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We describe an ultra-wide-bandwidth, low-frequency receiver recently installed on the Parkes radio telescope. The receiver system provides continuous frequency coverage from 704 to 4032 MHz. For much of the band (
), the system temperature is approximately 22 K and the receiver system remains in a linear regime even in the presence of strong mobile phone transmissions. We discuss the scientific and technical aspects of the new receiver, including its astronomical objectives, as well as the feed, receiver, digitiser, and signal processor design. We describe the pipeline routines that form the archive-ready data products and how those data files can be accessed from the archives. The system performance is quantified, including the system noise and linearity, beam shape, antenna efficiency, polarisation calibration, and timing stability.
Electrochemical capacitors featuring a modified acetonitrile (AN) electrolyte and a binder-free, activated carbon fabric electrode material were assembled and tested at <−40 °C. The melting point of the electrolyte was depressed relative to the standard pure AN solvent through the use of a methyl formate cosolvent, to enable operation at temperatures lower than the rated limit of typical commercial cells (−40 °C). Based on earlier electrolyte formulation studies, a 1:1 ratio of methyl formate to AN (by volume) was selected, to maximize freezing point depression while maintaining a sufficient salt solubility. The salt spiro-(1,1′)-bipyrrolidinium tetrafluoroborate was used, based on its improved conductivity at low temperatures, relative to linear alkyl ammonium salts. The carbon fabric electrode supported a relatively high rate capability at temperatures as low as −65 °C with a modest increase in cell resistance at this reduced temperature. The capacitance was only weakly dependent on temperature, with a specific capacitance of ∼110 F/g.
Treatment-resistant schizophrenia, affecting approximately 20–30% of patients with schizophrenia, has a high burden both for patients and healthcare services. There is a need to identify treatment resistance earlier in the course of the illness, in order that effective treatment, such as clozapine, can be offered promptly. We conducted a systemic literature review of prospective longitudinal studies with the aim of identifying predictors of treatment-resistant schizophrenia from the first episode. From the 545 results screened, we identified 12 published studies where data at the first episode was used to predict treatment resistance. Younger age of onset was the most consistent predictor of treatment resistance. We discuss the gaps in the literature and how future prediction models can identify predictors of treatment response more robustly.
Objectives: We sought to clarify the nature of self-reported cognitive function among healthy older adults by considering the short-term, within-person association (coupling) of subjective cognitive function with objective cognitive performance. We expected this within-person coupling to differ between persons as a function of self-perceived global cognitive decline and depression, anxiety, or neuroticism. Methods: This was an intensive measurement (short-term longitudinal) study of 29 older adult volunteers between the ages of 65 and 80 years without an existing diagnosis of dementia or mild cognitive impairment. Baseline assessment included neuropsychological testing and self-reported depression, anxiety, and neuroticism, as well as self- and informant-reported cognitive decline (relative to 10 years previously). Intensive within-person measurement occasions included subjective ratings of cognitive function paired with performance on a computerized working memory (n-back) task; each participant attended four or five assessments separated by intervals of at least one day. Statistical analysis was comprised of multilevel linear regression. Results: Comparison of models suggested that both neuroticism and self-rated cognitive decline explained unique variance in the within-person, across-occasion coupling of subjective cognitive function with objective working memory performance. Conclusions: Self-ratings of cognition may accurately reflect day-to-day variations in objective cognitive performance among older adults, especially for individuals lower in neuroticism and higher in self-reported cognitive decline. Clinicians should consider these individual differences when determining the validity of complaints about perceived cognitive declines in the context of otherwise healthy aging. (JINS, 2018, 24, 57–66)
Gaia will see little of the Galactic mid-plane and nuclear bulge due to high extinction at optical wavelengths. To study the structure and kinematics of the inner Galaxy we must look to longer wavelengths. The Vista Variables in the Via Lactea (VVV, Minniti et al. 2010) survey currently provides just over 4 years of observations covering approximately 560 square degrees of the Galactic bulge and plane. Typically each source is observed 50–150 times in the Ks band over this period. Using these data we provide relative proper motions for approximately 200 million unique sources down to Ks∼16 with uncertainties approaching 1 mas yr−1. In addition, we fit a solution of the parallactic motion of all sources with significant proper motion and discover a number of new nearby brown dwarfs. These results will allow us to identify faint common proper motion companions to stars with Gaia parallaxes, increasing the number of brown dwarf benchmark objects. Our absolute astrometric calibration precision is currently ∼ 2 mas yr−1, based on PPMXL. The Gaia absolute astrometric reference grid will allow us to precisely anchor our results and measure the streaming motions of stars in the bulge. Finally, we anticipate that the catalogue could provide kinematic distances to the numerous optically invisible high amplitude variable stars that VVV is discovering.
In the UK, most intermediate level radioactive waste is packaged in stainless steel containers. It is important that containers should maintain their integrity for extended periods of storage prior to final disposal. A prototype 4 metre box fabricated from 304S11 stainless steel was monitored at an inland rural building for over twelve years to gain experience in monitoring environmental conditions and corrosion during storage. A wide range of different types of aerosol particles were observed on the surfaces and in the air. They contained corrosive ions such as chloride, as well as other anions such as sulfate and nitrate. The chloride deposition rate was between 0.1 and 4 μg cm−2 yr−1 depending on the orientation and location of the surface, with a chloride/sulfate ratio ranging from ∼0.3–2. The temperature and relative humidity typically ranged from 0–30°C and 40–90%, respectively. The greatest degree of corrosion developed on the base of the box, which had elevated chloride concentrations (10–140 μg cm−2). However, there was little evidence of corrosion propagation on the surface of the box and no evidence of stress corrosion cracking. The average pit propagation rates on a 316L coupon mounted next to the 4 m box were <1 μm yr−1.
Intermediate-level radioactive waste is normally encapsulated in cementitious grout. However, for some wastes, grout may not be suitable and polymeric encapsulants are being considered as an alternative. One concern with such encapsulants is their long-term chemical stability and the possibility that release of aggressive degradation products could cause corrosion.
This paper evaluates the potential for three polymeric encapsulants: two epoxy resins (the APS polymer system, (APS) and Alchemix 4760 (ALC)) and a vinyl-ester styrene (VES); to cause internal corrosion of stainless steel waste containers. The corrosion behaviour of stainless steel 316L in contact with each encapsulant was studied in saturated Ca(OH)2 solutions and deionized (DI) water, at 80°C, under non-irradiated and γ-irradiated conditions.
In aerated, alkaline conditions, 316L was resistant to corrosion in all the conditions tested. However, in DI water, the pH fell to values as low as three due to release of acidic species from the polymers. The two epoxy materials (particularly APS) also released significant levels of chloride; VES did not. Chloride release appeared to be increased by γ-irradiation. As a result of the low pH chloride-containing environment created by the APS encapsulant, 316L experienced localized corrosion, whereas coupons in Alchemix 4760 and VES did not. Weight loss measurements correlated with visual observations. γ-irradiation appeared to increase the degree of corrosion.
Most of the discovered exoplanets are close to our sun. Usually their host star is with large proper motions, which is an important parameter for exoplanet searching. The first version of absolute proper motions catalog achieved based on Digitized Sky Survey Schmidt plate where outside the galactic plane |b|≥27° is presented, resulting in a zero point error less than ± 0.3 mas/yr, and the overall accuracy better than ± 4.5 mas/yr for objects brighter than RF=18.5, and ranging from 4.5 to 9.0 mas/yr for objects with magnitude 18.5<RF<20.5. The systematic errors of absolute proper motions related to the position, magnitude and color are practically all removed. The sky cover of this catalog is 22,525 degree2, the mean density is 6444 objects/degree2 and the magnitude limit is around RF=20.5.
Fire is often used in northern grasslands to control invasive grass species but has unknown effects on Tamarix spp., more recent invaders. Temperature (using an oven as a fire surrogate) and duration combinations that would be most lethal to Tamarix seeds and seedlings were determined. Tamarix seeds were sown in soil-lined dishes, water added to saturation, and seedlings grown for 1 to 5 d. Seeds were also placed in water-saturated or dry soil just before temperature exposure (79 to 204 C [175 to 400 F]) by duration (1 to 5 min) treatments. After treatment, soil water loss was measured by weight difference, and surviving seedlings were counted for 6 d. Tamarix seedling establishment and survival decreased with increasing temperature and duration. The 5-d-old seedlings were the most affected. No 5-d-old seedlings survived 1- and 2-min exposures to 204 C, whereas 1-d-old seedlings had greater than 25% survival. If soils were saturated, two to four times more seedlings established following seed exposure to 177 and 204 C. Longer durations at lower temperatures were required to reduce Tamarix survival. Increasing duration from 2 to 5 min at 121 C decreased 5-d-old seedling survival from more than 80% to less than 10% and eliminated those seedlings at 149 C. Five minutes at 149 C decreased dry-soil seed viability to about 15%, whereas germination on saturated soils remained high (∼75%). No seeds survived the exposure to 177 and 204 C. Soil moisture loss values associated with 90% mortality of 5- and 1-d-old seedlings were 1.7 and 2.2%, respectively. On saturated soils, 90% of seeds died with 2.5% water loss. Under suitable conditions, fire can decrease Tamarix seedling survival. Fire may be useful for controlling Tamarix seedlings in northern grasslands and should be considered for management of new invasions.
Controlled burns and grazing are being tested to manage invasive grasses in the Prairie Pothole region of the Northern Great Plains. These practices, however, may inadvertently promote saltcedar infestations from seed by opening the vegetative canopy. Saltcedar seedling establishment was investigated in greenhouse experiments using intact soil cores from one summit and three footslope sites in eastern South Dakota. Establishment tests were conducted in soil cores collected from treatment and control plots immediately after spring fire treatment (postburn) and in cores that contained peak cool- or peak warm-season vegetation, with or without clipping (simulated grazing treatment), to simulate vegetation conditions typical of saltcedar seed-shed in northern regions. Cores were seeded with 100 saltcedar seeds and subirrigated to maintain high soil water conditions, characteristic of the environment near potholes during late spring/early summer. Seedlings were counted during the first 3 wk to estimate establishment and the height of five seedlings core−1 were measured weekly to estimate growth rates. Opening the canopy with fire or clipping increased saltcedar establishment. Cores taken immediately after fire treatment had two times more seedlings establish (38% vs. 19%) and greater average seedling growth rate (1.5 mm d−1 vs. 0.9 mm d−1) when compared with no-fire controls. Fire after seeding reduced seedling establishment to 5%, but did not affect growth rate. Saltcedar establishment in peak cool-season vegetation cores was 6% regardless of earlier fire treatment, whereas in peak warm-season vegetation, establishment ranged from 8% (no spring fire) to 17% (spring fire). If soils remain wet, invasion risk following spring fire may be greatest when warm-season grasses are flowering because this time coincides with northern saltcedar seed production. Areas adjacent to viable saltcedar seed sources should be managed to maximize canopy cover when seeds are released to limit further establishment. Fire after saltcedar seed deposition may control propagules and young seedlings.
Botulism in UK cattle has been confirmed by demonstrating type C botulinum toxin in sera from affected animals. Evidence is presented indicating the source of intoxication to be poultry carcasses containing type C Clostridium botulinum and its toxin. The organism was also found in poultry litter and in alimentary tract samples from slaughtered animals. The implications of these findings are discussed.
The serotype distribution of 874 strains of Streptococcus pneumoniae was determined in relation to patients' age and to frequency of isolation from systemic disease. Types 14 and 18, in pre-school children, and types 1, 4, 7, 8 and 12 in patients over 5 years of age were significantly associated with systemic disease whereas type 23 in pre-school children, and type 6 in older patients was associated with upper respiratory tract carriage. No significant difference was found in the incidence of other types in systemic disease compared to upper respiratory tract carriage.
Fifteen diagnostic pneumococcal antisera (to types 1, 3, 4, 6, 7, 8, 9, 11, 12, 14, 17, 18, 19, 22 and 23) sufficed for typing 87% of strains.
Neuropsychologists routinely rely on response validity measures to evaluate the authenticity of test performances. However, the relationship between cognitive and psychological response validity measures is not clearly understood. It remains to be seen whether psychological test results can predict the outcome of response validity testing in clinical and civil forensic samples. The present analysis applied a unique statistical approach, classification tree methodology (Optimal Data Analysis: ODA), in a sample of 307 individuals who had completed the MMPI-2 and a variety of cognitive effort measures. One hundred ninety-eight participants were evaluated in a secondary gain context, and 109 had no identifiable secondary gain. Through recurrent dichotomous discriminations, ODA provided optimized linear decision trees to classify either sufficient effort (SE) or insufficient effort (IE) according to various MMPI-2 scale cutoffs. After “pruning” of an initial, complex classification tree, the Response Bias Scale (RBS) took precedence in classifying cognitive effort. After removing RBS from the model, Hy took precedence in classifying IE. The present findings provide MMPI-2 scores that may be associated with SE and IE among civil litigants and claimants, in addition to illustrating the complexity with which MMPI-2 scores and effort test results are associated in the litigation context. (JINS, 2008, 14, 842–852.)
We present the longest-duration directly dated terrestrial palaeoclimate record from the western Mediterranean region: a flowstone speleothem from Gitana Cave, southeast Spain. The main phase of growth was 274 to 58 ka, dated by multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) U-series methods. Effective precipitation, which we consider primarily responsible for flowstone calcite δ13C variations, measured at 300 μm resolution, was higher during interglacials associated with marine oxygen isotope stages (MIS) 7 and 5, and lower during glacial MIS 6. There is a close correspondence between speleothem δ13C and sea surface temperature (SST) estimates from adjacent Atlantic Ocean cores during MIS 6, which implies that oceanic conditions are critical in controlling the western Mediterranean terrestrial moisture balance during glacial periods. Other features of our record, such as the sequence of termination II warming/moistening between approximately 133 and 127 ka, including a "pause" around 130–128 ka, and the lagged termination of MIS 5 warm intervals (5e, 5c and 5a) are similar to other terrestrial records within the Mediterranean basin, indicating climate synchroneity along the northern Mediterranean coast. The Gitana cave region also may have been a refugium for temperate species during short-lived cold/arid periods during MIS 5.
Exercise-induced pulmonary haemorrhage (EIPH) is a major health concern in performance horses, but the presence and severity of this condition in racing greyhounds has received little attention. While equids and greyhounds share many physiological attributes, there are important structural and functional differences that may help protect greyhounds from EIPH. We tested the hypothesis that greyhounds performing a simulated 503 m race would experience EIPH and that the time course of recovery would be similar to the horse, even though the severity or relative extent as indexed by the concentration of red blood cells [RBCs] in bronchoalveolar lavage (BAL) fluid would be lower in comparison with that demonstrated previously in horses. Greyhound dogs (n = 6) raced on two occasions (separated by 7 weeks) and BAL was performed 1 week before, 2 h after and each week for 4 weeks following each race to examine the [RBC], concentration of white blood cells [WBCs], WBC differentials and haemosiderophages in the lungs. Racing increased 10 min post-exercise venous blood [lactate] to 18.6 ± 0.4 mmol l− 1. No epistaxis or pink froth was observed at the nose or mouth of any of the dogs. The [RBC] in the BAL fluid was increased significantly 2 h post-race (baseline = 109.6 ± 11.7 × 103; post-race = 292.3 ± 69.9 × 103 RBC ml− 1 BAL fluid, P < 0.05) and returned to baseline 1 week post-race (149.2 ± 46.2 × 103 RBC ml− 1 BAL fluid, P>0.05 versus baseline). The number of haemosiderophages was not different for any of the measurement periods. The [WBC] in the BAL fluid decreased from baseline and race values at 2, 3 and 4 weeks post-exercise (all P < 0.05). Alveolar neutrophil concentrations were also decreased from baseline and immediate post-race values for 4 weeks post-race. The increased [RBC] in the BAL fluid post-exercise is consistent with the presence of EIPH in these greyhounds. However, the relative extent of EIPH in greyhounds (as indexed by [RBC] in the BAL fluid), as compared with that in the horse, was mild, and the lack of elevation of WBC suggests that, unlike their equine counterparts, inflammatory airway disease was absent.
The electrochemical cycling performance of high purity single wall carbon nanotube (SWCNT) paper electrodes has been measured for a series of electrolyte solvent compositions. The effects of varying the galvanostatic charge rate and cycling temperature on lithium ion capacity have been evaluated between 25-100 °C. The measured reversible lithium ion capacities for SWCNT anodes range from 600-1000 mAh/g for a 1M LiPF6 electrolyte, depending on solvent composition and cycling temperature. The solid-electrolyte-interface (SEI) formation and first cycle charge loss are also shown to vary dramatically with carbonate solvent selection and illustrate the importance of solvent alkyl chain length and polarity on SWCNT capacity. SWCNT anodes have also been incorporated into full battery designs using LiCoO2 cathode composites. An electrochemical pre-lithiation sequence, prior to battery assembly, has been developed to mitigate the first cycle charge loss of SWCNT anodes. The pre-lithiated SWCNT anodes show reversible cycling at varying charge rates and depths of discharge with the cathode system. The summary of data shows that the structural integrity of individual SWCNTs is preserved after cycling, and that free-standing SWCNT paper electrodes represent an attractive material for lithium ion batteries.