926 resultados para subject and object


Relevância:

80.00% 80.00%

Publicador:

Resumo:

Brain mechanisms associated with artistic talents or skills are still not well understood. This exploratory study investigated differences in brain activity of artists and non-artists while drawing previously presented perspective line-drawings from memory and completing other drawing-related tasks. Electroencephalography (EEG) data were analyzed for power in the frequency domain by means of a Fast Fourier Transform (FFT). Low Resolution Brain Electromagnetic Tomography (LORETA) was applied to localize emerging significances. During drawing and related tasks, decreased power was seen in artists compared to non-artists mainly in upper alpha frequency ranges. Decreased alpha power is often associated with an increase in cognitive functioning and may reflect enhanced semantic memory performance and object recognition processes in artists. These assumptions are supported by the behavioral data assessed in this study and complement previous findings showing increased parietal activations in non-artists compared to artists while drawing. However, due to the exploratory nature of the analysis, additional confirmatory studies will be needed.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

The present study examined the neural basis of vivid motor imagery with parametrical functional magnetic resonance imaging. 22 participants performed motor imagery (MI) of six different right-hand movements that differed in terms of pointing accuracy needs and object involvement, i.e., either none, two big or two small squares had to be pointed at in alternation either with or without an object grasped with the fingers. After each imagery trial, they rated the perceived vividness of motor imagery on a 7-point scale. Results showed that increased perceived imagery vividness was parametrically associated with increasing neural activation within the left putamen, the left premotor cortex (PMC), the posterior parietal cortex of the left hemisphere, the left primary motor cortex, the left somatosensory cortex, and the left cerebellum. Within the right hemisphere, activation was found within the right cerebellum, the right putamen, and the right PMC. It is concluded that the perceived vividness of MI is parametrically associated with neural activity within sensorimotor areas. The results corroborate the hypothesis that MI is an outcome of neural computations based on movement representations located within motor areas.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Study Type--Therapy (case series) Level of Evidence 4. What's known on the subject? and What does the study add? Vasectomy reversal is often performed in general or neuraxial anaesthesia. Even though the site of vasectomy reversal is easily amenable to regional/local anaesthesia, spermatic cord blocks are rarely applied because of their risk of vascular damage within the spermatic cord. Recently, we described the technique of ultrasonography (US)-guided spermatic cord block for scrotal surgery, which, thanks to the US guidance, at the same time avoids the risk of vascular damage of blindly performed injections and the risks of general and neuraxial anaesthesia. Vasectomy reversal can easily be done in regional anaesthesia with the newly described technique of US-guided spermatic cord block without the risks of vascular damage by a blindly performed injection and the risks of standard general and neuraxial anaesthesia. In addition, this technique grants long-lasting postoperative pain relief and patients recover more quickly. Microsurgical conditions are excellent and patient satisfaction is high. Thanks to these advantages, more patients undergoing vasectomy reversal might avoid general or neuraxial anaesthesia.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

The aim of this study was to test the hypothesis that ear oximetry immediately after the release of a sustained Valsalva maneuver accurately detects patent foramen ovale (PFO). One hundred sixty-five scuba divers underwent transesophageal echocardiography (TEE; reference method) for PFO assessment. Ear oximetry of the right earlobe was performed in a different room within a time frame of 2 hours before or after TEE. The subject and the oximetry operator were unaware of the results of TEE. Oxygen saturation (SO(2)) measurements were obtained at baseline and during the release phase of 4 Valsalva maneuvers within 10 minutes, and the average SO(2) change (SO(2) at baseline minus SO(2) at Valsalva release) was determined as the primary study end point. One hundred seventeen divers had no PFO, and 48 (29%) had PFO by TEE (mean age 39 ± 8 years). The average SO(2) change was 0.79 ± 1.13% (i.e., a slight absolute SO(2) decrease in response to the Valsalva maneuver) in the group without PFO and 1.67 ± 1.19% in the PFO group (p <0.0001). Using receiver-operating characteristic curve analysis, a PFO as defined by TEE could be detected at a threshold of a Valsalva-induced decrease in SO(2) of ≥0.825 percentage points in comparison to baseline (sensitivity 0.756, specificity 0.706, area under the receiver-operating characteristic curve 0.763, p <0.0001, negative predictive value 0.882). In conclusion, the entirely noninvasive method of ear oximetry in response to repetitive Valsalva maneuvers is accurate and useful as a screening method for the detection of a PFO, as shown in this study of divers.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

What's known on the subject? and What does the study add? One area of particular growth for robotic surgery has been partial nephrectomy. Despite a perceived notion that robotic-assisted partial nephrectomy is more easily adaptable compared to laparoscopic partial nephrectomy, there is nonetheless an associated learning curve. Validated training models with a corresponding assessment method for robotic-assisted partial nephrectomy were previously unavailable. We have designed and validated a RAPN surgical model appropriate for resident and fellow training.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

What's known on the subject? and What does the study add? Nowadays radical prostatectomy (RP) is considered an effective treatment in high-risk prostate cancer (PCa) and the indications for a surgical approach are expanding, even in cases of very high PSA or node-positive disease. We explored the outcomes of debulking surgery in the setting of these very high-risk PCa patients, in order to assess its feasibility. This review confirms the important role achieved by surgery in the complex setting of patients with very high-risk PCA. Excellent survival rates have been reported, even when PSA exceeds 100 ng/mL. The completion of RP with lymphadenectomy might give a survival benefit in patients who were found intraoperatively to be node-positive. Furthermore, salvage RP confirmed to be the most effective treatment option after RT failure. On the contrary, up-to-date surgery of isolated nodal recurrences has shown only little benefit. Finally, there is no evidence supporting the efficacy of debulking surgery in metastatic or in hormone-refractory tumours. An accurate selection of the patient is essential.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

The ultimatum game is a commonly used economics game testing humans' sense of fairness. In the game, a "proposer" is given a sum of money and is told they can split it however they want with another human partner. The partner can then either accept the division and both proposer and responder receive the proposed amounts, or the responder can reject the offer and neither player will get anything. Human subjects from most western cultures typically share almost half of an allotted amount, but it remains unknown whether our close primate relatives share this generosity. Recent attempts to present chimpanzees with the ultimatum game have provided inconclusive results, with some studies finding the animals share humans' disposition to behave 'fairly' and others concluding that chimpanzees act selfishly to maximize their own rewards. Capuchin monkeys are known to share many human and chimpanzee social and cooperative behaviors, and this study was the first to present capuchin monkeys with a version of the ultimatum game. Subjects were presented with two differently colored tokens representing different qualitative reward contingencies, one equitable and the other inequitable in favor of the subject proposer. Subjects could select and place one of the tokens in a transfer container. The capuchins were first tested with a "dictator game" where, after the subject monkey selected a token, the rewards (equitable or inequitable) were distributed to the subject and a nearby partner monkey that was not an active participant. The capuchins were then tested on an ultimatum game in which after the subject selected and placed a token in the container, the container was moved to the partner. The partner needed to remove the token and transfer it back to the experimenter for the rewards to be distributed. As such, the partner could reject the subject's offer by refusing to participate and neither would receive a reward. The experiment was conducted to determine if the subject monkey would select the equitable reward option rather than the selfish option in order to maintain the partner's cooperation in the task. Capuchin subjects behaved selfishly and selected the inequitable token significantly more often than the equitable token in both the dictator and ultimatum game with no significant difference in preference between the two games. Interestingly, despite the occasional occurrence of rejection by the partner monkeys (resulting in no reward for the subject), subjects never altered their strategy, continuing to prefer the selfish token. The study may indicate that capuchin monkeys have an inability to judge the effect of their behavior on a conspecific's reward outcome, or an indifference to the outcome if there is an individual cost associated with behaving prosocially.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Conventional debugging tools present developers with means to explore the run-time context in which an error has occurred. In many cases this is enough to help the developer discover the faulty source code and correct it. However, rather often errors occur due to code that has executed in the past, leaving certain objects in an inconsistent state. The actual run-time error only occurs when these inconsistent objects are used later in the program. So-called back-in-time debuggers help developers step back through earlier states of the program and explore execution contexts not available to conventional debuggers. Nevertheless, even back-in-time debuggers do not help answer the question, ``Where did this object come from?'' The Object-Flow Virtual Machine, which we have proposed in previous work, tracks the flow of objects to answer precisely such questions, but this VM does not provide dedicated debugging support to explore faulty programs. In this paper we present a novel debugger, called Compass, to navigate between conventional run-time stack-oriented control flow views and object flows. Compass enables a developer to effectively navigate from an object contributing to an error back-in-time through all the code that has touched the object. We present the design and implementation of Compass, and we demonstrate how flow-centric, back-in-time debugging can be used to effectively locate the source of hard-to-find bugs.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Mainstream IDEs such as Eclipse support developers in managing software projects mainly by offering static views of the source code. Such a static perspective neglects any information about runtime behavior. However, object-oriented programs heavily rely on polymorphism and late-binding, which makes them difficult to understand just based on their static structure. Developers thus resort to debuggers or profilers to study the system's dynamics. However, the information provided by these tools is volatile and hence cannot be exploited to ease the navigation of the source space. In this paper we present an approach to augment the static source perspective with dynamic metrics such as precise runtime type information, or memory and object allocation statistics. Dynamic metrics can leverage the understanding for the behavior and structure of a system. We rely on dynamic data gathering based on aspects to analyze running Java systems. By solving concrete use cases we illustrate how dynamic metrics directly available in the IDE are useful. We also comprehensively report on the efficiency of our approach to gather dynamic metrics.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

During decades Distance Transforms have proven to be useful for many image processing applications, and more recently, they have started to be used in computer graphics environments. The goal of this paper is to propose a new technique based on Distance Transforms for detecting mesh elements which are close to the objects' external contour (from a given point of view), and using this information for weighting the approximation error which will be tolerated during the mesh simplification process. The obtained results are evaluated in two ways: visually and using an objective metric that measures the geometrical difference between two polygonal meshes.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Skin segmentation is a challenging task due to several influences such as unknown lighting conditions, skin colored background, and camera limitations. A lot of skin segmentation approaches were proposed in the past including adaptive (in the sense of updating the skin color online) and non-adaptive approaches. In this paper, we compare three skin segmentation approaches that are promising to work well for hand tracking, which is our main motivation for this work. Hand tracking can widely be used in VR/AR e.g. navigation and object manipulation. The first skin segmentation approach is a well-known non-adaptive approach. It is based on a simple, pre-computed skin color distribution. Methods two and three adaptively estimate the skin color in each frame utilizing clustering algorithms. The second approach uses a hierarchical clustering for a simultaneous image and color space segmentation, while the third approach is a pure color space clustering, but with a more sophisticated clustering approach. For evaluation, we compared the segmentation results of the approaches against a ground truth dataset. To obtain the ground truth dataset, we labeled about 500 images captured under various conditions.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

Map landscape-based segmentation of the sequences of momentary potential distribution maps (42-channel recordings) into brain microstates during spontaneous brain activity was used to study brain electric field spatial effects of single doses of piracetam (2.9, 4.8, and 9.6 g Nootropil® UCB and placebo) in a double-blind study of five normal young volunteers. Four 15-second epochs were analyzed from each subject and drug condition. The most prominent class of microstates (covering 49% of the time) consisted of potential maps with a generally anterior-posterior field orientation. The map orientation of this microstate class showed an increasing clockwise deviation from the placebo condition with increasing drug doses (Fisher's probability product, p < 0.014). The results of this study suggest the use of microstate segmentation analysis for the assessment of central effects of medication in spontaneous multichannel electroencephalographic data, as a complementary approach to frequency-domain analysis.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

What's known on the subject? and What does the study add? Local recurrence after radical prostatectomy (RP) for clinically organ-confined prostate cancer is largely assumed to occur at the anastomotic site, as reflected in European and North American guidelines for adjuvant and salvage radiotherapy after RP. However, the exact site of local recurrence often remains undetermined. The present study shows that roughly one out of five patients with local recurrence after RP has histologically confirmed tumour deposits at the resection site of the vas deferens, clearly above the anastomotic site. This should be considered when offering ‘blind’ radiotherapy to the anastomotic site in patients with biochemical recurrence alone. Objective To determine the anatomical pattern of local recurrence and the corresponding clinical and pathological variables of patients treated with retropubic radical prostatectomy (RRP). Patients and Methods In all, 41 patients with biopsy confirmed local recurrence after extended pelvic lymph node dissection and RRP performed between January 1992 and December 2009 at a single tertiary referral academic centre were retrospectively studied. The site of local recurrence as assessed on computed tomography or magnetic resonance imaging was reviewed. Two sites were identified: the vesicourethral anastomotic site and the cranial resection margin of the surgical bed, where the vas deferens was transected and clipped. Age and serum prostate-specific antigen (PSA) level at RRP, pathological tumour and nodal stage, Gleason score, tumour location, surgical margin status, age and serum PSA level at the time of local recurrence, and time to diagnosis of local recurrence were assessed for the two sites and compared with the chi-square or Wilcoxon rank sum tests as appropriate. Results Local recurrence occurred at the anastomotic site in 31/41 (76%) patients and at the resection site of the vas deferens in nine of 41 (22%) patients. One patient had distinct lesions at both sites. There was no significant difference in any of the clinical and pathological variables between patients with local recurrence in the former and latter site. Conclusion Most local recurrences after RRP occur exclusively at the anastomotic site. However, 22% of locally recurrent cases had tumour at the resection site of the vas deferens. This should be taken into account when considering adjuvant or salvage radiation therapy.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

What's known on the subject? and What does the study add? The EndoSew® prototype was first tested in a porcine model several years ago. The investigators found it both simple to master and reliable, its greatest advantage being a 2.4-fold time saving compared with straight laparoscopic suturing. In addition to that publication, there is a single case report describing the performance of an open EndoSew® suture to close parts (16 cm) of an ileal neobladder. The time for suturing the 16 cm ileum was 25 min, which is in line with our experience. The knowledge on this subject is limited to these two publications. We report on the first consecutive series of ileal conduits performed in humans using the novel prototype sewing device EndoSew®. The study shows that the beginning and the end of the suture process represent the critical procedural steps. It also shows that, overall, the prototype sewing machine has the potential to facilitate the intracorporeal suturing required in reconstructive urology for construction of urinary diversions. Objective To evaluate the feasibility and safety of the novel prototype sewing device EndoSew® in placing an extracorporeal resorbable running suture for ileal conduits. Patients and Methods We conducted a prospective single-centre pilot study of 10 consecutive patients undergoing ileal conduit, in whom the proximal end of the ileal conduit was closed extracorporeally using an EndoSew® running suture. The primary endpoint was the safety of the device and the feasibility of the sewing procedure which was defined as a complete watertight running suture line accomplished by EndoSew® only. Watertightness was assessed using methylene blue intraoperatively and by loopography on postoperative days 7 and 14. Secondary endpoints were the time requirements and complications ≤30 days after surgery. Results A complete EndoSew® running suture was feasible in nine patients; the suture had to be abandoned in one patient because of mechanical failure. In three patients, two additional single freehand stitches were needed to anchor the thread and to seal tiny leaks. Consequently, all suture lines in 6/10 patients were watertight with EndoSew® suturing alone and in 10/10 patients after additional freehand stitches. The median (range) sewing time was 5.5 (3–10) min and the median (range) suture length was 4.5 (2–5.5) cm. There were no suture-related complications. Conclusions The EndoSew® procedure is both feasible and safe. After additional freehand stitches in four patients all sutures were watertight. With further technical refinements, EndoSew® has the potential to facilitate the intracorporeal construction of urinary diversions.

Relevância:

80.00% 80.00%

Publicador:

Resumo:

The Gongduk language is spoken in an enclave in south central Bhutan comprising several villages and hamlets in the mountains west of the Kurichu. The language occupies a distinct phylogenetic position within the Tibeto-Burman language family. The intransitive verb agrees for person and number with the subject, and the transitive shows biactantial agreement for person and number with both agent and patient. A morphological analysis has identified the individual agreement morphemes, their precise grammatical meaning and their patterns of allomorphy. The cognacy of the greater part of the desinences of the Gongduk verb with morphemes identifiable in the biactantial agreement systems of other Tibeto-Burman languages supports the view that at least a portion of such conjugational morphology must be reconstructed to the common ancestral language.