Morphological and physiological responses of the invasive weed Isatis tinctoria to contrasting light, soil-nitrogen and water

We evaluated the morphological and physiological responses to contrasting above- and below-ground resources for the invasive weed, Isatis tinctoria L. (dyer's woad). Plants were grown under low and high levels of light [shade (50% of ambient) and full sun], soil water (50 and 100 mL day⁻¹), and soil nitrogen (N) (0 and 20 mg N kg⁻¹ soil) in 8 L pots in 63 day glasshouse experiments conducted during winter and spring. Soil-N enrichment did not increase any of the growth variables (shoot and root dry mass, shoot:root ratio, leaf area, and specific leaf area) or physiological variables (stomatal conductance and ¹³C discrimination) in either experiment. The absence of plasticity in response to changes in soil-N supply suggests that I. tinctoria may survive and persist in nutrient-poor conditions by having low-N requirements, low-N productivity, or both. In contrast, plants compensated for shaded conditions by altering leaf area, specific leaf area, and shoot:root ratio to improve light capture. We discuss the potential mechanisms whereby response to these variable resources may be associated with a series of adaptations that favour the ability to tolerate and colonize harsh, nutrient-poor conditions, as well as invade shaded and undisturbed sites.     

Regional Economic Diversity and Diversification

ABSTRACT Regional scientists have long attempted to develop meaningful definitions and measures of economic diversity and diversification, and to establish functional relationships between diversity, diversification, and economic performance. The multiplicity of definitions and measures explains, in part, the confusion about these relationships. A framework that sorts out the overlaps, contradictions, and gaps of the various definitions and measures IS needed. Such a framework would explicitly address the question, “What is the relationship between a region's changing economic structure and performance?” In this paper it is suggested that an input-output model that incorporates elements of portfolio theory be used as the integrating framework for analysis.     

Mandibular Fractures in the Dog A Retrospective Study of 157 Cases

One hundred fifty-seven mandibular fractures in 105 dogs occurred most frequently in male dogs less than 1 year of age. Automobile trauma was the most common cause. Fractures in the premolar region were significantly more frequent than fractures in other regions, and 113 fractures (72%) were open. One hundred forty-two fractures were stabilized, with tape muzzles being the most common method. Postoperative complications, the most common being dental malocclusion, occurred in 53 fractures (34%). Acceptable cosmetic and functional results were achieved in 89 dogs (85%). Fractures in the rostral portion of the mandible had shorter average time to clinical union than other mandibular fractures. Average time to clinical union for fractures in the caudal portions of the mandible was longer than that currently reported.     

A real-time polymerase chain reaction assay for the detection of Mycoplasma agalactiae

AIM: To develop a real-time PCR for the detection of Mycoplasma agalactiae, using PCR primers targeting the ma-mp81 gene.

METHODS: A group of 15 M. agalactiae isolates, 21 other Mycoplasma spp. isolates and 21 other bacterial isolates was used in evaluation of the assay.

RESULTS: All M. agalactiae isolates were detected by the assay and none of the non-target isolates was amplified. The analytical detection limit of the assay was 10 fg of purified genomic DNA and 10⁴ cfu/ml milk inoculated with M. agalactiae. When applied to goat-milk samples collected from three herds free of M. agalactiae infection, the assay had a specificity of 100%.

CONCLUSIONS: The assay would be useful in a diagnostic laboratory, providing specific, sensitive and rapid detection of M. agalactiae.     

CONTRAST-ENHANCED COMPUTED TOMOGRAPHY AS A PREOPERATIVE INDICATOR OF VASCULAR INVASION FROM ADRENAL MASSES IN DOGS

The purpose of this study was to determine if contrast-enhanced computed tomography (CT) accurately reflected vascular luminal invasion by adrenal masses in dogs. Medical records of 15 dogs with 17 adrenal masses that underwent preoperative CT imaging were reviewed. Presence or absence of vascular invasion was confirmed by surgery or necropsy/histology. Vascular invasion was identified correctly using contrast-enhanced CT in 11/12 dogs. The sensitivity and specificity of contrast-enhanced CT for vascular invasion compared with surgery or necropsy was 92% and 100%, respectively. The positive predictive value and negative predictive value of contrast-enhanced CT was 100% and 90%, respectively. The accuracy was 95%. In one dog, invasion of the phrenicoabdominal vein was not identified on CT images. Six of eight masses with vascular invasion where a histologic diagnosis was obtained were malignant. Four of four pheochromocytomas invaded adjacent vasculature. Contrast-enhanced CT provided accurate preoperative assessment of adrenal masses. Vascular invasion by adrenal masses in this study occurred by way of the lumen of the phrenicoabdominal vein with subsequent intraluminal extension into other veins, rather than by erosion through vessel walls.