bluuebunny/crossref_metadata_2025_split huggingface dataset:
Robust control of constrained max‐plus‐linear systems
Authors: Necoara Ion , De Schutter Bart , van den Boom Ton J. J. , Hellendoorn Hans 
Published: April 2008

AbstractMax‐plus‐linear (MPL) systems are a class of nonlinear systems that can be described by models that are ‘linear’ in the max‐plus algebra. We provide here solutions to the three types of finite‐horizon min–max control problems for uncertain MPL systems, depending on the nature of the control input over which we optimize: open‐loop input sequences, disturbances feedback policies, and state feedback policies. We assume that the uncertainty lies in a bounded polytope and that the closed‐loop input and state sequence should satisfy a given set of linear inequality constraints for all admissible disturbance realizations. Despite the fact that the controlled system is nonlinear, we provide sufficient conditions that allow one to preserve convexity of the optimal value function and its domain. As a consequence, the min–max control problems can be either recast as a linear program or solved via N parametric linear programs, where N is the prediction horizon. In some particular cases of the uncertainty description (e.g. interval matrices), by employing results from dynamic programming, we show that a min–max control problem can be recast as a deterministic optimal control problem. Copyright © 2008 John Wiley & Sons, Ltd.
Ranging error‐tolerable localization in wireless sensor networks with inaccurately positioned anchor nodes
Authors: Fan Rongfei , Jiang Hai , Wu Shaohua , Zhang Naitong 
Published: April 2008

AbstractLocalization is essential for wireless sensor networks (WSNs). It is to determine the positions of sensor nodes based on incomplete mutual distance measurements. In this paper, to measure the accuracy of localization algorithms, a ranging error model for time of arrival (TOA) estimation is given, and the Cramer—Rao Bound (CRB) for the model is derived. Then an algorithm is proposed to deal with the case where (1) ranging error accumulation exists, and (2) some anchor nodes broadcast inaccurate/wrong location information. Specifically, we first present a ranging error‐tolerable topology reconstruction method without knowledge of anchor node locations. Then we propose a method to detect anchor nodes whose location information is inaccurate/wrong. Simulations demonstrate the effectiveness of our algorithm. Copyright © 2008 John Wiley & Sons, Ltd.
Ledrappier’s system is almost mixing of all orders
Authors: ARENAS-CARMONA L. , BEREND D. , BERGELSON V. 
Published: April 2008

AbstractWe consider Ledrappier’s dynamical system, which was the first example of a $\mathbb {Z}^2$-action which is 2-mixing but not 3-mixing. Our main result is that, excluding certain small ‘constructible’ sets, the system is mixing of every order.
Modelling and prediction of weekly incidence of influenza A specimens in England and Wales
Authors: ŠALTYTĖ BENTH J. , HOFOSS D. 
Published: April 2008

SUMMARYWe propose a rather simple model, which fits well the weekly human influenza incidence data from England and Wales. A standard way to analyse seasonally varying time-series is to decompose them into different components. The residuals obtained after eliminating these components often do not reveal time dependency and are normally distributed. We suggest that conclusions should not be drawn only on the basis of residuals and that one should consider the analysis of squared residuals. We show that squared residuals can reveal the presence of the remaining seasonal variation, which is not exhibited by the analysis of residuals, and that the modelling of such seasonal variations undoubtedly improves model fit.
Predicting zebra mussel fouling on native mussels from physicochemical variables
Authors: JOKELA ANNELI , RICCIARDI ANTHONY 
Published: April 2008

Summary1. Predictive models of impact are needed for the risk assessment of invasive species. One such species is the Eurasian zebra mussel (Dreissena polymorpha), a fouling bivalve that overgrows and kills native mussels (Unionidae) in many North American lakes and rivers. The level of mortality in a native mussel population increases with the fouling intensity – i.e. the mean number of zebra mussels attached to each native mussel.2. We conducted a multi‐site survey within the St Lawrence and Richelieu rivers (Quebec, Canada) to determine whether zebra mussel fouling intensity can be predicted from environmental variables. We found fouling intensity to be positively correlated with calcium concentration [Ca2+] and negatively correlated with sediment size, but not affected by local macrophyte cover.3. A multiple regression model that includes calcium concentration and sediment size explains 86% of variation in fouling intensity across all sites.4. Analysis of data from invaded sites in North America and Europe revealed a nonlinear relationship in which fouling intensity increases with calcium concentration up to an asymptotic threshold of 24 mg L−1 Ca2+.5. Our results suggest that the community‐level impacts of zebra mussels are mediated by abiotic environmental variables and gradients in these variables may provide local habitat refugia for native mussels.
Teaching Computer Studies: an investigation based on teachers' lesson diaries
Authors: Moore J. 
Published: April 2008

Abstract In preparation for a programme of pre‐service and inservice teacher training, information was obtained on the teaching of Computer Studies to pupils aged 14 – 16 years. A structured document, the Lesson Diary Report Form (LDRF), completed by classroom teachers was used to gather data on nearly 700 lessons involving 1800 pupils. Information was obtained about the lesson type, the use of resources by teachers and pupils, homework assignments, and the timing of classroom activities.Analysis of the data showed many similarities and only a few differences between lessons given in the first and second years of the two‐year course. It was found that teacher training in Computer Studies teaching was a significant variable in deciding the choice of lesson type and the use of resources. No consistent pattern of lesson adaptation to pupils of different abilities was found.
Prediction of outcome shortly after delivery for the very low birth weight (≪1500 g) infant
Authors: Patterson C.C. , Halliday H.L. 
Published: April 2008

SummaryObstetric and perinatal data for 387 very low birthweight infants (≪1500 g) who were admitted to a neonatal intensive care unit were used to derive and test a multivariate statistical model for predicting shortly after birth the risk of death before hospital discharge. Using the gestational age, the Apgar score at 5 minutes and the presence or absence of respiratory distress, the model correctly predicted outcome for 94% of survivors but for only 53% of deaths. The model successfully identified a subgroup with a low (less than 1 in 20) predicted risk of death. This subgroup comprised over one‐third of the infants but included 47% of the survivors and only 5% of the deaths. The probabilities derived from the model are tabulated and may help paediatricians in maternity units without neonatal intensive care facilities to decide which very low birthweight infants to transfer for additional care.
Time‐trends in necropsy prevalence and birth prevalence of lung hypoplasia
Authors: Moessinger Adrien C. , Santiago Angelita , Paneth Nigel S. , Rey Henry R. , Blanc William A. , Jr John M. Driscoll 
Published: April 2008

Summary. Congenital lung hypoplasia (LH) has been identified with increasing frequency in perinatal and neonatal necropsy reviews. The available prevalence figures have been derived using various diagnostic criteria in different populations and at various times. We therefore reviewed our experience in 15 years of consecutive early neonatal necropsies using one constant set of diagnostic criteria for LH and looked for a time‐trend. We determined the necropsy prevalence (no. of cases of LH/no. of necropsies) and the birth prevalence (no. of cases of LH documented at necropsy per 1000 livebirths for inborn patients, and per 1000 referrals for outborn patients) between 1971 and 1985. We then divided this 15‐year period into five consecutive 3‐year periods to determine if a time‐trend was discernible.Whereas early neonatal mortality for neonatal intensive care unit (NICU) admissions progressively decreased from 11.4% to 4.0% between the first and the last 3‐year periods, the number of cases of LH per 3‐year period did not vary appreciably. As a result, the prevalence of LH at necropsy showed a slight upward trend with time. The overall prevalence was 18%; it was 13% during the first and 23% during the last 3‐year period. We found no time‐trend in birth or referral prevalence for this lesion, which averaged 1.1 per 1000 livebirths and 9.8 per 1000 referrals. We conclude that lung hypoplasia appears to be emerging as an increasingly prevalent necropsy finding as a result of a shift in proportionate mortality, with the number of patients dying of other causes (denominator) decreasing, and the number of patients dying with lung hypoplasia remaining constant.
Classification of small‐for‐gestational age births: weight‐by‐gestation standards of second birth conditional on the size of the first
Authors: Skjaerven Rolv , Bakketeig Leiv S. 
Published: April 2008

Summary. Percentiles of weight‐by‐gestational age were constructed for first and second births, based on linked sibship‐data from the Medical Birth Registry of Norway. Standards were made for weight‐by‐gestational age of second births conditional on whether the first birth was small‐for‐gestational age (SGA) or large‐for‐gestational age (LGA). These standards were compared with the conventional, cross‐sectional standard of all second births. The relevance of the conditional standards was assessed on the basis of perinatal mortality, using logistic regression analyses. When applying cross‐sectional standards of second births, more than 30% of the births following a SGA first birth were classified as SGA, compared with only 1.7% following an LGA first births. The overall risk for a perinatal loss in second births following a SGA first birth was twice that among second births following a LGA first birth.When second births were themselves categorised as SGA or non‐SGA using the cross‐sectional standards, the mortality among the SGA second births was such that the risk was 4 to 5 times higher following LGA first births compared with SGA first births. When conditional standards were applied to define SGA among second births, the risk relation between the subgroups (defined by classification of first birth) corresponded to the observed overall risk pattern. An unconditional SGA classification conceals important differences between clinically distinct subgroups.
Use of androgen deprivation therapy for metastatic prostate cancer in older men
Authors: Keating Nancy L. , O’Malley A. James , McNaughton‐Collins Mary , Oh William K. , Smith Matthew R. 
Published: April 2008

OBJECTIVETo assess factors associated with early or delayed androgen deprivation therapy (ADT) among men diagnosed with metastatic prostate cancer, and to assess the relationship between ADT and overall survival, as there is uncertainty about the ideal timing for initiating ADT in men with metastatic prostate cancer.PATIENTS AND METHODSWe studied a population‐based cohort of American men aged ≥66 years diagnosed with metastatic prostate cancer during 1992–2002 and followed to 2003. We assessed the receipt of ADT early (≤4 months from diagnosis), delayed (>4 months), or not at all, using multinomial logistic regression to identify factors associated with treatment, and Cox proportional‐hazard models to assess whether treatment was associated with survival.RESULTSOverall, 69.5% of men received early ADT and 7.3% delayed. Adjusted rates of early ADT were lower for black than white men (58.3% vs 71.0%), and of delayed ADT were higher for black than white men (12.7% vs 6.2%). Receipt of ADT was associated with improved survival (adjusted hazard ratio 0.69, 95% confidence interval 0.66–0.73). The benefit of early treatment did not differ from delayed treatment (P = 0.58).CONCLUSIONSA large minority of men with metastatic prostate cancer, particularly black men, receive delayed or no ADT. Early or delayed ADT was associated with similarly prolonged survival. After controlling for patient and tumour characteristics, survival did not differ by race, and receipt of ADT did not contribute to racial differences in survival.
Loss to follow‐up in an international, multicentre observational study
Authors: Mocroft A , Kirk O , Aldins P , Chies A , Blaxhult A , Chentsova N , Vetter N , Dabis F , Gatell J , Lundgren JD ,   for the EuroSIDA study group
Published: April 2008

ObjectiveThe aim of this work was to assess loss to follow‐up (LTFU) in EuroSIDA, an international multicentre observational cohort study.MethodsLTFU was defined as no follow‐up visit, CD4 cell count measurement or viral load measurement after 1 January 2006. Poisson regression was used to describe factors related to LTFU.ResultsThe incidence of LTFU in 12 304 patients was 3.72 per 100 person‐years of follow‐up [95% confidence interval (CI) 3.58–3.86; 2712 LTFU] and varied among countries from 0.67 to 13.35. After adjustment, older patients, those with higher CD4 cell counts, and those who had started combination antiretroviral therapy all had lower incidences of LTFU, while injecting drug users had a higher incidence of LTFU. Compared with patients from Southern Europe and Argentina, patients from Eastern Europe had over a twofold increased incidence of LTFU after adjustment (incidence rate ratio 2.16; 95% CI 1.84–2.53; P<0.0001). A total of 2743 patients had a period of >1 year with no CD4 cell count or viral load measured during the year; 743 (27.1%) subsequently returned to follow‐up.ConclusionsSome patients thought to be LTFU may have died, and efforts should be made to ascertain vital status wherever possible. A significant proportion of patients who have a year with no follow‐up visit, CD4 cell count measurement or viral load measurement subsequently return to follow‐up.
Characteristics of traditional Croatian ewe's cheese from the island of Krk
Authors: MIKULEC N , KALIT S , HAVRANEK J , ANTUNAC N , HORVAT I , PRPIC Z 
Published: April 2008

Krk cheese is a hard, full‐fat cheese made from raw sheep's milk, characterized by a delicate, full and strong flavour. The aim of this study was to determine farm influence on the chemical composition of sheep's milk for Krk cheese production, and the chemical characteristics of Krk cheese during ripening. Gross composition of the milk used complies with the average sheep's milk composition from the Croatian Adriatic region. During ripening, fat, protein, salt content and lactic acid concentration increased (P < 0.01), as well as the water‐soluble nitrogen fraction and the 12%‐trichloroacetic‐acid‐soluble nitrogen fraction (P < 0.05). Degradation of β‐casein could be an indicator of the ripening quality of Krk cheese.
Minimization of aflatoxin M1 content in Iranian white brine cheese
Authors: MOHAMMADI H , ALIZADEH M , BARI M R , KHOSROWSHAHI A , TAJIK H 
Published: April 2008

A chemometric approach was used to minimize the aflatoxin M1 (AFM1) content of Iranian white brine cheese. The effects of processing factors such as renneting temperature (30–40°C), cutting size (0.5–1 cm), stirring time (10–20 min), press time (1–2 h), curd size (64–256 cm3) and saturated brine pH (4.6–6) on the AFM1 content of the cheese curds were explored. Renneting temperature, press time and saturated brine pH were, respectively, the most significant factors. The aflatoxin content of the cheese samples decreased with increasing renneting temperature and press time. Lowering of the saturated brine pH reduced AFM1 in the cheese curds. Taking account of all of the factors studied, optimum processing conditions for minimization of AFM1 in the cheese curds were: renneting temperature = 39.91°C, cut size = 0.51 cm, stirring time = 17.71 min, press time = 19.48 min, curd size = 73.27 cm3 and saturated brine pH = 4.79.
Grass pollen allergens
Authors: Hrabina M. , Peltre G. , Van Ree R. , Moingeon P. 
Published: April 2008

SummaryTo date, eleven groups of grass pollen allergens eliciting a specific IgE response in atopic individuals have been identified. Groups 1 and 5 allergens are the most critical (major) pollen allergens leading to the sensitization of 90% and 65–85% allergic patients, respectively. Other allergens frequently involved in the IgE response include groups 2/3, 4, 6, 7, 10–13 allergens. Allergens found in various Pooideae exhibit high homology in terms of their amino acid sequence composition, which translates into significant cross‐reactivity in terms of antibody (IgE and IgG) as well as T cell responses. Nevertheless, for a given allergen group, there is evidence of both interspecies (i.e. differences in amino acid sequences) and intraspecies (multigenes, post‐translational modification, mRNA splicing or editing) molecular variability.
Effect of nicotine on the formation of prostaglandins in the rabbit kidney
Authors: Alster Pawel , Wennmalm Åke 
Published: April 2008

Summary. The effect of nicotine on the conversion of 14C‐labelled arachidonate (14C‐AA) to 14C‐labelled primary prostaglandins (PGs) was investigated in low‐speed super‐natants and high‐speed sediments of rabbit homogenized kidneys. Nicotine (2×10˜7 M‐2×10_4M) dose‐dependently inhibited the formation of the labelled PGs D2, E2 and F2a regardless of whether low‐speed supernatants or high‐speed sediments were the enzymatic source. The (I).0 of nicotine was about 10‐5M. Nicotine did not affect the distribution of the primary PGs formed in comparison to controls. Indomethacin also inhibited the formation of labelled PGs, being on a molar basis about 500 times more efficient than nicotine.It is concluded that nicotine attenuates the bioformation of primary PGs in the rabbit kidney, probably by eliciting an inhibitory effect on the cyclo‐oxygenase that converts A A to PGendoperoxides.
Clinical ventilation‐perfusion scintigraphy
Authors: Fazio F. , Wollmer P. 
Published: April 2008

Summary. Ventilation‐perfusion scintigraphy is an established procedure for the investigation of lung disease. Perfusion scans are commonly obtained with a y‐camera following injection of 99mTc‐labelled microspheres. For the assessment of regional lung ventilation, a number of techniques are now being employed, i.e. 133Xe and 127Xe single breath/ washout studies, continuous inhalation of 81mKr and inhalation of radioactive aerosols. The latter two methods are now gaining consideration in clinical practice.Lung perfusion scanning is highly sensitive for detection of regional abnormalities of blood flow; the diagnosis of pulmonary embolism remains the most important clinical application of the technique. In this context, the use of a ventilation scan is required in order to increase the specificity of the procedure.In general, lung ventilation‐perfusion scintigraphy is of great value for the management of patients with both primary lung disease and heart disease, by providing pathophysiological information of importance for the diagnosis, follow up and the functional evaluation of the patient.
51Cr‐EDTA clearance determined by one plasma sample
Authors: Groth Steffen , Aasted Michael 
Published: April 2008

Summary. 51Cr‐EDTA clearance was measured in 99 consecutive patients. Based on the individual plasma activity at 180,200, 220, and 240 min after injection (normalized with respect to injected dose/body surface area), a nomogram and a formula were derived for the relation between clearance and the plasma activity in one sample drawn between 180 and 240 min after injection. The nomogram was tested by the activity in 141 plasma samples from 53 consecutive patients. The clearance values calculated by means of the nomogram were compared to the corresponding clearance value calculated by a conventional standard method. The correlation coefficient for this comparison was r=0–982.It is recommended that the nomogram should only be used if clearance values above 30 ml/min are expected.
Early changes in oesophageal function in progressive systemic sclerosis: a comparison of manometry and radiology
Authors: Blom‐Bülow Berith , Sundström Gunnar , Jonson Björn , Tylén Ulf , Wollheim Frank A. 
Published: April 2008

Summary. The characteristics of oesophageal dysfunction were studied with manometry and cine radiography in a recumbent position in 21 patients with typical progressive systemic sclerosis (PSS). Manometry was also performed in a matched control group. Only one patient had a completely normal manometry. Mean resting pressure in both the upper and lower oesophageal sphincters were significantly decreased in PSS. Twelve patients had no detectable peristalsis in the lower oesophagus. In the upper oesophagus, the mean pressure amplitude of the peristaltic wave was found to be lower than normal in all patients with detectable peristalsis. In some patients, the only feature of oesophageal dysfunction observed was an increased speed of the peristaltic wave in the middle and lower oesophagus. This is interpreted as an impaired coordination of the propulsive peristalsis. Neuromuscular dysfunction of the oesophagus in its full length was thus clearly demonstrated.At cine radiography, three patients were judged as normal, and 13 patients had severe impairment of the peristaltic function in the distal two‐thirds of oesophagus.Oesophageal scoring based on manometry correlated well to scoring based on radiography. Cine radiography of the recumbent patient gives adequate information for clinical purposes. Detection of early changes in the amplitude and speed of the propagation wave requires manometry.
The size and strength of the quadriceps muscles of old
Authors: Men Young , Young Archie , Stokes Maria , Crowe Morgan 
Published: April 2008

Summary. The mean isometric strength of the stronger quadriceps muscles of 12 healthy men in their seventies was 39% less than that of 12 healthy men in their twenties (P < 0–001). The cross‐sectional area of the quadriceps was measured at mid‐thigh, by ultrasound scanning; the older men's stronger quadriceps were 25% smaller (P < 0–001).The ratio of the stronger quadriceps' strength to its cross‐sectional area was very similar in the old men to values obtained previously for both old and young women, but averaged 19% less than in the young men (P < 0–02). Quadriceps size and strength were correlated in the old men (P= 0–77, P= 0–03) but not in the young men (r= 0.15). The principal axis of the relationship between quadriceps size and strength in the old men was very similar to those previously reported for both old and young women.The quadriceps strength of some young men is greater than would be expected from the size of the muscle.