Kinematics of whip spider pedipalps: a 3D comparative morpho-functional approach

Amblypygi are tropical and subtropical ambush predators that use elongated, raptorial pedipalps for different activities. Although pedipalp use in predation and courtship has been explored in videography in vivo analyses, kinematic ex vivo examination of these appendages has not been conducted. Here, we rectify this lack of data by using micro-CT scans to 3D-kinematically model the appendage morphology and the range of motion (ROM) of the joints for Damon medius and Heterophrynus elaphus. We illustrate the successful application of this technique to terrestrial euarthropods in determining the maximum ROM values for each pedipalp joint. We also note that, in life, these values would be lower due to motion restricting structures like tendons, arthrodial membranes, and muscles. We further compare our maximum values obtained here with data from video-based motion analyses. The ROM of each joint shows the greatest flexibility in the femur-tibia joint (140–150°), the lowest in the basitarsus-claw joint (35–40°). ROM in the tibia-basitarsus joint is markedly distinct (D. medius: 44°; H. elaphus: 105°). This disparity reflects how H. elaphus uses the joint in the capture basket, while D. medius uses the femur-tibia joint to form the capture basket. We further illustrate notable vertical motion of the H. elaphus pedipalp compared to D. medius. This difference reflects the retro-ventral trochanter apophysis of H. elaphus. Our study opens the possibility to further whip spider kinematic understanding. Examination of other taxa using this approach will result in a more comprehensive understanding of the ecological significance and ethological implications of this unique arachnid group.     

Trees of prosperity: Agroforestry,markets and the African smallholder

Agroforestry Systems - In many developing countries, especially in Africa, farmers have been introduced to agroforestry with little consideration for the markets for trees and tree products aside...     

Effect of site preparation on survival and growth of Douglas-fir (Pseudotsuga menziessi Mirb. Franco.) seedlings

The performance (survival and growth) of Douglas-fir (Pseudotsuga menziesii Mirb. Franco.) seedlings planted in minimally disturbed, scalped, and bedded soils, both with and without herbicidal control of weeds, were compared. Douglas-fir growing for 3 years in bedded soils treated with herbicide were heavier, taller, and had deeper root systems than trees growing in other preparations. Scalping did not improve seedling performance when compared to minimally disturbed soils. Soils rich in organic matter benefited tree growth. Competing vegetation in raised beds was detrimental to seedling performance.     

Water movement in yellow-cedar seedlings and rooted cuttings: comparison of whole plant and root system pressurization methods

One-year-old yellow-cedar (Chamaecyparis nootkatensis (D. Don) Spach) seedlings and rooted cuttings were taken from cold-storage facilities and grown in aerated water in a controlled environment room for 21 days. Root areas of seedlings and rooted cuttings were initially comparable, but after 21 days seedlings had produced more than twice as much new root area as rooted cuttings. Water flow resistance through the plant-atmosphere continuum decreased in both stock types over the 21-day period. In both seedlings and rooted cuttings, transpirational flux density increased in a curvilinear manner as new root area increased. Root resistance to water movement decreased sharply with increasing new root area up to 20 cm(2) in both seedlings and rooted cuttings. Further increases in new root area did not result in further changes in root resistance of either stocktype. Plant water movement was measured by both the whole plant and the root system pressurization methods with results differing between the two techniques.     

Plexogenic pulmonary arteriopathy in a cat with non‐restrictive ventricular septal defect and chronic pulmonary hypertension

A 10‐week‐old, male, domestic long‐hair cat was medically managed for congenital heart disease over a period of 8 years. Regular clinical examinations, including sequential echocardiography, documented a non‐restrictive paramembranous ventricular septal defect, secundum‐type atrial septal defect and aortic dextroposition. Pulmonary arterial hypertension was diagnosed by the presence of high‐velocity tricuspid regurgitation, bidirectional low velocity flow across the ventricular septal defect, pulmonary arterial dilation and severe right ventricular hypertrophy without evidence of pulmonary outflow tract obstruction. The cat remained clinically stable until it died suddenly at 8 years of age. Histopathology of the lungs found evidence of plexogenic pulmonary arteriopathy. Despite severe pulmonary vascular lesions, other post‐mortem evidence of right heart failure was lacking and death was attributed to a fatal cardiac arrhythmia. In this case report of a cat with chronic pulmonary hypertension over 8 years, plexogenic lesions were found on histopathology. The microscopic findings resemble those previously reported in dogs.     

Pathology and Neurotoxicity in Dogs after Repeat Dose Exposure to a Serotonin 5-HT1B Inhibitor

AZD3783, a cationic amphiphilic drug and a potent inhibitor of the 5-hydroxytryptamine (5-HT_1B) receptor, was explored as a potential treatment for depression. To support clinical trials, repeat dose toxicity studies in rats and dogs were conducted. Here we report toxicity findings in dogs after dosing from 1 to 3 months. In the 1-month study, there were minimal neuronal vacuolation in the brain, a marked increase in liver enzymes accompanied by hepatocellular degeneration/necrosis and phospholipidosis (PLD), and PLD/cholecystitis in the gallbladder of animals dosed at 47 mg/kg/day. In the 3-month study, neurotoxicity resulted in euthanasia of one animal dosed at 30 mg/kg/day after 86 days. Extensive pathologic changes were seen in all animals in retina epithelium (inclusion bodies), brain (neuronal vacuolation, degeneration, or necrosis and nerve fiber degeneration), spinal ganglia (vacuolation, degeneration, or necrosis), as well as sciatic and optic nerves (degeneration). Pigment-laden macrophages were observed in the lung, kidney, liver, gallbladder, bone marrow, gastrointestinal tract, and lymphoid tissues. Also seen were vitrel and retinal hemorrhage in the eyes. A brain concentration and pathology study showed that the concentration of AZD3783 in the brain was approximately 4 times higher than in the plasma after 4 weeks of dosing, however, they were similar in all regions examined, and did not correlate with areas with pathologic findings. Our findings with AZD3783 in dogs have not been reported previously with other CNS compounds that effect through serotonergic pharmacology.     

Remedies for pseudoreplication

Pseudoreplication is the failure of a statistical analysis to properly incorporate the true structure of randomness present in the data. It has been well documented and studied in the ecological literature but has received little attention in the fisheries literature. Avoiding pseudoreplication in analyses of fisheries data can be difficult due to the complexity of the statistical procedures required. However, recent developments in statistical methodology are decreasing the extent to which pseudoreplication has to be tolerated. Seven examples are given here, beginning with simple design-based remedies and progressing to more challenging examples including the model-based remedies of mixed-effects modelling, generalized linear mixed models, state-space models, and geostatistics.     

Outbreak of Salmonella enterica serotype Newport in a beef cow-calf herd associated with exposure to bovine viral diarrhea virus

CASE DESCRIPTION: Severe disease and death in cows and calves affected 1 of 3 separate groups (A, B, and C) of cattle on a commercial cow-calf operation. CLINICAL FINDINGS: Clinical illness consisting of severe watery and bloody diarrhea, dehydration, weakness, and death affected adult cows and calves in 1 group (group B). Salmonella enterica serotype Newport was recovered from tissues of cows and calves from group B. TREATMENT AND OUTCOME: Despite supportive and antimicrobial treatment of cattle in group B, cow mortality rate attributable to salmonellosis in that group was 7.9% (32/407); calf mortality rate was 14.4% (52/361). None of the cows in Groups A or C died, and the calf mortality rate in those groups was low. Salmonella enterica serotype Newport was recovered from pooled fecal samples subsequently collected from each group of cows. Bovine viral diarrhea virus (BVDV) antigen was identified in an ear notch sample collected from a necropsied calf from group B. Subsequently, ear notch specimens from cattle in all 3 groups were tested for BVDV antigen. A significantly higher proportion of calves persistently infected with BVDV was identified in group B (8/295 [2.7%]), compared with the proportion in groups A and C combined (1/287 [0.3%]). CLINICAL RELEVANCE: Outbreaks of disease attributable to Salmonella Newport infection in beef cattle are unusual. Because of the immunosuppressive nature of BVDV, the possibility of animals persistently infected with BVDV within the herd should be considered during investigation of unusual outbreaks of infectious diseases.     

Use of index selection in recurrent selection programs in maize

Summary Phenotypic and genotypic correlations were examined for four traits in seven populations of maize (Zea mays L.) undergoing recurrent selection. Correlations among grain yield and percentage of grain moisture, root lodging, and stalk lodging were low (|r|<0.3) except for the correlation between grain yield and stalk lodging, which was high and negative. The phenotypic and genotypic correlations agreed well from cycle to cycle within populations. Variation of correlations among populations was not significantly larger than variation among cycles. Heritabilities of these traits generally were high (h²>0.5). Two indices, one that used heritabilities as index weights and one that used relative economic weights (base index) as index weights, were compared with the Smith-Hazel index (optimim index). Relative efficiencies of the two indices, in terms of predicted gains for the individual traits and the composite trait, compared with the Smith-Hazel index, were high. The use of an index in which heritabilities were used as index weights was recommended because:1) the heritabilities were the same as the optimum weights when the traits were uncorrelated, and for the data examined the correlations were low; and 2) heritabilities were computed in routine data analyses and were available at no additional cost.Joint contribution: USDA-SEA-AR and Journal Paper No. 10152 of the Iowa Agriculture and Home Economics Exp. Stn., Ames, Iowa. Project 2194.