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J Wolf

Publications and source records attributed to J Wolf.

At least 19 recordsLinked to original sources
PubMed2006

Modelling approaches for coastal simulation based on cellular automata: the need and potential.

The paper summarizes the theoretical and practical needs for cellular automata (CA)-type models in coastal simulation, and describes early steps in the development of a CA-based model for estuarine sedimentation. It describes the key approaches and formulae used for tidal, wave and sediment processes in a prototype integrated cellular model for coastal simulation designed to simulate estuary sedimentary responses during the tidal cycle in the short-term and climate driven changes in sea-level in the long-term. Results of simple model testing for both one-dimensional and two-dimensional models, and a preliminary parameterization for the Blackwater Estuary, UK, are shown. These reveal a good degree of success in using a CA-type model for water and sediment transport as a function of water level and wave height, but tidal current vectors are not effectively simulated in the approach used. The research confirms that a CA-type model for the estuarine sediment system is feasible, with a real prospect for coupling to existing catchment and nearshore beach/cliff models to produce integrated coastal simulators of sediment response to climate, sea-level change and human actions.

Computer Simulation↗
PubMed2006

[Chediak-Higashi syndrome].

Chediak-Higashi syndrome (CHS) is a rare autosomal recessive lysosomal disorder characterized by frequent infections, oculocutaneous albinism, high bleeding tendency, and various neurological symptoms. Onset in early childhood mostly leads to lymphohistiocytic infiltration into multiple organs, which is usually lethal without bone marrow transplantation. The adult form of CHS has a milder course, no lymphohistiocytic infiltration, and is characterized by neurological manifestations such as polyneuropathy, parkinsonism, dementia, and ataxia. In young adults, a combination of these defects with oculocutaneous albinism or recurrent infections should bring CHS into consideration. Diagnosis is established by the presence of characteristic eosinophilic peroxidase-positive giant granules in leukocytes. This article summarizes current knowledge about the pathogenesis, clinical course, and therapy of CHS and reports on experience with two adult CHS patients.

Adult↗
PubMed2006

Sensors made of RNA: tailored ribozymes for detection of small organic molecules, metals, nucleic acids and proteins.

Nucleic acids are well suited to serve as biosensors for the fast and reliable detection of small organic molecules, such as a number of metabolites or antibiotics, specific nucleic acid sequences, peptides, proteins or metal ions. One of the main advantages of using nucleic acids as biosensors is that they can be modulated to respond allosterically to specific effectors. Thus molecular recognition is transformed directly into a catalytic process with observable results. In particular, catalytic RNA structures, such as the hammerhead and hairpin ribozymes, have been used for biosensor engineering. The review reports on the function mode of nucleic acid biosensors and introduces recent developments and applications in the field.

Biosensing Techniques↗
PubMed2006

Effect of subsidy regimes on economic values of functional traits in beef cattle breeding.

We investigated the impact of five monetary subsidy regimes on economic values of traits in a cow-calf pasture production system with surplus calves fed for slaughter. The following regimes were analysed: (1) maximum prices for slaughter animals actually received in the Czech Republic during 2004, with no subsidies of any kind; (2) prices as in (1), with subsidies awarded per hectare of permanent grassland and per calf born; (3) prices as in (1), with subsidies awarded per hectare of agricultural land, per hectare of pasture and meadow, per beef cow in a forage system and per livestock unit; (4) prices as in (1), with subsidies awarded per hectare of agricultural land; (5) no subsidies, but prices received for slaughter animals that covered production costs and resulted in 1% profitability. The modelled farm showed negative profit under real price conditions with no subsidies (regime 1), which led to an underestimation of economic values for functional traits. The same results were obtained in regimes in which subsidies did not depend on the number of animals (3) or on meat production from the enterprise (4). Economic values of production traits (growth and carcass traits) did not vary among subsidy regimes. To determine optimum economic values for functional traits in beef cattle, we advocate using the method applied in subsidy regime 5, no subsidies but prices for slaughter animals that cover production cost and a small profit.

Animal Husbandry↗
PubMed2005

The 'accelerator hypothesis': relationship between weight, height, body mass index and age at diagnosis in a large cohort of 9,248 German and Austrian children with type 1 diabetes mellitus.

AIMS/HYPOTHESIS: The aim of this study was to investigate whether either increased weight or BMI are associated with the earlier manifestation of type 1 diabetes mellitus in children. METHODS: We evaluated anthropometric measurements in a large cohort of 9,248 patients of European extraction who were diagnosed in the years 1990-2003 in 116 pediatric clinics throughout Germany and Austria. RESULTS: Patients were divided into four groups according to age (0-4.9 years, 5-9.9 years, 10-14.9 years and 15-20 years). Significantly higher standard deviation scores (SDSs) for weight and BMI at diabetes onset were found for both boys and girls in the three younger age groups (up to 14.9 years of age) compared with the reference population (p<0.00001). In addition, the BMI SDS and the weight SDS were significantly higher in the 0-4.9-years age group than in all other groups (p<0.00001), and BMI SDS at onset gradually decreased with increasing age at manifestation (p<0.0001). Over the >10-year study period, there was a continuous rise in the weight-SDS and the BMI-SDS in the cohort (p<0.0001), especially in the 5-9.9-years and the 10-14.9-years age groups. Multivariate analysis revealed a significant influence of male sex and of year of manifestation on BMI SDS (p<0.0001) and demonstrated a negative association between the patients' BMI SDS and age at diagnosis, with a mean annual decrease in BMI SDS of -0.0248 (95% CI -0.0294 to -0.0202, p<0.0001). CONCLUSIONS/INTERPRETATION: A higher BMI was associated with a younger age at diabetes onset. Increased weight gain could therefore be a risk factor for the early manifestation of type 1 diabetes.

Adolescent↗
PubMed2005

Towards a vulnerability assessment of the UK and northern European coasts: the role of regional climate variability.

Within the framework of a Tyndall Centre research project, sea level and wave changes around the UK and in the North Sea have been analysed. This paper integrates the results of this project. Many aspects of the contribution of the North Atlantic Oscillation (NAO) to sea level and wave height have been resolved. The NAO is a major forcing parameter for sea-level variability. Strong positive response to increasing NAO was observed in the shallow parts of the North Sea, while slightly negative response was found in the southwest part of the UK. The cause of the strong positive response is mainly the increased westerly winds. The NAO increase during the last decades has affected both the mean sea level and the extreme sea levels in the North Sea. The derived spatial distribution of the NAO-related variability of sea level allows the development of scenarios for future sea level and wave height in the region. Because the response of sea level to the NAO is found to be variable in time across all frequency bands, there is some inherent uncertainty in the use of the empirical relationships to develop scenarios of future sea level. Nevertheless, as it remains uncertain whether the multi-decadal NAO variability is related to climate change, the use of the empirical relationships in developing scenarios is justified. The resulting scenarios demonstrate: (i) that the use of regional estimates of sea level increase the projected range of sea-level change by 50% and (ii) that the contribution of the NAO to winter sea-level variability increases the range of uncertainty by a further 10-20cm. On the assumption that the general circulation models have some skill in simulating the future NAO change, then the NAO contribution to sea-level change around the UK is expected to be very small (<4cm) by 2080. Wave heights are also sensitive to the NAO changes, especially in the western coasts of the UK. Under the same scenarios for future NAO changes, the projected significant wave-height changes in the northeast Atlantic will exceed 0.4m. In addition, wave-direction changes of around 20 degrees per unit NAO index have been documented for one location. Such changes raise the possibility of consequential alteration of coastal erosion.

Climate↗
PubMed2005

Modelling waves and surges during the 1953 storm.

Waves and sea levels have been modelled for the storm of 31 January-1 February 1953. Problems in modelling this event are associated with the difficulty of reconstructing wind fields and validating the model results with the limited data available from 50 years ago. The reconstruction of appropriate wind fields for surge and wave models is examined. The surges and waves are reproduced reasonably well on the basis of tide-gauge observations and the sparse observational information on wave heights. The maximum surge coincided closely in time with tidal high water, producing very high water levels along the coasts of the southern North Sea. The statistics of the 1953 event and the likelihood of recurrence are also discussed. Both surge and wave components were estimated to be approximately 1 in 50 year events. The maximum water level also occurred when the offshore waves were close to their maximum. The estimation of return period for the total water level is more problematic and is dependent on location. A scenario with the 1953 storm occurring in 2075, accounting for the effects of sea level rise and land movements, is also constructed, suggesting that sea level relative to the land could be 0.4-0.5m higher than in 1953 in the southern North Sea, assuming a rise in mean sea level of 0.4m.

Computer Simulation↗
PubMed2005

Estimation of genetic parameters of semen characteristics and reproductive traits in AI boars.

(Co)variance components and further genetic parameters of boar semen characteristics and reproductive traits were estimated using the REML procedure applied to multi-trait animal models. The calculations were based on data from 210,733 ejaculates stemming from 2862 AI boars and collected from 1990 to 1997 in insemination stations for boars in the Czech Republic. Equal model equations for all traits included the AI station and the breed or breed combination as fixed effects, the interval between two collections for the boar as covariable and the animal and residual effects as random effects. The following heritabilities were estimated: semen volume 0.58, sperm concentration 0.49, progressive motion of spermatozoa 0.38, abnormal spermatozoa 0.34, number of total spermatozoa 0.42, number of insemination doses 0.40, number of piglets born alive 0.08, total number of piglets born 0.05 and conception rate 0.29. Heritabilities and genetic correlations were estimated on average values for each boar.

Animals↗
PubMed2005

Analysing the robustness of cellular rhythms.

Autonomous oscillations at the cellular level are important for various timing and signalling functions. The rhythms depend on environmental influences in a specific manner. In particular, the period of some rhythms has been shown to be very robust to certain environmental factors whereas other rhythms show a high sensitivity towards these factors. It is discussed that the robustness of the systems towards environmental changes results from underlying design principles. However, a comparison of robustness properties of different rhythms is lacking. Here we analyse the sensitivity of the oscillatory period with respect to parameter variations in models describing oscillations in calcium signalling, glycolysis and the circadian system. By comparing models for the same and different rhythms it is shown that the sensitivity depends on the oscillatory mechanism rather than the details of the model description. In particular, we find models of calcium oscillations to be very sensitive, those for glycolytic oscillations intermediately sensitive and models for circadian rhythms very robust. The results are discussed with respect to the temperature dependency of the rhythms. The question of what impact design principles have on the robustness of an oscillator, is addressed more explicitly by a direct comparison of systems with positive and negative feedback regulation for various reaction chain lengths. We find that the systems with negative feedback are more robust than corresponding systems with positive feedback. An increase in the length of the reaction chain under regulation leads to a decrease in sensitivity.

Algorithms↗
PubMed2005

Non-additive effects on milk production in Czech dairy cows.

Crossbreeding effects on milk production traits of Czech dual-purpose and dairy cattle breeds were estimated. Nearly 370,000 cows with known gene proportions from Czech Pied, Ayrshire or Holstein cattle were selected from the national milk recording data base. Single-trait animal models were calculated for milk, fat and protein yield, fat and protein content. The model of Dickerson including additive, additive maternal, heterotic and recombination effects was used for the part of the animal model describing the crossbreeding effects in all calculations. For milk yield, the additive genetic effect (defined as deviation from Czech Pied cattle) was 850-900 kg for Holstein and 240-480 kg for Ayrshire. The maternal effects were low and negative. Low significant positive heterotic effects were observed being up to approximately 100 kg for Czech Pied x Holstein. The recombination effects were negative and statistically significant for Czech Pied x Holstein. The results for fat and protein yield were similar to the results for milk yield. For fat and protein content, nearly no statistically significant crossbreeding effects were found.

Animals↗
PubMed2005

Coeliac disease in children with Type 1 diabetes mellitus: the effect of the gluten-free diet.

PATIENTS AND METHODS: We assessed the frequency of coeliac disease in 281 children with Type 1 diabetes and the effect of gluten-free diet (GFD) in newly diagnosed cases. Serological screening was performed using anti-gliadin and anti-endomysium antibodies. Data were obtained about clinical symptoms, height and weight-for-height. RESULTS: A small intestinal biopsy was recommended to 18 patients (6.4%) with positive serological results and 12 children agreed. Nine of them had coeliac disease. Three out of nine coeliac children complained about gastrointestinal symptoms. On a GFD, the symptoms disappeared in two patients. Iron-deficiency anaemia was present in four subjects and disappeared in the three patients who accepted the GFD. In three patients (33%), coeliac disease was asymptomatic. Height and weight-for-height were in the normal range for all patients. For well-complying patients, there was a significant increase in height standard deviation at diagnosis and on follow-up (-0.28 vs. +0.35) (P = 0.03). Changes in weight-for-height were not significant (-4.0% vs. +1.4%) (P = 0.28). There was a trend to an improvement in HbA(1c) (8.0 vs. 7.3%) (P = 0.05). CONCLUSIONS: Serological screening is effective. There is a therapeutic benefit for some screening-detected patients, but confirmatory studies are needed.

Adolescent↗
PubMed2005

Injury prevention practices as depicted in G and PG rated movies: the sequel.

OBJECTIVE: To determine whether the depiction of injury prevention practices in children's movies released during 1998-2002 is different from an earlier study, which found that characters were infrequently depicted practicing recommended safety behaviors. METHODS: The top 25 G (general audience) and PG (parental guidance suggested) rated movies per year from 1998-2002 comprised the study sample. Movies or scenes not set in the present day, animated, documentary, or not in English were excluded; fantasy scenes were also excluded. Injury prevention practices of motor vehicle occupants, pedestrians, bicyclists, and boaters were recorded for characters with speaking roles. RESULTS: Compared with the first study, the proportion of scenes with characters wearing safety belts increased (27% v 35%, p<0.01), the proportion of scenes with characters wearing personal flotation devices decreased (17% v 0%, p<0.05), and no improvement was noted in pedestrian behavior or use of bicycle helmets. CONCLUSIONS: Despite a modest increase in safety belt usage, appropriate injury prevention practices are still infrequently shown in top grossing G and PG rated movies. The authors recommend that the entertainment industry incorporate safe practices into children's movies. Parents should call attention to the depiction of unsafe behaviors in movies and educate children to follow recommended safety practices.

Accident Prevention↗
PubMed2004

Expression of resistance markers to methotrexate predicts clinical improvement in patients with rheumatoid arthritis.

BACKGROUND: Methotrexate is transported into the cell by the reduced folate carrier (RFC) and out of the cell by members of the multidrug resistance protein family (MRP). Transport proteins may affect the therapeutic efficacy of this drug in patients with rheumatoid arthritis. OBJECTIVE: To investigate the potential benefit of the presence of RFC and the absence of functional MRP for the efficacy of methotrexate treatment. METHODS: The study involved 163 patients (116 female, 47 male; mean age 59.5 years) on methotrexate (mean weekly dose 12.2 mg). RFC was determined using reverse transcriptase polymerase chain reaction, and MRP function by flow cytometry, using a calcein acetoxymethylesther/probenecid assay. Clinical response to methotrexate was evaluated by the EULAR response criteria and the ACR 20% improvement criteria. The clinical data were obtained at the beginning of methotrexate treatment and at the time of blood sampling during ongoing therapy. Patients were divided into four groups according to the presence (+) or absence (-) of RFC and functional (f) MRP. RESULTS: fMRP+/RFC+ and fMRP-/RFC- patients more often had good EULAR response rates (60%, p = 0.014, and 53%, p = 0.035, respectively) in comparison with the fMRP-/RFC+ group (29%); fMRP+/RFC- patients had a low frequency of good disease activity responses. CONCLUSIONS: Absence of fMRP plus presence of RFC did not prove to be related to beneficial effects of methotrexate, but the lack or the presence of both fMRP and RFC led to a significantly better therapeutic outcome. Determination of these markers may predict responsiveness to methotrexate.

Antirheumatic Agents↗
PubMed2004

[Effects of slow-stroke massage as complementary treatment of depressed hospitalized patients].

BACKGROUND AND OBJECTIVE: Among methods of complementary treatment of depression, massage plays an important role, at least in the U.S.A. Although there are some pointers to the antidepressive and anxiolytic action of slow-stroke massage in various randoms studies of patient cohorts, there have been no controlled trials of depressed hospitalized patients. PATIENTS AND METHODS: 32 depressed patients (24 women, 8 men; average 48 years - coveringthe entire spectrum of affective disorders listed in the ICD but without comorbidity in axis 2) with a minimum BRMS score of 16,7 - were included in the study. The randomized cross-over trial involved three massage sessions at set times (M) and sessions in two control groups (C) (relaxation and perception) lasting for 60 min 2-3 days apart. Under the control conditions there was no touching. The effects of depression-specific variables (e.g. mood, drive, abnormal cognition, as well as typical progress variables of the slow-stroke massage (bodily awareness, general state of health, etc.) were measured by both the patients' own assessment and that of an independent observer. RESULTS: Under condition of both M and C, comparison of before and after effects, there was not only the primarily postulated mood-enhancing effect, but also some very marked changes in almost all dimension, the mean improvement ratio under M often being stronger than under C. After Bonferroni correction for multiple tests, the statistical significance there remained the stronger effect of M in four dimensions (global tenseness, restlessness, depressed mood, neck/shoulder tension). The intensive effect of M compared with C was confirmed by both female and male patients regarding the answers to various open questions. CONCLUSIONS: Slow-stroke massage is suitable for adjuvant acute treatment of patients with depression. It is very readily accepted also by very ill patients. In relation to the skin as an organ that aids identity, non-hedonic depressed patients are able to recognize the sensory quality of therapeutic touching as a positive stimulus. In view of the latent period of many weeks and the only moderate efficacy of antidepressants, the described complementary method, which does not require physiotherapeutic training, should be more often applied in both a hospital and general practice setting.

Complementary Therapies↗
PubMed2004

Laryngeal histoplasmosis.

Histoplasma capsulatum is an endemic fungus found in moist, fertile soil; in North America, it is most prevalent in the river valleys of the central United States. Most primary infections in the immunocompetent host are asymptomatic or are thought to be a flu-like illness. Disseminated histoplasmosis most commonly occurs in immunosuppressed patients. Histoplasmosis infection involving the larynx is an extremely rare manifestation. Here, we describe the case of an immunocompetent man with symptomatic, acute pulmonary histoplasmosis with laryngeal involvement who presented with a chief complaint of hoarseness. We also review the literature of immunocompetent patients with laryngeal histoplasmosis.

Adult↗
PubMed2004

Impact of the ESR gene on litter size and production traits in Czech Large White pigs.

To evaluate the effect of the PvuII polymorphism of the oestrogen receptor gene on litter size and production traits in Czech Large White swine, data from 1250 sows and 3600 litters were analysed with two four-trait animal models. The traits in the first model were number of piglets born alive in a sow's first litter, number of piglets born alive in second and subsequent litters, lifetime daily gain and lean meat percentage. The second model included number of piglets born, number of piglets born alive, number of piglets weaned and litter weight at weaning from first and subsequent litters. The oestrogen receptor (ESR) locus significantly affected prolicacy in the first parity and averaged over all parities (P < 0.05), with allele A superior to allele B. In the first parity, AA sows produced approximately 0.5 more live piglets per litter than BB sows. Averaged over all parities, this difference was c. 0.25 piglets. Results for total number of piglets born and number of piglets weaned were similar to results for numbers born alive. No significant dominance effect was found for prolificacy traits. For litter weight at weaning, no significant additive effect was observed at the ESR locus, but a significant negative dominance effect (-1.5 kg) was estimated averaged across parities (litters of AB sows were similar to litters of BB sows for this trait). No pleiotropic effect of the ESR polymorphism on average daily gain or lean meat percentage was found.

Animals↗
PubMed2003

Improved limits on nu(e) emission from mu+ decay.

We investigated mu(+) decays at rest produced at the ISIS beam stop target. Lepton flavor (LF) conservation has been tested by searching for nu(e) via the detection reaction p(nu(e),e(+))n. No nu(e) signal from LF violating mu(+) decays was identified. We extract upper limits of the branching ratio (BR) for the LF violating decay mu(+)-->e(+)+nu(e)+nu(-) compared to the standard model (SM) mu(+)-->e(+)+nu(e)+nu(mu) decay: BR<0.9(1.7) x 10(-3) (90% C.L.) depending on the spectral distribution of nu(e) characterized by the Michel parameter rho=0.75(0.0). These results improve earlier limits by one order of magnitude and restrict extensions of the SM in which nu(e) emission from mu(+) decay is allowed with considerable strength. The decay mu(+)-->e(+)+nu(e)+nu(mu) often proposed as a potential source for the nu(e) signal observed in the LSND experiment can be excluded.

Journal Article↗