Accurate forest projections require long-term wood decay experiments because plant trait effects change through time.

Whether global change will drive changing forests from net carbon (C) sinks to sources relates to how quickly deadwood decomposes. Because complete wood mineralization takes years, most experiments focus on how traits, environments and decomposer communities interact as wood decay begins. Few experiments last long enough to test whether drivers change with decay rates through time, with unknown consequences for scaling short-term results up to long-term forest ecosystem projections. Using a 7 year experiment that captured complete mineralization among 21 temperate tree species, we demonstrate that trait effects fade with advancing decay. However, wood density and vessel diameter, which may influence permeability, control how decay rates change through time. Denser wood loses mass more slowly at first but more quickly with advancing decay, which resolves ambiguity about the after-life consequences of this key plant functional trait by demonstrating that its effect on decay depends on experiment duration and sampling frequency. Only long-term data and a time-varying model yielded accurate predictions of both mass loss in a concurrent experiment and naturally recruited deadwood structure in a 32-year-old forest plot. Given the importance of forests in the carbon cycle, and the pivotal role for wood decay, accurate ecosystem projections are critical and they require experiments that go beyond enumerating potential mechanisms by identifying the temporal scale for their effects.

Spatiotemporal niche partitioning in a specious silphid community (Coleoptera: Silphidae Nicrophorus).

Resource niche partitioning mediates the coexistence of similar species by reducing the chance of competitive encounters. For co-occurring species that share an ephemeral resource, contrasting activity in space and time may facilitate their persistence. Burying beetles (Silphidae: Nicrophorus) depend entirely on small vertebrate carcasses to reproduce. Given the unpredictability of this resource, and its value to congeners and other scavenger species, burying beetles likely endure intense competition to secure a carcass. Here, contrasting spatial and temporal niche patterns are explored as resource allocation strategies among five sympatric species of burying beetles (N. americanus, N. marginatus, N. pustulatus, N. orbicollis, and N. tomentosus). Specifically, the space-use and daily activity patterns are measured, at a fine scale, across species pairs to extrapolate contrasting niche-use patterns within a nicrophorine-rich grassland community in North-Central Oklahoma, USA. The results of this study reveal an important interplay between space-use and daily temporal activity in mediating the scramble competition associated with carrion resources. Where spatial or temporal overlap between burying beetle species is high, direct competition is mediated along an alternative niche dimension. For instance, N. americanus and N. orbicollis, a species dyad thought to be in direct competition, do overlap temporally but were found to have segregated space-use patterns. Our findings provide key insights into the competitive interactions within a necrophilous community and further inform our broader understanding of the spatial and temporal resource dimensions that drive the ecological niche.

Negative density dependence is stronger in resource-rich environments and diversifies communities when stronger for common but not rare species.

Conspecific negative density dependence is thought to maintain diversity by limiting abundances of common species. Yet the extent to which this mechanism can explain patterns of species diversity across environmental gradients is largely unknown. We examined density-dependent recruitment of seedlings and saplings and changes in local species diversity across a soil-resource gradient for 38 woody-plant species in a temperate forest. At both life stages, the strength of negative density dependence increased with resource availability, becoming relatively stronger for rare species during seedling recruitment, but stronger for common species during sapling recruitment. Moreover, negative density dependence appeared to reduce diversity when stronger for rare than common species, but increase diversity when stronger for common species. Our results suggest that negative density dependence is stronger in resource-rich environments and can either decrease or maintain diversity depending on its relative strength among common and rare species.

Routine assessment of anxiety among adolescents in a primary care clinic.

BACKGROUND: Approximately 20% to 25% of all adolescents experience significant symptoms of anxiety, but only half of those adolescents are diagnosed and treated. Recent clinical guidelines recommend routine assessment of adolescent anxiety symptoms in the primary care setting to improve the rates of identification and treatment of anxiety in this population. The objective of this project was to increase early identification and referral for treatment of adolescent anxiety during primary care visits. METHODS: This project used the Generalized Anxiety Disorder-7 screening tool to assess anxiety symptoms in adolescents in a school-based primary care clinic. Upon arrival to the clinic, adolescent patients completed the brief self-assessment. The provider then used the assessment score to determine the need for further assessment and referral for treatment. RESULTS: Of the 51 participants, 21.6% were referred to a mental health provider following assessment, compared with 1.2% of adolescent patients seen in the 6-month period immediately preceding the project. CONCLUSION: The results indicate that screening for symptoms of anxiety in adolescents using a brief self-assessment survey is an effective method for achieving the desired outcome of increased identification and referral for treatment of anxiety symptoms in this population.

In vitro comparison of cortical bone temperature generation between traditional sequential drilling and a newly designed step drill in the equine third metacarpal bone.

OBJECTIVES: To compare heat generation and time to finish between a new step drill and sequential drilling in order to create a 6.2 mm pilot hole for insertion of a positive profile transfixation pin into the equine third metacarpal bone. METHODS: Nine pairs of equine third metacarpal bones from cadavers of adult horses were used. Maximum temperature rise of the bone was measured continuously at the cis- and trans-cortices 1, 2 and 3 mm from the final pilot hole during creation of a 6.2 mm hole using a step drill and sequential drilling with 4.5, 5.5 and 6.2 mm drill bits. Five holes were drilled into the mid diaphysis of each bone in lateral to medial direction, and drilling forces of 60, 80 and 120 N were used (15 holes in each group). Time from start to finish was measured and cortical thickness was recorded for each hole. RESULTS: The maximum heat generation (mean [95% CI]) with step drilling and sequential drilling was not significantly different at 60 N and 120 N of drilling force. However, at 80 N of drilling force, the 2.13 degrees C difference between the two drilling techniques was significant. The time to finish (seconds) was significantly shorter for the holes created by step drilling (35.1 [32.06 - 37.59]) than by sequential drilling (145.8 [138.52 - 151.67]) (P < 0.001). CLINICAL RELEVANCE: Based on our results, we concluded that the step drill is a viable alternative to traditional sequential drilling of equine third metacarpal bone because it did not result in excessive heat generation that can result in bone necrosis.

Dynamics of infections with gastrointestinal parasites and Dictyocaulus viviparus in dairy and beef cattle from Costa Rica.

A longitudinal survey was carried out to determine and describe the prevalence and intensity of gastrointestinal parasite infections and Dictyocaulus viviparus in a dairy and a beef cattle farm of two different ecological zones in Costa Rica. The influence of anthelmintic treatment, age and meteorological factors (rainfall, minimum and maximum temperatures) on gastrointestinal nematodes and D. viviparus counts was determined. Calves were subjected to monthly sampling of feces and blood between April 2002 and March 2003. Coprological techniques were used to detect gastrointestinal helminthes, protozoan and D. viviparus. Blood samples were analyzed for antibodies to D. viviparus by ELISA. The most prevalent gastrointestinal parasites detected on both farms (dairy cattle, A; beef cattle, B) were Eimeria spp. (94.7%, 93.7%), Strongylidae (75.0%, 81.4%), Buxtonella sulcata (38.0%, 21.6%) and Strongyloides papillosus (29.8%, 31.7%), whereas Moniezia benedeni (4.8%, 9.1%), Trichuris spp. (7.3%, 13.2%), Toxocara vitulorum (0.0%, 1.8%) and Entamoeba bovis (2.5%, 1.1%) were less prevalent. Mean fecal egg counts (FEC) showed highest values of Strongylidae in April, May and July (>335.3 eggs/g feces) on farm A, and April, May and August (>304.3 eggs/g feces) on farm B. S. papillosus presented low FEC throughout the year on farm A, on farm B the highest values were obtained in April (303.0 eggs/g feces). Trichuris spp. presented maximum FEC values in May (328.6 eggs/g feces) on farm A and in June (157.5 eggs/g feces) on farm B. Treatment and age had significant influence on infection intensity of Strongylidae (farms A and B), S. papillosus (farms A and B) and Trichuris spp. (farm A). Rainfall had significant effect on S. papillosus (farms A and B) and Trichuris spp. (farm B). Maximum temperature showed significant effect on S. papillosus (farm A) and Trichuris spp. (farms A and B). Minimum temperature had significant influence on Strongylidae (farm A), S. papillosus (farms A and B) and Trichuris spp. (farm B). Haemonchus spp. (57%, 66%) and Cooperia spp. (30.0%, 30.7%) were the most prevalent genera identified by coproculture on both farms, in contrast, Trichostrongylus spp. and Oesophagostomum spp. were less frequent. Patent lungworm infections were low on both farms (10.8%, 1.8%). On farm A, high prevalence of antibodies against D. viviparus was determined only at the beginning of the study, in contrast, on farm B the seroprevalence fluctuated throughout the year. Treatment, age and maximum temperature had significant effect on D. viviparus counts on farm A, but not on farm B.

Serological evidence of Leptospira interrogans serovar Bratislava infection and its association with abortions in cattle in northern Spain.

A cross-sectional study was carried out in the Basque Country of Spain to determine the seroprevalence of 10 Leptospira serovars in a population of dairy cattle with poor fertility, and a case-control study was carried out in another northern area to investigate the role of Leptospira interrogans serovar Bratislava in abortions. L. Bratislava was the most prevalent serovar in the cross-sectional study, with 25.4 per cent of the cows testing positive in the microagglutination test when a cut-off of 1:10 or higher was applied, followed by Leptospira Hardjo (8.2 per cent), Leptospira Pomona (7.7 per cent), Leptospira Autumnalis (0.7 per cent) and Leptospira Copenhageni (0.1 per cent). In the case-control study the seroprevalence of L. Bratislava was significantly higher among the cows which had aborted when a titre of 1:300 or more was used as a cut-off (9.7 per cent v 3.4 per cent, P=0.008); 69 per cent of the L. Bratislava-infected cows that had aborted apparently aborted as a result of the infection.

In vitro biomechanical evaluation and comparison of a new prototype locking plate and a limited-contact self compression plate for equine fracture repair.

OBJECTIVE: To determine if the mechanical properties (strength and stiffness) of a new prototype 4.5 mm broad locking plate (NP-LP) are comparable with those of a traditional 4.5 mm broad limited-contact self compression plate (LC-SCP), and to compare the bending and torsional properties of the NP-LP and LC-SCP when used in osteotomized equine third metacarpal bones (MC3). METHODS: The plates alone were tested in four-point bending single cycle to failure. The MC3-plate constructs were created with mid-diaphyseal osteotomies with a 1 cm gap. Constructs were tested in four-point bending single cycle to failure, four-point bending cyclic fatigue, and torsion single cycle to failure. RESULTS: There were not any significant differences in bending strength and stiffness found between the two implants. The MC3-NP-LP construct was significantly stiffer than the MC3-LC-SCP in bending. No other biomechanical differences were found in bending, yield load in torsion, or mean composite rigidity. Mean cycles to failure for bending fatigue testing were similar for both constructs. CLINICAL SIGNIFICANCE: The NP-LP was comparable to the LC-SCP in intrinsic, as well as structural properties. The NP-LP construct was more rigid than the LC-SCP construct under four-point bending, and both constructs behaved similarly under four-point bending cyclic fatigue testing and torsion single cycle to failure. The new NP-LP implant fixation is biomechanically comparable to the LC-SCP in a simulated MC3 fracture.