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Steller's Jays (Cyanocitta stelleri) with swollen legs and feet resembling the signs of scaly leg have been commonly seen around Arcata, California, US. The clinical signs are thought to be caused by knemidokoptic mites, a group of parasites specialized on avian hosts. Between February 2019 and March 2020, we analyzed the long-term database of Steller's Jays collected by Humboldt State University for trends in the prevalence of signs of scaly leg, compared the gripping position in the feet of Steller's Jays with variable signs of this condition as an index of their ability to perch, identified the mites using a partial sequence of the cytochrome oxidase subunit I gene, and examined genetic distances between mites collected from different host species both sequenced in this study and from GenBank. Overall, 27% of jays recorded in the long-term database had shown signs of scaly leg. Jays with signs captured in this study had greater variability in and a reduced degree of contraction in the gripping position of their feet compared to jays without signs, suggesting that infestation may have an impact on the host's ability to perch. The cytochrome oxidase subunit I sequence (578 base pairs) from mites collected from Steller's Jays was compared to sequences from Knemidokoptes jamaicensis, Knemidokoptes derooi, and to unidentified Knemidokoptes spp. collected from different hosts. The mites from Steller's Jays were most closely related to Knemidokoptes jamaicensis but had a relatively high sequence divergence, 7.8%, supporting the possibility that the form infesting these jays may be an undescribed species. [ABSTRACT FROM AUTHOR]

A total of 2,121 small mammals in California were assessed for Anaplasma phagocytophilum from 2006 through 2008. Odds ratios were >1 for 4 sciurids species and dusky-footed woodrats. High seroprevalence [...]

The ecology of Lyme borreliosis is complex in northwestern California, with several potential reservoir hosts, tick vectors, and genospecies of Borrelia burgdorferi sensu lato. The primary objective of this study was to determine the fine-scale spatial distribution of different genospecies in four rodent species, the California ground squirrel (Otospermophilus beecheyi), northern flying squirrel (Glaucomys sabrinus), dusky-footed woodrat (Neotoma fuscipes), and Allen’s chipmunk (Neotamias senex). Rodents were live-trapped between June 2004 and May 2005 at the Hoopa Valley Tribal Reservation (HVTR) in Humboldt County, California. Ear-punch biopsies obtained from each rodent were tested by polymerase chain reaction (PCR) and sequencing analysis. The programs ArcGIS and SaTScan were used to examine the spatial distribution of genospecies. Multinomial log-linear models were used to model habitat and host-specific characteristics and their effect on the presence of each borrelial genospecies. The Akaike information criterion (AICc) was used to compare models and determine model fit. Borrelia burgdorferi sensu stricto was primarily associated with chipmunks and B. bissettiae largely with woodrats. The top model included the variables “host species”, “month”, and “elevation” (weight = 0.84). Spatial clustering of B. bissettiae was detected in the northwestern section of the HVTR, whereas B. burgdorferi sensu stricto was clustered in the southeastern section. We conclude that the spatial distribution of these borreliae are driven at least in part by host species, time-of-year, and elevation. [ABSTRACT FROM AUTHOR]

Linked article: This is a mini commentary on Hoarau et al., pp.1047–1058 in this issue. To view this article visit https://doi.org/10.1111/1471‐0528.17460. [ABSTRACT FROM AUTHOR]

To the Editor: Anaplasma phagocytophilum was defined to include Ehrlichia phagocytophila, E. equi, and the agent of human granulocytic ehrlichiosis. Nevertheless, we and others have found phenotypic and genetic differences [...]

Objective: Spontaneous coronary artery dissection (SCAD) is a rare and potentially lethal cause of myocardial infarction (MI). The purpose of our study was to estimate the prevalence and maternal outcomes of pregnancies complicated by SCAD.Materials and Methods: A population-based cohort study on all births identified in the Healthcare Cost and Utilization Project from 2008 to 2012. Disease prevalence was calculated and logistic regression was used to estimate the adjusted odds ratio (aOR) for risk factors and different maternal complications.Results: A total of 4 363 343 pregnancy-related discharges were evaluated. 79 cases of SCAD were identified resulting in a prevalence of 1.81 per 100 000 pregnancies. The mean maternal age at the time of diagnosis was 33.4 years (±5.2). Chronic hypertension (aOR, 2.67; 95% CI 1.18 to 6.03), lipid profile abnormalities (aOR, 48.22; 95% CI 24.25 to 95.90), chronic depression (aOR, 3.56; 95% CI 1.43 to 8.83) and history of migraine (aOR, 3.93; 95% CI 1.52 to 10.17) were associated with an elevated risk for SCAD. MI was diagnosed in 66 (85.5%) cases of SCAD with anterior and subendocardial territories being the most common locations. Thirty one patients (40%) with SCAD underwent angioplasty with the majority receiving stents, which was associated with a longer hospital stay than those treated conservatively or with bypass.Conclusions: SCAD is a rare aetiology of MI; risk factors and outcomes are illustrated in the current study. The puerperium is an important period for the development of pregnancy-related SCAD. Careful evaluation of pregnant and postpartum women with chest pain is warranted, especially if these risk factors are identified. [ABSTRACT FROM AUTHOR]

To implement active aeroelastic control, control surfaces on a given wing configuration are moved using actuators having their own dynamic characteristics. The inclusion of actuator dynamics leads to the coupling of aeroelastic and actuator modes, and may result in instability in the closed-loop coupled aeroservoelastic system. During the design phase, various types of actuators may be considered, and hence, the stability and performance of the coupled system needs to be evaluated. In this research, a simultaneous control for aeroelastic and actuator poles is developed, which allows for the desired pole placement in a coupled aeroservoelastic system. This enables flutter boundary extension and suppression of flutter instabilities. The design of the controller is based on the method of receptances and requires the transfer functions associated with the aeroelastic structure and the actuators. This approach also allows the partial control of some selected aeroelastic modes without influencing the actuator modes, which ensures the stability of a coupled aeroservoelastic system irrespective of the selected actuator model. Different wing models having multiple control surfaces have been considered in the simulation. By using the associated numerical receptances, several examples have also been presented to demonstrate the solution strategy and performance of the controller. [ABSTRACT FROM AUTHOR]

Wildlife populations of conservation concern are limited in distribution, population size and persistence by various factors, including mortality. The fisher (Pekania pennanti), a North American mid-sized carnivore whose range in the western Pacific United States has retracted considerably in the past century, was proposed for threatened status protection in late 2014 under the United States Endangered Species Act by the United States Fish and Wildlife Service in its West Coast Distinct Population Segment. We investigated mortality in 167 fishers from two genetically and geographically distinct sub-populations in California within this West Coast Distinct Population Segment using a combination of gross necropsy, histology, toxicology and molecular methods. Overall, predation (70%), natural disease (16%), toxicant poisoning (10%) and, less commonly, vehicular strike (2%) and other anthropogenic causes (2%) were causes of mortality observed. We documented both an increase in mortality to (57% increase) and exposure (6%) from pesticides in fishers in just the past three years, highlighting further that toxicants from marijuana cultivation still pose a threat. Additionally, exposure to multiple rodenticides significantly increased the likelihood of mortality from rodenticide poisoning. Poisoning was significantly more common in male than female fishers and was 7 times more likely than disease to kill males. Based on necropsy findings, suspected causes of mortality based on field evidence alone tended to underestimate the frequency of disease-related mortalities. This study is the first comprehensive investigation of mortality causes of fishers and provides essential information to assist in the conservation of this species. [ABSTRACT FROM AUTHOR]

American black bears ( Ursus americanus) are common, widely distributed, and broad-ranging omnivorous mammals in northern California forests. Bears may be susceptible to pathogens infecting both domestic animals and humans. Monitoring bear populations, particularly in changing ecosystems, is important to understanding ecological features that could affect bear population health and influence the likelihood that bears may cause adverse impacts on humans. In all, 321 bears were captured between May, 2001, and October, 2003, and blood samples were collected and tested for multiple zoonotic and vector-borne diseases. We found a PCR prevalence of 10% for Anaplasma phagocytophilum, and a seroprevalence of 28% for Toxoplasma gondii, 26% for Borrelia burgdorferi, 26% for A. phagocytophilum, 8% for Trichinella spiralis, 8% for Francisella tularensis and 1% for Yersinia pestis. In addition, we tested bears for pathogens of domestic dogs and found a seroprevalence of 15% for canine distemper virus and 0.6% for canine parvovirus. Our findings show that black bears can become infected with pathogens that are an important public health concern, as well as pathogens that can affect both domestic animals and other wildlife species. [ABSTRACT FROM AUTHOR]

Roosevelt elk (Cervus canadensis roosevelti) have historically populated the Pacific Northwest from the Olympic Peninsula to the south of San Francisco Bay, and several management actions have supported restoring elk into parts of this historic range. In 1982, 17 Roosevelt elk were translocated from Gold Bluffs Beach State Park to Sinkyone Wilderness State Park. In 2020, the Sinkyone elk herd was observed to have lower body condition scores and poor coat conditions in comparison to the Gold Bluffs Beach elk herd. Therefore, the objectives of this study were to investigate the difference in health between the two herds. Fecal samples were collected (n = 20) from each herd to measure species richness and abundance of parasites. We determined there was a significant difference in species richness and abundance of parasite eggs between the two herds. The Sinkyone herd's overall higher endoparasite load may be attributed to a low immune response due to low nutrition but, causation is unknown. [ABSTRACT FROM AUTHOR]

Objective: To compare the rates and aetiologies of stillbirth over the past 50 years. Study design: We reviewed all autopsy reports for stillbirths occurring between 1989 and 2009 at the McGill University Health Centre to determine the pathological aetiology of stillbirths. We also reviewed maternal characteristics. We compared our results with a previous study published in 1992 on aetiologies of stillbirth from 1961 to 1988 at the same institution. Results: From among the 79 410 births between 1989 and 2009, 217 stillbirths were included in our study. The mean maternal age was 31.05 (±5.8) years. In 28.1% of cases, there was a history of subfertility. The mean gestational age at diagnosis was 32.69 (±5.58) weeks, with a birthweight of 1888 (±1084) g. The main causes of stillbirth were unknown (26.7%), placental factors (19.8%) and abruptio placentae (12.9%). Other causes included haematogenous or ascending infection (10.6%), fetal malformations (8.3%), maternal hypertension (3.2%), intrauterine growth restriction (2.8%), diabetes (1.8%) and intrapartum asphyxia (1.4%). Other fetal causes were found in 12.4% of cases. Conclusions: Owing to detailed pathological examination of most stillbirth cases over the past five decades at our tertiary obstetrical centre, we could study the trends in the aetiology of stillbirths in a cohort of more than 150 000 births. In 50 years, the rate of stillbirth has decreased from 115 to 32 cases/ 10 000 births from the 1960s to 2000s, which represents a reduction of 72%. Stillbirth from unknown cause remains the most common contributor, with 40% of these cases occurring in late pregnancy. [ABSTRACT FROM AUTHOR]

In this review, we discuss aspects of the prenatal diagnosis of fetal skeletal malformations, concentrating on the advantages offered by different imaging techniques and the approaches that are of value in evaluating a suspected skeletal dysplasia. We also briefly address the findings in some of the commoner malformations of the fetal skeleton that may be encountered. [ABSTRACT FROM AUTHOR]

Introduction: Cisterna magna (CM) measurement constitutes part of the sonographic assessment of the posterior fossa. CM enlargement (ECM) is defined as a measurement exceeding 10 mm, although it has previously been noted that the CM varies in size with gestation. Existing data do not appear to reflect observations regarding CM biometry within our population and this study was therefore undertaken in order to re-evaluate CM biometry. Materials and Methods: Data from 4,750 normal pregnancies between 15 and 32 weeks of gestation were collected and used to construct a reference range for the CM. Results: Regression analysis was used to model CM across gestational age and thereby define the upper limits for normal CM measurements across gestation. The CM increases with gestation. These data suggest that a 10-mm cut-off underestimates ECM, notably in the gestational age period below 24 weeks, whilst overestimating isolated ECM beyond this. Differences in CM measurements between genders were confirmed (p < 0.0001). Conclusions: Defining ECM based upon a cut-off of 10 mm across all gestations may be inappropriate given the variation observed with gestational age. More accurate identification of fetuses with, in particular, isolated ECM may facilitate more precise evaluation of the clinical significance of this finding. Copyright © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

A method is developed for analyzing vibratory systems that may exhibit yielding or other hysteretic behavior under broad-band random forcing. The techniques rely on a balance of power supplied by the forcing and dissipated in hysteretic effects. Since the application area involves the practical case of lightly damped structures, a transformation into normal-mode coordinates is used even for systems exhibiting nonlinear damping. One- and two-degree of-freedom examples are considered in detail and general concepts are given where possible. Limitations inherent in the method are discussed. [ABSTRACT FROM AUTHOR]

Abstract: Uterine rupture is an established risk of previous uterine trauma. Conventionally this has been considered most likely following prior classical or midline hysterotomies at cesarean section or subsequent to abdominal myomectomy in which the uterine cavity was breached. Although there are reports of such cases after laparoscopic procedures such as myomectomy the incidence is believed to be very small. We present an extreme case of uterine rupture at 27 weeks with a previous laparoscopically repaired uterine perforation. [Copyright &y& Elsevier]

When using the statistical energy analysis (SEA) technique to compute the structureborne and acoustic power flow through complex structures, a parameter of paramount importance is the coupling loss factor which characterizes the power flow across substructure boundaries. For many simple boundary types (e.g., plates connected to plates) the coupling loss factors are available in the literature, but in applying the SEA method to structures with more complex connections the finite element method can be used to advantage in computing these factors. The structure studied here consists of two beams, capable of supporting flexural, compressional, and torsional motion, connected by a small, builtup box which has several resonances in the frequency range of interest. The admittance matrix of the box structure was computed using NASTRAN. From this admittance matrix the coupling loss factors are computed. The resonant structure of the 'coupler' (the box) is apparent in the results, which compared well with results from experiment. [ABSTRACT FROM AUTHOR]

It has long been known that large hydrophones filter out the high-wave number, convective components of turbulent boundary layer (TBL) noise. A two-dimensional array constructed of N×M hydrophones might be expected to increase the filtering by a factor of N×M, but, in practice, inter-hydrophone spaces (''gaps'') diminish this benefit. An analysis, based on a wave-vector approach, has been done to study the effect of gaps in two-dimensional arrays. It is shown that the effect of gaps is to allow leakage into the array response function at wave numbers corresponding to aliasing lobes. This leakage can extend to moderately high wave numbers, although the details of the leakage are sensitive to the exact gap size. Numerical estimates of array self-noise due to flow noise are made using models of the TBL wall pressure wave-vector spectrum. It is shown that, at low values of k0L (k0 is the acoustic wave number and L is characteristic array length), the leakage from the convective and subsonic components of the TBL can be substantial, even for relatively small gaps. [ABSTRACT FROM AUTHOR]

In practical applications of the statistical energy analysis (SEA) or other power flow techniques, the calculation of the power flow between subsystems is of fundamental concern. When the subsystems are connected by multimodal structures, for instance, vibration mounts, values for the coupling loss factors as found in the literature are not suitable. In this paper we present a general theoretical framework for calculating the coupling loss factor when the coupler is numerically modeled by classical dynamics, notably by means of a finite element analysis (FEA). After presenting some pertinent results and definitions from SEA, FEA, and structural dynamical theory, an expression for the 'coupling' impedance matrix, which relates the forces and free velocities at nodes along the subsystem/coupler boundaries, is derived. This impedance is formed from the admittance matrix of the coupler, calculated using FEA, and input impedances for the systems, analytically calculated. From the coupling impedance, expressions for the coupling loss factors are derived for the cases where the SEA subsystems are plates or beams and include flexural, longitudinal, and torsional forms of energy transmission. Finally, numerical examples are given for the application of this technique to structures consisting of two beams or plates connected by a multimodal coupler. [ABSTRACT FROM AUTHOR]

A scheme for generating vibration by using two closely spaced piezoelectric transducers to create a moment rather than a force drive is described. The advantage of the moment drive is the reduced acoustic emission from the nearfield vibration of the drive. This can be important in situations where the radiation from other regions of a structure [for example frames, stringers, etc.) is being studied. The two transducers are spaced at less than a structural 1/2 wavelength. The amplitude and phase of the electrical driving signals are adjusted to produce out-of-phase accelerations at each transducer's drive point. Measurements on a flat plate in a reverberant test room verified theoretical estimates of the lesser radiated sound power. Over a frequency range of 0.2 to 2 kHz, the moment drive produced 15-0 dB less sound power than a force drive, for the same average level of vibration on the plate. A benefit is that the most reduction occurs at the lowest frequency where other means of suppression are less effective. [Work supported by ONR.] [ABSTRACT FROM AUTHOR]

A large area transducer was desired for the measurement of wall pressures beneath turbulent boundary layers. Characteristics desired were small thickness so that it could be applied to a surface without disrupting the flow, and cheapness so that it could be considered expendable and could be applied in mosaic patterns as wave-vector filter elements. A degree of flexibility was also desired for application to curved surfaces. A transducer design using PVDF film was developed toward these ends. The principle problem to be overcome was the sensitivity of the device to vibratory motion of the surface to which it is applied. The particular design includes a sandwich of films on a substrate with a pattern of line supports. The assembly is arranged to suppress outputs due to vibratory bending motion of the substrate while enhancing outputs due to normal stresses (pressure). The preliminary design was 0.020 in. thick and 1 in. square. It had a calculated sensitivity of -220 dB re V/μPa. The actual sensitivity to pressure and vibration was also measured. [ABSTRACT FROM AUTHOR]

Regularly ribbed plate constructions are common in marine, aircraft, and other applications. Since vibration of these structures can be responsible for unwanted acoustic emissions, the response of ribbed plates has been a subject of many theoretical and a few experimental studies over the years. In determining radiation and near-field acoustic levels it is important to have a knowledge of the distribution of surface velocity in wave-number space. In this paper, the elegant solution of Berkman et al. [''Radiation from Periodically Supported Fluid-Loaded Plates,'' BBN Rep. 3999 (1979)] to the ribbed plate equation of motion is used to estimate the distribution in wave number of the surface velocity. In particular, the two-dimensional solution to excitation by a point force is used. The results of the study show several distinctive features: a high level, broad-(spatial) band in the bays near the excitation force; Bragg scattering of flexural energy by the periodically spaced ribs (which is accompanied by acoustic radiation due to aliasing), an alignment of flexural traveling waves to the direction normal to the ribs, and the relative inconsequence of stop/pass band behavior. Experimental data are presented showing the existence of these features. [ABSTRACT FROM AUTHOR]

Most ship-mounted planar hydrophone array systems employ stiff structures for isolation from local noise. One type of structure is a plate (''window''), which isolates the hydrophones from high wave-number turbulence on the outer surface. Most arrays also use a heavy steel plate behind the array to achieve isolation from the inner surface. These plates support bending waves, which can be induced by TBL forces. Even though these waves are subsonic over the frequency region of interest, the noise stress can enter the array output through an aliasing lobe when the array is steered. This noise increase is frequency dependent, and increases with frequency after a critical value. This talk will indicate how this noise contaminates the array response and discuss the interplay of element spacing, steering, and frequency performance of the array. [ABSTRACT FROM AUTHOR]