923 resultados para Network control


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Inhibitory control refers to the ability to suppress planned or ongoing cognitive or motor processes. Electrophysiological indices of inhibitory control failure have been found to manifest even before the presentation of the stimuli triggering the inhibition, suggesting that pre-stimulus brain-states modulate inhibition performance. However, previous electrophysiological investigations on the state-dependency of inhibitory control were based on averaged event-related potentials (ERPs), a method eliminating the variability in the ongoing brain activity not time-locked to the event of interest. These studies thus left unresolved whether spontaneous variations in the brain-state immediately preceding unpredictable inhibition-triggering stimuli also influence inhibitory control performance. To address this question, we applied single-trial EEG topographic analyses on the time interval immediately preceding NoGo stimuli in conditions where the responses to NoGo trials were correctly inhibited [correct rejection (CR)] vs. committed [false alarms (FAs)] during an auditory spatial Go/NoGo task. We found a specific configuration of the EEG voltage field manifesting more frequently before correctly inhibited responses to NoGo stimuli than before FAs. There was no evidence for an EEG topography occurring more frequently before FAs than before CR. The visualization of distributed electrical source estimations of the EEG topography preceding successful response inhibition suggested that it resulted from the activity of a right fronto-parietal brain network. Our results suggest that the fluctuations in the ongoing brain activity immediately preceding stimulus presentation contribute to the behavioral outcomes during an inhibitory control task. Our results further suggest that the state-dependency of sensory-cognitive processing might not only concern perceptual processes, but also high-order, top-down inhibitory control mechanisms.

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The achievable region approach seeks solutions to stochastic optimisation problems by: (i) characterising the space of all possible performances(the achievable region) of the system of interest, and (ii) optimisingthe overall system-wide performance objective over this space. This isradically different from conventional formulations based on dynamicprogramming. The approach is explained with reference to a simpletwo-class queueing system. Powerful new methodologies due to the authorsand co-workers are deployed to analyse a general multiclass queueingsystem with parallel servers and then to develop an approach to optimalload distribution across a network of interconnected stations. Finally,the approach is used for the first time to analyse a class of intensitycontrol problems.

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Revenue management practices often include overbooking capacity to account for customerswho make reservations but do not show up. In this paper, we consider the network revenuemanagement problem with no-shows and overbooking, where the show-up probabilities are specificto each product. No-show rates differ significantly by product (for instance, each itinerary andfare combination for an airline) as sale restrictions and the demand characteristics vary byproduct. However, models that consider no-show rates by each individual product are difficultto handle as the state-space in dynamic programming formulations (or the variable space inapproximations) increases significantly. In this paper, we propose a randomized linear program tojointly make the capacity control and overbooking decisions with product-specific no-shows. Weestablish that our formulation gives an upper bound on the optimal expected total profit andour upper bound is tighter than a deterministic linear programming upper bound that appearsin the existing literature. Furthermore, we show that our upper bound is asymptotically tightin a regime where the leg capacities and the expected demand is scaled linearly with the samerate. We also describe how the randomized linear program can be used to obtain a bid price controlpolicy. Computational experiments indicate that our approach is quite fast, able to scale to industrialproblems and can provide significant improvements over standard benchmarks.

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Little is known about how human amnesia affects the activation of cortical networks during memory processing. In this study, we recorded high-density evoked potentials in 12 healthy control subjects and 11 amnesic patients with various types of brain damage affecting the medial temporal lobes, diencephalic structures, or both. Subjects performed a continuous recognition task composed of meaningful designs. Using whole-scalp spatiotemporal mapping techniques, we found that, during the first 200 ms following picture presentation, map configuration of amnesics and controls were indistinguishable. Beyond this period, processing significantly differed. Between 200 and 350 ms, amnesic patients expressed different topographical maps than controls in response to new and repeated pictures. From 350 to 550 ms, healthy subjects showed modulation of the same maps in response to new and repeated items. In amnesics, by contrast, presentation of repeated items induced different maps, indicating distinct cortical processing of new and old information. The study indicates that cortical mechanisms underlying memory formation and re-activation in amnesia fundamentally differ from normal memory processing.

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Purpose/Objective(s): Primary bone lymphoma (PBL) represents less than 1% of all malignant lymphomas, and 4-5% of all extranodal lymphomas. In this study, we assessed the disease profile, outcome, and prognostic factors in patients with stage I and II PBL.Materials/Methods: Between 1987 and 2008, 116 consecutive patients with PBL treated in 13 RCNinstitutions were included in this study. Inclusion criteriawere: age.17 yrs, PBLin stage I and II, andminimum6months follow-up. The median agewas 51 yrs (range: 17-93).Diagnosticwork-up included plain boneXray (74%of patients), scintigraphy (62%), CT-scan (65%),MRI (58%), PET (18%), and bone-marrow biopsy (84%).All patients had biopsy-proven confirmation of non-Hodgkin's lymphoma (NHL). The histopathological type was predominantly diffuse large B-cell lymphoma (78%) and follicular lymphoma (6%), according to theWHOclassification. One hundred patients had a high-grade, 7 intermediate and 9 low-gradeNHL. Ninety-three patients had anAnn-Arbor stage I, and 23 had a stage II. Seventy-seven patients underwent chemoradiotherapy (CXRT), 12 radiotherapy (RT) alone, 10 chemotherapy alone (CXT), 9 surgery followed by CXRT, 5 surgery followed by CXT, and 2 surgery followed by RT. One patient died before treatment.Median RT dosewas 40Gy (range: 4-60).Themedian number ofCXTcycleswas 6 (range, : 2-8).Median follow-upwas 41months (range: 6-242).Results: Following treatment, the overall response rate was 91% (CR 74%, PR 17%). Local recurrence was observed in 12 (10%) patients, and systemic recurrence in 17 (15%) patients. Causes of death included disease progression in 16, unrelated disease in 6, CXT-related toxicity in 1, and secondary cancer in 2 patients. The 5-yr overall survival (OS), disease-free survival (DFS), lymphoma- specific survival (LSS), and local control (LC) were 76%, 69%, 78%, and 92%, respectively. In univariate analyses (log-rank test), favorable prognostic factors for survival were: age\50 years (p = 0.008), IPI score #1 (p = 0.009), complete response (p\0.001), CXT (p = 0.008), number of CXT cycles $6 (p = 0.007), and RT dose . 40 Gy (p = 0.005). In multivariate analysis age, RT dose, complete response, and absence of B symptoms were independent factors influencing the outcome. There were 3 patients developing grade 3 or more (CTCAE.V3.0) toxicities.Conclusions: This large multicenter study, confirms the relatively good prognosis of early stage PBL, treated with combined CXRT. Local control was excellent, and systemic failure occurred infrequently. A sufficient dose of RT (. 40 Gy) and completeCXT regime (. 6 cycles) were associated with a better outcome. Combined modality appears to be the treatment of choice.Author Disclosure: L. Cai, None; M.C. Stauder, None; Y.J. Zhang, None; P. Poortmans, None; Y.X. Li, None; N. Constantinou, None; J. Thariat, None; S. Kadish, None; M. Ozsahin, None; R.O. Mirimanoff, None.

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This study investigated the neural regions involved in blood pressure reactions to negative stimuli and their possible modulation by attention. Twenty-four healthy human subjects (11 females; age = 24.75 ± 2.49 years) participated in an affective perceptual load task that manipulated attention to negative/neutral distractor pictures. fMRI data were collected simultaneously with continuous recording of peripheral arterial blood pressure. A parametric modulation analysis examined the impact of attention and emotion on the relation between neural activation and blood pressure reactivity during the task. When attention was available for processing the distractor pictures, negative pictures resulted in behavioral interference, neural activation in brain regions previously related to emotion, a transient decrease of blood pressure, and a positive correlation between blood pressure response and activation in a network including prefrontal and parietal regions, the amygdala, caudate, and mid-brain. These effects were modulated by attention; behavioral and neural responses to highly negative distractor pictures (compared with neutral pictures) were smaller or diminished, as was the negative blood pressure response when the central task involved high perceptual load. Furthermore, comparing high and low load revealed enhanced activation in frontoparietal regions implicated in attention control. Our results fit theories emphasizing the role of attention in the control of behavioral and neural reactions to irrelevant emotional distracting information. Our findings furthermore extend the function of attention to the control of autonomous reactions associated with negative emotions by showing altered blood pressure reactions to emotional stimuli, the latter being of potential clinical relevance.

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The Network Revenue Management problem can be formulated as a stochastic dynamic programming problem (DP or the\optimal" solution V *) whose exact solution is computationally intractable. Consequently, a number of heuristics have been proposed in the literature, the most popular of which are the deterministic linear programming (DLP) model, and a simulation based method, the randomized linear programming (RLP) model. Both methods give upper bounds on the optimal solution value (DLP and PHLP respectively). These bounds are used to provide control values that can be used in practice to make accept/deny decisions for booking requests. Recently Adelman [1] and Topaloglu [18] have proposed alternate upper bounds, the affine relaxation (AR) bound and the Lagrangian relaxation (LR) bound respectively, and showed that their bounds are tighter than the DLP bound. Tight bounds are of great interest as it appears from empirical studies and practical experience that models that give tighter bounds also lead to better controls (better in the sense that they lead to more revenue). In this paper we give tightened versions of three bounds, calling themsAR (strong Affine Relaxation), sLR (strong Lagrangian Relaxation) and sPHLP (strong Perfect Hindsight LP), and show relations between them. Speciffically, we show that the sPHLP bound is tighter than sLR bound and sAR bound is tighter than the LR bound. The techniques for deriving the sLR and sPHLP bounds can potentially be applied to other instances of weakly-coupled dynamic programming.

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BACKGROUND: The nuclear receptors are a large family of eukaryotic transcription factors that constitute major pharmacological targets. They exert their combinatorial control through homotypic heterodimerisation. Elucidation of this dimerisation network is vital in order to understand the complex dynamics and potential cross-talk involved. RESULTS: Phylogeny, protein-protein interactions, protein-DNA interactions and gene expression data have been integrated to provide a comprehensive and up-to-date description of the topology and properties of the nuclear receptor interaction network in humans. We discriminate between DNA-binding and non-DNA-binding dimers, and provide a comprehensive interaction map, that identifies potential cross-talk between the various pathways of nuclear receptors. CONCLUSION: We infer that the topology of this network is hub-based, and much more connected than previously thought. The hub-based topology of the network and the wide tissue expression pattern of NRs create a highly competitive environment for the common heterodimerising partners. Furthermore, a significant number of negative feedback loops is present, with the hub protein SHP [NR0B2] playing a major role. We also compare the evolution, topology and properties of the nuclear receptor network with the hub-based dimerisation network of the bHLH transcription factors in order to identify both unique themes and ubiquitous properties in gene regulation. In terms of methodology, we conclude that such a comprehensive picture can only be assembled by semi-automated text-mining, manual curation and integration of data from various sources.

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Purpose/Objective(s): Mammary adenoid cystic carcinoma (ACC) is a rare breast cancer variant. It accounts for less than 0.1% of all invasive breast malignancies. Typically, it presents as a small breast lump with a low propensity to metastasize to regional lymph nodes or distant sites. The aim of this retrospective multicenter Rare Cancer Network study is to assess prognostic factors and patterns of failure in ACC, as well as the role of radiation therapy (RT) in this rare disease. Materials/Methods: Between January 1980 and December 2007, 61 women with breast ACC were included in this study. Median age was 59 years (range, 28-94 years). The majority of the patients had good performance status (49 patients with WHO 0, 12 patients with WHO 1), and 70% of the patients (n = 42) were premenopausal. Surgery consisted of tumorectomy in 35 patients, mastectomy in 20, or quadrantectomy in 6. Median tumor size was 20 mm (range, 6-170 mm). Surgical margins were clear in 50 (82%) patients. Axillary dissection (n = 41) or sentinel node assessment (n = 10) was realized in the majority of the patients. There were 53 (87%) pN0 and 8 pNx (13%) patients. Estrogen (ER) and progesterone receptor (PR) was negative in 43 (71%) and 42 (69%) patients, respectively. In 16 patients (26%), the receptor status was unknown. Adjuvant chemotherapy or hormonotherapy was administered in 8 (13%) and 7 (12%) patients, respectively. Postoperative RT with a median total dose of 50 Gy (1.8-2.0 Gy/fraction; range, 44-70 Gy) was given in 40 patients. Results: With a median follow-up of 79 months (range, 6-285 months), 5-year overall and disease-free survival (DFS) rates were 94% (95% confidence interval [CI]: 88-100%) and 82% (95% CI: 71-93%), respectively. Five-year locoregional control rate was 95% (95% CI: 89-100%). There were only 4 patients with local relapse who were all salvaged successfully, and 4 other patients developed distant metastases. According to the Common Terminology Criteria for Adverse Events v3.0, late toxicity consisted of grade 2-3 cutaneous fibrosis in 4 (10%) patients, grade 1-2 edema in 2 (5%), and grade 3 lung fibrosis in 2 (5%). In univariate analyses, the outcome was influenced neither by the type of surgery nor the use of postoperative RT. However, positive receptor status had a negative influence on the outcome. Multivariate analysis (Cox model) revealed that negative ER (p = 0.006) or PR (p = 0.04) status was associated with improved DFS. Conclusions: ACC of the breast is a relatively indolent disease with excellent local control and survival. The prognosis of patients with ACC is much better than that for patients with other breast cancers, especially those who are ER and PR negative. The role of postoperative RT is not clear. More aggressive treatments may be warranted for patients with positive receptor status.

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Introduction. This paper studies the situation of research on Catalan literature between 1976 and 2003 by carrying out a bibliometric and social network analysis of PhD theses defended in Spain. It has a dual aim: to present interesting results for the discipline and to demonstrate the methodological efficacy of scientometric tools in the humanities, a field in which they are often neglected due to the difficulty of gathering data. Method. The analysis was performed on 151 records obtained from the TESEO database of PhD theses. The quantitative estimates include the use of the UCINET and Pajek software packages. Authority control was performed on the records. Analysis. Descriptive statistics were used to describe the sample and the distribution of responses to each question. Sex differences on key questions were analysed using the Chi-squared test. Results. The value of the figures obtained is demonstrated. The information obtained on the topic and the periods studied in the theses, and on the actors involved (doctoral students, thesis supervisors and members of defence committees), provide important insights into the mechanisms of humanities disciplines. The main research tendencies of Catalan literature are identified. It is observed that the composition of members of the thesis defence committees follows Lotka's Law. Conclusions. Bibliometric analysis and social network analysis may be especially useful in the humanities and in other fields which are lacking in scientometric data in comparison with the experimental sciences.

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Purpose/Objective(s): Adenosquamous carcinoma (AC) of the head and neck is a distinct entity first described in 1968. Its natural history is more aggressive than squamous cell carcinoma but this is based on very small series reported in the literature. The goal of this study was to assess the clinical profile, outcome, patterns of failure and prognostic factors in patients with AC of the head and neck treated by radiation therapy (RT) with or without chemotherapy (CT).Materials/Methods: Data from 18 patients with Stage I (n = 3), II (n = 1), III (n = 4), or IVa (n = 10) AC, treated between 1989 and 2009, were collected in a retrospective multicenter Rare Cancer Network study. Median age was 60 years (range, 48 - 73 years). Fourteen patients were male and 4 female. Risk factors, including perineural invasion, lymphangitis, vascular invasion, positive margins, were present in 83% of the patients. Tumor sites included oral cavity in 4, oropharynx in 4, hypopharynx in2, larynx in 2, salivary glands in 2, nasal vestibule in 2, nasopharynx in 1, and maxillary sinus in 1 patient. Surgery (S) was performed in all but 5 patients. S alone was performed in only 1 patient, and definitive RT alone in 3 patients. Fourteen patients received combined modality treatment (S+RT in 10, RT+CT in 2, and all of the three modalities in 2 patients). Median RT dose to the primary and to the nodes was 66 Gy (range, 50 - 72 Gy) and 53 Gy (range, 44 - 66 Gy), respectively (1.8 - 2.0 Gy/fr., 5 fr./ week). In 4 patients, the planning treatment volume included the primary tumor site only. Seven patients were treated with 2D RT, 7 with 3D conformal RT, and 2 with intensity-modulated RT.Results: After a median follow-up period of 38 months (range, 9 - 62 months), 8 patients developed distant metastases (lung, bone, mediastinum, and liver), 6 presented nodal recurrences, and only 4 had a local relapse at the primary site (all in-field recurrences). At last follow-up, 6 patients were alive without disease, 1 alive with disease, 9 died from progressive disease, and 2 died from intercurrent disease. The 3-year and median overall survival, disease-free survival (DFS) and locoregional control rates were 52% (95% confidence interval [CI]: 28 - 76%) and 39 months, 36% (95% CI: 13 - 49%) and 12 months, and 54% (95% CI: 26 - 82%) and 40 months, respectively. In multivariate analysis (Cox model), DFS was negatively influenced by the presence of extracapsular extension (p = 0.02) and advanced stage (IV versus I-III, p = 0.003).Conclusions: Overall prognosis of locoregionally advanced AC remains poor, and distant metastases and nodal relapse occur in almost half of the cases. However, local control is relatively good, and early stage AC patients had prolonged DFS when treated with combined modality treatment.

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Purpose: To assess the outcome in patients with olfactory neuroblastoma (ONB). Methods and Materials: Seventy-seven patients treated for nonmetastatic ONB between 1971 and 2004 were included. According to Kadish classification, there were 11 patients with Stage A, 29 with Stage B, and 37 with Stage C. T-classification included 9 patients with T1, 26 with T2, 16 with T3, 15 with T4a, and 11 with T4b tumors. Sixty-eight patients presented with N0 (88%) disease. Results: Most of the patients (n = 56, 73 %) benefited from surgery (S), and total excision was possible in 44 patients (R0 in 32, R1 in 13, R2 in 11). All but five patients benefited from RT, and chemotherapy was given in 21(27%). Median follow-up period was 72 months (range, 6-315). The 5-year overall survival (OS), disease-free survival (DES), locoregional control, and local control were 64%, 57%, 62%, and 70%, respectively. In univariate analyses, favorable factors were Kadish A or B disease, T1 T3 tumors, no nodal involvement, curative surgery, R0/R1 resection, and RT-dose 54 Gy or higher. Multivariate analysis revealed that the best independent factors predicting the outcome were T1 T3, N0, R0/R1 resection, and total RT dose (54 Gy or higher). Conclusion: In this multicenter retrospective study, patients with ONB treated with R0 or R1 surgical resection followed by at least 54-Gy postoperative RT had the best outcome. Novel strategies including concomitant chemotherapy and/or higher dose RT should be prospectively investigated in this rare disease for which local failure remains a problem.

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Purpose: Primary bone lymphoma (PBL) accounts for less than 1% of all malignant lymphomas, and 4-5% of all extra-nodal lymphomas. In this study, the disease profile, outcome, and prognostic factors were assessed in patients with stage I and II PBL.Patients and Methods: Thirteen Rare Cancer Network (RCN) institutions enrolled 116 consecutive patients with PBL treated between 1987 and 2008 in this study. Inclusion criteria were age > 16 years, stage I and II, minimum 6 months follow-up and a biopsy-proven confirmation of non-Hodgkin's lymphoma (NHL). Eighty-seven patients underwent chemoradiotherapy (CXRT), 15 radiotherapy (RT) without (13) or with (2) surgery, 14 chemotherapy (CXT) without (9) or with (5) surgery. Median RT dose was 40 Gy (range: 4-60). The median number of CXT cycles was 6 (range: 2-8). Median follow-up was 41 months (range: 6-242).Results: The overall response rate at the end of treatment was 91% (CR 74%, PR 17%). Local recurrence or progression was observed in 12 (10%) patients, and systemic recurrence in 17 (15%). Causes of death included disease progression in 21, unrelated in 5, CXT-related toxicity in 1, and second primary cancer in 2 patients. The 5-yr overall survival (OS), lymphoma-specific survival (LSS), and local control (LC) were 76%, 78% and 92%, respectively. In univariate analyses (log-rank test), favorable prognostic factors for OS were age <50 years (P=0.008), international prognostic index (IPI) score ≤1 (P=0.009), high grade histology (P=0.04), CXRT (P=0.05), CXT (P=0,0004), complete response (CR) (P<0.0001), number of CXT cycles ( ≥6 ) (P=0.01), and RT dose > 40 Gy (P=0.005). All above-mentioned parameters were also significant for LSS except for age and number of chemotherapy cycles. For LC, only CR and stage I were favorable factors. In multivariate analysis, IPI score, RT dose, complete response, and chemotherapy were independently influencing the outcome (OS and LSS). Complete response at the end of treatment was the only predicting factor for LC. Six patients developed grade 3 or more toxicities, according to Common Terminology Criteria for Adverse Events (CTCAE) V3.0.Conclusion: This large multicenter study confirms the relatively good prognosis of early stage PBL treated with combined CXRT. Local control was excellent, while systemic failures were rare. An adequate dose of RT (40 Gy or more) and complete CXT regime (≥ 6 cycles) were associated with better outcome.

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Background: This study analyzed prognostic factors and treatment outcomes of primary thyroid lymphoma. Patients and Methods: Data were retrospectively collected for 87 patients (53 stage I and 34 stage II) with median age 65 years. Fifty-two patients were treated with single modality (31 with chemotherapy alone and 21 with radiotherapy alone) and 35 with combined modality treatment. Median follow-up was 51 months. Results: Sixty patients had aggressive lymphoma and 27 had indolent lymphoma. The 5- and 10-year overall survival (OS) rates were 74% and 71%, respectively, and the disease-free survival (DFS) rates were 68% and 64%. Univariate analysis revealed that age, tumor size, stage, lymph node involvement, B symptoms, and treatment modality were prognostic factors for OS, DFS, and local control (LC). Patients with thyroiditis had significantly better LC rates. In multivariate analysis, OS was influenced by age, B symptoms, lymph node involvement, and tumor size, whereas DFS and LC were influenced by B symptoms and tumor size. Compared with single modality treatment, patients treated with combined modality had better 5-year OS, DFS, and LC. Conclusions: Combined modality leads to an excellent prognosis for patients with aggressive lymphoma but does not improve OS and LC in patients with indolent lymphoma.

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BACKGROUND: Poor long-term adherence is an important cause of uncontrolled hypertension. We examined whether monitoring drug adherence with an electronic system improves long-term blood pressure (BP) control in hypertensive patients followed by general practitioners (GPs). METHODS: A pragmatic cluster randomised controlled study was conducted over one year in community pharmacists/GPs' networks randomly assigned either to usual care (UC) where drugs were dispensed as usual, or to intervention (INT) group where drug adherence could be monitored with an electronic system (Medication Event Monitoring System). No therapy change was allowed during the first 2 months in both groups. Thereafter, GPs could modify therapy and use electronic monitors freely in the INT group. The primary outcome was a target office BP<140/90 mmHg. RESULTS: Sixty-eight treated uncontrolled hypertensive patients (UC: 34; INT: 34) were enrolled. Over the 12-month period, the likelihood of reaching the target BP was higher in the INT group compared to the UC group (p<0.05). At 4 months, 38% in the INT group reached the target BP vs. 12% in the UC group (p<0.05), and 21% vs. 9% at 12 months (p: ns). Multivariate analyses, taking account of baseline characteristics, therapy modification during follow-up, and clustering effects by network, indicate that being allocated to the INT group was associated with a greater odds of reaching the target BP at 4 months (p<0.01) and at 12 months (p=0.051). CONCLUSION: GPs monitoring drug adherence in collaboration with pharmacists achieved a better BP control in hypertensive patients, although the impact of monitoring decreased with time.