117,746 research outputs found
An Efficient Data Aggregation Algorithm for Cluster-based Sensor Network
No full textData aggregation in wireless sensor networks eliminates redundancy to improve bandwidth utilization and energy-efficiency of sensor nodes. One node, called the cluster leader, collects data from surrounding nodes and then sends the summarized information to upstream nodes. In this paper, we propose an algorithm to select a cluster leader that will perform data aggregation in a partially connected sensor network. The algorithm reduces the traffic flow inside the network by adaptively selecting the shortest route for packet routing to the cluster leader. We also describe a simulation framework for functional analysis of WSN applications taking our proposed algorithm as an exampl
A CUDA-based implementation of an improved SPH method on GPU
No full textWe present a CUDA-based parallel implementation on GPU architecture of a modified version of the Smoothed Particle Hydrodynamics (SPH) method. This modified formulation exploits a strategy based on the Taylor series expansion, which simultaneously improves the approximation of a function and its derivatives with respect to the standard formulation. The improvement in accuracy comes at the cost of an additional computational effort. The computational demand becomes increasingly crucial as problem size increases but can be addressed by employing fast summations in a parallel computational scheme.
The experimental analysis showed that our parallel implementation significantly reduces the runtime, with speed-ups of up to 90,when compared to the CPU-based implementation
Different tracheotomy tube diameters influence diaphragmatic effort and indices of weanability in difficult to wean patients
No full textOBJECTIVE: To determine the effects of different tracheotomy tube sizes on diaphragm effort and weanability indices.
METHODS: Ten tracheotomized and difficult to wean subjects were randomized to 2 T-piece trials, with different tracheotomy tube diameters: inner diameters 8 mm and 6.5 mm. Diaphragm pressure-time product per min. (PTP(di/min)), lung compliance and resistance (C(L) and R(L)), breathing pattern, tension-time index of the diaphragm (TT(di)), and the ratio of breathing frequency to tidal volume (f/V(T)) were recorded. In an in vitro model, the flow-pressure relationship was measured using the 2 tracheotomy tubes and 2 endotracheal tubes of the same diameter.
RESULTS: The use of a smaller diameter resulted in an increase of PTP(di) (337.63 ± 194.35 cm H(2)O · s/min vs 263.28 ± 156.23 cm H(2)O · s/min for 6.5 mm and 8 mm, respectively, P = .004) and R(L) (16.74 ± 8.10 cm H(2)O · s/min vs 11.72 ± 7.88 cm H(2)O · s/min, respectively, P = .008). Both weanability indices were also significantly higher using the smaller tube: f/V(T) 93.32 ± 20.91 vs 77.06 ± 19.26 for 6.5 mm and 8 mm, respectively, P < .02; TT(di) 0.09 ± 0.052 vs 0.08 ± 0.04, respectively, P < .02. In vitro measurements confirmed that the resistances were higher with the smaller diameter and similar between the tracheotomy tubes and the endotracheal tubes of the same diameters.
CONCLUSIONS: In tracheotomized difficult to wean subjects the decrease of the tracheotomy tube size was associated with an increased PTP(di), f/V(T), and TT(di), that were otherwise normal, using a higher diameter. The in vitro study showed that the resistances increased similarly for tracheotomy tube and endotracheal tube, decreasing the diameter and increasing the flows
Crescita e differenziazione di cellule epiteliali di ghiandola mammaria: effetto di diverse concentrazioni di metionina e lisina
No full textPreoperative care in emergency surgery
No full textBe prepared. Sir Robert Baden-Powell Introduction Surgical emergencies in the elderly concern mainly trauma, intra-abdominal and vascular surgery. Abdominal pain constitutes 10-15% of all complaints and the unspecific nature of initial symptoms often makes accurate diagnosis difficult. Radiological imaging is often employed in aiding diagnosis and delay in performing these investigations can impact on surgical outcomes. Delays can be attributed to unstable hemodynamic conditions, delayed presentation of the illness, lack of physical signs at first presentation and inability to obtain proper history. The overall morbidity seems to be reduced when surgery is performed within the first 24-48 hours, whilst delays are associated with complications and higher mortality rates (Ryan et al. 2015). Emergency surgery is more frequent in the elderly than in younger patients and emergency cases have higher morbidity and mortality compared to elective surgery. The increased prevalence of age-related disease and comorbidity contrasts with the ability to recover from the physiological challenges of surgery and anesthesia and, especially in the setting of emergency surgery, there may not be time for complete evaluation and correction of risk factors. Clear understanding of the importance of identifying priorities, adequate organization in care delivery and a team approach is the most valid key for ensuring the best achievable outcome. Care Priorities in Geriatric Emergencies Pre-existing conditions and/or severe anatomical injuries increase the risk of poor outcome in elderly patients. Triage is defined as the identification of the severity of injury, the degree of physiological derangement and allocation of treatment according to priorities meant to increase the maximum number of survivors. A priority-wise approach should be employed when dealing with geriatric emergencies in order to correct all life-threatening conditions and give immediate organ support when required. Airway Control During the classic Airway, Breathing, Circulation, Disability, Exposure (ABCDE) assessment it is important to bear in mind the increased risk of aspiration as elderly patients have reduced protective airway reflexes secondary to muscular and neural degenerative changes. Correction of Hypovolemia Hypovolemia is very common in elderly patients presented for emergency surgery, even in the absence of bleeding or shock (Table 11.1). The tolerance to hypovolemia is poor in this specific population mainly because of the decreased β-receptor responsiveness and inadequate increase of heart rate in response to low cardiac output
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