Physical drivers of seagrass spatial configuration: the role of thresholds

Context

Seagrass landscapes vary substantially in extent and pattern, resulting from depth zonation and hydrodynamic stress gradients and may exhibit threshold behavior in response to changes in physical drivers. Seagrass landscapes persist in a delicate balance between processes of disturbance and recovery and therefore may exhibit behavior typical of classic critical systems.

Objectives

Examine how hydrodynamic drivers and physical setting influence seagrass landscape composition and configuration. Determine if seagrass patch size distributions typify patterns observed for critical systems.

Methods

We used landscape metrics to quantify the spatial configuration of seagrass and then modeled the response of these metrics to wave energy, tidal current speed, and water depth at 62 estuarine sites in North Carolina, USA. Seagrass landscapes were representative of cover types observed in the estuary generated by wave energy.

Results

Percent cover, patch size, and number of patches all declined with increasing wave energy. Threshold behavior occurred at wave energy change points between 675–774 J m^?1. Seagrass landscapes differed in spatial configuration and physical setting, above and below change points. There was moderate support for a power law relationship for patch size distribution across a wide range of seagrass landscape cover and wave energy.

Conclusions

With weather extremes on the rise, much of this estuarine seagrass will be exposed to increased wave energy. Where seagrass exists just below the wave energy change points, increases in wave energy could tip those habitats into a new stable state of lower cover resulting in less cover overall in the estuary.

     

Eastern equine encephalitis in 9 South American camelids

BACKGROUND: Eastern equine encephalitis (EEE) virus is a mosquito-borne togavirus (alphavirus) that causes severe (often fatal) encephalitis in many mammalian species, but it has not been reported previously in South American camelids. Hypothesis: South American camelids can become naturally infected with EEE virus and show encephalitic signs similar to those observed in other affected species. ANIMALS: Nine cases (8 alpacas and 1 llama, aged 3.5 weeks to 12 years) were identified; 4 of 9 were 510 weeks old. All cases were from the East Coast of the United States and presented in late summer and fall. METHODS: A retrospective study was performed to include confirmed cases of EEE in camelids in North America before 2006. RESULTS: Eight of nine (89%) camelids died or were euthanized in extremis, with the mean time to death of 2 days. Clinical signs were consistent with encephalitis and included fever, lethargy, ataxia, seizures, recumbency, torticollis, opisthotonus, and vestibular signs. No consistent hematologic abnormalities were identified, and cerebrospinal fluid contained an increased protein concentration in the single camelid analyzed. No successful therapy was identified. EEE was confirmed by alphavirus detection by using immunohistochemistry (IHC) and polymerase chain reaction (PCR) in the central nervous system (CNS) and by serology. Findings included polioencephalitis with lymphocytic perivascular cuffing; neutrophil infiltration; gliosis; neuron satellitosis; necrosis; and edema, with intracytoplasmic alphavirus within neurons and glial cells. No virus was detected in extraneural tissues. CONCLUSIONS AND CLINICAL IMPORTANCE: In endemic areas, EEE should be considered a differential diagnosis for young and adult camelids with CNS disease. Brain histopathology with indirect IHC or PCR is diagnostic.     

Cytologic diagnosis of generalized cutaneous sporotrichosis in a hunting hound

A 1-year-old male Foxhound/Walker Hound mix was presented to the small animal internal medicine service at Louisiana State University School of Veterinary Medicine with a 6-week history of progressive, multifocal, ulcerative and draining, well-circumscribed lesions in a generalized distribution. Prior to referral, a presumptive diagnosis was made of sterile pyogranulomatous disease; immunosuppressive therapy was instituted but resulted in clinical deterioration. At presentation, the dog had marked neutropenia (1100 neutrophils/microL), and a mild toxic left shift (400 bands/microL). Cytologic findings in the exudates from a draining skin lesion included high numbers of markedly degenerate neutrophils (about 95% of nucleated cells) as well as low numbers of macrophages, small mature lymphocytes, and eosinophils. Low numbers of intracellular (within neutrophils and macrophages) and extracellular, pleomorphic, cigar-to-ovoid shaped organisms ( approximately 3x9 microm) consistent with Sporothrix were observed. Histopathologic examination of a skin biopsy showed marked, chronic, active, ulcerative, pyogranulomatous dermatitis and panniculitis, with intralesional yeast consistent with Sporothrix sp. The etiologic agent was confirmed as Sporothrix schenckii by macerated tissue fungal culture. The patient was treated with itraconazole, enrofloxacin, and clindamycin, with clinical resolution occurring over a 3-month period. This case is a rare example of the cytologic diagnosis of Sporothrix schenckii in a canine patient. Diagnosis of canine sporotrichosis is often challenging and usually requires tissue culture, as infected dogs typically harbor very few organisms. The patient's prior immunosuppressive therapy likely contributed to higher numbers of organisms in exudates from the cutaneous lesions, facilitating cytologic diagnosis.     

Choanal atresia in a Himalayan cat--first reported case and successful treatment

A 2-year-old Himalayan cat was presented for investigation of chronic, persistent, unilateral nasal discharge that was unresponsive to antibiotics. Unilateral choanal atresia was diagnosed on nasopharyngoscopy. Following surgical repair using the transnasal route and temporary stenting all clinical signs resolved. This is the first reported case of choanal atresia in a cat. It serves to alert practitioners to the occurrence of this unusual condition which should be included in the differential diagnoses of upper respiratory tract signs in young cats.     

Improving the science–policy–practice interface: decision support system uptake and use in the forestry sector in Great Britain

Over the last decade, researchers have developed a range of decision support systems (DSS) which seek to improve the evidence-base for decision-making in the forestry sector in Great Britain. Many are now integral to the systems of forest management and planning used. However, in some cases, levels of adoption have been lower than expected. This problem is neither unique to Great Britain nor to forestry, and increasingly it is being explained in terms of the quality of stakeholder engagement during DSS development and implementation. Thus, social research was undertaken to understand the factors affecting DSS uptake. The methods included an online survey completed by 81 members of the Institute of Chartered Foresters and Forestry Commission staff and 30 semi-structured interviews with stakeholders. Four sets of factors were seen to influence uptake: professional judgement and cultural resistance; communication and access; training, support and consolidation; and meeting user requirements. More generally, our conclusions highlight the need for a shift in the quality of interactions at the science–policy–practice interface: from knowledge-transfer (a unidirectional “bridging of gaps”) to knowledge-exchange (dialogue between collaborating partners) and knowledge-interaction (shared cultures and institutions).     

Feasibility and repeatability of thermal quantitative sensory testing in normal dogs and dogs with hind limb osteoarthritis-associated pain

The objectives of this study were to determine whether thermal quantitative sensory testing (QST) can be performed in client-owned dogs, is repeatable and whether QST differs between normal dogs and dogs with hind limb osteoarthritis (OA). This clinical, prospective, observational study used clinically normal dogs (n = 23) and dogs with OA-associated hind limb pain (n = 9). Thermal QST was performed in standing dogs using a high-powered light source delivered by a previously validated system. Dogs were tested on two occasions, 2 weeks apart. Five tests were performed on each hind limb at each time point. Repeated measures analysis of variance was used to evaluate the effects of leg, time point and OA/normal status on thermal threshold latencies (TTL). Additionally, paired t tests were used to compare the TTL of left and right limbs within groups and between time points.Thermal thresholds were successfully measured in 32 client-owned dogs without prior training. TTL were significantly different between normal and OA dogs (P = 0.012). There was no difference between limbs (P = 0.744) or time periods (P = 0.572), when analyzed by repeated measures analysis of variance, and no interactions between group and limb, visit and limb, or visit and group. In conclusion, thermal thresholds can be measured in client owned dogs with no prior training and are repeatable from week to week. Further data are required to determine if OA results in thermal hypoalgesia as measured at the distal hind limb and whether this is an indication of central sensitization.     

Abundance estimates of three cetacean species in the coastal waters of Matang,Perak, Peninsular Malaysia

1. The paucity of baseline data on coastal cetaceans due to a lack of research in developing countries frequently precludes assessment of their status and informed management actions for conservation.
2. This study provides the first abundance estimates of Indo-Pacific humpback dolphins, Irrawaddy dolphins, and Indo-Pacific finless porpoises in the coastal waters of Matang, Peninsular Malaysia.
3. Boat-based surveys covering 1,152 km² of coastal waters with 4,108 km of survey effort were conducted between 2013 and 2016 to collect data for line transect analysis of Irrawaddy dolphins and finless porpoises. Photo-identification data of humpback dolphins were concurrently collected for mark–recapture analysis.
4. Estimates of abundance from four sampling strata totalled 763 Irrawaddy dolphins (CV = 13%, 95% confidence interval (CI) [588, 990]) and 600 Indo-Pacific finless porpoises (CV = 27%, 95% CI [354, 1,016]).
5. The annual abundance estimates of humpback dolphins ranged between 171 (95% CI [148, 208]) in 2014–2015 and 81 (95% CI [67, 98]) in 2015–2016, likely due to the presence of offshore individuals that moved in and out of the study area. The estuarine strata were inhabited by 68 (95% CI [63, 73]) inshore humpback dolphins in 2013–2014 to 87 (95% CI [78, 97]) dolphins in 2014–2015.
6. As an International Union for Conservation of Nature important marine mammal area, the productive coastal waters of Matang are shown to support a high density of small coastal cetaceans, and the results serve as an important baseline for future studies to identify population trends for conservation management plans.

     

Efficacy of egg surface disinfectants in captive spawning Atlantic cod Gadus morhua L. and haddock Melanogrammus aeglefinus L.

In an effort to optimize the efficiency of high‐density incubation of Atlantic cod Gadus morhua and haddock Melanogrammus aeglefinus eggs, the per cent hatch of eggs treated with four disinfectants (3% hydrogen peroxide, 1% polyvinylpyrrolidone iodine, 0.1% sodium hypochlorite and a 0.005% antibiotic solution – penicillin/streptomycin) was compared in both species. The per cent hatch of eggs of each species was greatest after a 24 h treatment with the antibiotic solution. The hatching success of eggs treated within the different disinfectant treatments depended upon the embryonic developmental stage in both species. The sodium hypochlorite treatment had the lowest % coverage of colony growth after disinfected haddock eggs were plated onto sterile agar media, highest survival rates to the end of the embryonic period, but the lowest per cent hatch.     

T cell receptor signaling precedes immunological synapse formation

The area of contact between a T cell and an antigen-presenting cell (APC) is known as the immunological synapse. Although its exact function is unknown, one model suggests that it allows for T cell receptor (TCR) clustering and for sustained signaling in T cells for many hours. Here we demonstrate that TCR-mediated tyrosine kinase signaling in na?ve T cells occurred primarily at the periphery of the synapse and was largely abated before mature immunological synapses had formed. These data suggest that many hours of TCR signaling are not required for T cell activation. These observations challenge current ideas about the role of immunological synapses in T cell activation.