10-min Sample Research Articles

Wind Turbine Blade Damage Evaluation under Multiple Operating Conditions and Based on 10-Min SCADA Data

The present paper aims to enable the assessment of the fatigue damage of wind turbine blades over a long duration (e.g., several months/years) in conjunction with different operating regimes and based on two information sources: the 10-min SCADA data and an interpolation using response surfaces identified using the FAST aeroelastic numerical tool. To assess blade damage, prior studies highlighted the need for a high-frequency (>1 Hz) sampling rate. Because of data availability and computation resource limitations, such methods limit the duration of the analysis period, making the direct use of such an approach based on a 1 Hz wind speed signal in current wind farms impractical. The present work investigates the possibility of overcoming these issues by estimating the equivalent damage using a 1 Hz wind speed for each 10-min sample stored in the SCADA data. In the literature, the influence of operating regimes is not considered in fatigue damage estimation, and for the first time, the present project takes a pioneering approach by considering these operating regimes.

Toward Standardized Aerovirology: A Critical Review of Existing Results and Methodologies.

Understanding the airborne survival of viruses is important for public health and epidemiological modeling and potentially to develop mitigation strategies to minimize the transmission of airborne pathogens. Laboratory experiments typically involve investigating the effects of environmental parameters on the viability or infectivity of a target airborne virus. However, conflicting results among studies are common. Herein, the results of 34 aerovirology studies were compared to identify links between environmental and compositional effects on the viability of airborne viruses. While the specific experimental apparatus was not a factor in variability between reported results, it was determined that the experimental procedure was a major factor that contributed to discrepancies in results. The most significant contributor to variability between studies was poorly defined initial viable virus concentration in the aerosol phase, causing many studies to not measure the rapid inactivation, which occurs quickly after particle generation, leading to conflicting results. Consistently, studies that measured their reference airborne viability minutes after aerosolization reported higher viability at subsequent times, which indicates that there is an initial loss of viability which is not captured in these studies. The composition of the particles which carry the viruses was also found to be important in the viability of airborne viruses; however, the mechanisms for this effect are unknown. Temperature was found to be important for aerosol-phase viability, but there is a lack of experiments that directly compare the effects of temperature in the aerosol phase and the bulk phase. There is a need for repeated measurements between different research groups under identical conditions both to assess the degree of variability between studies and also to attempt to better understand already published data. Lack of experimental standardization has hindered the ability to quantify the differences between studies, for which we provide recommendations for future studies. These recommendations are as follows: measuring the reference airborne viability using the "direct method"; use equipment which maximizes time resolution; quantify all losses appropriately; perform, at least, a 5- and 10-min sample, if possible; report clearly the composition of the virus suspension; measure the composition of the gas throughout the experiment. Implementing these recommendations will address the most significant oversights in the existing literature and produce data which can more easily be quantitatively compared.

Behavior and welfare impacts of water provision via misting in commercial Pekin ducks.

Ducks will access water to maintain feather condition and exhibit natural water-related behaviors such as wet preening. Providing water to ducks commercially is challenging as it may reduce litter and air quality leading to higher duck mortality or illness. This research aimed to measure the behavioral and welfare impacts of water provision via a misting system for commercial Pekin grower ducks in Victoria, Australia. Seven grower flocks were observed (four misted and three nonmisted in open-sided sheds) during May and November 2021. From 26 until 33 d of age, treatment ducks were provided 1 h of misting with shed curtains closed in both treatment and control sheds. At the start and end of the misting application period, external health and welfare measures were taken directly on the ducks via transect walks throughout each shed and catch-and-inspect observations on a sample of 150 ducks from each shed. Video recordings were also made of the misted and nonmisted ducks for 3 h representing time periods prior to, during, and after the 1-h misting across all sheds for all 8 d of the treatment period. Observations were made of all behavior that ducks exhibited at 10-min scan sample intervals across four cameras per shed, totaling 4,198 scans across the seven sheds. General linear mixed models showed the misting application predominantly had impacts on the patterns of behavioral change across the treatment time periods between the misted and nonmisted ducks rather than increasing or decreasing the overall expression of specific behaviors (interaction terms all P ≤ 0.003). The misted ducks increased drinking, tail wagging, and walking, and reduced preening, rooting litter, sitting, and stretching during misting relative to what they showed prior. The nonmisted ducks showed less sitting and more panting during misting relative to prior. Pearson's Chi-square tests showed some differences between the treatment groups in feather cleanliness on the back and wings (both P < 0.0001), likely resulting from pre-existing differences between sheds in blood from pin feathers. Most welfare indicators showed no positive or negative effect of the misting treatment. These results indicate overhead misting does affect duck behavior to some degree without compromising their welfare, but further research with larger water droplet sizes resulting in greater accumulation of surface water or extended durations of misting may lead to greater effects.

A semi-automated device rapidly determine circulating blood volume in healthy males and carbon monoxide uptake kinetics of arterial and venous blood.

We examined whether a semi-automated carbon monoxide (CO) rebreathing method accurately detect changes in blood volume (BV) and total hemoglobin mass (tHb). Furthermore, we investigated whether a supine position with legs raised reduced systemic CO dilution time, potentially allowing a shorter rebreathing period. Nineteen young healthy males participated. BV and tHb was quantified by a 10-min CO-rebreathing period in a supine position with legs raised before and immediately after a 900ml phlebotomy and before and after a 900ml autologous blood reinfusion on the same day in 16 subjects. During the first CO-rebreathing, arterial and venous blood samples were drawn every 2 min during the procedure to determine systemic CO equilibrium in all subjects. Phlebotomy decreased (P < 0.001) tHb and BV by 166 ± 24g and 931 ± 247ml, respectively, while reinfusion increased (P < 0.001) tHb and BV by 143 ± 21g and 862 ± 250ml compared to before reinfusion. After reinfusion BV did not differ from baseline levels while tHb was decreased (P < 0.001) by 36 ± 21g. Complete CO mixing was achieved within 6 min in venous and arterial blood, respectively, when compared to the 10-min sample. On an individual level, the relative accuracy after donation for tHb and BV was 102-169% and 55-165%, respectively. The applied CO-rebreathing procedure precisely detect acute BV changes with a clinically insignificant margin of error. The 10-min CO-procedure may be reduced to 6min with no clinical effects on BV and tHb calculation.Notwithstanding, individual differences may be of concern and should be investigated further.

Impact of Breathing Pattern and Nebulization on Expelled Viral Content During Mechanical Ventilation Using an Ex Vivo Porcine Lung System.

Little is known about the fate of expelled viral particulates during the aerosolization of inhaled medications during mechanical ventilation. We hypothesized that breathing patterns that generate a greater degree of shear stress and turbulent air flow will produce a greater concentration of exhaled viral RNA with the presence of a nebulizer during mechanical ventilation. Eight ex vivo pig lungs were utilized as the physiological model. Each lung was dedicated to a specific breathing pattern that consisted of tidal breathing, respiratory distress, cough, and sneeze. Breath simulations were carried out through a commercial mechanical ventilator. Ninety mL of a bacteriophage stock at a concentration of 108 PFU/mL were introduced into the lungs during a 10-min sample collection session. The number of viral particles collected in exhalate was measured using quantitative polymerase chain reaction. The impact of breathing pattern on measured viruses was analyzed through two-way analysis of variance. The interaction effect between nebulization and breath pattern on exhaled viral quantity was not statistically significant P = .80, partial η2 = 0.167. The analysis of the main effects indicated that the effects of the breathing pattern and nebulization phase were not statistically significant P = .26, partial η2 = 0.519; P = .98, partial η2 = 0, respectively. There were no statistically significant differences among the breathing patterns related to measurable viral RNA. Coughing produced the most measurable increase in measured viral quantity during the nebulization phase and non-nebulization phase with a mean exhaled viral quantity (3.5 × 105 ng/μL [95% CI 1.6 × 105-5.5 × 105] and 2.7 × 105 ng/μL [95% CI 7.1 × 103-5.5 × 105], respectively). Tidal breathing with the presence of a nebulizer and respiratory distress without a nebulizer produced the lowest measured viral quantities (M = 1.1 × 105 ng/μL [95% CI -1.7 × 105 to 3.9 × 105]; M = 1.2 × 105 ng/μL [95% CI -1.6 × 105 to 4.0 × 105]). In this ex vivo porcine model, the introduction of a nebulizer did not increase the mean viral RNA captured throughout all of the breathing patterns.

The Reliability of Short Conversational Language Sample Measures in Children With and Without Developmental Language Disorder.

Language sample analysis (LSA) represents an ecologically valid method for diagnosing, identifying goals, and measuring progress in children with developmental language disorder (DLD). LSA is, however, time consuming. The purpose of this study was to determine the length of sample needed to obtain reliable LSA measures for children in kindergarten and first grade with typical language (TL) and DLD using automated analyses from the Systematic Analysis of Language Transcripts software. Play-based conversational language samples collected on kindergarten to first-grade children with TL (n = 21) and DLD (n = 21) from a community-based sample were analyzed. Eight LSA measures were calculated from 1-, 3-, 5-, 7-, and 10-min sample cuts and compared to 20-min samples for reliability. Reliability estimates were similar for the TL and DLD groups except for errors and omissions, which showed overall higher levels of reliability in the DLD group and reached acceptable levels at 3 min. Percent grammatical utterances were reliable at 7 min in the DLD group and not reliable in shorter samples in the TL group. The subordination index was reliable at 10 min for both groups. Number of different words reached acceptable reliability at the 3-min length for the DLD group and at the 10-min length for the TL group. Utterances and words per minute were reliable at 3 min and mean length of utterance at 7 min in both groups. Speech-language pathologists can obtain reliable LSA measures from shorter, 7-min conversational language samples from kindergarten to first-grade children with DLD. Shorter language samples may encourage increased use of LSA. https://doi.org/10.23641/asha.19529287.

Technical note: Personalized treatment gating thresholds in frameless stereotactic radiosurgery using predictions of dosimetric fidelity and treatment interruption.

Gamma Knife Icon (GKI) enables a user-defined gating threshold for intrafraction motion during stereotactic radiosurgery (SRS). An optimal threshold would ensure dosimetric fidelity of the planned distribution and minimize treatment time extension by gating. A prediction of motion characteristics for a patient based on a retrospective database of motion traces could be beneficial to evaluating the choice of gating threshold. A short acquisition of motion may help to define a personalized threshold that balances dosimetric accuracy and treatment length. This study aims to evaluate the performance of a prediction of motion and the resultant dosimetric consequences for a range of motion gating thresholds. A database of 2552 motion traces (776 patients) was analyzed using previously published methods to characterize patient intrafraction motion on the GKI. For a selection of six fractionated SRS patient cases (two patients with single brain metastasis, four vestibular schwannomas), a 10-min sample of motion was used to classify motion and identify traces in the database with similar metrics. The similar motion traces were used to perform a predictive reconstruction of the selected patient's delivered dose for a range of motion thresholds. The remaining fractions were reconstructed and compared to that predicted. From the six cases, 26 fractions were used to predict the number of interruptions (n=26), change in target coverage (n=26), and change in brainstem maximum dose (vestibular cases only, n=20). The difference between mean predicted and reconstructed values was compared for accuracy. The difference between mean prediction and reconstructed values was 0.32 ± 0.38% in target coverage, 2.36 ± 5.06 interruptions, and 0.15 ± 0.24Gy for the brainstem maximum dose. Sixty-seven of the 72 predictions (26 coverage, 26 interruptions, and 20 brainstem maximum dose) were within one standard deviation of the predicted mean. Large databases of motion traces were used to characterize patient performance and predict motion performance. Dosimetric deterioration due to motion and extension of treatment duration can be predicted in some cases using only a short acquisition of motion and the treatment plan. This reconstruction may provide benefit in generating a patient-specific motion threshold.

Applying Generalizability Theory to Optimize Analysis of Spontaneous Teacher Talk in Elementary Classrooms.

Purpose Although sampling teachers' child-directed speech in school settings is needed to understand the influence of linguistic input on child outcomes, empirical guidance for measurement procedures needed to obtain representative samples is lacking. To optimize resources needed to transcribe, code, and analyze classroom samples, this exploratory study assessed the minimum number and duration of samples needed for a reliable analysis of conventional and researcher-developed measures of teacher talk in elementary classrooms. Method This study applied fully crossed, Person (teacher) × Session (samples obtained on 3 separate occasions) generalizability studies to analyze an extant data set of three 10-min language samples provided by 28 general and special education teachers recorded during large-group instruction across the school year. Subsequently, a series of decision studies estimated of the number and duration of sessions needed to obtain the criterion g coefficient (g > .70). Results The most stable variables were total number of words and mazes, requiring only a single 10-min sample, two 6-min samples, or three 3-min samples to reach criterion. No measured variables related to content or complexity were adequately stable regardless of number and duration of samples. Conclusions Generalizability studies confirmed that a large proportion of variance was attributable to individuals rather than the sampling occasion when analyzing the amount and fluency of spontaneous teacher talk. In general, conventionally reported outcomes were more stable than researcher-developed codes, which suggests some categories of teacher talk are more context dependent than others and thus require more intensive data collection to measure reliably.

Sex, diurnal variation and retention interval differently affect performance of marmoset monkeys in a recognition memory task for object location

In the spontaneous object-location (SOL) task, the ability to recognize where stimuli were located in a past encounter is assessed. Even if widely used in rodents, several aspects can affect task performance. It is thus important to assess potentially intervening variables in the new monkey SOL task. Here we assessed whether sex (male vs. females), circadian time (morning vs. afternoon) and retention interval (24 vs. 48 h) affect the performance of adult marmosets in this task. Two identical stimuli were initially explored on a 10-min sample trial. Thereafter, preferential exploration of the displaced vs. the stationary object was analyzed on a 10-min test trial. Both sexes similarly explored the displaced object quicker and longer than the stationary item after a 24 h inter-trial interval. This response pattern was also seen when males were similarly assessed in the morning or afternoon. However, males tested after 48 h explored both objects equally and after a similar latency, yet spent more time where the displaced item had been previously located. Task performance was not related to object exploration during encoding and general activity remained constant. Therefore, sex and diurnal variation in circadian time had no effect on this version of the task, whereas place memory naturally decayed after 24 h. Our results underscore the importance of alternative task parameters to evaluate memory decay. Given the widespread use of spontaneous recognition tasks, a more ecologically-inclined task in monkeys will help translate animal data to clinical research.

Differential modulatory effects of cocaine on marmoset monkey recognition memory.

Acute and repeated exposure to cocaine alters the cognitive performance of humans and animals. How each administration schedule affects the same memory task has yet to be properly established in nonhuman primates. Therefore, we assessed the performance of marmoset monkeys in a spontaneous object-location (SOL) recognition memory task after acute and repeated exposure to cocaine (COC; 5mg/kg, ip). Two identical neutral stimuli were explored on the 10-min sample trial, after which preferential exploration of the displaced vs the stationary object was analyzed on the 10-min test trial. For the acute treatment, cocaine was given immediately after the sample presentation, and spatial recognition was then tested after a 24-h interval. For the repeated exposure schedule, daily cocaine injections were given on 7 consecutive days. After a 7-day drug-free period, the SOL task was carried out with a 10-min intertrial interval. When given acutely postsample, COC improved the marmosets' recognition memory, whereas it had a detrimental effect after the repeated exposure. Thus, depending on the administration schedule, COC exerted opposing effects on the marmosets' ability to recognize spatial changes. This agrees with recent studies in rodents and the recognition impairment seen in human addicts. Further studies related to the effects of cocaine's acute×prior drug history on the same cognitive domain are warranted.

Concurrent validity and classification accuracy of curriculum-based measurement for written expression.

The study presents a critical analysis of written expression curriculum-based measurement (WE-CBM) metrics derived from 3- and 10-min test lengths. Criterion validity and classification accuracy were examined for Total Words Written (TWW), Correct Writing Sequences (CWS), Percent Correct Writing Sequences (%CWS), and Correct Minus Incorrect Writing Sequences (CMIWS). Fourth grade students (n = 109) from 6 schools participated in the study. To assess criterion validity of each metric, total scores from writing tasks were correlated with the state achievement test's composition subtest. Each index investigated was moderately correlated with the subtest. Correlations increased with the longer sampling period, however they were not statistically significant. The accuracy at distinguishing between proficient and not proficient writers on the state assessment was analyzed for each index using discriminant function analysis and Receiver Operating Characteristic (ROC) curves. CWS and CMIWS, indices encompassing production and accuracy, were most accurate for predicting proficiency. Improvements were observed in classification accuracy with an increased sampling time. Utilizing cut scores to hold sensitivity above .90, specificity for each metric increased with longer probes. Sensitivity and specificity increased for all metrics with longer probes when using a 25th percentile cut. Visual analyses of ROC curves reveal where classification improvements were made. The 10-min sample for CWS more accurately identified at-risk students in the center of the distribution. Without measurement guiding decisions, writers in the middle of the distribution are more difficult to classify than those who clearly write well or struggle. The findings have implications for screening using WE-CBM. (PsycINFO Database Record

Variability of P-wave morphology predicts the outcome of circumferential pulmonary vein isolation in patients with recurrent atrial fibrillation

IntroductionSevere atrial structural remodeling may reflect irreversible damage of the atrial tissue in patients with atrial fibrillation (AF) and is associated with changes of P-wave duration and morphology. Our aim was to study whether variability of P-wave morphology (PMV) is associated with outcome in patients with AF after circumferential PV isolation (CPVI). Methods and results70 consecutive patients (aged 60±9years, 46 men) undergoing CPVI due to symptomatic AF were studied. After cessation of antiarrhythmic therapy, standard 12-lead ECG during sinus rhythm was recorded for 10min at baseline and transformed to orthogonal leads. Beat-to-beat P-wave morphology was subsequently defined using a pre-defined classification algorithm. The most commonly observed P-wave morphology in a patient was defined as the dominant morphology. PMV was defined as the percentage of P waves with non-dominant morphology in the 10-min sample. At the end of follow-up, 53 of 70 patients had no arrhythmia recurrence. PMV was greater in patients without recurrence (19.5±17.1% vs. 8.2±6.7%, p<0.001). In the multivariate logistic regression model, PMV≥20% (upper tertile) was the only independent predictor of ablation success (OR=11.4, 95% CI 1.4–92.1, p=0.023). A PMV≥20% demonstrated a sensitivity of 41.5%, a specificity of 94.1%, a PPV of 96.7%, and an NPV of 34.0% for free of AF after CPVI. ConclusionsWe report a significant association between increased PMV and 6-month CPVI success. PMV may help to identify patients with very high likelihood of freedom of AF 6-months after CPVI.

A novel process utilizing mechanochemical sulfidization to remove lead from cathode ray tube funnel glass

A novel process of mechanochemical sulfidization for the treatment of cathode ray tube (CRT) funnel glass has been investigated by co-grinding with the element sulfur. The ground samples were characterized by means of a set of analytical methods, including scanning electron microscopy (SEM), x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and thermogravimetric analysis (TG). The analytical results showed that during the co-grinding of the CRT funnel glass with sulfur, the Si–O–Pb bond in glass and S–S bond broke and recombined into lead sulfide (PbS). The sulfidizing reaction proceeded with an increase in grinding time and the amount of the added sulfur. The sulfidizing rate increased rapidly from 16.6% for the 10-min ground sample to 96.7% for the 120-min ground sample. Using this process, current mineral processing technology, such as flotation separation, might be used to recover PbS. The proposed technology could also be used to treat other leaded glass and even other lead-containing wastes. Implications: In this research, a mechanochemical sulfidization method was proposed to recover lead from waste cathode ray tube (CRT) funnel glass. CRT funnel glass was co-ground with sulfur in N2 atmosphere by mechanical milling. After milling, lead in CRT funnel glass was transferred into lead sulfide (PbS). Using this process, current mineral processing technology, such as flotation separation, might be used to recover PbS from the ground sample. The process can be applied to treat other leaded glass or lead-containing wastes.

Narrative skill and syntactic complexity in school‐age children with and without late language emergence

Children who do not produce single words by the expected age have been described as 'late talkers' or as demonstrating 'late language emergence' (LLE). Although their short-term growth in vocabulary is often strong, longer-term consequences of LLE remain in dispute. It has been argued that the majority of school-age children who had LLE move into the average range for narrative production, though studies have not examined narrative comprehension. It has also been argued that school-age children with LLE score in the average range on standardized tests of syntax, though studies have not examined performance in conversational contexts. This article compared school-age children with and without histories of LLE for performance on standardized narrative comprehension and production tasks, as well as the use of complex sentences and relative clauses in narration and conversation. Both complex syntax and relative clause use are reduced in children with specific language impairment (SLI), so these structures may be useful as indicators of linguistic weakness. The participants were twenty-two 8-year-old children, divided into two groups. Eleven children who had been diagnosed with LLE at 30 months were compared with a control group of 11 children with typical development (TD). All participants completed a standardized test of narrative comprehension and production and a 10-min conversational sample. Both narrative and conversational samples were analysed for the number of complex sentences and relative clauses. Overall results indicated that children with a history of LLE did not have comprehension or production scores that were significantly different from the TD group on the standardized narrative test; nor did groups differ for production of complex sentences or relative clauses in narrative samples. However, a significant difference was found for the production of complex sentences in conversational samples, with the children diagnosed with LLE producing fewer complex sentences than the TD group. There was no difference between groups for relative clause use in conversation or in narratives. These data suggest that children with a history of LLE may exhibit age-appropriate performance on a standardized narrative test, but still lack the syntactic complexity of their TD peers in conversation. Assessments for school-age children with a history of language delay should include analysis of syntactic complexity in conversation to identify continuing weakness. Future research should examine use of other specific types of complex structures (e.g. infinitival and clausal complements) in this population, as well the feasibility of increasing complex sentence production through intervention. In addition, future studies should examine whether this decreased production of complex syntax in conversation is noted by naive listeners.

Weight Difference Between Double Parathyroid Adenomas Is the Cause of False‐positive IOPTH Test After Resection of the First Lesion

Some patients with double parathyroid adenoma show a greater than 50% decline in intraoperative parathyroid hormone (IOPTH) after resection of the first lesion. The present study was designed to test the hypothesis that significant adenoma weight differences may explain this inappropriate decline of IOPTH. We reviewed prospective database records at two tertiary institutions. Patients with a histopathologic diagnosis of double adenoma and no familial history of hyperparathyroidism were included. Diagnosis of double adenoma was confirmed either preoperatively (double uptake), intraoperatively (bilateral exploration), or at reintervention. IOPTH was determined following the Miami protocol. The 10-min postexcision sample was considered as the 0-min sample for IOPTH determinations at the time of resection of the second lesion. Thirteen patients met the inclusion criteria. After resection of the first lesion, IOPTH failed to decline in four patients and a second adenoma was removed. They had similar weight (404 vs. 598 mg). In nine patients IOPTH showed a false greater than 50% decline. These patients had the largest adenoma removed first (846 +/- 226 mg), and only two had normal PTH serum concentrations 10 min after resection. The second adenoma was always smaller (284 +/- 177 mg; P = 0.02) and its resection either during the same operation (7 cases) or at reoperation (2 cases) led to normalization of IOPTH at 10 min in all cases. Two-thirds of patients with double parathyroid adenoma show a false-positive decline of IOPTH after resection of the first adenoma. This appears to be due to the initial removal of the larger lesion.

The Proteome of the Mouse Photoreceptor Sensory Cilium Complex

Primary cilia play critical roles in many aspects of biology. Specialized versions of primary cilia are involved in many aspects of sensation. The single photoreceptor sensory cilium (PSC) or outer segment elaborated by each rod and cone photoreceptor cell of the retina is a classic example. Mutations in genes that encode cilia components are common causes of disease, including retinal degenerations. The protein components of mammalian primary and sensory cilia have not been defined previously. Here we report a detailed proteomics analysis of the mouse PSC complex. The PSC complex comprises the outer segment and its cytoskeleton, including the axoneme, basal body, and ciliary rootlet, which extends into the inner segment of photoreceptor cells. The PSC complex proteome contains 1968 proteins represented by three or more unique peptides, including approximately 1500 proteins not detected in cilia from lower organisms. This includes 105 hypothetical proteins and 60 proteins encoded by genes that map within the critical intervals for 23 inherited cilia-related disorders, increasing their priority as candidate genes. The PSC complex proteome also contains many cilia proteins not identified previously in photoreceptors, including 13 proteins produced by genes that harbor mutations that cause cilia disease and seven intraflagellar transport proteins. Analyses of PSC complexes from rootletin knock-out mice, which lack ciliary rootlets, confirmed that 1185 of the identified PSC complex proteins are derived from the outer segment. The mass spectrometry data, benchmarked by 15 well characterized outer segment proteins, were used to quantify the copy number of each protein in a mouse rod outer segment. These results reveal mammalian cilia to be several times more complex than the cilia of unicellular organisms and open novel avenues for studies of how cilia are built and maintained and how these processes are disrupted in human disease.

Exploring the basis of divergent selection for ‘temperament’ in domestic sheep

In previous studies, sheep that are More Active and vocal in an arena test or during social isolation have been considered to be more fearful than Less Active and vocal sheep. Merino sheep at the University of Western Australia have been selectively bred for their behavioural responses to the presence of a human in an arena test and to social isolation, resulting in the creation of two divergent lines. The aim of this study was to determine whether More Active (MA) sheep were actually more fearful than Less Active (LA) sheep. We chose animals from the extremes of each selection line (i.e. the most active MA lambs and least active LA lambs) and measured for differences in their behavioural and adrenocortical responses to a human presented in an arena test. As expected, MA sheep crossed more zones and bleated more often than LA sheep; they also spent more time in proximity to the human, and investigated him more often and sooner (all Ps<0.01). Multivariate analysis of behaviour revealed two independent factors, the first reflecting the expression of active behaviours and the second, vigilance. The first factor may indicate the level of fear experienced in the arena test or the propensity of the individual to take risks (boldness). MA sheep were more bold (less fearful) than LA sheep (P=0.0001) and had lower plasma cortisol concentrations immediately after the arena test (10-min sample back-transformed mean±S.E.: MA 48.9±3.4nmol/L, LA 60.3±4.2nmol/L; P=0.046). There was no difference between the flocks in vigilance (P=0.422), and behavioural and adrenocortical responses were not significantly correlated. The difference between the groups appears to have been in the level of fear experienced or their boldness in the arena test. Although the animals used in this study were not representative of the two selection lines, the behavioural and adrenocortical evidence suggests that, contrary to expectation, the MA sheep were less fearful than the LA sheep in this test situation.

Objects as enrichment: Effects of object exposure time and delay interval on object recognition memory of the domestic pig

A modified spontaneous object recognition test was used to examine object recognition memory in the domestic pig. This test uses preference for a novel object over a previously encountered sample object as indicating recognition of the sample object, and no preference as indicating no recognition. Two factors hypothesized to affect object recognition are duration of exposure to the sample stimulus and delay interval before re-exposure. Both of these factors could be manipulated in a rotational object enrichment program for pigs. Reducing exposure time and increasing the delay interval before re-exposure should decrease object recognition and prolong novelty-induced object exploration. We exposed 5-week-old pigs to different sample objects in their home pens for 10 min and 2 days, respectively. We tested for object recognition memory at various delay intervals after initial exposure by placing littermate pairs in a test pen for 10 min and recording snout contact with a sample object and a completely novel object. At a 1-h delay, half the pairs were tested with the 2-day sample object; the other half received the 10-min sample object. At a 3-h delay, pairs were tested with the opposite sample object. Pairs were also tested with the 2-day sample at a 5-day delay and the 10-min sample at a 6-day delay. We predicted that pigs would show a preference for the novel versus the 2-day sample object at all three delays, but would only prefer the novel object over the 10-min sample object at the 1-h and 3-h delays. Pigs did not show novelty preference in the presence of the 10-min sample object at any delay. Novelty preference in the presence of the 2-day sample object occurred at the 3-h ( P < 0.05) and 5-day delays ( P < 0.001), but not the 1-h delay. The lack of novelty preference when pigs were tested with the 10-min sample object may have been due to failure to habituate to the sample object. Testing in a different location from the initial sample object exposure and retroactive interference from exposure to the 10-min sample object may have contributed to a temporary lack of novelty preference when pigs were tested with the 2-day sample object at the 1-h delay. The finding that pigs retained a memory for the 2-day sample object for at least 5 days suggests that restricting object exposure to less than 2 days may help to preserve the exploratory value of objects rotated among pens.

Grooming in desert bighorn sheep (Ovis canadensis mexicana) and the ghost of parasites past

Ectoparasites such as ticks have a negative effect on host fitness, whereas parasite-defense grooming is effective in removing ticks. The central control (programmed grooming) model proposes that animals engage in preventive tick-defense grooming in response to an internal timing mechanism, even in the absence of peripheral stimulation from parasites. This model predicts that smaller animals will groom more frequently than larger ones because of the higher cost of parasitism for a small animal (body size principle). The peripheral stimulation (stimulus driven) model predicts no size-related differences in grooming rate in the absence of tick bite irritation. We observed grooming behavior in a Chihuahuan desert population of bighorn sheep (Ovis canadensis mexicana), where ticks have been absent for perhaps thousands of years. Although not exposed to ticks, bighorns self groomed by means of oral and scratch grooming, albeit at very low rates compared to size-matched ungulates in both tick-infested and tick-free environments. Logistic regression and general linear models revealed both the probability that grooming was performed during a 10-min focal sample and the rate of grooming when it occurred was greater for younger, smaller age/sex categories of less body mass. Oral and scratch grooming were negatively associated with body mass during both years, with juveniles (X ¼ 15 kg) grooming the most frequently and the oldest males (X ¼ 70‐85 kg) grooming the least. Assuming that programmed grooming evolved in a tick-infested environment, the current grooming behavior of this population is a relict of their ancestral environment, an adaptation to the ‘‘ghost of parasites past.’’ Key words: body size principle, desert bighorn, grooming, programmed grooming model, ticks. [Behav Ecol]

Simultaneous intra-accumbens remifentanil and dopamine kinetics suggest that neither determines within-session operant responding

The ultra-short-acting mu opioid agonist analgesic/anesthetic remifentanil (RMF) is extremely rapidly eliminated from blood (half-life in rats, 0.3-0.7 min). This extremely fast elimination is thought to be the main reason why RMF maintains such high rates of responding in animal operant-conditioning models of drug addiction. The present study investigated if such a fast elimination of RMF also occurs in the extracellular space of the brain, i.e., in the pharmacokinetic compartment that is thought to be ultimately mediating the reinforcing effect, and hence, the abuse liability of drugs. Nucleus accumbens (NAC) RMF and dopamine (DA) were simultaneously quantified by in vivo microdialysis followed by tandem mass spectrometry both in rats that traversed an alley to receive intravenous injections of 0.032 mg kg(-1) RMF in an operant runway procedure (contingent RMF) and in rats that passively received RMF in the runway (noncontingent RMF). Regardless of the mode of administration (i.e., contingent or noncontingent), intra-accumbens RMF peaked in the first 10-min sample and decreased exponentially with a t(1/2) of 10.0+/-1.2 min (N=31). RMF-stimulated DA peaked in the 10-min sample immediately after the RMF peak and decreased with a time course very similar to that of RMF. Crosscorrelation of the NAC RMF and NAC DA curves showed them to be tightly synchronized. Noncontingent single-dose RMF was eliminated from the whole brain with a half-life of 1.1+/-0.2 min and from blood with a half-life of 0.3 min or less. The comparison of blood-vs-brain RMF pharmacokinetics with rat RMF self-administration behavior, either in operant runway (present study) or in lever-press-based operant-conditioning procedures, suggests that titration of blood RMF, whole-brain RMF, intra-accumbens RMF, or accumbal DA levels (assessed with the limited temporal resolution of in vivo microdialysis) does not determine a rat's decision to reemit a response during a multiple-injection drug self-administration session.