We use cookies to distinguish you from other users and to provide you with a better experience on our websites. Close this message to accept cookies or find out how to manage your cookie settings.
To save content items to your account,
please confirm that you agree to abide by our usage policies.
If this is the first time you use this feature, you will be asked to authorise Cambridge Core to connect with your account.
Find out more about saving content to .
To save content items to your Kindle, first ensure no-reply@cambridge.org
is added to your Approved Personal Document E-mail List under your Personal Document Settings
on the Manage Your Content and Devices page of your Amazon account. Then enter the ‘name’ part
of your Kindle email address below.
Find out more about saving to your Kindle.
Note you can select to save to either the @free.kindle.com or @kindle.com variations.
‘@free.kindle.com’ emails are free but can only be saved to your device when it is connected to wi-fi.
‘@kindle.com’ emails can be delivered even when you are not connected to wi-fi, but note that service fees apply.
Processing and extracting actionable information, such as fault or anomaly indicators originating from vibration telemetry, is both challenging and critical for an accurate assessment of mechanical system health and subsequent predictive maintenance. In the setting of predictive maintenance for populations of similar assets, the knowledge gained from any single asset should be leveraged to provide improved predictions across the entire population. In this paper, a novel approach to population-level health monitoring is presented adopting a transfer learning approach. The new methodology is applied to monitor multiple rotating plant assets in a power generation scenario. The focus is on the detection of statistical anomalies as a means of identifying deviations from the typical operating regime from a time series of telemetry data. This is a challenging task because the machine is observed under different operating regimes. The proposed methodology can effectively transfer information across different assets, automatically identifying segments with common statistical characteristics and using them to enrich the training of the local supervised learning models. The proposed solution leads to a substantial reduction in mean square error relative to a baseline model.
Young stellar objects (YSOs) are protostars that exhibit bipolar outflows fed by accretion disks. Theories of the transition between disk and outflow often involve a complex magnetic field structure thought to be created by the disk coiling field lines at the jet base; however, due to limited resolution, these theories cannot be confirmed with observation and thus may benefit from laboratory astrophysics studies. We create a dynamically similar laboratory system by driving a $\sim$1 MA current pulse with a 200 ns rise through a $\approx$2 mm-tall Al cylindrical wire array mounted to a three-dimensional (3-D)-printed, stainless steel scaffolding. This system creates a plasma that converges on the centre axis and ejects cm-scale bipolar outflows. Depending on the chosen 3-D-printed load path, the system may be designed to push the ablated plasma flow radially inwards or off-axis to make rotation. In this paper, we present results from the simplest iteration of the load which generates radially converging streams that launch non-rotating jets. The temperature, velocity and density of the radial inflows and axial outflows are characterized using interferometry, gated optical and ultraviolet imaging, and Thomson scattering diagnostics. We show that experimental measurements of the Reynolds number and sonic Mach number in three different stages of the experiment scale favourably to the observed properties of YSO jets with $Re\sim 10^5\unicode{x2013}10^9$ and $M\sim 1\unicode{x2013}10$, while our magnetic Reynolds number of $Re_M\sim 1\unicode{x2013}15$ indicates that the magnetic field diffuses out of our plasma over multiple hydrodynamical time scales. We compare our results with 3-D numerical simulations in the PERSEUS extended magnetohydrodynamics code.
The effects of the evolution of vortices on the aeroacoustics generated by a hovering wing are numerically investigated by using a hybrid method of an immersed boundary–finite difference method for the three-dimensional incompressible flows and a simplified model based on the Ffowcs Williams-Hawkings acoustic analogy. A low-aspect-ratio ($AR=1.5$) rectangular wing at low Reynolds ($Re=1000$) and Mach ($M=0.04$) numbers is investigated. Based on the simplified model, the far-field acoustics is shown to be dominated by the time derivative of the pressure on the wing surface. Results show that vortical structure evolution in the flow fields, which is described by the divergence of the convection term of the incompressible Navier–Stokes equations in a body-fixed reference frame, determines the time derivative of the surface pressure and effectively the far-field acoustics. It dominates over the centrifugal acceleration and Coriolis acceleration terms in determining the time derivative of the surface pressure. The position of the vortex is also found to affect the time derivative of the surface pressure. A scaling analysis reveals that the vortex acoustic source is scaled with the cube of the flapping frequency.
Flow control of a low-aspect-ratio flat-plate heaving wing at an average angle of attack of $10^{\circ }$ by a steady-blowing jet is numerically studied by using a feedback immersed boundary–lattice Boltzmann method. Blowing jets at the leading edge, mid-chord and trailing edge are considered. The wing enjoys the highest lift production with the trailing-edge downstream blowing jet, which improves the average lift by 50.0 % at $Re = 1000$ and 22.9 % at $Re = 5000$ through the enhancement of the tip vortex circulation caused by the increase in the mass flux of the shear layer at the wing tips. This increase in mass flux decreases as $Re$ increases from 1000 to 5000 due to its self-limiting mechanism. A mid-chord vertical blowing jet induces a middle vortex which enhances the lift production but the enhancement is smaller than that of trailing-edge downstream blowing jet. Other jet arrangements do not significantly increase the lift coefficient, but the mid-chord upstream blowing jet experiences a significant reduction in the drag coefficient, leading to an increase of 50.6 % in the average lift-to-drag ratio. The effectiveness of the flow control is not significantly affected by the aspect ratio.
To identify clusters of patients with post-traumatic stress disorder (PTSD) according to symptom profile and to examine the association of the A1 allele of the D2 dopamine receptor (DRD2) gene with these clusters.
Method.
Fifty-seven untreated Caucasian Vietnam veterans with PTSD were administered the General Health Questionnaire-28 (GHQ) and the Mississippi Scale for combat-related PTSD. DRD2 allelic status was determined by PCR.
Results.
Subjects with the DRD2 Al allele compared to those without this allele had significantly higher scores on GHQ 2 (anxiety/insomnia), GHQ 3 (social dysfunction) and GHQ 4 (depression). Cluster analysis of the GHQ data identified two primary groups. A high psychopathology cluster (cluster 3), featured by high co-morbid levels of somatic concerns, anxiety/insomnia, social dysfunction and depression, and a low psychopathology cluster (cluster 1), manifested by the reverse pattern. Scores in each of the four GHQ groups were significantly higher in cluster 3 than cluster 1, as was Mississippi Scale PTSD score. DRD2 A1 allele veterans compared to those without this allele were significantly more likely to be found in the high than the low psychopathology cluster group.
Conclusions.
DRD2 variants are associated with severe co-morbid psychopathology in PTSD subjects.
Indicators are necessary to monitor national progress toward commitments made to the Convention on Biological Diversity (CBD), but countries often struggle to mobilize quantitative indicators for many biodiversity targets. Assessing the extent to which countries are using measurable indicators from global and national sources by surveying 5th National Reports to the CBD, we found that nationally generated indicators were used 11 times more frequently than global indicators and only one-fifth of indicators matched those recommended by the CBD, suggesting that countries and indicator experts should work more closely to agree upon measurable, scalable, fit-for-purpose indicators for the next generation of CBD targets.
An animal egg such as amphibian, mammalian or sea urchin egg receives only a single sperm at fertilisation. After binding of the first sperm, the egg is prevented from allowing the entry of additional sperm. In fact, polyspermy results in aborted development of the zygote. It has been generally accepted that a molecule(s) released from cortical granules participates in the block to polyspermy. As one such molecule, a cortical granule lectin has been isolated from unfertilised Xenopus eggs (Xenopus cortical granule lectin; XCGL). XCGL is released into the perivitelline space after fertilisation, and forms a complex with J1 jelly molecules to form an F layer, resulting in a block to additional sperm penetration.
A lectin molecule has also been purified from the eggs of several species of fish. The fish egg lectin is located in the cortical alveoli and is released from them after fertilisation. However, its biological function is unclear. We isolated cortical alveolar lectin from unfertilised eggs of Chinook salmon through affinity column chromatography (salmon egg lectin; SEL). The lectin activity was estimated by haemagglutination. The activity of the purified SEL was most strongly inhibited by L-rhamnose and D-galactose, but not by EDTA. Further analysis by C4 reverse-phase column chromatography using HPLC revealed that the lectin was composed of three subunit proteins: 24K, 26Ka and 26Kb proteins. In addition, we cloned cDNAs for them by RT-PCR. The deduced amino acid sequence of the 26Ka protein was homologous with that of the 26Kb protein (identity, 96.4%). Identities of the 24K with the 26Ka and the 26Kb proteins were 55.9% and 66.7%, respectively. A database search revealed that a lectin molecule similar to the SEL had been identified in Anthocidaris crassispina egg (sea urchin egg lectin; SUEL). The SUEL is composed of 105 amino acids, and is similar to both amino-terminal and carboxyl-terminal halves of the SELs. Thus, the SEL molecule is composed of two repeats of such SUEL-like domains, suggesting that the SEL gene was produced by gene duplication.
Salt rabbitbrush [Chrysothamnus nauseosus (Pallas) Britt., ssp. consimilis (Greene)] and greasewood [Sarcobatus vermiculatus (Hook.) Torr.] grow slowly in early spring until mid to late May. They then begin a period of rapid growth, at which time susceptibility to foliar herbicides is probably greatest. Greasewood ceases rapid growth in mid June to early July, but salt rabbitbrush continues to grow rapidly until early August. Greasewood that resprouts after herbicide application has a longer rapid-growth period than shrubs in an untreated stand. An average leader length of 4 cm indicates that rapid growth of salt rabbitbrush is underway, and first opening of the flower buds indicates that rapid growth is over. Appearance of greasewood staminate spikes indicates that rapid growth has begun, and the first appearance of dried spikes indicates that growth has ceased. Simultaneous control of these shrubs with a single application of phenoxy herbicides may only be possible during the relatively short period when both are growing rapidly. This period may only occur from late May to mid June in some stands and years, but may occur from mid May to early July in other cases.
The control of greasewood [Sarcobatus vermiculatus (Hook.) Torr.] and salt rabbitbrush [Chrysothamnus nauseosus ssp. consimilis (Greene) Hall and Clem.] was investigated with application of 2,4-D [(2,4-dichlorophenoxy)acetic acid] and a mixture of 2,4-D and picloram (4-amino-3,5,6-trichloropicolinic acid). The herbicides were applied at 2-week intervals from May 1 to August 1. Greasewood had accelerated shoot growth and was most susceptible to application of 2,4-D during June. Accelerated shoot growth and maximum susceptibility to 2,4-D of salt rabbitbrush began in June and extended into July. Mortality of greasewood and salt rabbitbrush from 2,4-D at 2.2 kg/ha applied at optimum dates averaged 72 and 87%, respectively. The picloram/2,4-D mixture was more effective for greasewood control than 2,4-D alone in 1 yr at very early and late application dates on a xeric site and only at the last date of application on a mesic site. Reapplication of 2,4-D at 2.2 and 3.3 kg/ha in June to partially controlled stands gave excellent control of both greasewood and rabbitbrush.
Incremental stages of major evolutionary transitions within a single animal lineage are rarely observed in the fossil record. However, the extraordinarily complete sequence of well preserved material spanning the 27-Myr existence of the marine squamate subfamily Mosasaurinae provides a unique exception. By comparison with extant and extinct analogs, the tail morphology of four mosasaurine genera is examined, revealing a pattern of evolution that begins with the generalized varanoid anatomy and culminates in a high-aspect-ratio fin, similar to that of sharks. However, unlike the epicercal caudal fluke of selachians in which the tail bends dorsocaudally, derived mosasaurs develop a hypocercal tail with a ventrocaudal bend. Progressive caudal regionalization, reduced intervertebral mobility, increased tail depth due to a marked downturn of the posterior caudal segment, and the development of finlike paired appendages reveal a pattern of adaptation toward an optimized marine existence. This change in morphology reflects a transition from anguilliform or sub-carangiform locomotion to carangiform locomotion, and indicates a progressive shift from nearshore dwellers to pelagic cruisers—a change in foraging habitat independently corroborated by paleobiogeographic, stable isotope, osteohistological, and paleopathological data. Evolutionary patterns similar to those observed in mosasaurine mosasaurs are seen in other secondarily aquatically adapted amniotes, notably metriorhynchid crocodyliforms, cetaceans, and ichthyosaurs, and may be explained by developmental modularity governing the observed phenotypic expression.
The imputed pig death loss contained in the reported monthly U.S. Department of Agriculture (USDA) pig crop data over the December 1995-June 2006 period ranged from —4.93% to 12.75%. Clearly, there are substantial measurement errors in the USDA monthly pig crop data. In this paper, we present alternative monthly U.S. pig crop data using the biological production process, which is compatible with prior knowledge of the U.S. hog industry. Alternative pig crop data are applied to a slaughter hog model and tested comparatively to USDA pig crop. Test results reject the validity of USDA pig crop data in favor of the alternative data.
A case study is presented of a 13-year-old adolescent male with a long history of anxious symptoms related to school attendance. At the time of referral to the school refusal clinic, the adolescent had significant difficulty attending school, having attended for only 1 day in the past 3 weeks. A cognitive-behavioural treatment program was conducted over 3 weeks, consisting of seven sessions with the adolescent, seven sessions with his parents, and consultation to school personnel. Treatment focused on the implementation of behaviour management techniques by caregivers as well as teaching anxiety management skills to the adolescent. Positive treatment outcomes included the adolescent's return to full-time attendance at school as well as a decrease in emotional distress. The implications of treatment are discussed in relation to the simultaneous application of behaviour management and anxiety management strategies in the treatment of school refusal.
Traditionally, mental health professionals and school authorities have found school refusal to be a perplexing and challenging problem. Relevant to an understanding of school refusal, we initially review some important developmental-normative considerations. The clinical features, epidemiology, and etiology of school refusal are also briefly discussed. We then describe a number of behavioural strategies that have been used in the management of school refusal. Finally, we review the research support for the efficacy and acceptability of behavioural strategies in the treatment of school refusal.
Following Bandura's theory, a Self-efficacy Questionnaire for School Situations (SEQ-SS) was developed to assess the cognitions of school refusers. The instrument contains twelve school-related situations which are rated by children according to their belief about their ability to cope with each situation. Factor analysis yielded two reliable factors labelled Academic/Social Stress and Separation/Discipline Stress. Psychometric evaluation also revealed good internal consistency and test-retest reliability. Total self-efficacy scores for 135 school refusers ranged from very low to very high. Self-efficacy was highest with regard to doing school work and lowest with regard to answering peers' questions about absences. The clinical utility of the SEQ-SS is discussed, with implications for the selection of cognitive and behavioural treatment procedures. The application of the instrument in future research is also considered.
This article describes a cognitive-behavioural intervention implemented over 10 sessions with an adolescent girl experiencing school refusal and depression. Treatment focused on the learning of various coping skills to deal with stressful situations at home and school. Following a decision to change schools, a rapid school return was employed. A multimethod, multisource evaluation was used at pretreatment, posttreatment, and follow-up assessments. The data indicated positive treatment outcomes: the adolescent returned to full-time attendance at school and exhibited decreased levels of emotional distress. The treatment gains were maintained at a 3-month follow-up.
This article describes the application of cognitive behavioural therapy to three sexually abused young people. We emphasise developmental influences and the nuances of the therapeutic approach. An exposure-based treatment approach was used with the youths. A multimodal assessment evaluation was conducted at pretreatment and posttreatment, and at a 3-month follow-up. Results on outcome measures indicated a positive therapeutic effect for the youths.
Research on star clusters and associations includes the observation and theory of stellar groupings as they form and evolve, cluster disruption, stellar interactions inside clusters, and star formation in dense environments. In what follows, we list past, present and future meetings (http://www2.cadc-ccda.hia-iha.nrc-cnrc.gc.ca/meetings/), publications statistics and important surveys, reviews, and databases about clusters.