Ultrasound‐guided approach for axillary brachial plexus,femoral nerve,and sciatic nerve blocks in dogs

Objective To describe an ultrasound‐guided technique and the anatomical basis for three clinically useful nerve blocks in dogs. Study design Prospective experimental trial. Animals Four hound‐cross dogs aged 2 ± 0 years (mean ± SD) weighing 30 ± 5 kg and four Beagles aged 2 ± 0 years and weighing 8.5 ± 0.5 kg. Methods Axillary brachial plexus, femoral, and sciatic combined ultrasound/electrolocation‐guided nerve blocks were performed sequentially and bilaterally using a lidocaine solution mixed with methylene blue. Sciatic nerve blocks were not performed in the hounds. After the blocks, the dogs were euthanatized and each relevant site dissected. Results Axillary brachial plexus block Landmark blood vessels and the roots of the brachial plexus were identified by ultrasound in all eight dogs. Anatomical examination confirmed the relationship between the four ventral nerve roots (C6, C7, C8, and T1) and the axillary vessels. Three roots (C7, C8, and T1) were adequately stained bilaterally in all dogs. Femoral nerve block Landmark blood vessels (femoral artery and femoral vein), the femoral and saphenous nerves and the medial portion of the rectus femoris muscle were identified by ultrasound in all dogs. Anatomical examination confirmed the relationship between the femoral vessels, femoral nerve, and the rectus femoris muscle. The femoral nerves were adequately stained bilaterally in all dogs. Sciatic nerve block. Ultrasound landmarks (semimembranosus muscle, the fascia of the biceps femoris muscle and the sciatic nerve) could be identified in all of the dogs. In the four Beagles, anatomical examination confirmed the relationship between the biceps femoris muscle, the semimembranosus muscle, and the sciatic nerve. In the Beagles, all but one of the sciatic nerves were stained adequately. Conclusions and clinical relevance Ultrasound‐guided needle insertion is an accurate method for depositing local anesthetic for axillary brachial plexus, femoral, and sciatic nerve blocks.     

Improving Estimates of Rangeland Carbon Sequestration Potential in the US Southwest

Rangelands make an important contribution to carbon dynamics of terrestrial ecosystems. We used a readily accessible interface (COMET VR) to a simulation model (CENTURY) to predict changes in soil carbon in response to management changes commonly associated with conservation programs. We also used a subroutine of the model to calculate an estimate of uncertainty of the model output based on the similarity between climate, soil, and management history inputs and those used previously to parameterize the model for common land use (cropland to perennial grassland) and management (stocking rate reductions and legume addition) changes to test the validity of the approach across the southwestern United States. The conversion of small grain cropland to perennial cover was simulated acceptably (<20% uncertainty) by the model for soil, climate, and management history attributes representative of 32% of land area currently in small grain production, while the simulation of small grain cropland to perennial cover + legumes was acceptable on 73% of current small grain production area. The model performed poorly on arid and semiarid rangelands for both management (reduced stocking) and restoration (legume addition) practices. Only 66% of land area currently used as rangeland had climate, soil, and management attributes that resulted in acceptable uncertainty. Based on our results, it will be difficult to credibly predict changes to soil carbon resulting from common land use and management practices, both at fine and coarse scales. To overcome these limitations, we propose an integrated system of spatially explicit direct measurement of soil carbon at locations with well-documented management histories and climatic records to better parameterize the model for rangeland applications. Further, because the drivers of soil carbon fluxes on rangelands are dominated by climate rather than management, the interface should be redesigned to simulate soil carbon changes based on ecological state rather than practice application.     

Net Carbon Fluxes Over Burned and Unburned Native Tallgrass Prairie

Prescribed burning of aboveground biomass in tallgrass prairie is common and may influence dynamics and magnitudes of carbon (C) movement between the surface and atmosphere. Carbon dioxide (CO₂) fluxes were measured for 2 yr using conditional sampling systems on two adjacent watersheds in an ungrazed tallgrass prairie near Manhattan, Kansas. One watershed was burned annually (BA) and the other biennially (BB). Leaf and soil CO₂ fluxes were measured in the source area. Net ecosystem exchange (NEE) of CO₂ reached a maximum daily gain of 26.4 g CO₂·m^?2·d^?1 (flux toward surface is positive) in July 1998 (year when both sites were burned and precipitation was above normal); gains were similar between sites in 1998. The maximum daily NEE loss of CO₂ was ?21.8 g CO₂·m^?2·d^?1 from BA in September 1997 (year when only BA was burned and precipitation was below normal). When data were integrated over the two years, both sites were net sources of atmospheric CO₂; NEE was ?389 g C·m^?2·2 yr^?1 on BA and ?195 g C·m^?2·2 yr^?1 on BB. Burning increased canopy size and photosynthesis, but the greater photosynthesis was offset by corresponding increases in respiration (from canopy and soil). Carbon losses from fire represented 6–10% of annual CO₂ emissions (bulk came from soil and canopy respiration). Data suggest that annual burning promotes C loss compared to less-frequently burned tallgrass prairie where prairie is not grazed by ungulates. Greater precipitation in 1998 caused large increases in biomass and a more positive growing season NEE, indicating that C sequestration appears more likely when precipitation is high. Because C inputs (photosynthesis) and losses (canopy and soil respiration) were large, small measurement or modeling errors could confound attempts to determine if the ecosystems are long-term CO₂ sources or sinks.     

Understanding the role of urban forests for migrants – uses,perception and integrative potential

Worldwide migration and integration are current issues facing big cities. Immigrants and their descendants represent an important percentage of today's urban populations. Different policies ranging from labour markets to education, housing or health policies address the specific needs of this part of society. However, public policy and planning concepts related to urban forests rarely focus on immigrants. Very few studies investigate the recreation patterns of immigrants despite the potential influence of their different cultural backgrounds on their perceptions or preferences regarding urban woodlands. In addition, urban woodlands could potentially play a role in the social integration of migrants into the society due to being an element of nature with a strong symbolic identification potential and also a public space for social interactions. This paper discusses the results of a qualitative enquiry carried out in Freiburg, Germany, involving migrants from Turkey, the Balkan countries and Russia-Germans. The results point towards many differences in their recreational use patterns and their perception of urban forests, especially between the Turkish interviewees and the other two groups. Furthermore, the results suggest that the emotional attachment to forests can play diverse roles in the identification process of immigrants to their host country. Finally, social interactions were depicted in the interviews as being an important aspect of a forest visit. Nevertheless, social contact between forest visitors seemed to remain mostly on a ‘small-talk’ level.     

Conservation of northern bobwhite on private lands in Georgia, USA under uncertainty about landscape-level habitat effects

Large-scale habitat enhancement programs for birds are becoming more widespread, however, most lack monitoring to resolve uncertainties and enhance program impact over time. Georgia’s Bobwhite Quail Initiative (BQI) is a competitive, proposal-based system that provides incentives to landowners to establish habitat for northern bobwhites (Colinus virginianus). Using data from monitoring conducted in the program’s first years (1999–2001), we developed alternative hierarchical models to predict bobwhite abundance in response to program habitat modifications on local and regional scales. Effects of habitat and habitat management on bobwhite population response varied among geographical scales, but high measurement variability rendered the specific nature of these scaled effects equivocal. Under some models, BQI had positive impact at both local farm scales (1, 9 km²), particularly when practice acres were clustered, whereas other credible models indicated that bird response did not depend on spatial arrangement of practices. Thus, uncertainty about landscape-level effects of management presents a challenge to program managers who must decide which proposals to accept. We demonstrate that optimal selection decisions can be made despite this uncertainty and that uncertainty can be reduced over time, with consequent improvement in management efficacy. However, such an adaptive approach to BQI program implementation would require the reestablishment of monitoring of bobwhite abundance, an effort for which funding was discontinued in 2002. For landscape-level conservation programs generally, our approach demonstrates the value in assessing multiple scales of impact of habitat modification programs, and it reveals the utility of addressing management uncertainty through multiple decision models and system monitoring.     

Microbial Community Analysis of Water, Foregut, and Hindgut during Growth of Pacific White Shrimp, Litopenaeus vannamei, in Closed-System Aquaculture

In closed recirculating systems, a particulate matter consisting of bacteria, algae, fungi, and detritus develops spontaneously. This microbial floc can serve as a high‐protein food source for finfish and shellfish and has the potential to supplement the protein required in shrimp feed. To advance the use of microbial floc as a feed supplement, it is necessary to manipulate its microbial components, which requires thorough characterization of the bacterial components. Pacific white shrimp, Litopenaeus vannamei, were raised in a closed recirculating system, and water was compared to the contents of shrimp foreguts and hindguts. Water consistently contained less microbial biomass than did shrimp guts, but 16S rDNA sequences indicated that water was more diverse than shrimp guts. Phylogenetic analysis of 16S rDNA sequences retrieved from water and shrimp foregut grouped these sequences into various unrelated generic clusters. Fatty acid analysis demonstrated that shrimp feed was not a major contributor of microbial fatty acids to shrimp tanks, as the feed mostly contained polyunsaturated fatty acids, which are typically found only in eukaryotes. It is hoped that elucidating more details about the various components of microbial floc will help in understanding its development and will lead to its use as a high‐protein feed supplement.     

Abundance and conservation status of the Yangtze finless porpoise in the Yangtze River, China

The Yangtze finless porpoise (Neophocaena phocaenoides asiaeorientalis) is endemic to the middle and lower reaches of the Yangtze River, China. It is the only freshwater population of porpoises in the world and is currently listed as Endangered by IUCN. In November and December 2006 we used two boats and line transect methods to survey the entire current range of the population, except for two lakes (Poyang and Dongting). Sighting results were similar for both boats, so we pooled all data and analyzed them using two line transect models and a strip transect model. All models produced similar estimates of abundance (1111, 1225 and 1000). We then added independent estimates of the number of porpoises from the two lakes for a total estimate of approximately 1800 porpoises. Our findings indicate that the population continues to decline and that its distribution is becoming more fragmented. Our current estimate in the main river is slightly less than half the estimate from surveys between 1984 and 1991 (which was probably an underestimate). We also found an apparent gap in the distribution of porpoises between Yueyang and Shishou (∼150 km), where sightings had previously been common. Continued threats to Yangtze finless porpoises include bycatch in unregulated and unselective fishing, habitat degradation through dredging, pollution and noise, vessel strikes and water development. Immediate protective measures are urgently needed to ensure the persistence of finless porpoises in the Yangtze River. The survey design and analytical methods developed in this study might be appropriate for surveys of cetaceans in other river systems.     

Historical Changes in Stocking Densities on Texas Rangelands

Stocking density, both current and past, is a major determinant of the nature and condition of rangelands. Despite this fact, there have been few detailed examinations of historical trends in stocking density. We used data from the U.S. Census of Agriculture to track the density of domestic livestock from the early 1900s to the present, for six rangeland regions in the State of Texas: (1) the Edwards Plateau; (2) the Trans-Pecos; (3) the Lampasas Cut Plain; (4) the South Texas Plains; (5) the Rolling Plains; and (6) the High Plains. We find that stocking densities have declined across the state—ranging from a decline of about 40% in some regions to as much as 75% in the Trans-Pecos and Edwards Plateau regions. The period of sharpest decline, which began in the middle of the last century, reflects important, but not fully understood, socioeconomic changes. These most likely include changing land ownership, fragmentation of land holdings, and increasing emphasis on wildlife conservation. Other factors potentially contributing to the destocking of Texas rangelands include woody plant encroachment and a rise in predation. We argue that the dramatic reduction in stocking densities documented here has profound socioeconomic, ecological, and hydrological implications that need to be better understood.     

Evaluation of diode endoscopic cyclophotocoagulation in bovine cadaver eyes

Objective-To evaluate the anterior chamber approach and energy levels for endoscopic cyclophotocoagulation (ECPC) and assess ECPC-induced tissue damage in phakic eyes of bovine cadavers. Sample-12 bovine cadaver eyes. Procedures-Angle of reach was measured in 6 eyes following placement of a curved endoscopic probe through multiple corneal incisions. In another 6 eyes, each ocular quadrant underwent ECPC at 1 of 3 energy levels (0.75, 0.90, and 1.05 J) or remained untreated. Visible effects on tissues (whitening and contraction of ciliary processes) were scored (scale of 0 [no effects] to 6 [severe effects]), and severity and extent of histologic damage to the pigmented and nonpigmented ciliary epithelium and fibromuscular stroma were each scored (scale of 0 [no effect] to 3 [severe effect]) and summed for each quadrant. Overall mean scores for 6 quadrants/treatment were calculated. Results-Mean ± SD combined angle of reach was 148 ± 24° (range, 123 ± 23° [ventromedial] to 174 ± 11° [dorsolateral]). At the 0.75-, 0.90-, and 1.05-J levels, mean visible tissue effect scores were 3.12 ± 0.47, 3.86 ± 0.35, and 4.68 ± 0.58, respectively; mean histologic damage scores were 4.79 ± 1.38 (mild damage), 6.82 ± 1.47 (moderate damage), and 9.37 ± 1.42 (severe damage), respectively. Occasional popping noises (venting of vaporized interstitial water) were heard at the 1.05-J level. Conclusions and Clinical Relevance-Multiple incisions were necessary to facilitate 360° ECPC treatment in bovine eyes. For ECPC in vivo, the 0.75- and 0.90-J energy levels had the potential to effectively treat the ciliary epithelium.     

Probing the faintest stars in a globular star cluster

NGC 6397 is the second closest globular star cluster to the Sun. Using 5 days of time on the Hubble Space Telescope, we have constructed an ultradeep color-magnitude diagram for this cluster. We see a clear truncation in each of its two major stellar sequences. Faint red main-sequence stars run out well above our observational limit and near to the theoretical prediction for the lowest mass stars capable of stable hydrogen burning in their cores. We also see a truncation in the number counts of faint blue stars, namely white dwarfs. This reflects the limit to which the bulk of the white dwarfs can cool over the lifetime of the cluster. There is also a turn toward bluer colors in the least luminous of these objects. This was predicted for the very coolest white dwarfs with hydrogen-rich atmospheres as the formation of H(2) and the resultant collision-induced absorption cause their atmospheres to become largely opaque to infrared radiation.