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Linkage disequilibrium (LD) mapping is commonly used as a fine mapping tool in human genome mapping and has been used with some success for initial disease gene isolation in certain isolated in-bred human populations. An understanding of the population history of domestic dog breeds suggests that LD mapping could be routinely utilized in this species for initial genome-wide scans. Such an approach offers significant advantages over traditional linkage analysis. Here, we demonstrate, using canine copper toxicosis in the Bedlington terrier as the model, that LD mapping could be reasonably expected to be a useful strategy in low-resolution, genome-wide scans in pure-bred dogs. Significant LD was demonstrated over distances up to 33.3 cM. It is very unlikely, for a number of reasons discussed, that this result could be extrapolated to the rest of the genome. It is, however, consistent with the expectation given the population structure of canine breeds and, in this breed at least, with the hypothesis that it may be possible to utilize LD in a genome-wide scan. In this study, LD mapping confirmed the location of the copper toxicosis in Bedlington terrier gene (CT-BT) and was able to do so in a population that was refractory to traditional linkage analysis.

The early effects of a clinical dose of cisplatin (100 mg/m2) on distortion-product otoacoustic emissions (DPOAE) thresholds and the relationship between DPOAE threshold shifts and changes in plasma concentrations of filterable and total platinum (Pt) following infusion of cisplatin in a dog model were investigated. The DPOAE thresholds (based on input-output function) were measured 2 days before a single high dose of cisplatin administration, and compared with measurements recorded 2 and 4 days after infusion. The results revealed DPOAE thresholds to be elevated by 4 days after the administration of cisplatin. However, this elevation could not be correlated with plasma concentrations of filterable and total Pt, which showed little variation over the 48-hour postinfusion period between animals. The present study demonstrated that DPOAE thresholds have the potential to be used as an indicator of cisplatin-induced ototoxicity, and cisplatin-induced ototoxicity could not be explained by plasma Pt kinetics in individual animals.

Objective To describe the ontogeny of blood cells throughout foetal development in sheep. Design A haematological study on blood and bone marrow from 42 sheep foetuses aged between 19 days gestation and full term. Procedure Virgin Merino ewes were mated and the developing foetuses removed surgically at different stages of gestation. Blood and bone marrow samples were collected, stained for cytological examination or processed for electron microscopy. Blood samples were also examined haematologically. Foetuses were incubated with H-3-thymidine and autoradiographed. Results During the first 4 weeks of development primitive erythroblast constituted the majority of the circulating blood cells. Definitive erythroid cells, originating in the liver, first appeared in the blood at around 27 days gestation and entirely replaced the primitive erythroblasts by 50 days gestation. Leukocyte numbers, especially lymphocyte count, increased rapidly after 49 days gestation. Erythropoiesis predominated in the marrow of all foetuses older than 70 days. In bone marrow, myelopoiesis was the major activity and lymphopoiesis was not significant. Conclusions Red blood cell numbers and haemoglobin content progressively increases during foetal development. Primitive erythroblasts are not the precursors of the definitive erythroblasts. There are no significant differences in morphological features or maturation sequence between hepatic and bone marrow erythroblasts. Myelopoiesis is a major activity of bone marrow rather than of foetal liver.

To measure the prevalence of megabacteria in budgerigar-breeding colonies and to evaluate possible methods to reduce the prevalence.A monitoring study over several years.Two budgerigar (Melopsittacus undulatus) colonies with over 300 birds each.The prevalence of megabacteria in the faeces in two budgerigar breeding colonies, colony 1 and 2, was determined by faecal examination of each bird. Following an initial survey (1990), most of the birds that were scored 2+ or more were culled and a management practice was implemented to discriminate against positive birds. Consecutive yearly surveys (1991, 1992) were conducted on the young birds bred in these colonies. The prevalence of megabacteria in colony 2 was also evaluated in 1994 and 1996 after all the birds were treated with amphotericin B administered in drinking water.The prevalence of megabacteria in the two colonies was significantly (P0.001) different. Overall the prevalence of megabacteria adjusted for colony differences was significantly higher (P0.025) in males compared to females. Age was not an influencing factor. After the initial survey, the prevalence in the offspring did not significantly (P0.05) decrease in the following two annual breeding seasons but by inference it did significantly decrease after amphotericin B treatment.The practice of culling most birds with more megabacteria in faeces and discriminating against positive birds when selecting birds for breeding or culling birds on show quality does not decrease megabacteria prevalence in the offspring. However, a reduction in prevalence does occur with administration of amphotericin B. Birds may have amphotericin B-resistant organisms and these birds need to be identified and culled.

Transient (click)-evoked oto-acoustic emissions (TEOAEs) and distortion product oto-acoustic emissions (DPOAEs) were recorded in a feasibility study in 7 healthy mixed-breed dogs using the ILO 92 OAE analyser (Otodynamics, Hartfield, UK). Five dogs were found to have normal hearing in both ears and 2 dogs in the left ear only following otoscopy, tympanometry and auditory brainstem response audiometry. Twelve sets of TEOAEs (click-evoked) to 80 dB peSPL click stimulus and 9 sets of DPOAEs (2F1-F2) to 8 different stimulus levels of the primary tones (L1/L2) were collected at 11 test frequencies (F2) in these normal-hearing dogs. TEOAEs were successfully recorded in 11 of the 12 ears using the default user setting and in all 12 ears using the quickscreen program. DPOAEs were successfully recorded in all 9 ears tested. While the TEOAEs parameters matched those for humans, the average signal-to-noise ratio of DPOAEs was considerably higher in the dogs. Stimulus levels at 55/55, 55/45 and 55/35 dB SPL were demonstrated to produce DPOAEs that seem to reflect the active dynamic status of the outer hair cell system. Postmortem DPOAEs at these stimulus levels and TEOAEs at 80 Db peSPL could not be elicited 5 min following euthanasia of dogs. However, DPOAEs could still be recorded albeit with reduced amplitude at stimulus levels where L1 > 55 dB SPL. The results suggest that TEOAEs and DPOAEs in dogs have the potential to provide valuable insights into their mechanisms of generation, and the specific role and behaviour of outer hair cells of the cochlea in certain pathological conditions, particularly in drug-induced ototoxicity, in humans.

Water samples, collected trimonthly along the Uruguay River between February 1988 and December 1989, were analyzed for alpha- and gamma-HCH, heptachlor and its epoxide, aldrin, dieldrin, and the o-p′ and p-p′ isomers of DDE, DDD and DDT to assess the present status of the contamination in this South American region. In general, chlorinated pesticides were encountered at very low concentrations. HCH isomers were the most commonly detected compounds with concentrations ranging from the detection limits to 10 ng L−1. Heptachlor, heptachlor epoxide, aldrin, dieldrin, p-p′ DDE and p-p′ DDT were occasionally encountered while o-p′ DDE, p-p′ DDD, o-p′ DDD and o-p′ DDT were never detected. Compared to previous studies in the area, the present data seems to indicate that there was a decrease in the concentrations of these compounds.

Cyclosporin A pharmacokinetics were studied following intravenous and abomasal dosing in an open, crossover study in healthy, merino ewes. Five different doses of cyclosporin A were dispersed in milk and administered into the abomasum through a surgically inserted fistula which simulates oral administration. Cyclosporin A was well tolerated. Whole blood concentrations of cyclosporin A were measured by HPLC and mean clearance (0·45 ± 0·05 L h−1 kg−1), distribution volume (4·4 ± 2·0 L kg−1), mean residence time (9·6 ± 4·1 h) and half-life (12·1 ± 3·1 h) were calculated. Negligible cyclosporin A was excreted in urine or bile. Area under the curve increased proportionally with doses up to 26·3 mg kg−1, but was curvilinear above this dose. Abomasal bioavailability at 6·4 mg kg−1 was 0·26 ± 0·09, and mean absorption time was 4·7 ± 11·1 h. Considerable pharmacokinetic variability was observed, particularly after abomasal administration. Cyclosporin A pharmacokinetics in sheep lie within the values reported in man after renal, bone marrow and cardiac transplantation.

An aqueous suspension of air-dried, hammer-milled leaf of Terminalia oblongata (yellow-wood) was administered to sheep by gavage, as a single dose of 5 to 20 g (dry weight)/kg body weight. Doses of 15 g/kg, or more, caused depression, inappetence, abdominal pain and reduced ruminal movements within 24 to 48 h and some sheep also showed dyspnoea, opisthotonus and champing of the jaws. Haematology and blood gas and acid-base measurements were unaffected. In sheep given a dose of 12.5 g/kg, or more, plasma osmolality, aspartate aminotransferase activity and potassium and bilirubin concentrations increased while plasma total protein markedly decreased and plasma sodium concentration and alkaline phosphatase activity remained normal. Most sheep were necropsied 48 h after dosing. The liver showed zonal hepatocellular necrosis, the pattern of which varied with the dose given. No renal lesions were observed, although one sheep given a very high dose became azotaemic and hyperkalaemic. Hydrothorax, hydropericardium and ascites developed in sheep given doses of 15 or 20 g/kg.

Acute tannic acid intoxication was studied in mice and sheep. In mice, following oral administration of 2.0 to 4.6 g of tannic acid kg-1 bodyweight, periacinar coagulative and haemorrhagic necrosis occurred in the liver. In sheep, following oral (8 g kg-1 bodyweight) administration of tannic acid, liver necrosis was not observed either histologically or detected biochemically, although transmission electron microscopy showed focal hepatocellular necrosis, steatosis and acicular crystal cleft formation. In sheep given tannic acid intraperitoneally (0.1 g kg-1 bodyweight), liver necrosis occurred and plasma sodium and glucose levels significantly (P < 0.05) decreased while packed cell volume and plasma aspartate aminotransferase, alkaline phosphatase, creatinine and bilirubin significantly (P < 0.01) rose. The results for blood-gas and acid-base determinations, blood haemoglobin and oxygenation showed significant increases in arterial blood methaemoglobin concentration (P < 0.05) and decreases in blood pH (P < 0.01) and oxyhaemoglobin concentration (P < 0.05) in sheep by 32 hours after oral dosing with 8 g of tannic acid kg-1 bodyweight. In sheep given tannic acid intraperitoneally, methaemoglobinaemia was not detected, but metabolic acidosis with a compensatory respiratory alkalosis occurred. Thus, it would appear that although tannic acid is hepatotoxic when given orally to mice or intraperitoneally to sheep, it does not produce renal or significant hepatic injury in sheep when given orally, but rather causes metabolic acidosis and methaemoglobinaemia.

A method for the identification and determination of tannic acid and its phenolic metabolites in biological fluids by high-performance liquid chromatography was developed. Tannic acid and four phenolic compounds, namely gallic acid, pyrogallol, 4-O-methylgallic acid and ellagic acid, were successfully extracted from the biological fluids by using ethyl acetate at acidic conditions. Gallic acid, pyrogallol and 4-O-methylgallic acid were found in the sheep urine, gallic acid, 4-O-methylgallic acid and ellagic acid in plasma, and gallic acid and ellagic acid in abomasal fluid after abomasal dosing of tannic acid. Tannic acid was found in the plasma apart from the abomasal fluid into which it was administered. The concentrations of tannic acid, gallic acid, pyrogallol, 4-O-methylgallic acid and ellagic acid in plasma, abomasal fluid and urine were measured. This method could be applied to measurement of other hydrolysable tannins and their phenolic metabolites in biological materials.

El objeto de este trabajo es analizar empíricamente la relación existente entre el uso de sistemas de control de gestión (SCG) y la innovación sobre el rendimiento de las Pequeñas y Medianas Empresas (PYMES) en México. Para cumplir este propósito se realiza un estudio con 170 PYMES industriales manufactureras de Yucatán, México. A través de la ANOVA pudo comprobarse que variables como un mayor tamaño, una posición tecnológica buena-fuerte y una estrategia de innovación exploradora-analizadora, están relacionadas con un mayor uso de SCG y que las empresas más innovadoras son jóvenes, de mayor tamaño y con una posición tecnológica buenafuerte. Los resultados de las regresiones estadísticas muestran que los SCG y la innovación ejercen una influencia positiva sobre el rendimiento de las PYMES. Estos resultados refuerzan la Teoría de los Recursos y Capacidades, pues si los SCG y la innovación están bien desarrollados y estructurados, pueden considerarse una ventaja competitiva sostenible. The objective of this work is to analyze the existing relationship between the use of Management Control Systems (MCS) and the innovation on the performance of the Small and Medium Enterprises (SMEs) in México. In order to accomplish this purpose, this paper presents a study with 170 manufacturing industrial SME of Yucatán, México. Through the ANOVA, we could verify that variables as a greater size, a good-strong technological position and an explorer-analyzer strategy of innovation, are related to a greater use of MCS. The more innovating companies are young, have a greater size and a good-strong technological position. The results of the statistical regressions show that MCS and the innovation exert a positive influence on the SMEs performance. These results reinforce the Resources and Capacities Theory, which assure that MCS and the innovation could be considered competitive and sustainable advantages, if they are well developed and well structured. 135-152 luciouc@fca.uady.mx domingo.garcia@upct.es fco.bastida@upct.es

The need to measure and assess the electronic information made available by the Web has given rise to the development of indicators that can be used to evaluate the final quality of this information. Web spaces of the informational units, which include virtual university libraries, are prime candidates for such a process of assessment. The present study has a look at the quality of the informational services supplied by virtual university libraries in Spain, adopting as the variable of analysis the evolution that certain quality indicators of a formal character have exhibited over an exemplary period of six months. The interpretation of our results makes manifest an overall satisfactory evolution, though the breakdown by regions or Autonomous Communities of Spain reveals deficiencies in some cases

Background: Extraintestinal infections caused by multidrug-resistant (MDR) Escherichia coli and Enterobacter are becoming more common in veterinary medicine. Objective: To generate hypotheses for risk factors for dogs acquiring extraintestinal infection caused by MDR E. coli and Enterobacter, describe antimicrobial resistance profiles and analyze treatment and clinical outcomes. Animals: Thirty-seven dogs diagnosed with extraintestinal infection caused by MDR E. coli and Enterobacter spp. between October 1999 and June 2006. Methods: Retrospective case series assembled from hospital records data, including clinical history before 1st MDR isolation and treatment outcome. Identity and antimicrobial susceptibility profiles were confirmed by standard microbiological techniques for 57 isolates. Results: Most dogs had an underlying disease condition (97%), received prior antimicrobial treatment (87%), were hospitalized for ≥3 days (82%), and had a surgical intervention (57%). The urinary tract was the most common infection site (62%), and urinary catheterization, bladder stasis, or both were common among dogs (24%). Some dogs were treated with high doses of co-amoxyclavulanate (n = 14) and subsequently recovered even though the isolates showed in vitro resistance to this antimicrobial. Other dogs were successfully treated with chloramphenicol (n = 11) and imipenem (n = 2). Conclusion and Clinical Importance: Predisposing disease condition, any prior antimicrobial use rather than a specific class of antimicrobial, duration of hospitalization, and type of surgical procedure might be risk factors for acquiring MDR extraintestinal infections. Whereas culture and sensitivity results can indicate use of last-resort antimicrobials such as imipenem for MDR infections, some affected dogs can recover after administration of high doses of co-amoxyclavulanate.

Inherited copper toxicosis in Bedlington terriers is a chronic progressive hepatic disease caused by an abnormal accumulation of copper due to genetic derangement in the biliary copper excretion pathway. In this study, we screened a group of Australian Bedlington terriers for a previously identified mutation, an exon 2 deletion in the COMMD1 gene. The DNA samples used in this study were collected from 149 Bedlington terriers (60 males and 89 females), aged between four weeks to 13 years from eight different pedigrees obtained over a period of three years. We found 60 dogs (40%) were homozygous wild type, 42 dogs (28%) were homozygous mutant, and 47 dogs (32%) were heterozygous for the deletion of exon 2 in the COMMD1 gene. Not only this reports the first large scale genetic screening of the known COMMD1 mutation in Bedlington terriers, but our results also indicate a high prevalence of the COMMD1 mutation in Bedlington terriers that might also be useful as a marker of copper toxicosis. Inherited copper toxicosis was first identified in Bedlington terrier in USA, in 1975 (Hardy et al. 1975) and has since been reported in other countries including Australia (Eriksson 1983; Robertson et al. 1983; Kelly et al. 1984). This disease is an inherited autosomal recessive disorder characterized by a progressive accumulation of copper, predominantly in the liver (Hardy 1984; Johnson et al. 1980). The main pathogenesis of the copper toxicosis in Bedlington terrier appears to be related to the reduced biliary excretion of stored copper resulting from a genetic derangement in copper metabolism (Hardy 1984; Hyun and Filippich 2004). A mutation resulting in the deletion of exon 2 in the COMMD1 (formerly known asMurr1) gene was found to be responsible for copper toxicosis in a subpopulation of Bedlington terriers (Van de Sluis et al. 2002)

El objeto de este trabajo es analizar empíricamente la relación existente entre el uso de sistemas de control de gestión (SCG) y la innovación sobre el rendimiento de las Pequeñas y Medianas Empresas (PYMES) en México. Para cumplir este propósito se realiza un estudio con 170 PYMES industriales manufactureras de Yucatán, México. A través de la ANOVA pudo comprobarse que variables como un mayor tamaño, una posición tecnológica buena-fuerte y una estrategia de innovación exploradora-analizadora, están relacionadas con un mayor uso de SCG y que las empresas más innovadoras son jóvenes, de mayor tamaño y con una posición tecnológica buenafuerte. Los resultados de las regresiones estadísticas muestran que los SCG y la innovación ejercen una influencia positiva sobre el rendimiento de las PYMES. Estos resultados refuerzan la Teoría de los Recursos y Capacidades, pues si los SCG y la innovación están bien desarrollados y estructurados, pueden considerarse una ventaja competitiva sostenible.

The genetic determinants involved in reduced susceptibility to third-generation cephalosporins and aztreonam were identified in ten canine Enterobacter isolates associated with opportunistic infections in three veterinary hospitals in Brisbane, Australia. All isolates were evaluated by a combination of phenotypic (broth microdilution and disc susceptibility, modified disc diffusion and IEF) and genotypic (PFGE, plasmid analysis, Southern blot hybridization, bacterial conjugation, PCR and sequencing) methods to investigate genetic relatedness and to identify plasmid-mediated resistance genes, in particular beta-lactamase genes responsible for extended-spectrum cephalosporin resistance. The ten canine isolates were genotypically diverse based on PFGE and belonged to either Enterobacter cloacae or Enterobacter hormaechei on the basis of 16S rRNA gene sequence analysis. Plasmid profiles were also diverse. Nine isolates contained a transmissible blaSHV-12-carrying plasmid (approximately 140 kb) that also conferred resistance to chloramphenicol, gentamicin, spectinomycin, tetracycline, trimethoprim and sulfonamides. In all plasmid-mediated extended-spectrum beta-lactamase (ESBL)-producing isolates including transconjugants, blaSHV-12 was shown to reside in a approximately 6.5 kb plasmid fragment. The remaining isolate that was not an ESBL producer possessed an AmpC beta-lactamase gene (blaCMY-2) on a approximately 93 kb transmissible plasmid. This plasmid did not contain any other antimicrobial resistance genes. Additional plasmid-mediated beta-lactamases identified in some isolates included bla(TEM) and blaOXA-10. This is the first report of canine Enterobacter isolates containing transmissible plasmid-mediated blaSHV-12 and blaCMY-2 resistance genes. Therefore, Enterobacter isolated from opportunistic infections in dogs may be an important reservoir of plasmid-mediated resistance genes, which could potentially be spread to other members of the Enterobacteriaceae.

The pharmacokinetics of doxorubicinol, a cytotoxic metabolite of the anticancer drug, doxorubicin, were studied in four healthy sulphur-crested cockatoos (Cacatua galerita) after a 20 min intravenous infusion of 2 mg/kg. Plasma doxorubicinol concentrations were measured by HPLC. The pharmacokinetic parameters were estimated using a non-compartmental method. The mean (+/- SD) peak concentration was 8341 +/- 3132 microg/L at 17.5 +/- 5.0 min after the start of the infusion, and doxorubicinol concentrations declined biexponentially to 154.3 +/- 34.5 microg/L, 40 min after the end of the infusion. Systemic clearance was 0.940 +/- 0.473 L/h/kg, mean residence time was 0.165 +/- 0.133 h, and steady-state volume of distribution was 0.123 +/- 0.0526 L/kg. The terminal half-life was 0.660 +/- 0.611 h. Detectible but unquantifiable concentrations of doxorubicinol were present in the plasma ultrafiltrate of two birds during the infusion, indicating very extensive plasma protein binding. Physiological, haematological and biochemical monitoring over 3 weeks showed that doxorubicinol at a single infused dose of 2 mg/kg caused no toxicities of major concern.

To survey finches in pet shops for Cochlosoma infection and evaluate the efficacy of antiprotozoal therapy with metronidazole or ronidazole.A survey of pet shop finches and drug efficacy trials.Finches in pet shops were randomly selected and their faeces examined microscopically for motile Cochlosoma sp trophozoites. Drug trials were carried out on 60 adult finches with naturally occurring infections. Body weight was measured and the faeces of each bird was examined for trophozoites at the beginning and 7 days after the end of treatment. In some birds, additional daily faecal examinations were done until three consecutive negative results were obtained. Metronidazole was administered at various dose rates by crop gavage or in drinking water to eight groups of five to ten finches each. Ronidazole was given in water for 7 days to ten finches. In addition, six finches whose faeces tested positive were necropsied and their tissues collected for histological examination.Motile flagellates in the faeces were identified as C anatis-like protozoa. Red-headed parrot-finches, Bengalese and Lady Gould finches were found to be most commonly infected. Cochlosoma sp was also found in the blue-faced parrot-finch, zebra finch, painted finch, nutmeg mannikin and double-barred finch. Metronidazole and ronidazole were found to be effective against Cochlosoma sp. Histological findings on infected adult finches were normal, except for the presence of numerous flagellates between the colorectal villi and cloacal mucosal folds.Cochlosoma anatis-like organisms can infect several species of finches and in adult finches are confined to the colorectum and cloaca. Infection in adult finches was mostly subclinical and could be treated effectively with metronidazole or ronidazole.

A 12-year-old cat was presented to the University of Queensland's Small Animal Teaching Hospital with a 1-day history of left hemiparesis of acute onset, with no evidence of trauma or toxin exposure. Neurological examination findings were consistent with a lesion in the caudal left cervical spinal cord (C6 to C8), which was non-painful and had not progressed since the onset of clinical signs. No other abnormalities were found, although myelography showed a mild swelling involving the caudal cervical and cranial thoracic spinal segments. A diagnosis of suspected fibrocartilaginous embolism was made on the basis of the history, clinical presentation and diagnostic tests results, making this case the first report of a suspected fibrocartilaginous embolism in a cat that returned to normal function.

El objetivo del trabajo fue determinar los efectos genéticos aditivos, dominantes y epistáticos; cuantificar heterosis y depresión endogámica en maíz tropical, Zea mays L., durante el año 2003 en 2 fechas de siembra en la localidad de Úrsulo Galván, Veracruz, México. Los datos se basaron en un diseño genético de medias generacionales. Las variables son plantas con achaparramiento, mazorcas con Fusarium, cobertura de mazorca, prolificidad y rendimiento de grano. Los resultados indicaron que los efectos dominantes fueron más importantes que los aditivos para la resistencia. De los efectos digénicos epistáticos el más importante fue el aditivo x aditivo (2,18) y el menos fue dominante x dominante (-1,89). Para la variable mazorcas con Fusarium el efecto dominante y el epistático a x d fueron superiores (2,64 y 4,10). En la cobertura de mazorca el efecto genético es pequeño, sobresaliendo el digénico aditivo x aditivo (1,88). Para la característica prolificidad, el efecto de dominancia (49,87) fue 4 veces superior al efecto aditivo (12,12), asimismo, en el rendimiento, todos los efectos resultaron positivos a excepción del dominante x dominante (-5,50), no obstante, el efecto dominante fue superior (15,57). La heterosis, resultó negativa para achaparramiento, mazorcas con Fusarium y prolificidad, no así, para rendimiento. La depresión endogámica para achaparramiento fue de -11,21%, también negativa resultó para mazorcas con Fusarium y prolificidad; en rendimiento la pérdida de vigor de la F1 a la F2 fue de 57,14%.

A new microscale method is reported for the determination of doxorubicin and its active metabolite, doxorubicinol, in parrot plasma. Sample workup involved acetonitrile protein precipitation, ethyl acetate extraction, followed by back extraction into HCl. Separations were achieved on a phenyl-hexyl column at 30 degrees C using acetonitrile (17%, v/v) in 0.01 M orthophosphoric acid (83%, v/v) delivered via a linear flow program. Fluorometric detection wavelengths were 235 nm (excitation) and 550 nm (emission). Calibration plots were linear (1 2 > 0.999), and recoveries were 71-87% from 20 to 400 ng/mL. Assay imprecision was

En este trabajo presentamos un nuevo diseño de fuente de ondas milimétricas coherentes basada en la conversión paramétrica hacia abajo en un cristal fotónico unidimensional. Nuestra propuesta se basa en la sintonización del campo eléctrico en la orilla de la banda o en el modo de un defecto localizado al centro de la banda prohibida. Los resultados numéricos muestran que con este diseño es posible obtener radiación coherente en una variedad de intensidades y anchos de banda en toda la región del espectro terahertz. Esto puede ser llevado a cabo variando el número de periodos y/o el contraste del índice de refracción entre las capas del cristal.

Sudden cardiac death in small animals is uncommon but often occurs due to cardiac conduction defects or myocardial diseases. Primary cardiac conduction defects are mainly caused by mutations in genes involved in impulse conduction processes (e.g., gap-junction genes and transcription factors) or repolarisation processes (e.g., ion-channel genes), whereas primary cardiomyopathies are mainly caused by defective force generation or force transmission due to gene mutations in either sarcomeric or cytoskeleton proteins. Although over 50 genes have been identified in humans directly or indirectly related to sudden cardiac death, no genetic aetiologies have been identified in small animals. Sudden cardiac deaths have been also reported in German Shepherds and Boxers. A better understanding of molecular genetic aetiologies for sudden cardiac death will be required for future study toward unveiling aetiology in sudden cardiac death in small animals.

Chemotherapy as a treatment modality is increasingly being used in avian oncology. Currently, most chemotherapeutic agents can only be used empirically, as pharmacokinetic data in birds are lacking.Recently, the pharmacokinetic profile of the platinum analogs,cisplatin, and carboplatin has been reported in Sulfur-crested cockatoos,paving the way for clinical and toxicity trials.

Objective To determine the pharmacokinetics of platinum (Pt) in cockatoos. Design A pharmacokinetic study of Pt, following a single IV infusion of cisplatin, was done in six healthy sulphur-crested cockatoos (Cacatua galerita). Procedure Birds were hydrated for 1 h before and 2 h after a 1-h cisplatin infusion (1 mg/kg, IV). Serial blood samples were collected for 96 h after initiation of the infusion and urine was collected for 2 h during the hydration period after cisplatin administration. Tissue samples from 10 organs were obtained at necropsy, 96 h after cisplatin infusion. Total Pt and filterable Pt in plasma, urinary Pt and tissue Pt concentrations were assayed by inductively coupled plasma-mass spectrometry. A noncompartmental pharmacokinetic analysis was performed on the plasma and urine data. Results For total Pt and filterable Pt, the respective mean systemic clearances were 0.373 and 0.699 L/kg hourly, the steady stale volumes of distribution were 4.19 and 0.356 L/kg, and the mean residence times were 111 and 0.512 h. Total plasma Pt displayed a bi-exponential decay profile with average half-lives of 0.398 and 79.0 h, while filterable Pt had a monoexponential decay with mean half-life of 0.413 h. The renal clearance during the 2-h postinfusion period was 0.167 L/kg hourly. The kidneys had the highest Pt accumulation (4.54 mu g/g DM). Conclusions and Clinical Relevance Cisplatin infusion in cockatoos was well tolerated and PI plasma concentrations were similar to those measured during treatment of solid tumours in human patients. Despite anatomical, physiological and biochemical differences among animal species, the pharmacokinetic disposition of Pt in the cockatoo shares some features with the kinetics reported previously in rodents, dogs and human beings.

Budgerigars (Melopsittacus undulatus) from two different breeding colonies were found to have Giardia infection. Light microscopy, scanning electron microscopy and in-vitro and in-vivo studies confirmed the species was G psittaci. Chicks were clinically affected and showed signs of retarded growth, dehydration and diarrhoea. The faeces of adult birds treated with metronidazole in drinking water were negative for Giardia 5 days after treatment. Megabacteria were also found in adult birds but were not treated. This study extends the known host range for Giardia in Australia to include budgerigars.

We work out predictions of the Linear Sigma Model for the $����\to��^0 ��^0$ cross section. We consider the sigma width, which is introduced in a consistent way with chiral Ward identities. The results of Chiral Perturbation Theory are recovered in the $m_��\to \infty$ limit. A fit to existing experimental results is consistent with a light and broad $��$ meson., 7 pages, 3 figures. The sigma width is introduced in a consistent way with chiral symmetry. Results for the cross section are affected by the corresponding changes