIDES program uses a set of rules to identify suspect herbicide(s) that is the candidate for causing the observed injury and possible sources of the suspect herbicide(s). Case-based reasoning is used to propose a probable cause of injury by making an analogy to previously solved cases. A four-step procedure is followed when using HIDES: information collection, suspect herbicide identification, suspect herbicide source determination, injury reason suggestion, and knowledge accumulation.