RESUMO
Grasslands cover around 25% of the global ice-free land surface, they are used predominantly for forage and livestock production and are considered to contribute significantly to soil carbon (C) sequestration. Recent investigations into using 'nature-based solutions' to limit warming to <2 °C suggest up to 25% of GHG mitigation might be achieved through changes to grassland management. In this study we evaluate pasture management interventions at the Rothamsted Research North Wyke Farm Platform, under commercial farming conditions, over two years and consider their impacts on net CO2 exchange. We investigate if our permanent pasture system (PP) is, in the short-term, a net sink for CO2 and whether reseeding this with deep-rooting, high-sugar grass (HS) or a mix of high-sugar grass and clover (HSC) might increase the net removal of atmospheric CO2. In general CO2 fluxes were less variable in 2018 than in 2017 while overall we found that net CO2 fluxes for the PP treatment changed from a sink in 2017 (-5.40 t CO2 ha-1 y-1) to a source in 2018 (6.17 t CO2 ha-1 y-1), resulting in an overall small source of 0.76 t CO2 ha-1 over the two years for this treatment. HS showed a similar trend, changing from a net sink in 2017 (-4.82 t CO2 ha-1 y-1) to a net source in 2018 (3.91 t CO2 ha-1 y-1) whilst the HSC field was a net source in both years (3.92 and 4.10 t CO2 ha-1 y-1, respectively). These results suggested that pasture type has an influence in the atmospheric CO2 balance and our regression modelling supported this conclusion, with pasture type and time of the year (and their interaction) being significant factors in predicting fluxes.
Assuntos
Ciclo do Carbono , Dióxido de Carbono , Agricultura , Dióxido de Carbono/análise , Solo , AçúcaresRESUMO
Trapezoidal integration by linear interpolation of data points is by far the most commonly used method of cumulative flux calculations of nitrous oxide (N2O) in studies that use flux chambers; however, this method is incapable of providing accurate uncertainty estimates. A Bayesian approach was used to calculate N2O emission factors (EFs) and their associated uncertainties from flux chamber measurements made after the application of nitrogen fertilisers, in the form of ammonium nitrate (AN), urea (Ur) and urea treated with Agrotain® urease inhibitor (UI) at four grassland sites in the UK. The comparison between the cumulative fluxes estimated using the Bayesian and linear interpolation methods were broadly similar (R2â¯=â¯0.79); however, the Bayesian method was capable of providing realistic uncertainties when a limited number of data points is available. The study reports mean EF values (and 95% confidence intervals) of 0.60⯱â¯0.63, 0.29⯱â¯0.22 and 0.26⯱â¯0.17% of applied N emitted as N2O for the AN, Ur and UI treatments, respectively. There was no significant difference between N2O emissions from the Ur and UI treatments. In the case of the automatic chamber data collected at one site in this study, the data did not fit the log-normal model, implying that more complex models may be needed, particularly for measurement data with high temporal resolution.
Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Fertilizantes/análise , Nitrogênio/análise , Óxido Nitroso/análise , Teorema de Bayes , Inglaterra , Pradaria , Escócia , País de GalesRESUMO
Fluxes of carbon monoxide (CO) were measured using a fast-response quantum cascade laser absorption spectrometer and the eddy covariance method at a long-term intensively grazed grassland in southern Scotland. Measurements lasted 20 months from April 2016 to November 2017, during which normal agricultural activities continued. Observed fluxes followed a regular diurnal cycle, peaking at midday and returning to values near zero during the night, with occasional uptake observed. CO fluxes correlated well with the meteorological variables of solar radiation, soil temperature and soil moisture content. Using a general additive model (GAM) we were able to gap fill CO fluxes and estimate annual fluxes of 0.38⯱â¯0.046 and 0.35⯱â¯0.045â¯gâ¯C m-2 y-1g C m-2 y-1 for 2016 and 2017, respectively. If the CO fluxes reported in this study are representative of UK grasslands, then national annual emissions could be expected to be in the order of 61.91 (54.3-69.5) Gg, which equates to 3.8% (3.4-4.3%) of the current national inventory total.
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Brown dwarfs are massive analogs of extrasolar giant planets and may host types of atmospheric circulation not seen in the solar system. We analyzed a long-term Spitzer Space Telescope infrared monitoring campaign of brown dwarfs to constrain cloud cover variations over a total of 192 rotations. The infrared brightness evolution is dominated by beat patterns caused by planetary-scale wave pairs and by a small number of bright spots. The beating waves have similar amplitudes but slightly different apparent periods because of differing velocities or directions. The power spectrum of intermediate-temperature brown dwarfs resembles that of Neptune, indicating the presence of zonal temperature and wind speed variations. Our findings explain three previously puzzling behaviors seen in brown dwarf brightness variations.
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Concerns regarding the potential for broken chains and "reneges" within kidney paired donation (KPD) and its effect on chain length have been raised previously. Although these concerns have been tested in simulation studies, real-world data have yet to be evaluated. The purpose of this study was to evaluate the actual rate and causes of broken chains within a large KPD program. All patients undergoing renal transplantation through the National Kidney Registry from 2008 through May 2016 were included for analysis. Broken chains and loops were identified. A total of 344 chains and 78 loops were completed during the study period, yielding a total of 1748 transplants. Twenty broken chains and one broken loop were identified. The mean chain length (number of transplants) within broken chains was 4.8 compared with 4.6 of completed chains (p = 0.78). The most common causes of a broken chain were donor medical issues incurred while acting as a bridge donor (n = 8), donors electing not to proceed (n = 6), and kidneys being declined by the recipient surgeon (n = 4). All recipients involved in a broken chain subsequently received a transplant. Based on the results, broken chains are infrequent, are rarely due to lack of donor motivation, and have no significant impact on chain length.
Assuntos
Seleção do Doador , Falência Renal Crônica/cirurgia , Transplante de Rim , Doadores Vivos/provisão & distribuição , Obtenção de Tecidos e Órgãos , Humanos , Prognóstico , Sistema de Registros , Listas de EsperaRESUMO
Working memory is the small amount of information that we hold in mind and use to carry out cognitive processes such as language comprehension and production, problem solving, and decision making. In order to understand cognitive development, it would be helpful to know whether working memory increases in capacity with development and, if so, how and why. I will focus on two major stumbling blocks toward understanding working memory development, namely that (1) many potentially relevant aspects of the mind change in parallel during development, obscuring the role of any one change; and (2) one cannot use the same test procedure from infancy to adulthood, complicating comparisons across age groups. With regard to the first stumbling block, the parallel development of different aspects of the mind, we discuss research in which attempts were made to hold constant some factors (knowledge, strategies, direction of attention) to investigate whether developmental differences remain. With regard to the second stumbling block, procedural differences in tests for different age groups, I suggest ways in which the results might be reconciled across procedures. I highlight the value of pursuing research that could distinguish between two different key hypotheses that emerge: that there is a developmental increase in the number of working memory slots (or in a basic resource that holds items in working memory), and that there is a developmental increase in the amount of detail that each of these slots can hold.
Assuntos
Desenvolvimento Infantil , Cognição , Memória de Curto Prazo , Reconhecimento Visual de Modelos , Adulto , Fatores Etários , Atenção , Criança , Pré-Escolar , Tomada de Decisões , Humanos , Lactente , Testes Neuropsicológicos , Resolução de Problemas , Retenção PsicológicaRESUMO
Objectives. Level 1 evidence supports the use of neoadjuvant chemotherapy (NAC) to improve overall survival in muscle invasive bladder cancer; however utilization rates remain low. The aims of our study were to determine factors associated with NAC use, to more clearly define reasons for low utilization, and to determine the current rate of NAC use among urologic oncologists. Materials and Methods. Active members of the Society for Urologic Oncology were provided a 20-question survey. Descriptive statistical analysis was conducted for each question and univariate analysis was performed. Results. We achieved a response rate of 21%. Clinical T3/T4 disease was the most often selected reason for recommending NAC (87%). Concerns with recommending NAC were age and comorbidities (54%) followed by delay in surgery (35%). An association was identified between urologic oncologists who discussed NAC with >90% of their patients and medical oncologists "always" recommending NAC (P = 0.0009). NAC utilization rate was between 30 and 57%. Conclusions. Amongst this highly specialized group of respondents, clinical T3-T4 disease was the most common reason for implementation of NAC. Respondents who frequently discussed NAC were more likely to report their medical oncologist always recommending NAC. Reported NAC use was higher in this surveyed group (30-57%) compared with recently published rates.
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Neural computation is inescapably closed-loop: the nervous system processes sensory signals to shape motor output, and motor output consequently shapes sensory input. Technological advances have enabled neuroscientists to close, open, and alter feedback loops in a wide range of experimental preparations. The experimental capability of manipulating the topology-that is, how information can flow between subsystems-provides new opportunities to understand the mechanisms and computations underlying behavior. These experiments encompass a spectrum of approaches from fully open-loop, restrained preparations to the fully closed-loop character of free behavior. Control theory and system identification provide a clear computational framework for relating these experimental approaches. We describe recent progress and new directions for translating experiments at one level in this spectrum to predictions at another level. Operating across this spectrum can reveal new understanding of how low-level neural mechanisms relate to high-level function during closed-loop behavior.
Assuntos
Comportamento/fisiologia , Retroalimentação , Modelos Neurológicos , Fenômenos Fisiológicos do Sistema Nervoso , Teoria de Sistemas , Animais , HumanosRESUMO
CONTEXT: New data regarding treatment of muscle-invasive and metastatic bladder cancer (MiM-BC) has emerged and led to an update of the European Association of Urology (EAU) guidelines for MiM-BC. OBJECTIVE: To review the new EAU guidelines for MiM-BC with a specific focus on treatment. EVIDENCE ACQUISITION: New literature published since the last update of the EAU guidelines in 2008 was obtained from Medline, the Cochrane Database of Systematic Reviews, and reference lists in publications and review articles and comprehensively screened by a group of urologists, oncologists, and a radiologist appointed by the EAU Guidelines Office. Previous recommendations based on the older literature on this subject were also taken into account. Levels of evidence (LEs) and grades of recommendations (GRs) were added based on a system modified from the Oxford Centre for Evidence-based Medicine Levels of Evidence. EVIDENCE SYNTHESIS: Current data demonstrate that neoadjuvant chemotherapy in conjunction with radical cystectomy (RC) is recommended in certain constellations of MiM-BC. RC remains the basic treatment of choice in localised invasive disease for both sexes. An attempt has been made to define the extent of surgery under standard conditions in both sexes. An orthotopic bladder substitute should be offered to both male and female patients lacking any contraindications, such as no tumour at the level of urethral dissection. In contrast to neoadjuvant chemotherapy, current advice recommends the use of adjuvant chemotherapy only within clinical trials. Multimodality bladder-preserving treatment in localised disease is currently regarded only as an alternative in selected, well-informed, and compliant patients for whom cystectomy is not considered for medical or personal reasons. In metastatic disease, the first-line treatment for patients fit enough to sustain cisplatin remains cisplatin-containing combination chemotherapy. With the advent of vinflunine, second-line chemotherapy has become available. CONCLUSIONS: In the treatment of localised invasive bladder cancer (BCa), the standard treatment remains radical surgical removal of the bladder within standard limits, including as-yet-unspecified regional lymph nodes. However, the addition of neoadjuvant chemotherapy must be considered for certain specific patient groups. A new drug for second-line chemotherapy (vinflunine) in metastatic disease has been approved and is recommended.
Assuntos
Neoplasias da Bexiga Urinária/patologia , Neoplasias da Bexiga Urinária/terapia , Cistectomia , Feminino , Humanos , Masculino , Invasividade Neoplásica , Metástase Neoplásica , Neoplasias da Bexiga Urinária/cirurgia , Derivação UrináriaRESUMO
CONTEXT: New data regarding diagnosis and treatment of muscle-invasive and metastatic bladder cancer (MiM-BC) has emerged and led to an update of the European Association of Urology (EAU) guidelines for MiM-BC. OBJECTIVE: To review the new EAU guidelines for MiM-BC. EVIDENCE ACQUISITION: A comprehensive workup of the literature obtained from Medline, the Cochrane central register of systematic reviews, and reference lists in publications and review articles was developed and screened by a group of urologists, oncologists, and radiologist appointed by the EAU Guideline Committee. Previous recommendations based on the older literature on this subject were taken into account. Levels of evidence and grade of guideline recommendations were added, modified from the Oxford Centre for Evidence-based Medicine Levels of Evidence. EVIDENCE SYNTHESIS: The diagnosis of muscle-invasive bladder cancer (BCa) is made by transurethral resection (TUR) and following histopathologic evaluation. Patients with confirmed muscle-invasive BCa should be staged by computed tomography (CT) scans of the chest, abdomen, and pelvis, if available. Adjuvant chemotherapy is currently only advised within clinical trials. Radical cystectomy (RC) is the treatment of choice for both sexes, and lymph node dissection should be an integral part of cystectomy. An orthotopic bladder substitute should be offered to both male and female patients lacking any contraindications, such as no tumour at the level of urethral dissection. Multimodality bladder-preserving treatment in localised disease is currently regarded only as an alternative in selected, well-informed, and compliant patients for whom cystectomy is not considered for clinical or personal reasons. An appropriate schedule for disease monitoring should be based on: a) natural timing of recurrence; b) probability of disease recurrence; c) functional deterioration at particular sites; and d) consideration of treatment of a recurrence. In metastatic disease, the first-line treatment for patients fit enough to sustain cisplatin is cisplatin-containing combination chemotherapy. Presently, there is no standard second-line chemotherapy. CONCLUSIONS: These EAU guidelines are a short, comprehensive overview of the updated guidelines of (MiM-BC) as recently published in the EAU guidelines and also available in the National Guideline Clearinghouse.
Assuntos
Carcinoma de Células de Transição/secundário , Neoplasias da Bexiga Urinária , Urologia/normas , Antineoplásicos/uso terapêutico , Carcinoma de Células de Transição/diagnóstico , Carcinoma de Células de Transição/epidemiologia , Carcinoma de Células de Transição/terapia , Quimioterapia Adjuvante , Cistectomia/métodos , Diagnóstico por Imagem , Medicina Baseada em Evidências , Feminino , Humanos , Excisão de Linfonodo , Masculino , Terapia Neoadjuvante , Invasividade Neoplásica , Estadiamento de Neoplasias/métodos , Cuidados Paliativos , Fatores de Risco , Neoplasias da Bexiga Urinária/diagnóstico , Neoplasias da Bexiga Urinária/epidemiologia , Neoplasias da Bexiga Urinária/patologia , Neoplasias da Bexiga Urinária/terapia , Derivação Urinária/métodosRESUMO
AIM: To evaluate and compare the diagnostic accuracy of multidetector computed tomography urography (CTU) and ultrasonography (US) for diagnosing bladder cancer. MATERIALS AND METHODS: A consecutive series of 143 patients over 40-years of age, presenting with macroscopic haematuria and without urinary tract infection underwent same-day CTU, US, and flexible cystoscopy. CTU and US were independently rated on a five-point scale for the presence of bladder cancer without knowledge of the reference standard of flexible or rigid cystoscopy and/or biopsy results. Diagnostic accuracy was assessed by receiver operating characteristic (ROC) analysis and likelihood ratios. RESULTS: For CTU, a rating of 5 (definitely tumour) was highly specific for bladder cancer (96.5%, 95%CI: 91.3-99%), effectively confirming diagnosis (positive likelihood ratio 25.6, 95%CI: 9.7-67.4). For US, specificity was also high (94.7%, 95%CI: 88.9-98%) with a positive likelihood ratio of 13.1 (95%CI: 5.8-29.6). Sensitivity at this rating was substantially higher for CTU (89.7%, 95%CI: 72.7-97.8%) than US (69%, 95%CI: 49.2-84.7%). Standardized partial area (Az) under the ROC curve between 95-100% specificity, representing the average sensitivity in this range, was significantly greater (0.88 versus 0.61, p<0.05) for CTU than US. CONCLUSION: The specificities of CTU and US for the diagnosis of bladder cancer were similar, but CTU was more sensitive. Although the sensitivity of CTU was not high enough to replace flexible cystoscopy in the diagnostic pathway, the high specificity enables direct referral to rigid cystoscopy, bypassing flexible cystoscopy and expediting diagnosis and treatment in those patients testing positive.
Assuntos
Hematúria , Tomografia Computadorizada por Raios X/métodos , Neoplasias da Bexiga Urinária/diagnóstico por imagem , Urografia/métodos , Adulto , Idoso , Idoso de 80 Anos ou mais , Algoritmos , Cistoscopia/métodos , Reações Falso-Negativas , Feminino , Hematúria/diagnóstico por imagem , Humanos , Aumento da Imagem , Masculino , Pessoa de Meia-Idade , Curva ROC , Sensibilidade e Especificidade , UltrassonografiaRESUMO
Multidetector computed tomography (MDCT) is well established for the detection of stones and renal masses, but more recently MDCT urography (MDCTU) is becoming widely used for examination of the entire urinary tract aimed specifically for diagnosing urothelial lesions. Evidence is rapidly accumulating to support the use of MDCTU in this manner. Familiarity with the MDCTU signs of urothelial malignancy is a prerequisite for optimum radiological practice. This article provides a review of the appearances of transitional cell cancer in the upper urinary tract and bladder.
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Carcinoma de Células de Transição/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Neoplasias Urológicas/diagnóstico por imagem , Humanos , Cálices Renais/diagnóstico por imagem , Neoplasias Renais/diagnóstico por imagem , Neoplasias Pélvicas/diagnóstico por imagem , Doses de Radiação , Tomografia Computadorizada por Raios X/efeitos adversos , Neoplasias Ureterais/diagnóstico por imagem , Neoplasias da Bexiga Urinária/diagnóstico por imagem , Urografia/métodos , Urotélio/diagnóstico por imagemRESUMO
The American cockroach, Periplaneta americana, is reported to follow walls at a rate of up to 25 turns s(-1). During high-speed wall following, a cockroach holds its antenna relatively still at the base while the flagellum bends in response to upcoming protrusions. We present a simple mechanosensory model for the task-level dynamics of wall following. In the model a torsional, mass-damper system describes the cockroach's turning dynamics, and a simplified antenna measures distance from the cockroach's centerline to a wall. The model predicts that stabilizing neural feedback requires both proportional feedback (difference between the actual and desired distance to wall) and derivative feedback (velocity of wall convergence) information from the antenna. To test this prediction, we fit a closed-loop proportional-derivative control model to trials in which blinded cockroaches encountered an angled wall (30 degrees or 45 degrees ) while running. We used the average state of the cockroach in each of its first four strides after first contacting the angled wall to predict the state in each subsequent stride. Nonlinear statistical regression provided best-fit model parameters. We rejected the hypothesis that proportional feedback alone was sufficient. A derivative (velocity) feedback term in the control model was necessary for stability.
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Comportamento Animal/fisiologia , Baratas/fisiologia , Tato/fisiologia , Animais , Retroalimentação Fisiológica , Locomoção/fisiologia , Masculino , Órgãos dos Sentidos/fisiologiaRESUMO
The authors present 14 cases from the film interpretation session of the 11th annual meeting of the European Society of Urogenital Radiology presented in September, 2004. The cases demonstrate the imaging findings, differential diagnoses, and clinical relevance of a wide variety of genitourinary tract diseases. The cases include examples of benign and malignant urinary tract neoplasms, inflammatory processes, vascular diseases, traumatic injuries, and congenital anomalies.
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Doenças Urogenitais Femininas/diagnóstico , Linfoma/diagnóstico , Doenças Urogenitais Masculinas , Sociedades Médicas , Neoplasias Urológicas/diagnóstico , Adolescente , Adulto , Idoso , Diagnóstico Diferencial , Europa (Continente) , Feminino , Humanos , Histerossalpingografia/métodos , Rim/diagnóstico por imagem , Imageamento por Ressonância Magnética/métodos , Masculino , Pessoa de Meia-Idade , Ultrassonografia , Sistema Urogenital/patologia , Urografia/métodosRESUMO
AIM: To determine the optimum approach for double-pigtail stent placement in malignant ureteric obstruction. PATIENTS AND METHODS: Retrograde stent placement was attempted in a consecutive series of patients presenting with malignant ureteric obstruction. If retrograde stent placement was unsuccessful, percutaneous nephrostomy was performed immediately followed by elective antegrade stent placement. Identical digital C-arm fluoroscopy for image-guidance and conditions for anaesthesia and analgesia were employed for both retrograde and antegrade procedures. Identical 8 Fr (20-26 cm) double-pigtail hydrophilic coated stents were used for each approach. RESULTS: Retrograde placement was attempted in 50 ureters in 30 patients {19 male, 11 female, average age 61.4 yr (range 29-90 yr)} over a 24-month period. The success rate for retrograde ureteric stent placement was 50% (n = 25/50). Technical failures were due to failure to identify the ureteric orifice (n = 22), failure to cross the stricture (n = 1), failure to pass the stent (n = 1) and failure to pass a 4 Fr catheter (n = 1). Antegrade placement was attempted in 25 ureters with a success rate of 96% (n = 24/25). Failure in the one case was due to inability to cross an upper third stricture secondary to pyeloureteritis cystica. CONCLUSION: It is suggested that retrograde route should be the initial approach if imaging shows no involvement of ureteric orifice (UO), when nephrostomy is technically very difficult or in cases of solitary kidney. The antegrade route is preferred if imaging shows tumour occlusion of the UO or if there is a tight stricture very close to the uretero-vesical junction (UVJ) making purchase within the ureter difficult for crossing the stricture.
Assuntos
Neoplasias/complicações , Stents , Obstrução Ureteral/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Feminino , Fluoroscopia , Humanos , Masculino , Pessoa de Meia-Idade , Nefrostomia Percutânea , Cuidados Paliativos/métodos , Estudos Prospectivos , Falha de Tratamento , Resultado do Tratamento , Obstrução Ureteral/diagnóstico por imagem , Obstrução Ureteral/etiologiaRESUMO
Recent improvements in helical CT hardware and software have provided imagers with the tools to obtain an increasingly large number of very thin axial images. As a result, a number of new applications for multislice CT have recently been developed, one of which is CT urography. The motivation for performing CT urography is the desire to create a single imaging test that can completely assess the kidneys and urinary tract for urolithiasis, renal masses and mucosal abnormalities of the renal collecting system, ureters and bladder. Although the preferred technique for performing multislice CT urography has not yet been determined and results are preliminary, early indications suggest that this examination can detect even subtle benign and malignant urothelial abnormalities and that it has the potential to completely replace excretory urography within the next several years. An important limitation of multislice CT urography is increased patient radiation exposure encountered when some of the more thorough recommended techniques are utilized.
Assuntos
Tomografia Computadorizada por Raios X/métodos , Urografia/métodos , Doenças Urológicas/diagnóstico por imagem , Urologia/instrumentação , Meios de Contraste , Análise Custo-Benefício , Humanos , Interpretação de Imagem Assistida por Computador/métodos , Doses de Radiação , Tomografia Computadorizada por Raios X/economia , Urografia/economia , Urologia/economia , Urologia/métodosRESUMO
OBJECTIVE: To review the risks of placing double-pigtail stents during pregnancy in women presenting with loin pain associated with hydronephrosis. PATIENTS AND METHODS: A consecutive series of women presenting with loin pain and hydronephrosis in pregnancy were treated with double-pigtail ureteric stents. A flexible cystoscope was used to identify the ureteric orifice and to pass a guidewire into the renal pelvis under fluoroscopic guidance. Stents were placed using the exchange technique over a stiff guidewire. Procedures were carried out under none or limited sedoanalgesia. Screening times and radiation dose were recorded. Data were collected for the average uterine radiation dose from a variety of radiological procedures. Previous publications were reviewed to determine the lethal, teratogenic and carcinogenic risk to the developing fetus from radiation exposure. RESULTS: Seven patients referred with symptomatic hydronephrosis during pregnancy were treated. The screening time during placement was minimized. The mean (range) uterus (i.e. fetal) dose was 0.40 (0.03-0.79) mGy. Most radiological procedures involve uterine doses of < 20 mGy, far below the 100 mGy that may result in fetal damage during periods of maximum radiosensitivity. CONCLUSION: Minimized radiation exposure from a range of uroradiological procedures in pregnant women has limited fetal risk. The use of fluoroscopy for symptomatic hydronephrosis during pregnancy allows ureteric stents to be placed safely and reliably. The average excess risk to the fetus from this procedure is 1 in 43 000 of cancer induction and 1 in 100 000 of heritable disease, i.e. very small when compared with the natural incidence. Pregnancy should not exclude the use of appropriate diagnostic radiation exposure and urologists may conduct appropriate diagnostic and therapeutic procedures, taking care to limit X-ray exposure without fear of risk to the developing fetus.
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Fluoroscopia/efeitos adversos , Hidronefrose/diagnóstico por imagem , Dor Pélvica/diagnóstico por imagem , Complicações na Gravidez/diagnóstico por imagem , Stents , Adulto , Relação Dose-Resposta à Radiação , Feminino , Idade Gestacional , Humanos , Hidronefrose/terapia , Dor Pélvica/cirurgia , Gravidez , Complicações na Gravidez/terapia , Efeitos Tardios da Exposição Pré-Natal , Radiografia Intervencionista/efeitos adversos , Fatores de RiscoRESUMO
PURPOSE: We evaluated retrograde double pigtail stent placement in patients with ureteroileal anastomosis. MATERIALS AND METHODS: Procedures were performed under digital C-arm fluoroscopic guidance and the patient under sedation analgesia. Radiography of the conduit was done to delineate urinary diversion anatomy and identify ureteral reflux. A purpose designed, angled tip catheter was used to direct a straight glide wire across the ureteroileal anastomosis. The glide wire was exchanged for a stiff guide wire for stent placement. We retrospectively evaluated the clinical records of 7 men and 5 women with a mean age of 54.3 years in a 7-year period. In 11 patients a new stent was placed because of ureteroileal stricture in 5, anastomotic leakage in 3, ureterolithiasis in 2 and recurrent malignancy in 1. RESULTS: New stent placement was successful in 10 of the 11 patients (90.9%, 13 of 16 ureters or 81.3%). Stent placement was successful in the 8 ureters in which reflux was noted on radiography of the conduit and in 5 of the 9 (55.6%) in which no reflux was noted. Stent replacement was accomplished in all 22 ureters (6 patients) in which it was attempted. Mean radiological screening time for new stent placement was 13.3 minutes (range 4.7 to 19.7), while for exchange it was 6.4 minutes (range 0.8 to 15.1). There were no immediate complications. CONCLUSIONS: This technique represents a useful approach to the ureter and should be considered an alternative to percutaneous nephrostomy and surgical revision. The approach is also useful for other ureteral procedures, including stone or migrated stent retrieval.
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Fluoroscopia , Complicações Pós-Operatórias/terapia , Stents , Obstrução Ureteral/terapia , Derivação Urinária , Adolescente , Adulto , Idoso , Anastomose Cirúrgica , Criança , Cistectomia , Estudos de Viabilidade , Feminino , Humanos , Íleo/cirurgia , Masculino , Pessoa de Meia-Idade , Complicações Pós-Operatórias/diagnóstico por imagem , Obstrução Ureteral/diagnóstico por imagemRESUMO
Wood and Cowan (1995) replicated and extended Moray's (1959) investigation of the cocktail party phenomenon, which refers to a situation in which one can attend to only part of a noisy environment, yet highly pertinent stimuli such as one's own name can suddenly capture attention. Both of these previous investigations have shown that approximately 33% of subjects report hearing their own name in an unattended, irrelevant message. Here we show that subjects who detect their name in the irrelevant message have relatively low working-memory capacities, suggesting that they have difficulty blocking out, or inhibiting, distracting information.
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Atenção , Rememoração Mental , Reconhecimento Visual de Modelos , Mascaramento Perceptivo , Percepção da Fala , Adulto , Feminino , Humanos , Inibição Psicológica , Masculino , PsicofísicaRESUMO
Miller (1956) summarized evidence that people can remember about seven chunks in short-term memory (STM) tasks. However, that number was meant more as a rough estimate and a rhetorical device than as a real capacity limit. Others have since suggested that there is a more precise capacity limit, but that it is only three to five chunks. The present target article brings together a wide variety of data on capacity limits suggesting that the smaller capacity limit is real. Capacity limits will be useful in analyses of information processing only if the boundary conditions for observing them can be carefully described. Four basic conditions in which chunks can be identified and capacity limits can accordingly be observed are: (1) when information overload limits chunks to individual stimulus items, (2) when other steps are taken specifically to block the recording of stimulus items into larger chunks, (3) in performance discontinuities caused by the capacity limit, and (4) in various indirect effects of the capacity limit. Under these conditions, rehearsal and long-term memory cannot be used to combine stimulus items into chunks of an unknown size; nor can storage mechanisms that are not capacity-limited, such as sensory memory, allow the capacity-limited storage mechanism to be refilled during recall. A single, central capacity limit averaging about four chunks is implicated along with other, noncapacity-limited sources. The pure STM capacity limit expressed in chunks is distinguished from compound STM limits obtained when the number of separately held chunks is unclear. Reasons why pure capacity estimates fall within a narrow range are discussed and a capacity limit for the focus of attention is proposed.