RESUMO
Dissolved oxygen is a critical component of river water quality. This study investigated average weekly dissolved oxygen (AWDO) and average weekly water temperature (AWT) in the Savannah River during 2015 and 2016 using data from the Intelligent River® sensor network. Weekly data and seasonal summary statistics revealed distinct seasonal patterns that impact both AWDO and AWT regardless of location along the river. Within seasons, spatial patterns of AWDO and AWT along the river are also evident. Linear mixed effects models indicate that AWT and low and high river flow conditions had a significant impact on AWDO, but added little predictive information to the models. Low and high river flow conditions had a significant impact on AWT, but also added little predictive information to the models. Spatial linear mixed effects models yielded parameter estimates that were effectively the same as non-spatial linear mixed effects models. However, components of variance from spatial linear mixed effects models indicate that 23-32% of the total variance in AWDO and that 12-18% of total variance in AWT can be apportioned to the effect of spatial covariance. These results indicate that location, week, and flow-directional spatial relationships are critically important considerations for investigating relationships between space- and time-varying water quality metrics.
Assuntos
Monitoramento Ambiental/métodos , Oxigênio/análise , Rios/química , Temperatura , Água Doce , Estações do Ano , Qualidade da ÁguaRESUMO
Fluid-feeding insects, such as butterflies, moths and flies (20% of all animal species), are faced with the common selection pressure of having to remove and feed on trace amounts of fluids from porous surfaces. Insects able to acquire fluids that are confined to pores during drought conditions would have an adaptive advantage and increased fitness over other individuals. Here, we performed feeding trials using solutions with magnetic nanoparticles to show that butterflies and flies have mouthparts adapted to pull liquids from porous surfaces using capillary action as the governing principle. In addition, the ability to feed on the liquids collected from pores depends on a relationship between the diameter of the mouthpart conduits and substrate pore size diameter; insects with mouthpart conduit diameters larger than the pores cannot successfully feed, thus there is a limiting substrate pore size from which each species can acquire liquids for fluid uptake. Given that natural selection independently favoured mouthpart architectures that support these methods of fluid uptake (Diptera and Lepidoptera share a common ancestor 280 Ma that had chewing mouthparts), we suggest that the convergence of this mechanism advocates this as an optimal strategy for pulling trace amounts of fluids from porous surfaces.
Assuntos
Estruturas Animais/anatomia & histologia , Borboletas/anatomia & histologia , Comportamento Alimentar , Mariposas/anatomia & histologia , AnimaisRESUMO
OBJECTIVE: To determine whether 2.0 mm cancellous screws are superior to 2.0 mm cortical screws when inserted into cancellous and bicortical bone. STUDY DESIGN: Biomechanical study. METHODS: The 2.0 mm cancellous screws and 2.0 mm cortical screws were inserted according to the recommended guidelines in synthetic cancellous and bicortical blocks. Fifteen screw-block constructs per group were tested to failure in axial pullout. Axial pullout strength and yield strength were calculated. Data were analyzed using a one-way ANOVA. RESULTS: The 2.0 mm cortical screws achieved lower axial pullout strength than 2.0 mm cancellous screws in cancellous blocks. The 2.0 mm cortical screws achieved greater pullout strength than 2.0 mm cancellous screws in bicortical blocks. CONCLUSION: The 2.0 mm cancellous screws may offer a biomechanical advantage in bone with thin cortices (<1 mm thick), whereas 2.0 mm cortical screws may be preferred in cortical bone with cortices measuring at least 1 mm in thickness.
Assuntos
Parafusos Ósseos/veterinária , Osso Esponjoso/cirurgia , Osso Cortical/cirurgia , Fenômenos Biomecânicos , Parafusos Ósseos/classificaçãoRESUMO
Mycoplasma gallisepticum (MG) is a major and economically significant pathogen of avian species. When administered before lay, F-strain MG (FMG) can reduce egg production during lay, but the ts-11 strain of MG (ts11MG) does not exert this effect. Two trials were conducted to determine the effects of pre-lay vaccinations of ts11MG, MG-Bacterin (MGBac), or their combination, in conjunction with an FMG challenge overlay after peak production on the blood characteristics of commercial layers. In each trial, 160 mycoplasma-free Hy-Line W-36 layers were housed in negative-pressure biological isolation units (4 units per treatment, 10 birds per unit) from 9 through 52 wk of age (woa). The following vaccination treatments were administered at 10 woa: 1) Control (no vaccinations); 2) MGBac; 3) ts11MG; and 4) ts11MG and MGBac combination (ts11MG+MGBac). At 45 woa, half of the birds were challenged with a laboratory stock of high-passage FMG. Parameters measured in both trials were whole-blood hematocrit and serum concentrations of cholesterol (SCHOL), triglycerides, calcium, and total protein (STP). An age×treatment interaction (P=0.04) was observed for STP between 23 and 43 woa. The STP concentration in the ts11MG and ts11MG+MGBac groups was higher at 33 woa, but was lower at 43 woa, in comparison to the Control group. Also, at 38 woa, the STP of the ts11MG+MGBac group was higher than that of the MGBac group. Although use of the ts11MG vaccine alone or in combination with MGBac may influence circulating STP concentrations when administered before lay, it remains effective in protecting layers against the adverse effect of a post-peak challenge of FMG on egg production, as was observed in a previous companion study.
Assuntos
Vacinas Bacterianas/farmacologia , Sangue/efeitos dos fármacos , Galinhas/sangue , Animais , Vacinas Bacterianas/administração & dosagem , Análise Química do Sangue/veterinária , Feminino , Hematócrito/veterinária , Vacinas Combinadas/administração & dosagem , Vacinas Combinadas/farmacologiaRESUMO
OBJECTIVE: To determine acute load to failure (ALF) and suture abrasion (SA) at 0° and 90° for a novel screw-type mini-anchor design. STUDY DESIGN: Biomechanical in vitro study. SAMPLE POPULATION: Synthetic bone. METHODS: Twenty mini-anchors were inserted into synthetic bone blocks assigned to 1 of 2 groups (0° ALF, 90° ALF). Pullout was performed at 5 mm/min. ALF, yield strength and stiffness were calculated. SA constructs were created with 4 groups of 5 anchors each with either 30 lb nylon leader line (NLL), 40 lb NLL, #2 Fiberwire or #5 Fiberwire. SA was performed at 0° and 90° with a sinusoidal wave form at 0.5 Hz and 10 N load for 1000 cycles or until failure. Data were summarized as mean ± SD. ALF data were analyzed using t-tests. SA data were analyzed using log rank, Tukey-adjusted pairwise comparisons and sign tests. Significance was set at P = .05. RESULTS: Mean ± SD ALF at 0° and 90° was 431.8 ± 70.8 N and 683 ± 48.7 N, respectively. 90° ALF was significantly higher. Yield strength and stiffness were not significantly different at 0° and 90°. #5 and #2 Fiberwire survived significantly more cycles than 40 lb and 30 lb NLL at 90°. At 0°, 30 lb NLL survived significantly less cycles than either Fiberwire size. Suture orientation did not have a significant effect on SA for Fiberwire constructs. CONCLUSION: The novel mini-anchor has ALF comparable to other mini-anchors. Fiberwire survived more cycles in the novel anchor eyelet than NLL and FW suture orientation in the eyelet did not affect SA.
Assuntos
Parafusos Ósseos/veterinária , Animais , Fenômenos Biomecânicos , Parafusos Ósseos/normas , Osso e Ossos/cirurgia , Falha de Equipamento , Técnicas In Vitro , Suturas/normas , Suturas/veterinária , Suporte de CargaRESUMO
OBJECTIVE: To radiographically define the anatomic origin and insertion of the cranial cruciate ligament translated to the lateral radiographic projection of the stifle (CrCL-Lo and CrCL-Li, respectively), to correlate these landmarks for identification of the CrCL-Lo intraoperatively, and to compare the isometry of the CrCL-Lo to the lateral fabella. STUDY DESIGN: Experimental study. SAMPLE POPULATION: Pelvic limbs (n = 12) from dogs weighing 13-26 kg. METHODS: A radiographic quadrant method was used to localize the CrCL-Lo. Mediolateral radiographic projections of each stifle were taken through a range of motion. Maximum percent change in length between each tibial marker and femoral marker during range of motion determined isometry. RESULTS: The CrCL-Lo is located at the caudal 33% and distal 50% of the lateral femoral condyle using Blumensaat's line or a line from the origin of the long digital extensor (LDE) to the lateral fabella, with no significant difference (P = .766) between the 2 reference lines. The CrCL-Li is located at the proximal 20% of the tibial plateau. No significant difference (P < .05) in isometry was found between the CrCL-Lo and lateral fabella. CONCLUSION: The CrCL-Lo is located at the caudal 1/3 and distal ½ of the lateral femoral condyle. The CrCL-Lo and lateral fabella are not significantly different in isometry when used as a proximal anchor point in extracapsular stifle stabilization.
Assuntos
Ligamento Cruzado Anterior/anatomia & histologia , Ligamento Cruzado Anterior/diagnóstico por imagem , Cães/anatomia & histologia , Joelho de Quadrúpedes/anatomia & histologia , Joelho de Quadrúpedes/diagnóstico por imagem , Animais , Fenômenos Biomecânicos , Cadáver , Contração Isométrica , RadiografiaRESUMO
Effects of the in ovo injection of various levels of L-ascorbic acid (L-AA) on the performance and corneal erosion incidence in Ross 708 broilers exposed to 50 parts per million (ppm) of atmospheric ammonia (NH3) after hatch were determined. A total of 1440 Ross 708 broiler embryos were randomly assigned to 4 treatments: non-injected (control), 0.85% sterile saline-injected (control), or saline containing 12 or 25 mg of L-AA. At hatch, 12 male chicks were randomly assigned to each of 48 battery cages with 12 replicate cages randomly assigned to each treatment group. All birds were exposed to 50 ppm of NH3 for 35 d and the concentration of NH3 in the battery cage house was recorded every 20 s. Mortality was determined daily, and mean body weight (BW), BW gain (BWG), average daily BW gain (ADG), and feed intake, as well as feed conversion ratio (FCR), were determined weekly. From 0 to 35 d of post-hatch age (doa), six birds from each cage were selected and sampled for eye erosion scoring. Incidences of corneal erosion were significantly higher at 21 and 28 doa in comparison to those at 14 and 35 doa, and at 21 doa, birds in the saline-injected group exhibited a higher incidence of corneal erosion compared to all other treatment groups. The in ovo injection of 12 mg of L-AA increased BWG (p = 0.043) and ADG (p = 0.041), and decreased FCR (p = 0.043) from 0 to 28 doa in comparison to saline-injected controls. In conclusion the in ovo administration of 12 mg of L-AA may have the potential to improve the live performance of broilers chronically exposed to high aerial NH3 concentrations, but further study is needed to determine the physiological and immunological factors that may contribute to this improvement.
RESUMO
By inhibiting soil enzymes, tannins play an important role in soil carbon (C) and nitrogen (N) mineralization. The role of tannin chemistry in this inhibitory process, in conjunction with enzyme classes and isoforms, is less well understood. Here, we compared the inhibition efficiencies of mixed tannins (MTs, mostly limited to angiosperms) and condensed tannins (CTs, produced mostly by gymnosperms) against the potential activity of ß-glucosidase (BG), N-acetyl-glucosaminidase (NAG), and peroxidase in two soils that differed in their vegetation histories. Compared with CTs, MTs exhibited 50% more inhibition of almond (Prunus dulcis) BG activity and greater inhibition of the potential NAG activity in the gymnosperm-acclimatized soils. CTs exhibited lower BG inhibition in the angiosperm-acclimated soils, whereas both types of tannins exhibited higher peroxidase inhibition in the angiosperm soils than in gymnosperm soils. At all of the tested tannin concentrations, irrespective of the tannin type and site history, the potential peroxidase activity was inhibited two-fold more than the hydrolase activity and was positively associated with the redox-buffering efficiency of tannins. Our finding that the inhibitory activities and mechanisms of MTs and CTs are dependent on the vegetative history and enzyme class is novel and furthers our understanding of the role of tannins and soil isoenzymes in decomposition.
Assuntos
Inibidores Enzimáticos/farmacologia , Folhas de Planta/química , Solo , Taninos/química , Taninos/farmacologia , Acetilglucosaminidase/antagonistas & inibidores , Acetilglucosaminidase/metabolismo , Antioxidantes/farmacologia , Cycadopsida/química , Ecossistema , Magnoliopsida/química , Peroxidases/antagonistas & inibidores , Peroxidases/metabolismo , Pinus/química , Proantocianidinas/química , Proantocianidinas/farmacologia , Prunus/enzimologia , Quercus/química , Relação Estrutura-Atividade , beta-Glucosidase/antagonistas & inibidores , beta-Glucosidase/metabolismoRESUMO
Effects of the dietary and in ovo administration of L-ascorbic acid (L-AA) on the performance, plasma nitric oxide, and eye L-AA concentrations of Ross 708 broilers were investigated. At 17 days of incubation, live embryonated hatching eggs were randomly assigned to a non-injected or sham-injected (100 µL of saline) control group, or a group injected with either 12 or 25 mg of L-AA suspended in 100 µL of saline. Chicks received a commercial diet with or without 200 mg/kg of supplemental L-AA and were randomly assigned to each of 6 replicate floor pens in each in ovo injection-dietary treatment combination. Weekly live performance variables through 14 days of post hatch age (doa) and the eye weights in both sexes at 0, 7, and 14 doa were determined. At 0 and 14 doa, plasma nitric oxide levels and eye L-AA concentrations of one bird of each sex in each pen were determined. Dietary supplemental L-AA decreased feed intake and growth between 0 and 7 doa, but from 8 to 14 doa; all birds fed supplemental L-AA had a lower feed conversion ratio. At 14 doa, male chicks had higher eye L-AA concentrations and lower plasma nitric oxide levels when treated in ovo with 12 mg of L-AA. In conclusion, dietary L-AA may be used to improve feed conversion in the second week of broiler post hatch growth. However, the in ovo administration of 12 mg of L-AA can increase male eye L-AA concentrations and is effective in reducing their general inflammatory response.
RESUMO
The transmission of the ts-11 strain of Mycoplasma gallisepticum (MG) vaccine (ts-11MGV) between incubated eggs and between hatchlings that was administrated via in ovo injection, and its subsequent effects on their posthatch performance were evaluated. Marek's disease diluent alone (sham-injected) or containing either 3.63 × 101, 102, 103, or 104 cfu of ts-11MGV was manually in ovo-injected into the amnion on 18 days of incubation. Egg residue analysis, percentage incubational egg weight loss, hatchability of viable injected eggs, and hatchling body weight (BW) were assessed. Selected hatchlings from each treatment replicate group were swabbed in the choanal cleft for MG DNA detection. Female chick live performance was also assessed through 21 days of posthatch age. Unexposed control sentinel chicks were allocated to each treatment replicate group to assess horizontal transmission. Birds were later swabbed and bled respectively, for detection of MG DNA and IgM production at 21 days posthatch. In all birds, no MG DNA was detected and SPA tests for IgM were negative. Among all variables, only 0 to 21 day BW gain was significantly affected by treatment and was lower in the 3.63 × 104 ts-11 MGV treatment in comparison to all the other treatments. Because ts-11MGV does not exhibit vertical or horizontal transmission capabilities under commercial conditions, it may not be a good candidate for in ovo injection.
RESUMO
⢠Climate change could increase the frequency with which plants experience abiotic stresses, leading to changes in their metabolic pathways. These stresses may induce the production of compounds that are structurally and biologically different from constitutive compounds. ⢠We studied how warming and altered precipitation affected the composition, structure, and biological reactivity of leaf litter tannins in Acer rubrum at the Boston-Area Climate Experiment, in Massachusetts, USA. ⢠Warmer and drier climatic conditions led to higher concentrations of protective compounds, including flavonoids and cutin. The abundance and structure of leaf tannins also responded consistently to climatic treatments. Drought and warming in combination doubled the concentration of total tannins, which reached 30% of leaf-litter DW. This treatment also produced condensed tannins with lower polymerization and a greater proportion of procyanidin units, which in turn reduced sequestration of tannins by litter fiber. Furthermore, because of the structural flexibility of these tannins, litter from this treatment exhibited five times more enzyme (ß-glucosidase) complexation capacity on a per-weight basis. Warmer and wetter conditions decreased the amount of foliar condensed tannins. ⢠Our finding that warming and drought result in the production of highly reactive tannins is novel, and highly relevant to climate change research as these tannins, by immobilizing microbial enzymes, could slow litter decomposition and thus carbon and nutrient cycling in a warmer, drier world.
Assuntos
Acer/metabolismo , Chuva , Taninos/metabolismo , Temperatura , Mudança Climática , Flavonoides/metabolismo , Lipídeos de Membrana/metabolismo , Ressonância Magnética Nuclear Biomolecular , Fenóis/metabolismo , Folhas de Planta/metabolismo , Análise de Componente Principal , Espectroscopia de Infravermelho com Transformada de Fourier , Estresse Fisiológico , Taninos/químicaRESUMO
OBJECTIVE: To evaluate use of a transcondylar toggle system (TCTS) for stabilization of the cranial cruciate ligament (CrCL) deficient stifle in small dogs and cats. STUDY DESIGN: Prospective clinical study. ANIMALS: Small dogs (<7 kg; n=14) and cats (2) with CrCL-associated lameness of <3 months duration and a tibial plateau angle <32 degrees. METHODS: Affected animals had an extracapsular CrCL repair using the TCTS. Lameness score, muscle atrophy, osteoarthritis (OA) score, and range of motion (ROM) were evaluated preoperatively, and at 6 weeks and 7-10 months postoperatively. RESULTS: Operative time was 75 +/- 16 minutes. Fifty-six percent required >1 bone tunnel attempts. One dog required revision at 2 weeks because of suture loosening. All stifles were stable at 6 weeks postoperatively. Fifteen animals were available for follow-up (7-10 months). Lameness improved significantly at 6 weeks (P<.0001), whereas muscle atrophy was worse at 6 weeks (P=.008) but improved at 7-10 months (P<.0001). OA scores were unchanged at 6 weeks (P=.08) but were significantly worse at 7-10 months (P<.0001). ROM remained unchanged at 6 weeks (P=1) and 7-10 months (P=.6). CONCLUSIONS: The medially placed toggle provides a reliable short-term proximal anchor for the extracapsular suture with outcomes similar to other extracapsular techniques. The aiming device and drill bit are not recommended in their current form. CLINICAL RELEVANCE: The TCTS appears to be a well-tolerated technique for proximal suture anchoring in extracapsular CrCL repair in small dogs and cats where instrumentation and anatomic constraints preclude other techniques.
Assuntos
Gatos/cirurgia , Cães/cirurgia , Joelho de Quadrúpedes/cirurgia , Animais , Ligamento Cruzado Anterior/cirurgia , Gatos/fisiologia , Cães/fisiologia , Feminino , Coxeadura Animal/cirurgia , Masculino , Patela/cirurgia , Período Pós-Operatório , Estudos Prospectivos , Amplitude de Movimento Articular/fisiologia , Joelho de Quadrúpedes/fisiologia , Resultado do TratamentoRESUMO
A container experiment was conducted to test the hypothesis that uncomposted wool wastes could be used as nutrient source and growth medium constituent for container-grown plants. The treatments were: (1) rate of wool-waste application (0 or unamended control, 20, 40, 80, and 120 g of wool per 8-in. pot), (2) growth medium constituents [(2.1) wool plus perlite, (2.2) wool plus peat, and (2.3) wool plus peat plus perlite], and (3) plant species (basil and Swiss chard). A single addition of 20, 40, 80, or 120 g of wool-waste to Swiss chard (Beta vulgaris L.) and basil (Ocimum basilicum L.) in pots with growth medium provided four harvests of Swiss chard and five harvests of basil. Total basil yield from the five harvests was 1.6-5 times greater than the total yield from the unamended control, while total Swiss chard yield from the four harvests was 2-5 times greater relative to the respective unamended control. The addition of wool-waste to the growth medium increased Swiss chard and basil tissue N, and NO(3)-N and NH(4)-N in growth medium relative to the unamended control. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) microanalysis of wool fibers sampled at the end of the experiments indicated various levels of decomposition, with some fibers retaining their original surface structure. Furthermore, most of the wool fibers' surfaces contained significant concentrations of S and much less N, P, or K. SEM/EDX revealed that some plant roots grow directly on wool-waste fibers suggesting either (1) root directional growth towards sites with greater nutrient concentration and/or (2) a possible role for roots or root exudates in wool decomposition. Results from this study suggest that uncomposted wool wastes can be used as soil amendment, growth medium constituent, and nutrient source for container-grown plants.
Assuntos
Beta vulgaris/crescimento & desenvolvimento , Fertilizantes , Ocimum basilicum/crescimento & desenvolvimento , Resíduos , Lã , Animais , Jardinagem , OvinosRESUMO
OBJECTIVE To determine mortality rates for dogs undergoing cholecystectomy and variables associated with failure to survive to hospital discharge. DESIGN Retrospective cohort study. ANIMALS 70 dogs that underwent cholecystectomy for biliary tract disease at a companion animal referral hospital from 2009 through 2015. PROCEDURES Medical records of dogs were reviewed and data collected; dogs with biliary diversion surgery were excluded. Included dogs were grouped by whether cholecystectomy had been elective (ie, dogs with no or mild clinical signs, with no indication of biliary obstruction, or that initially underwent surgery for a different procedure) or nonelective (ie, dogs with icterus and questionable patency of the biliary system). Mortality rates (proportions of dogs that failed to survive to hospital discharge) were compared between various groups. RESULTS 45 (64%) dogs were included in the elective group and 25 (36%) in the nonelective group. Group mortality rates were 2% (1/45) and 20% (5/25), respectively, and differed significantly. Overall mortality rate was 9% (6/70). Serum albumin concentration was significantly lower and serum alanine aminotransferase activity and total bilirubin concentration were significantly higher in nonsurviving versus surviving dogs. Dogs with vomiting, signs of lethargy or anorexia, icterus, or azotemia were less likely to survive than dogs without these signs. CONCLUSIONS AND CLINICAL RELEVANCE Dogs that underwent elective cholecystectomy had a considerably lower mortality rate than previously reported. Elective cholecystectomy may be an appropriate recommendation for dogs with early signs of biliary disease to avoid the greater mortality rate associated with more advanced disease and nonelective cholecystectomy.
Assuntos
Doenças do Cão/mortalidade , Doenças da Vesícula Biliar/veterinária , Animais , Colecistectomia/veterinária , Estudos de Coortes , Doenças do Cão/sangue , Cães , Procedimentos Cirúrgicos Eletivos/veterinária , Feminino , Doenças da Vesícula Biliar/mortalidade , Doenças da Vesícula Biliar/cirurgia , Masculino , Registros/veterinária , Estudos Retrospectivos , South Carolina , Resultado do TratamentoRESUMO
Because xenosensing nuclear receptors are also lipid sensors that regulate lipid allocation, we hypothesized that toxicant-induced modulation of HR96 activity would alter lipid profiles and the balance between adult survival and neonate production following exposure in Daphnia magna. Adult daphnids were exposed to unsaturated fatty acid- and toxicant- activators or inhibitors of HR96 and later starved to test whether chemical exposure altered allocation toward survival or reproduction. The HR96 activators, linoleic acid and atrazine, decreased reproduction as expected with concomitant changes in the expression of HR96 regulated genes such as magro. The HR96 inhibitors, docosahexaenoic acid (DHA) and triclosan, increased reproduction or neonate starvation survival, respectively. However, pre-exposure to triclosan increased in neonate survival at the expense of reproductive maturation. Lipidomic analysis revealed that sphingomyelins (SM) are predominantly found in neonates and therefore we propose are important in development. DHA and triclosan increased neonatal SM, consistent with HR96's regulation of Niemann-Pick genes. While DHA altered expression of magro, Niemann-Pick 1b, mannosidase, and other HR96-regulated genes as expected, triclosan primarily perturbed sphingomyelinase and mannosidase expression indicating different but potentially overlapping mechanisms for perturbing SM. Overall, SM appears to be a key lipid in Daphnia maturation and further support was provided by carmofur, which inhibits sphingomyelin/ceramide metabolism and in turn severely represses Daphnia maturation and initial brood production. In conclusion, toxicants can perturb lipid allocation and in turn impair development and reproduction.
Assuntos
Daphnia/metabolismo , Metabolismo dos Lipídeos , Esfingomielinas/metabolismo , Animais , Atrazina/toxicidade , Daphnia/efeitos dos fármacos , Daphnia/crescimento & desenvolvimento , Gorduras na Dieta/metabolismo , Ácidos Graxos Insaturados/metabolismo , Fertilidade/efeitos dos fármacos , Fluoruracila/análogos & derivados , Fluoruracila/toxicidade , Regulação da Expressão Gênica , Metabolismo dos Lipídeos/efeitos dos fármacos , Metabolismo dos Lipídeos/genética , Fosfatidilcolinas/metabolismo , Triclosan/toxicidade , Poluentes Químicos da Água/toxicidadeRESUMO
During breeding, foraging marine birds are under biological, geographic, and temporal constraints. These contraints require foraging birds to efficiently process environmental cues derived from physical habitat features that occur at nested spatial scales. Mesoscale oceanography in particular may change rapidly within and between breeding seasons, and findings from well-studied systems that relate oceanography to seabird foraging may transfer poorly to regions with substantially different oceanographic conditions. Our objective was to examine foraging behavior of a pan-tropical seabird, the Masked Booby (Sula dactylatra), in the understudied Caribbean province, a moderately productive region driven by highly dynamic currents and fronts. We tracked 135 individuals with GPS units during May 2013, November 2013, and December 2014 at a regionally important breeding colony in the southern Gulf of Mexico. We measured foraging behavior using characteristics of foraging trips and used area restricted search as a proxy for foraging events. Among individual attributes, nest stage contributed to differences in foraging behavior whereas sex did not. Birds searched for prey at nested hierarchical scales ranging from 200 m-35 km. Large-scale coastal and shelf-slope fronts shifted position between sampling periods and overlapped geographically with overall foraging locations. At small scales (at the prey patch level), the specific relationship between environmental variables and foraging behavior was highly variable among individuals but general patterns emerged. Sea surface height anomaly and velocity of water were the strongest predictors of area restricted search behavior in random forest models, a finding that is consistent with the characterization of the Gulf of Mexico as an energetic system strongly influenced by currents and eddies. Our data may be combined with tracking efforts in the Caribbean province and across tropical regions to advance understanding of seabird sensing of the environment and serve as a baseline for anthropogenic based threats such as development, pollution, and commercial fisheries.
Assuntos
Comportamento Apetitivo , Aves , Animais , Aves/fisiologia , Cruzamento , Região do Caribe , Ecossistema , Comportamento Alimentar , Feminino , Golfo do México , Masculino , Comportamento de Nidação , Oceanografia , Estações do AnoRESUMO
Fluid-feeding insects ingest a variety of liquids, which are present in the environment as pools, films, or confined to small pores. Studies of liquid acquisition require assessing mouthpart structure and function relationships; however, fluid uptake mechanisms are historically inferred from observations of structural architecture, sometimes unaccompanied with experimental evidence. Here, we report a novel method for assessing fluid-uptake abilities with butterflies (Lepidoptera) and flies (Diptera) using small amounts of liquids. Insects are fed with a 20% sucrose solution mixed with fluorescent, magnetic nanoparticles from filter papers of specific pore sizes. The crop (internal structure used for storing fluids) is removed from the insect and placed on a confocal microscope. A magnet is waved by the crop to determine the presence of nanoparticles, which indicate if the insects are able to ingest fluids. This methodology is used to reveal a widespread feeding mechanism (capillary action and liquid bridge formation) that is potentially shared among Lepidoptera and Diptera when feeding from porous surfaces. In addition, this method can be used for studies of feeding mechanisms among a variety of fluid-feeding insects, including those important in disease transmission and biomimetics, and potentially other studies that involve nano- or micro-sized conduits where liquid transport requires verification.
Assuntos
Borboletas/fisiologia , Dípteros/fisiologia , Comportamento de Ingestão de Líquido/fisiologia , Corantes Fluorescentes/administração & dosagem , Nanopartículas de Magnetita/administração & dosagem , Animais , Borboletas/metabolismo , Dípteros/metabolismo , Corantes Fluorescentes/farmacocinéticaRESUMO
Forestland application of poultry manure offers an alternative to the conventional practice of pastureland application. Before such a practice is considered viable, however, it must be demonstrated that the forest ecosystem is capable of absorbing the nutrients contained in poultry manure, especially nitrogen (N) and phosphorus (P). From the forestry perspective, it must also be demonstrated that tree growth is not diminished. We investigated these questions using loblolly pine (Pinus taeda L.) stands growing in central Mississippi in an area of high poultry production. Stockpiled broiler litter was applied to newly thinned, 8-yr-old stands at 0, 4.6, and 18.6 dry Mg ha-1, supplying 0, 200, and 800 kg N ha-1 and 0, 92, and 370 kg P ha-1, respectively. Levels of nitrate in soil water, monitored at a 50-cm depth with porous cup tension lysimeters, exceeded 10 mg N L-1 during the first two years after application in the 18.6 Mg ha-1 rate but only on two occasions in the first year for the lower rate of application. Phosphate was largely absent from lysimeter water in all treatments. Other macronutrients (K, Ca, Mg, S) were elevated in lysimeter water in proportion to litter application rates. Soil extractable nitrate showed similar trends to lysimeter water, with substantial elevation during the first year following application for the 18.6 Mg ha-1 rate. Mehlich III-extractable phosphate peaked in excess of 100 microg P g-1 soil during the third year of the study for the 18.6 Mg ha-1 rate. The 4.6 Mg ha-1 rate did not affect extractable soil P. Tree growth was increased by the poultry litter. Total stem cross-sectional area, or basal area, was approximately 20% greater after 2 yr for both rates of litter application. Overall, the nutrients supplied by the 4.6 Mg ha-1 rate were contained by the pine forest and resulted in favorable increases in tree growth. The higher rate, by contrast, did pose some risk to water quality through the mobilization of nitrate. These results show that, under the conditions of this study, application of poultry litter at moderate rates of approximately 5 Mg ha-1 to young stands of loblolly pine offers an alternative disposal option with minimal impacts to water quality and potential increases in tree growth.
Assuntos
Esterco , Pinus/crescimento & desenvolvimento , Aves Domésticas , Animais , Nitrogênio/metabolismo , Fósforo/metabolismo , Pinus/metabolismo , Folhas de Planta/metabolismo , Solo/análiseRESUMO
Acclimating to toxicant stress is energy expensive. In laboratory toxicology tests dietary conditions are ideal, but not in natural environments where nutrient resources vary in quality and quantity. We compared the effects of additional lipid resources, docosahexaenoic acid (n-3; DHA) or linoleic acid (n-6; LA), or the effects of the toxicants, atrazine or triclosan on post-treatment starvation survival, reproduction, and lipid profiles. Chemical exposure prior to starvation had chemical-specific effects as DHA showed moderately beneficial effects on starvation survival and all of the other chemicals showed adverse effects on either survival or reproduction. Surprisingly, pre-exposure to triclosan inhibits adult maturation and in turn completely blocks reproduction during the starvation phase. The two HR96 activators tested, atrazine and LA adversely reduce post-reproduction survival 70% during starvation and in turn show poor fecundity. DHA and LA show distinctly different lipid profiles as DHA primarily increases the percentage of large (>37 carbon) phosphatidylcholine (PC) species and LA primarily increases the percentage of smaller (<37 carbon) PC species. The toxicants atrazine and triclosan moderately perturb a large number of different phospholipids including several phosphatidylethanolamine species. Some of these polar lipid species may be biomarkers for diets rich in specific fatty acids or toxicant classes. Overall our data demonstrates that toxicants can perturb lipid utilization and storage in daphnids in a chemical specific manner, and different chemicals can produce distinct polar lipid profiles. In summary, biological effects caused by fatty acids and toxicants are associated with changes in the production and use of lipids.
Assuntos
Daphnia/efeitos dos fármacos , Poluentes Ambientais/toxicidade , Ácidos Graxos Insaturados/farmacologia , Privação de Alimentos/fisiologia , Metabolismo dos Lipídeos/efeitos dos fármacos , Adaptação Fisiológica , Animais , Atrazina/toxicidade , Daphnia/crescimento & desenvolvimento , Daphnia/metabolismo , Dieta , Ácidos Docosa-Hexaenoicos/farmacologia , Fertilidade/efeitos dos fármacos , Fosfolipídeos/farmacologia , Reprodução/efeitos dos fármacos , Análise de Sobrevida , Testes de Toxicidade Crônica , Triclosan/toxicidadeRESUMO
Clustered binary data occur frequently in many application areas. When analyzing data of this form, ignoring key features, such as the intracluster correlation, may lead to inaccurate inference; e.g., inflated Type I error rates. For clustered binary data, Gerard and Schucany (2007) proposed an exact test for examining whether the marginal probability of a response differs from 0.5, which is the null hypothesis considered in the classic sign test. This new test maintains the specified Type I error rate and has more power, when compared to both the classic sign and permutation tests. The test statistic proposed by these authors equally weights the observed data from each cluster, regardless of whether the clusters are of equal size. To further improve the performance of the Gerard and Schucany test, a weighted test statistic is proposed and two weighting schemes are investigated. Seeking to further improve the performance of the proposed test, empirical Bayes estimates of the cluster level success probabilities are utilized. These adaptations lead to 5 new tests, each of which are shown through simulation studies to be superior to the Gerard and Schucany (2007) test. The proposed tests are further illustrated using data from a chemical repellency trial.