The responsibility turn Andrea Saltelli and Monica Di Fiore, Eds. Oxford University Press, 2023. 272 pp

Lessons from the COVID-19 pandemic inspire a guide to recognizing the politics of modeling.

The challenge of unprecedented floods and droughts in risk management

Risk management has reduced vulnerability to floods and droughts globally^1,2, yet their impacts are still increasing³. An improved understanding of the causes of changing impacts is therefore needed, but has been hampered by a lack of empirical data^4,5. On the basis of a global dataset of 45 pairs of events that occurred within the same area, we show that risk management generally reduces the impacts of floods and droughts but faces difficulties in reducing the impacts of unprecedented events of a magnitude not previously experienced. If the second event was much more hazardous than the first, its impact was almost always higher. This is because management was not designed to deal with such extreme events: for example, they exceeded the design levels of levees and reservoirs. In two success stories, the impact of the second, more hazardous, event was lower, as a result of improved risk management governance and high investment in integrated management. The observed difficulty of managing unprecedented events is alarming, given that more extreme hydrological events are projected owing to climate change³.

Integrated modelling to assess the impacts of water stress in a transboundary river basin: Bridging local-scale water resource operations to a river basin economy

In this study, we develop a hydro-economic modelling framework for river-basin scales by integrating a water resources system model and an economic model. This framework allows for the representation of both local-scale features, such as reservoirs, diversions, and water licenses and priorities, and regional- and provincial-scale features, such as cross-sectoral and inter-regional connectedness and trade flows. This framework is able to: (a) represent nonlinearities and interactions that cannot be represented by either of typical water resources or economic models; (b) analyze the sensitivity of macro-scale economy to different local water management decisions (called 'decision levers' herein); and (c) identify water allocation strategies that are economically sound across sectors and regions. This integrated model is applied to the multi-jurisdictional Saskatchewan River Basin in Western Canada. Our findings reveal that an economically optimal water allocation strategy can mitigate the economic losses of water stress up to 80% compared to the existing water allocation strategy. We draw lessons from our analysis and discuss how integrated inter-regional hydro-economic modelling can benefit vulnerability assessment and robust decision making.

Great Lakes Runoff Intercomparison Project Phase 3: Lake Erie (GRIP-E)

Hydrologic model intercomparison studies help to evaluate the agility of models to simulate variables such as streamflow, evaporation, and soil moisture. This study is the third in a sequence of the Great Lakes Runoff Intercomparison Projects. The densely populated Lake Erie watershed studied here is an important international lake that has experienced recent flooding and shoreline erosion alongside excessive nutrient loads that have contributed to lake eutrophication. Understanding the sources and pathways of flows is critical to solve the complex issues facing this watershed. Seventeen hydrologic and land-surface models of different complexity are set up over this domain using the same meteorological forcings, and their simulated streamflows at 46 calibration and seven independent validation stations are compared. Results show that: (1) the good performance of Machine Learning models during calibration decreases significantly in validation due to the limited amount of training data; (2) models calibrated at individual stations perform equally well in validation; and (3) most distributed models calibrated over the entire domain have problems in simulating urban areas but outperform the other models in validation.

Socio-technical scales in socio-environmental modeling: Managing a system-of-systems modeling approach

System-of-systems approaches for integrated assessments have become prevalent in recent years. Such approaches integrate a variety of models from different disciplines and modeling paradigms to represent a socio-environmental (or social-ecological) system aiming to holistically inform policy and decision-making processes. Central to the system-of-systems approaches is the representation of systems in a multi-tier framework with nested scales. Current modeling paradigms, however, have disciplinary-specific lineage, leading to inconsistencies in the conceptualization and integration of socio-environmental systems. In this paper, a multidisciplinary team of researchers, from engineering, natural and social sciences, have come together to detail socio-technical practices and challenges that arise in the consideration of scale throughout the socio-environmental modeling process. We identify key paths forward, focused on explicit consideration of scale and uncertainty, strengthening interdisciplinary communication, and improvement of the documentation process. We call for a grand vision (and commensurate funding) for holistic system-of-systems research that engages researchers, stakeholders, and policy makers in a multi-tiered process for the co-creation of knowledge and solutions to major socio-environmental problems.

IL-10 IS DOWN-REGULATED IN THE CARDIOVASCULAR DISEASES SUSPECTED PATIENTS, INDEPENDENT OF ANGIOGRAPHY

IL-10 and interferon-gamma (IFN-γ) are the important anti and pro-inflammatory cytokines, respectively, which may participate in the cardiovascular disease pathogenesis. Additionally, environmental factors, such as the X-ray, can modulate cytokine expression. Due to the fact that X-ray is used during angiography, hence, angiography may alter expression of the cytokines.

OBJECTIVE

Accordingly, this project was aimed to assess IL-10 and IFN-γ serum levels within cardiovascular patients (with and without vessel stenosis) versus healthy controls and also the effects of angiography on the serum levels of the cytokines.

MATERIAL AND METHODS

This study was performed on the 80 participants, including twenty cases in each group (healthy controls and cardiovascular patients without vessel stenosis, stenosis of 1 vessel and stenosis of more than 1 vessel) to evaluate IL-10 and IFN-γ serum levels using ELISA technique. The IL-10 and IFN-γ serum levels also compared within group 2, 3 and 4 before and after angiography to explore the effects of the technique on the IL-10 and IFN-γ serum levels.

RESULTS

IL-10, but not IFN-γ, serum levels were higher in the healthy controls than all cardiovascular patients. IL-10 and IFN-γ serum levels were not altered after angiography and also were not differ in the smoker versus non- smoker and opium consuming versus non-opium consuming participants.

CONCLUSION

Due to the results it may be concluded that IL-10 can be considered as a plausible inhibitor of cardio- vascular diseases independent of angiography duration and X-ray, however, IFN-γ has no effects in the Iranian patients suffering from cardiovascular diseases.

Immunogenicity of a fusion protein containing PilQ and disulphide turn region of PilA from Pseudomonas aeruginosa in mice

Interference with bacterial adhesion is a new means to prevent or treat bacterial infections. In this experimental study we evaluated the immunogenic properties of a chimeric protein composed of PilQ and disulphide turn region of PilA from Pseudomonas aeruginosa in mice as an anti-adhesion based vaccine. First of all, a chimeric bivalent protein composed of PilQ and PilA was constructed and following subcutaneous immunization with merely the purified protein or in its admixed form with alum, the immunogenicity of the chimeric antigen was assessed in BALB/c mice. Then, the characteristics of the developed antibodies were studied by ELISA. Furthermore, the immunoreactivity of the purified recombinant protein was confirmed by immunoblotting. Alum as a common adjuvant boosted immunogenicity of the construct, resulting significantly greater anti-pili IgG titre. Mice antibody response consisted of IgG1, IgG2a, IgG2b and IgG3 subtypes with predominance of IgG1 subclass. The developed antibodies were capable to inhibit motility of PAO1 strain. In conclusion, our primary results revealed that the designed recombinant protein is a protective construct and may be used as a potential candidate for prophylactic purposes against P. aeruginosa infection.

SIGNIFICANCE AND IMPACT OF THE STUDY

In this study we examined the potential of integrated PilQ/PilA (QA) antigen as a vaccine candidate against Pseudomonas aeruginosa. Nowadays, anti-adhesion based vaccines are considered as new means to prevent or treat bacterial infections. Our study revealed that chimeric protein PilQ and disulphide turn region of PilA triggers production of specific antibodies. This humoral immune responses augmented when QA was administered in combination with an adjuvant. The results demonstrated efficacy of the designed recombinant chimeric antigen as an effective candidate in prevention of P. aeruginosa infection.

OT2-03-01: Incidence of Mastalgia as a Presenting Complaint in Iranian Population with Regard to Age, BMI, Education, Residency (City or Rural), State of Marriage and Compare with Western Countries

As it is has usually been stated, breast pain (mastalgia) is among the most common (or the commonest) cause of women referring to a breast clinic. The incidence has been reported in different ranges, and some studies (e.g. Canadian groups) have stated that mastalgia has its lowest incidence in middle east (compared to western countries). Based on this information, I have recently planned a study to investigate this issue.

To evaluate this data, I planned a questionnaire for every new patient coming to my breast clinic randomly. Every questionnaire was double checked & if still incomplete, was completed by phone communication.

The only inclusion criteria were to be a new patient. In this way over 550 questioners were completed during over 4 months. The aim is to find if there is any statistical difference in incidence rate and if there is any, evaluate any demographic difference that can be a cause.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr OT2-03-01.

A new formulation for feedforward neural networks

Feedforward neural network is one of the most commonly used function approximation techniques and has been applied to a wide variety of problems arising from various disciplines. However, neural networks are black-box models having multiple challenges/difficulties associated with training and generalization. This paper initially looks into the internal behavior of neural networks and develops a detailed interpretation of the neural network functional geometry. Based on this geometrical interpretation, a new set of variables describing neural networks is proposed as a more effective and geometrically interpretable alternative to the traditional set of network weights and biases. Then, this paper develops a new formulation for neural networks with respect to the newly defined variables; this reformulated neural network (ReNN) is equivalent to the common feedforward neural network but has a less complex error response surface. To demonstrate the learning ability of ReNN, in this paper, two training methods involving a derivative-based (a variation of backpropagation) and a derivative-free optimization algorithms are employed. Moreover, a new measure of regularization on the basis of the developed geometrical interpretation is proposed to evaluate and improve the generalization ability of neural networks. The value of the proposed geometrical interpretation, the ReNN approach, and the new regularization measure are demonstrated across multiple test problems. Results show that ReNN can be trained more effectively and efficiently compared to the common neural networks and the proposed regularization measure is an effective indicator of how a network would perform in terms of generalization.

Evaluation of sperm selection procedure based on hyaluronic acid binding ability on ICSI outcome

PURPOSE

To compare the efficiency of routine sperm selection method with HA-selection procedure for fertilization rate, embryo development, implantation and pregnancy rates as well as evaluating the relationship between HA-binding ability with sperm protamine deficiency and DNA fragmentation.

METHODS

Semen samples were obtained from the 50 couples undergoing ICSI. The percentage of fertilization rate, cleavage and quality of embryos compared between two procedures (routine sperm selection and HA-binding selection). The semen samples were assessed for DNA fragmentation and protamine deficiency by sperm chromatin dispersion (SCD) test and Chromomycin A3 (CMA3) staining, respectively.

RESULTS

A significant inverse correlation was observed between percentage of HA binding with protamine deficiency, DNA fragmentation and abnormal sperm morphology (P < 0.05). Furthermore, in current study, oocytes inseminated by HA sperm selection procedure had significantly higher fertilization rate (P < 0.05). While the pregnancy and implantation rates were insignificantly increased.

CONCLUSION

The results suggest that normal sperm have higher chance to bind HA and therefore, HA sperm selection procedure may select sperm with normal protamine content and low DNA fragmentation, but to confirm the effect of HA sperm selection on the ICSI outcome requires further studies.

Étude rétrospective comparant la translocation maculaire limitée et la photothérapie dynamique dans la néovascularisation choroïdienne rétrofovéale de la myopie forte

PURPOSE

To analyze the results of limited macular translocation (MT) and photodynamic therapy (PDT) in subfoveal choroidal neovascularization due to degenerative myopia, with a minimum follow-up of 12 months.

METHODS

Retrospective review of 55 consecutive patients: 31 eyes were treated using PDT and 24 were operated on with the limited macular translocation technique with chorioscleral infolding described by de Juan. Before and after each treatment, a complete examination comprised visual acuity, fundus examination, fluorescein angiography, and optical coherence tomography. Mean follow-up was 14 months in the PDT group and 19 months in the MT group.

RESULTS

The improvement in visual acuity was better in the MT group than in the PDT group and was correlated with younger age (p<0.001). At month 12, visual acuity improved by 3 ETDRS lines or more in 6 six eyes of the PDT group (19%), with no improvement over 6 lines. In the MT group, visual acuity improved by 3 lines in 14 eyes (58%) including 8 eight eyes (33%) with an improvement of 6 lines or more. Final visual acuity remain unchanged (+/-2 lines) in 16 eyes of the PDT group (66%) and 8 eight eyes of the MT group (33%), and decreased in 9 nine eyes in the PDT group (29%) versus 2 two eyes in the MT group (8%). Mean gain in visual acuity at 12 months was +3.5 ETDRS lines in the MT group and -0.1 line in the PDT group (p=0.001). The mean displacement of the fovea after translocation was 950 microm. The mMean number of PDT treatments was 2.3 during the 12-month follow-up.

CONCLUSIONS

Limited macular translocation allowed provided a significant improvement in visual acuity in some eyes with subfoveal neovascularization in myopia, especially in young patients, and resulted in a moderate rate of complications. Longer follow-up and further controlled and randomized studies are required to confirm these encouraging findings.

Can sperm protamine deficiency induce sperm premature chromosomal condensation?

Sperm premature chromatin condensation (PCC) has been considered as the second cause of failed fertilization post-intracytoplasmic sperm injection (post-ICSI). Cytoplasmic factors, including oocyte cytoplasmic immaturity have been suggested to induce PCC sperm. However, recent studies suggest that sperm chromatin anomaly might also lead to PCC sperm. During this study, human sperm from infertile patients with protamine deficiency or with adequate amount of protamine assessed by chromomycin A3 were injected into metaphase II mouse oocyte, treated with colcemid. Chromatin analysis was carried out on the injected oocyte. The results of this study show that contrary to the percentage of intact sperm, percentage of PCC sperm was significantly higher in oocytes injected with protamine deficient sperm (36.43 +/- 4.46) compared to oocytes injected with sperm with an adequate amount of protamine (11.99 +/- 3.54, P < 0.001). A significant correlation was also observed between percentage of PCC sperm and protamine deficiency (r = 0.46, P = 0.004). Therefore, it can be suggested that oocytes injected with protamine deficient sperm have a higher chance of forming PCC sperm and may result in failed fertilization post-ICSI.

Relationship between protamine deficiency with fertilization rate and incidence of sperm premature chromosomal condensation post-ICSI

After aneuploidy, sperm premature chromatin condensation (PCC) is the next prevalent cause of fertilization failure. Therefore the aim of this study was to evaluate the effect of sperm protamine deficiency on sperm PCC formation post-ICSI. Chromatin analysis was carried out on failed fertilized oocytes post-ICSI and incidences of sperm PCC were evaluated and the results were compared with the extent of protamine deficiency assessed by chromomycin A3. The results show that incidence of sperm PCC was significantly different in failed fertilized oocytes injected from semen samples with greater or less than 30% CMA3 positivity (P = 0.04). However, except for fertilization rate (P < 0.001), the mean number of MII, MI and germinal vesicles oocytes and percentage normal sperm were not significantly different between the two groups (P > 0.05). A significant correlation was observed between sperm protamine deficiency with fertilization rate. Hence sperm protamine deficiency affects fertilization rate and possibly prones sperm to PCC post-ICSI.

Effect of protamine-2 deficiency on ICSI outcome

During spermiogenesis, histones are replaced by protamines (P1 and P2), resulting in sperm chromatin condensation followed by a halt to gene expression in haploid spermatids and spermatozoa. As a consequence, protamine deficiency and aberrant P1/P2 ratio have a profound effect on both fertilization and embryo development. However, reports on the effect of the P1/P2 ratio on fertilization and embryo development after intracytoplasmic sperm injection (ICSI) are contradictory between human and animal studies. The question that still remains to be elucidated is which type of protamine deficiency is most common among protamine deficient samples. The present study has a direct bearing on this issue investigating the correlation of the P1/P2 ratio with protamine deficiency, fertilization, embryo quality and embryo development in ICSI patients. This study was carried out on 71 patients. Chromomycin A3 (CMA3) staining was used to determine protamine deficiency. Since this procedure does not indicate the type of protamine deficiency, the P1/P2 ratio was evaluated by nuclear protein extraction, acetic acid urea polyacrylamide gel electrophoresis and analysis of protein bands with software. Polyclonal anti-P1 and anti-P2 antibodies were used to confirm P1 and P2 presence. Results show a negative significant correlation of fertilization rate with protamine deficiency and P1/P2 ratio. No significant correlation was observed between protamine deficiency and P1/P2 ratio. Therefore, it can be concluded that altered P1/P2 ratio effects fertilization rate and embryo quality which subsequently may affect implantation and pregnancy outcome.

[Alternative therapies for choroidal neovessels resulting from age-related macular degeneration]

Classic neovessels (CNVs) identified on fluorescein angiography may benefit from thermal laser photocoagulation when sparing the fovea. If they extend into it, photodynamic therapy may halt the natural progression to a central scotoma. Occult CNVs, when subfoveal, may benefit from photodynamic therapy when isolated (not associated with classic CNV or with a pigment epithelium detachment). A number of therapeutic approaches are being evaluated in order to diversify the therapeutic choices available for treatment of CNVs. Transpupillary thermotherapy, which causes a limited increase in retinal temperature, could produce a sclerosis of occult isolated CNV. This approach has shown interesting results in pilot studies but also carries a risk for iatrogenic effects. The American randomized clinical trial currently under way will provide an evaluation of this treatment. An antiangiogenic therapy currently in progress is studying anecortave acetate and another is investigating anti-VEGF compounds. Anecortave acetate, which demonstrated its angiostatic activity in experimental models as well as in a phase II study, is now in a worldwide randomized clinical trial. The anti-VEGF molecules (antibodies and oligonucleotides) have shown very interesting preliminary results and are being evaluated in a large number of patients. Finally, a preventive therapy consisting of oral supplementation with antioxidants (vitamins C, E, and A) and zinc is a major step forward, providing the possibility of a real and effective prevention of the complications of age-related maculopathy.

Effect of human sperm chromatin anomalies on fertilization outcome post-ICSI

The aim of this study was to evaluate the effect of sperm chromatin anomalies on fertilization outcome post-intracytoplasmic sperm injection (ICSI). Therefore, along with semen parameters, Chromomycin A3 (CMA3) staining for protamine deficiency, aniline blue staining for excessive histones, SDS for sperm chromatin stability and SDS + EDTA for the ability of sperm to undergo decondensation were carried out on 55 semen samples from patients referred to the Isfahan Fertility and Infertility Center for ICSI. The results showed that among the aforementioned tests and semen parameters only CMA3 showed a significant correlation with fertilization outcome post-ICSI. Patients were also grouped according to CMA3 level of <30% or >30% or fertilization rate of <50% or >50%. The results show that the mean percentage fertilization and mean percentage of CMA3 positivity is different in both groups, respectively. The area under receiver operator characteristics curve shows that CMA3 is a highly sensitive and specific test for prediction of fertilization outcome post-ICSI. In conclusion, that sperm protamine deficiency has profound effect on fertilization failure in ICSI.

[Age related macular degeneration: a review of anti-angiogenic treatments]

In Western countries, age-related macular degeneration is the leading cause of visual loss in people aged 65 and over. Laser photocoagulation has been shown to be beneficial in patients with extra- or juxta-foveal classic choroidal neovascularization (CNV), but the majority of patients with exudative maculopathy have occult or subfoveal CNV. Laser photocoagulation is plagued by recurrences, which occur in more than 50% of cases. Because of the limited efficacy of laser photocoagulation and the small number of patients who are eligible for treatment, investigators are attempting to develop new modalities to treat CNV. These modalities can be classified into three major categories: surgery, photodynamic and pharmacological treatments. The general mechanism, the regulation of ocular angiogenesis, and current anti-angiogenic treatments are the subject of this review of the recent literature.

Bloodletting acupuncture for the prevention of stridor in children after tracheal extubation: a randomised, controlled study

Bloodletting acupuncture has been used for the treatment of a variety of upper respiratory tract problems, especially those of laryngeal origin. This study assesses its efficacy in reducing the incidence of stridor after tracheal extubation in children undergoing general anaesthesia with halothane. Sixty children were randomly allocated to an acupuncture group and a control group. In the acupuncture group, bloodletting acupuncture was performed before extubation. A blinded observer determined the presence and severity of postextubation stridor. The incidence of stridor in the acupuncture group was significantly higher than in the control group. In addition, the severity of stridor was significantly greater in the acupuncture group. It is concluded that in children undergoing halothane anaesthesia, the incidence of postextubation stridor cannot be reduced by bloodletting acupuncture.

Relation between different human sperm nuclear maturity tests and in vitro fertilization

PURPOSE

To consider the relationship between different sperm nuclear maturity tests and in vitro fertilization (IVF) rate, in order to select the most sensitive, specific, and independent factor(s) for prediction of in vitro fertilization.

METHODS

Infertile couples (101) were randomly selected from IVF candidates referred to Isfahan Fertility and Infertility center. Semen samples were collected on the day of oocyte recovery. Following routine semen analysis, major portion of the semen was prepared for routine IVF insemination and the remaining was used for following sperm nuclear maturity tests: chromomycin A3 (CMA3), aniline blue, sodium dodecyl sulphate (SDS) test, and acridine orange test with or without heat shock (87 degrees C, 5 min). Sperms (200) were evaluated for each test. The results were recorded and analyzed for their correlation to fertilization rate, using correlation coefficient, logistic regression analysis, student t-test, and receiver operating characteristics (ROC) curve.

RESULTS

Among these tests, aniline blue and CMA3, and semen parameters, sperm morphology, and sperm motility showed a significant correlation with fertilization rate. Using logistic regression analysis, sperm morphology and CMA3 were the only independent factors related to in vitro fertilization. ROC curves showed that among above tests, CMA3 is the most specific and sensitive for sperm nuclear maturity.

CONCLUSION

Among CMA3, aniline blue, SDS test, and acridine orange, CMA3 was the most sensitive and specific test that can be used along with routine semen analysis for more precise prediction of fertilization rate.

Down-regulation of high mobility group-I(Y) protein contributes to the inhibition of nitric-oxide synthase 2 by transforming growth factor-beta1

The inducible isoform of nitric-oxide synthase (NOS2) catalyzes the production of nitric oxide (NO), which participates in the pathophysiology of systemic inflammatory diseases such as sepsis. NOS2 is transcriptionally up-regulated by endotoxin and inflammatory cytokines, and down-regulated by transforming growth factor (TGF)-beta1. Recently we have shown that high mobility group (HMG)-I(Y) protein, an architectural transcription factor, contributes to NOS2 gene transactivation by inflammatory mediators. The aim of the present study was to determine whether regulation of HMG-I(Y) by TGF-beta1 contributes to the TGF-beta1-mediated suppression of NOS2. By Northern blot analysis, we show that TGF-beta1 decreased cytokine-induced HMG-I(Y) mRNA levels in vascular smooth muscle cells and macrophages in vitro and in vivo. Western analysis confirmed the down-regulation of HMG-I(Y) protein by TGF-beta1. To determine whether the down-regulation of HMG-I(Y) contributed to a decrease in NOS2 gene transactivation by TGF-beta1, we performed cotransfection experiments. Overexpression of HMG-I(Y) was able to restore cytokine inducibility of the NOS2 promoter that was suppressed by TGF-beta1. The effect of TGF-beta1 on NOS2 gene transactivation was not related to a decrease in binding of HMG-I(Y) to the promoter of the NOS2 gene, but due to a decrease in endogenous HMG-I(Y) protein. These data provide the first evidence that cytokine-induced HMG-I(Y) can be down-regulated by TGF-beta1. This down-regulation of HMG-I(Y) contributes to the TGF-beta1-mediated decrease in NOS2 gene transactivation by proinflammatory stimuli.

[Use of topical cyclosporin in microcrystalline keratopathy due to Streptococcus]

Infectious crystalline keratopathy is an exceptional but serious complication of penetrating keratoplasty. Streptococcus viridans and a steroid treatment are very often found. The treatment is always lengthy and difficult. The high number of bacteria and the steroid treatment, necessary to prevent rejection, worsen the infection. We report a case of Streptococcus crystalline keratopathy that evolved, despite the treatment, simultaneously toward abscess and acute rejection. Topical cyclosporin treatment was used to maintain an immunosuppression without worsening the infection.

[Cryptococcal chorioretinitis and acquired immunodeficiency syndrome]

We report a case of cryptococcal chorioretinitis discovered at ophthalmological examination of a 68-year-old woman with acquired immune deficiency syndrome. This localization revealed cryptococcal septicemia, without involvement of the central nervous system unlike most cases reported. Therapy with fluconazole (400 mg per day) led to gradual regression of the chorioretinal lesion.

This button makes you go up: three-year-olds and the Nintendo controller

Forty three-year-old children used the Nintendo controller in a simple cursor-placement task, with two different software interfaces. The directional interface required children to map specific directions of movement on to specific buttons on the controller. The non-directional interface simply advanced the cursor in a clockwise direction to the next placement location, regardless of the specific directional button pressed. Results indicate that while the youngest three-year-old children find the non-directional interface slightly easier to use, older three-year-olds are more successful with the directional interface. In addition, all three-year-olds actually experienced problems using the simpler, non-directional interface - and problems increased with age. The results are discussed with reference to designing appropriate interfaces for the wide variety of skill levels present in the pre-school population.