The economics of the carbon sequestration potential of plantation forestry in south-western Uganda

This study assessed the amount of carbon stored and the economic viability of the small-scale Clean Development Mechanism (CDM) carbon offsets in Pinus caribaea and Eucalyptus grandis plantations under varying rotations. Volume equations were used to estimate carbon stocks and merchantable wood volume in the plantations, while net present value (NPV) and annual equivalent value (AEV) were used as measures of profitability at the optimum economic rotation age as well as at the CDM-defined crediting period of 20 years. The findings show that over a 20-year rotation, E. grandis and P. caribaea plantations sequestered 638 and 418 t CO₂-e ha^?1, respectively. The NPVs of E. grandis and P. caribaea with carbon credits over the CDM carbon-crediting period of 20 years were US$2 540 ha^?1 and US$1 814 ha^?1, respectively. This is higher than the NPVs without carbon credits of US$1 543 ha^?1 and US$1 390 ha^?1 for E. grandis and P. caribaea, respectively. The AEV of E. grandis harvested at its optimal economic rotation of 10 years was US$316 ha^?1. This is slightly higher than the AEV of US$298 ha^?1, utilising the CDM carbon-crediting period of 20 years. In contrast, the AEV of P. caribaea under the 20-year CDM carbon-crediting period was higher than harvesting at the optimal economic rotation of 16 years without carbon credits. When the average CDM contract establishment costs exceed US$500 ha^?1 and US$1 000 ha^?1 for P. caribaea and E. grandis woodlots, respectively, it is not economically viable for one to participate in the CDM forest carbon offsets programme. In conclusion, the study results indicate that whereas E. grandis has a higher biological potential to sequester carbon than P. caribaea, it is currently not economically viable for participation in the CDM forest carbon offset scheme. In contrast, it is economically viable for P. caribaea plantations to participate in the CDM, if the CDM contract establishment costs are low.     

Polymerase Chain Reaction Assays for the Detection and Discrimination of the Soybean Rust Pathogens Phakopsora pachyrhizi and P. meibomiae

ABSTRACT Soybean rust occurs in Australia and many countries throughout Africa, Asia, and South America. The causal agents of soybean rust are two closely related fungi, Phakopsora pachyrhizi and P. meibomiae, which are differentiated based upon morphological characteristics of the telia. Determination of the nucleotide sequence of the internal transcribed spacer (ITS) region revealed greater than 99% nucleotide sequence similarity among isolates of either P. pachyrhizi or P. meibomiae, but only 80% sequence similarity between the two species. Utilizing differences within the ITS region, four sets of polymerase chain reaction (PCR) primers were designed specifically for P. pachyrhizi and two sets for P. meibomiae. Classical and real-time fluorescent PCR assays were developed to identify and differentiate between P. pachyrhizi and P. meibomiae. Identification of P. pachyrhizi from infected soybean leaves using the real-time PCR assay will allow for more rapid diagnoses.     

Identification and Differentiation of Tilletia indica and T. walkeri Using the Polymerase Chain Reaction

ABSTRACT Karnal bunt of wheat, caused by Tilletia indica, was found in regions of the southwestern United States in 1996. Yield losses due to Karnal bunt are slight, and the greatest threat of Karnal bunt to the U.S. wheat industry is the loss of its export market. Many countries either prohibit or restrict wheat imports from countries with Karnal bunt. In 1997, teliospores morphologically resembling T. indica were isolated from bunted ryegrass seeds and wheat seed washes. Previously developed PCR assays failed to differentiate T. indica from the recently discovered ryegrass pathogen, T. walkeri. The nucleotide sequence of a 2.3 kb region of mitochondrial DNA, previously amplified by PCR only from T. indica, was determined for three isolates of T. indica and three isolates of T. walkeri. There was greater than 99% identity within either the T. indica group or the T. walkeri group of isolates, whereas there was =3% divergence between isolates of these two Tilletia species. Five sets of PCR primers were made specific to T. indica, and three sets were designed specifically for T. walkeri based upon nucleotide differences within the mitochondrial DNA region. In addition, a 212 bp amplicon was developed as a target sequence in a fluorogenic 5' nuclease PCR assay using the TaqMan system for the detection and discrimination of T. indica and T. walkeri.     

A study of the microbial flora of the anterior vagina of normal sows during different stages of the reproductive cycle

SUMMARY Sterile guarded swabs were used to sample the anterior vaginal and cervical area of 23 normal healthy sows during various stages of the reproductive cycle. The samples were collected one week before farrowing, within 24 hours of farrowing, weekly up to weaning, at mating and at 2 and 3 weeks after mating, and then plated and incubated aerobically and anaerobically. At least one positive sample was obtained from each sow and at each stage of the reproductive cycle. Most positive samples (78.3%) were obtained on the day of farrowing and the least 3 weeks after mating (19.0%). The second highest number of positive samples (45.5%) was found immediately after mating. Although there was no significant difference among sows of different parities, there was a trend for older sows to have more positive samples after farrowing (84.6%). There was a greater decrease in positive samples after farrowing and after mating among younger sows compared with older sows. A wide range of bacteria including aerobic and anaerobic species, were recovered from 142 Isolates. The more representative bacteria were Streptococcus spp (23.2%); Escherichia coll (22.5%); Staphylococcus spp (19.0%) and Corynebacterium spp (13.4%). Of the cultures, 54.7% were pure and 45.3% were mixed. Both the percentage of bacterial isolates as well as the type of culture (pure or mixed) were similar to those frequently reported in clinical cases of vulval discharge syndrome. The results indicate that sows usually develop infections of the reproductive tract at farrowing and mating but these infections do not normally persist.     

Confirmation of epidural needle placement using nerve stimulation in dogs

Caudal epidural anesthesia is useful when anesthesia of the lumbar and sacral dermatomes is needed. Its success relies on the proper placement of the needle in the epidural space. However, accurate positioning of the needle can be difficult in certain patients (i.e.obesity). The purpose of this preliminary study was to document the use of nerve stimulation as a means of confirming accurate needle positioning in the epidural space prior to drug administration. Twenty large breed dogs undergoing hindlimb or perineal surgery were enrolled. Following induction of general anesthesia, patients were prepared for routine epidural drug administration. A 17 ga, 3.5” shielded Tuohy needle was used and was connected to a peripheral nerve stimulator set to deliver a current at 1 Hz, with a pulse width of 0.2 m sec. Initial current was set at 1.2 mA as the needle was advanced into position. Confirmation of epidural needle placement was confirmed when twitches were observed in the hindlimbs and/or tail. Current setting was then decreased incrementally by 0.2 mA until no further twitches were observed. Success of epidural drug placement was confirmed subjectively by motor blockade to the blocked dermatomes and clinical signs of balanced anesthesia (lack of sympathetic response to surgical stimulation while maintained at light plane of anesthesia). Lowest mean (range) current to elicit hindlimb twitches was 0.72 mA (0.4–1.0 mA). Lowest mean (range) current to elicit tail twitches was 0.58 mA (0.4–1.0 mA). Tail twitches were reliably lost at mean current of 0.37 mA (0.2–0.8). Epidural anesthesia was considered to be successful in 19/20 dogs. In only 9/20 dogs, needle placement would have been correct based on using ‘classic’ indicators alone (‘pop’ as enter epidural space, loss of resistance to injection). The results of this study suggest that nerve stimulation may be useful in confirming correct epidural needle placement prior to drug administration.     

Evaluation of veterinarian and veterinary student knowledge and clinical use of pulse oximetry

We hypothesized that veterinarians and veterinary students may lack key knowledge about pulse oximetry, which may result in this type of patient monitor not being used on appropriate patient populations or to its full capabilities. A questionnaire was developed to assess an individual's knowledge and understanding of pulse oximetry. Residents and specialists in anesthesiology and critical care at several academic institutions were surveyed first to assess the questionnaire for clarity and to serve as a control group. General veterinary practitioners (GPs) attending continuing education courses at the University of Georgia were surveyed over a 24-month period. Students entering their senior year anesthesiology rotation at the University of Georgia were also surveyed. Residents and specialists (69% correct responses) scored significantly higher than senior students (46%), who scored significantly higher than GPs (34%). Only 15% of GPs and 21% of senior students reported that they had received training in pulse oximetry in school. Those who had received training scored significantly higher than those who did not. Many GPs did not report using a pulse oximeter on their critical patients under anesthesia, a group that would be expected to benefit from its use. Veterinarians have a poor understanding about how pulse oximetry works, the information provided by pulse oximetry, and how to best apply it to their patients. Furthermore, the respondents did not use pulse oximeters in a manner that would derive the most information and result in the greatest benefit to the patient relative to the cost of the instrument. Didactic training in veterinary curricula and during continuing education opportunities continues to be necessary in order to produce veterinarians, who have an understanding of the technologies available that can be used to improve patient care.     

Effects of Cryopreservation on Bull Spermatozoa Distribution in Morphometrically Distinct Subpopulations

Assisted sperm morphometry analysis (ASMA) was used in this study to determine the effects of cryopreservation on bull spermatozoa distribution in morphometrically distinct subpopulations. Ejaculates were collected from five bulls and were divided. One portion was diluted at 30 degrees C in a skim milk-egg yolk medium, containing glycerol. A microscope slide was prepared from single extended sperm samples prior to freezing. The remainder of each sample was frozen in nitrogen vapours. After thawing, sperm smears were prepared as described above. All slides were air dried and stained with Hemacolor. The sperm-head dimensions for a minimum of 200 sperm heads were analysed from each sample by means of the Sperm-Class Analyser (SCA), and the mean measurements recorded. Our results showed that applying the ASMA technology and multivariate cluster analyses, it was possible to determine that three separate subpopulations of spermatozoa with different morphometric characteristics coexist in bull ejaculates (large, average and small spermatozoa). The mean values of each sperm head dimension among the three subpopulations of spermatozoa were significantly different (p < 0.001). Besides, there were significant (p < 0.001) differences in the distribution of these three sperm subpopulations between fresh and thawed samples. Thus, the percentage of representation of the subpopulation that includes those spermatozoa whose dimensions are the biggest, decreased from 52.06% in extended fresh samples to 15.51% in the thawed ones. Contrarily, the percent of representation of the subpopulation containing the smallest spermatozoa, increased from 8.70% in extended fresh samples to 34.04% in the thawed ones. In conclusion, the present study confirms the heterogeneity of sperm head dimensions in bull semen, heterogeneity that vary through the cryopreservation procedure.