Search Results

You are looking at 1 - 10 of 12 items

  • Author: Marta Santos x
Clear All Modify Search


The traffic intensity (ρ) is a vital parameter of queueing systems because it is a measure of the average occupancy of a server. Consequently, it influences their operational performance, namely queue lengths and waiting times. Moreover, since many computer, production and transportation systems are frequently modelled as queueing systems, it is crucial to use control charts to detect changes in ρ. In this paper, we pay particular attention to control charts meant to detect increases in the traffic intensity, namely: a short-memory chart based on the waiting time of the n-th arriving customer; two long-memory charts with more sophisticated control statistics, and the two cumulative sum (CUSUM) charts proposed by Chen and Zhou (2015). We confront the performances of these charts in terms of some run length related performance metrics and under different out-of-control scenarios. Extensive results are provided to give the quality control practitioner a concrete idea about the performance of these charts.


This paper describes the application of simple quality control charts to monitor the traffic intensity of single server queues, a still uncommon use of what is arguably the most successful statistical process control tool. These charts play a vital role in the detection of increases in the traffic intensity of single server queueing systems such as the M/G/1, GI/M/1 and GI/G/1 queues. The corresponding control statistics refer solely to a customer-arrival/departure epoch as opposed to several such epochs, thus they are termed short-memory charts. We compare the RL performance of those charts under three out-of-control scenarios referring to increases in the traffic intensity due to: a decrease in the service rate while the arrival rate remains unchanged; an increase in the arrival rate while the service rate is constant; an increase in the arrival rate accompanied by a proportional decrease in the service rate. These comparisons refer to a broad set of interarrival and service time distributions, namely exponential, Erlang, hyper-exponential, and hypo-exponential. Extensive results and striking illustrations are provided to give the quality control practitioner an idea of how these charts perform in practice.

Retesting The Validity Of A Specific Field Test For Judo Training

The main goal of this research project was to retest the validity of a specifically designed judo field test (Santos Test) in a different group of judokas. Eight (n=8) national-level male judokas underwent laboratory and field testing. The mean data (mean +/- SD) obtained in the laboratory tests was: HRmax: 200 ± 4.0 beats × min-1, VO2 max: 52.8 ± 7.9 ± ml × kg-1 × min-1, lactate max: 12 ± 2.5 mmol × l-1, HR at the anaerobic threshold: 174.2 ± 9.4 beats × min-1, percentage of maximum heart rate at which the anaerobic threshold appears: 87 ± 3.6 %, lactate threshold: 4.0 ± 0.2 mmol × l-1, and RPE: 17.2 ± 1.0. The mean data obtained in the field test (Santos) was: HRmax: 201.3 ± 4.1 beats × min-1, VO2 max: 55.6 ± 5.8 ml × kg-1 × min-1, lactate max: 15.6 ± 2.8 mmol × l-1, HR at the anaerobic threshold: 173.2 ± 4.3 beats × min-1, percentage of maximum heart rate at which the anaerobic threshold appears: 86 ± 2.5 %, lactate threshold: 4.0 ± 0.2 mmol × l-1, and RPE: 16.7 ± 1.0. There were no significant differences between the data obtained on both tests in any of the parameters, except for maximum lactate concentration. Therefore, the Santos test can be considered a valid tool specific for judo training.



The incidence of pediatric metabolic syndrome (MS) has progressively increased. The incidence of type 1 diabetes mellitus (T1DM) has also increased. Thus, some children and adolescents with T1DM exhibit MS parameters. The aim of the study was to evaluate the presence of MS parameters in female adolescents with T1DM based on their nutritional status.


We evaluated 44 adolescents with T1DM (consecutive non-randomized sample) aged between 14 and 18 years, who were on intensive therapy with insulin. Patients were subdivided according to their body mass index (BMI). Variables evaluated include: age, age at diagnosis, weight, height, BMI, abdominal circumference, blood pressure, glycated hemoglobin (HbA1c), abdominal and pelvic ultrasound and lipoprotein profile. Gynecological history data were also collected.


Lipid profile changes were identified in 32% of overweight or obese girls and in 23% of those with an adequate weight. Hypertension (HT) was observed in 19% of overweight or obese girls and in 14% of those with a BMI≥85th percentile (Pc). The only statistically significant difference between the groups was the presence of abdominal adiposity. All other features, including the presence of dyslipidemia, HT, abdominal adiposity, non-alcoholic steatohepatitis (NASH) and polycystic ovarian syndrome (PCOS), were present in both groups.


Although being overweight and/or obese aggravates the risk of cardiovascular disease, MS is already present in many young adolescents with T1DM of normal weight. It is necessary that MS risk factors are routinely evaluated in all diabetic adolescents, including those with an adequate BMI.


Introduction: Neuropathy is a frequent complication of diabetes mellitus (DM), increasing with the duration of the disease, poor glycemic control and advanced age. Acute presentation of a neuropathy in the setting of a newly diagnosed type 1 DM is rare and holds a diagnostic challenge.

Case report: A 10-year-old girl, presented at the emergency service with complaints of polydipsia, polyuria, asthenia and weight lost over the last 15 days, accompanied by difficulties in flexing the right foot, during the previous week. The patient denied any pain, paresthesias, or altered sensibility. There was no fever documented, or recent infectious intercurrence or trauma. On physical examination, she was conscious, collaborative and space and time-orientated, had a diminished strength in the right foot, namely in the dorsiflexion, conditioning a steppage gait ipsilateral. Hyperalgesia was felt in the dorsum of the right feet to the ankle. DM type 1 was diagnosed based on serum glucose of 629 mg/dL and mild ketoacidosis. Investigation for infectious, immune and nutritional aetiologies for the mononeuropathy was negative. Electrophysiological study was suggestive of a lesion of the peroneal nerve on the popliteal cesspit, but was not conclusive. The patient started physiotherapy during her hospital stay and exhibited a slight improvement in the dorsiflexion of the foot. Four months later she was asymptomatic and with good glycaemic control.

Conclusion: Diabetic neuropathy is a heterogeneous group that still lacks adequate comprehension. Its approach is empirical and demands exclusion of other etiologies. A definitive diagnosis is not always possible and sometimes is retrospective.


The northern Portuguese coast is a biogeographic transition zone where many macroalgal species have their distribution limits; it is thus a particularly interesting region for investigating species distribution shifts. An updated and complete list of species for this region is not available in spite of its baseline importance for comparative studies with past and present data. Based on new records, literature references, and herbarium data, we provide an updated checklist of the benthic marine algae of the northern Portuguese coast. This checklist includes 346 species: 26 Cyanobacteria, 200 Rhodophyta, 70 Ochrophyta, and 50 Chlorophyta. From these, 21 species are new records for the Portuguese coast (Lyngbya aestuarii, Lyngbya semiplena, Microcoleus acutirostris, Myxosarcina gloeocapsoides, Aiolocolax pulchella, Antithamnion densum, Antithamnion villosum, Antithamnionella spirographidis, Dasya sessilis, Furcellaria lumbricalis, Neosiphonia harveyi, Porphyrostromium boryanum, Chorda filum, Dictyopteris ambigua, Sphacelaria rigidula, Undaria pinnatifida, Vaucheria coronata, Vaucheria velutina, Ulothrix implexa, Ulva scandinavica, and Umbraulva olivascens) and 33 were recorded for the first time in the north of Portugal. Alien species have increased in number and extended their distribution range over the last 10 years in the study area. Distribution shifts of northern cold water species with southern distribution limit in the north of Portugal were not consistent among species.


The objective of this study was to evaluate the impacts of castor meal, a by-product of the biodiesel industry, on growth performance and feeding behavior of heifers in a pasture production system in Northeast Brazil. Forty Holstein × Zebu crossbred heifers with an initial body weight of 257±26 kg were kept on a Brachiaria decumbens pasture under continuous grazing. The experiment lasted 140 days and was conducted in a completly randomized design with five levels of replacement of soybean meal with castor meal (0, 200, 500, 750, and 1000 g/kg of dry matter) in the supplements. Intake, digestibility, feeding behavior, performance, and carcass characteristics were evaluated. The total intakes of dry matter (DM), crude protein (CP), organic matter (OM), ether extract, and total digestible nutrients (TDN) decreased as the castor meal levels were increased. The digestibility coefficients of DM, CP, OM, and TDN decreased as the levels of castor meal in the supplement were increased. The castor meal levels in the supplement did not affect final body weight, average daily gain, feed conversion, hot carcass weight, or carcass dressing of the heifers. The use of supplements containing up to 1000 g/kg DM castor meal replacing soybean meal reduced the DM intake but did not change the average daily gain and feed efficiency of the heifers. Thus, the use of castor meal is a recommendable strategy to reduce production costs in a beef cattle grazing system.



Recovered Out-of-Hospital Cardiac Arrest (rOHCA) population is heterogenous. Few studies focused on outcomes in the rOHCA subgroup with proven significant coronary artery disease (SigCAD). We aimed to characterize this subgroup and study the determinants of in-hospital mortality.


Retrospective study of consecutive rOHCA patients submitted to coronary angiography. Only patients with SigCAD were included.


60 patients were studied, 85% were male, mean age was 62.6 ± 12.1 years. In-hospital mortality rate was 43.3%. Patients with diabetes and history of stroke were less likely to survive. Significant univariate predictors of in-hospital mortality were further analysed separately, according to whether they were present at hospital admission or developed during hospital evolution. At hospital admission, initial non-shockable rhythm, low-flow time>12min, pH<7.25mmol/L and lactates >4.75mmol/L were the most relevant predictors and therefore included in a score tested by Kaplan-Meyer. Patients who had 0/4 criteria had 100% chance of survival till hospital discharge, 1/4 had 77%, 2/4 had 50%, 3/4 had 25%. Patients with all 4 criteria had 0% survival. During in-hospital evolution, a pH<7.35 at 24h, lactates>2mmol/L at 24h, anoxic brain injury and persistent hemodynamic instability proved significant. Patients who had 0/4 of these in-hospital criteria had 100% chance of survival till hospital discharge, 1/4 had 94%, 2/4 had 47%, 3/4 had 25%. Patients with all 4 criteria had 0% survival. Contrarily, CAD severity and ventricular dysfunction didn’t significantly correlate to the outcome.


Classic prehospital variables retain their value in predicting mortality in the specific group of OHCA with SigCAD. In-hospital evolution variables proved to add value in mortality prediction. Combining these simple variables in risk scores might help refining prognostic prediction in these patients’s subset.


Aspartyl-type peptidases are promising chemotherapeutic targets in protozoan parasites. In the present work, we identified an aspartyl peptidase activity from the soluble extract of Leishmania amazonensis promastigotes, which cleaved the fluorogenic peptide 7-methoxycoumarin-4-acetyl-Gly-Lys-Pro-Ile-Leu-Phe-Phe-Arg-Leu-Lys(DNP)-D-Arg-amide (cathepsin D substrate) under acidic pH conditions at 37°C, showing a K M of 0.58 μM and V max of 129.87 fluorescence arbitrary units/s mg protein. The leishmanial aspartyl peptidase activity was blocked by pepstatin A (IC50 = 6.8 μM) and diazo-acetyl-norleucinemetilester (IC50 = 10.2 μM), two classical aspartyl peptidase inhibitors. Subsequently, the effects of 6 asymmetric peptidomimetics, containing L-tartaric acid core, were tested on both aspartyl peptidase and growth of L. amazonensis promastigotes. The peptidomimetics named 88, 154 and 158 promoted a reduction of 50% on the leishmanial aspartyl peptidase activity at concentrations ranging from 40 to 85 μM, whereas the peptidomimetic 157 was by far the most effective, presenting IC50 of 0.04 μM. Furthermore, the peptidomimetics 157 and 154 reduced the parasite proliferation in a dose-dependent manner, displaying IC50 values of 33.7 and 44.5 μM, respectively. Collectively, the peptidomimetic 157 was the most efficient compound able to arrest both aspartyl peptidase activity and leishmanial proliferation, which raises excellent perspectives regarding its use against this human pathogenic protozoan.



Permanent primary congenital hypothyroidism (CH) can be caused by thyroid dysgenesis or dyshormonogenesis. A molecular genetic study is recommended in dyshormonogenesis, in syndromic hypothyroidism and when there is a family history of CH. The aim of this study was to identify a monogenic etiology for CH in selected individuals from a cohort of primary permanent CH.


From an initial cohort of 79 patients with permanent CH (3–19 years), 11 patients were selected for molecular analyses. Nine patients with dyshormonogenesis (normal in-situ gland or goiter) were screened for causative variants, by next-generation sequencing (NGS), in 28 genes known to be responsible for CH. One patient with a family history of CH was screened for the paired-box gene 8 (PAX8) gene and another patient with a syndromic CH was screened for the NKX2-1 gene.


We found a monogenic basis of disease in eight patients, involving the thyroid peroxidase (TPO) gene (four patients), the thyroglobulin (TG) gene (two patients), and the PAX8 and NKX2-1 genes (one patient each). Two patients were heterozygotes, one harboring a variant in the TG gene and the other in the SLC5A5 gene. In one patient, we found no potential causative variants in any of the 28 genes screened. We described five novel variants: three in the TG gene, one in the NKX2-1 and one in the SLC5A5 gene, all of them classified as pathogenic.


In eight of the 11 screened patients, a monogenic disease was found. These results highlight the advantage of using an NGS panel and provide further data regarding the molecular basis of CH.