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Forest biomass and carbon are critical for ecological monitoring, and yet poorly modelled in complex ecosystems such as the tropical rainforests. To overcome this challenge incurred due to the complex biophysical properties of tropical forests, Airborne and Terrestrial LiDAR (Light Detection and Ranging) technologies have been used combinedly. Airborne LiDAR data ‘from above’ are largely restricted to analyses of lower canopy layer trees. Its combination with Terrestrial LiDAR allows the assessment of tree crowns under the upper canopy layer, thus opening up new possibilities for a more complete assessment of all the trees in a multi-layer stand. In this study, Airborne LiDAR was used for upper canopy tree measurements while Terrestrial LiDAR was complimented for lower canopy layer trees. The result showed that LiDAR-based tree measurements of DBH and height were highly accurate. We highly improved the accuracy of estimated above-ground biomass (AGB)/carbon from 87% of Terrestrial and 90% of Airborne LiDAR-based estimates to 97% through combining the use of the two technologies. This approach contributes to the development of efficient techniques for forest monitoring systems and bears the potential to extend the modelling options from remote sensing data to understory layer trees. © 2021 Informa UK Limited, trading as Taylor & Francis Group.

The shallow subsurface of Groningen, the Netherlands, is heterogeneous due to its formation in a Holocene tidal coastal setting on a periglacially and glacially inherited landscape with strong lateral variation in subsurface architecture. Soft sediments with low, small-strain shear wave velocities (VS30around 200 m s−1) are known to amplify earthquake motions. Knowledge of the architecture and properties of the subsurface and the combined effect on the propagation of earthquake waves is imperative for the prediction of geohazards of ground shaking and liquefaction at the surface. In order to provide information for the seismic hazard and risk analysis, two geological models were constructed. The first is the ‘Geological model for Site response in Groningen’ (GSG model) and is based on the detailed 3D GeoTOP voxel model containing lithostratigraphy and lithoclass attributes. The GeoTOP model was combined with information from boreholes, cone penetration tests, regional digital geological and geohydrological models to cover the full range from the surface down to the base of the North Sea Supergroup (base Paleogene) at ~800 m depth. The GSG model consists of a microzonation based on geology and a stack of soil stratigraphy for each of the 140,000 grid cells (100 m × 100 m) to which properties (VSand parameters relevant for nonlinear soil behaviour) were assigned. The GSG model serves as input to the site response calculations that feed into the Ground Motion Model. The second model is the ‘Geological model for Liquefaction sensitivity in Groningen’ (GLG). Generally, loosely packed sands might be susceptible to liquefaction upon earthquake shaking. In order to delineate zones of loosely packed sand in the first 40 m below the surface, GeoTOP was combined with relative densities inferred from a large cone penetration test database. The marine Naaldwijk and Eem Formations have the highest proportion of loosely packed sand (31% and 38%, respectively) and thus are considered to be the most vulnerable to liquefaction; other units contain 5–17% loosely packed sand. The GLG model serves as one of the inputs for further research on the liquefaction potential in Groningen, such as the development of region-specific magnitude scaling factors (MSF) and depth–stress reduction relationships (rd).

An improved correlation between shear-wave velocity VS and cone penetration test (CPT) parameters was derived for the Groningen region, the Netherlands, using a set of 154 pairs of CPTs and seismic CPTs. An analysis of a high-quality subset showed that the subdivision into Holocene versus Pleistocene intervals or into cohesive versus non-cohesive intervals did not significantly improve correlation, nor did filtering out of the transition intervals between clay and sand in the non-cohesive dataset. In addition, using qt or qc resulted in similar regression results. We therefore propose a single new equation and we applied this to all available CPTs in the region. The analysis of the fitting bias showed that there is a trend relative to the measured VS. We therefore recommend performing SCPT measurements when very soft soils (VS The comparison of the VS30 values from CPTs to the model VS30 of Groningen shows that correlation is excellent: 90% of the calculated VS30 values from the CPTs fall within one standard deviation of the VS30 of the corresponding geological zone of the model. Although the resulting CPT-VS correlation is specific for the Groningen region, the approach can be applied to other regions with a paired SCPT-CPT dataset.

Although there is evidence to suggest that adolescents with autism spectrum disorder (ASD) have difficulty interpreting complex social situations, little is known about their understanding of bullying. Given the high rates of victimization in this population, it is important to investigate how adolescents with ASD comprehend bullying. Male adolescents with ASD and IQ-matched typically-developing (TD) controls (Mage = 14.62, SD = 1.91) watched six videos portraying bullying scenarios and were interviewed after each video. The interviews were coded for the participants’ understanding of the bullying scenarios. Results indicated that adolescents with ASD had significantly lower bullying understanding scores than TD adolescents. These novel findings suggest that male adolescents with ASD understand bullying differently than their TD peers. Implications for experiences with victimization are discussed.

The present study examined the association between trait emotional intelligence (TEI) and ADHD symptomatology in samples of 1388 adolescents (ages 14–17 years) and 3313 young adults (ages 18–24 years). Consistent with the notion that difficulties in emotion processing and affect regulation are important features of ADHD, TEI was found to be a moderate to strong predictor in both samples. The TEI dimensions of stress management and adaptability uniquely predicted both hyperactivity–impulsive and inattentive symptomatology for both samples. Implications are discussed in terms of the usefulness of the TEI framework for enhancing understanding of the socio-emotional difficulties associated with ADHD symptoms and for informing interventions and coping strategies.

Building upon work by Rasmussen and Eisen, our group has proposed a model comprising two core motivational dimensions underlying obsessive-compulsive symptoms: harm avoidance and incompleteness. The model has received increasing attention; however the structural soundness and divergence of its factors are yet to be investigated fully, either as symptom-specific motivations for clinical OCD symptoms or as stylistic traits in the nonclinical population. This paper presents four studies designed to investigate the structural validity of harm avoidance and incompleteness in clinical and nonclinical samples. Results yielded support across the method of assessment (interview, questionnaire), level of generality (symptom-specific state, trait), and population (clinical, nonclinical). Evidence was also found of the model׳s method invariance, with both factors strongly self-associated across method forms when ascertained as symptom-specific motivations. The results provide support for key assertions of the core dimensions model and also point to the utility of the interviewer-rated and questionnaire measures developed during this work: the Obsessive-Compulsive Core Dimensions Interview (OC-CDI) and Core Dimensions Questionnaire (OC-CDQ). Clinical and theoretical implications and challenges for future research are discussed.

The present study examined pragmatic language and executive functions (EF) as predictors of peer victimization in three groups: high-functioning adolescent boys with an Autism Spectrum Disorder (ASD) (n = 30); typically developing adolescent boys (n = 40); and adolescent boys (n = 22) without ASD with special education needs (SN). Controlling for age and bullying others, regression analyses revealed EF as measured by the Behavior Rating Inventory of Executive Functioning (Gioia et al., 2000) to be a significant predictor across all types of peer victimization (physical, social, and verbal) regardless of group membership. It is concluded that EF may play a pivotal role in explaining why some SN adolescents with and without ASD are at-risk for peer victimization.

Objective To validate a fully automated scoring algorithm for the Rey-Osterrieth Complex Figure Test (ROCFT) by comparing the scoring results of the algorithm to the results of human raters. Method The algorithm consisted of a cascade of deep neural networks which were trained on human rater scores to extract the 18 segments of the figure, and to quantify the patient’s performance. Algorithm results were compared to six expert raters for 303 drawings. We tested whether the average correlation between algorithm scores and scores by all human raters was equivalent to the average inter-rater correlation (with equality bound Δr < .05). The immediate and delayed recall trial were used; the copy trial showed a strong ceiling effect. Results The mean Pearson correlation between raters was .94 (SD = 0.01). The correlation between to algorithm and the raters was .88 (SD = 0.02). A two-one-sided t-tests (TOST) equivalence test showed that these correlations were not strictly equivalent, t(5) = 4.02, p = .995, 95% CI [0.35, 0.52]. Conclusions Although not strictly equivalent to human ratings, the algorithm’s performance is high, approaching a level of reliability found among human raters. We expect that improved individual segment detection will bring the algorithm scoring accuracy on par with that of human raters. Algorithmic scoring of the ROCFT will likely save valuable time and lead to higher levels of standardization in clinical practice.

The study examined the relationship between emotional intelligence (EI) and several addiction-related behaviours (gambling problems, Internet abuse, and computer gaming misuse) in two adolescent samples: 270 clinical outpatients (180 males and 90 females) and 256 special needs students (160 males and 96 females). Gambling problems, Internet abuse, and computer gaming misuse were positively inter-correlated in both samples; approximately half of the variability in these addiction-related behaviours could be accounted for by a common dysfunctional preoccupation latent variable. Latent variable path analysis found emotional intelligence to be a moderate predictor of dysfunctional preoccupation in both adolescent samples.

Being victimized by one's peers is a major problem in adolescence, and research has suggested that individuals with autism spectrum disorders (ASD) may experience higher rates of bullying than their typically-developing (TD) peers. However, it is currently unclear whether adolescents with ASD are victimized more by their peers simply because they are ‘different’. This study was designed to examine percentage rates across different types of bullying behaviour in adolescents with an ASD (n = 24), in comparison to a group of special-needs adolescents without an ASD (n = 22), and a group of typically developing peers (n = 24), to determine whether simply being ‘different’ leads to higher rates of victimization. We also examined the agreement between parental and self-reports of bullying behaviour experienced by these groups. Overall, more adolescents with ASD reported victimization than adolescents in the other two groups. In addition, those with ASD reported more social bullying in comparison to the other two groups and more physical bullying than the TD group. No difference was found between parental and self-reports for the bullying experienced by the adolescents with ASD or special needs; however, TD adolescents reported higher levels of victimization than their parents reported for them. Contributing factors for the victimization experienced by adolescents with an ASD are discussed.

The obsessive-compulsive behaviors central to Obsessive-Compulsive Disorder (OCD) are not uncommon in Autism Spectrum Disorders (ASD), however the association between these disorders is not yet clear. One construct which may be useful in delineating their overlapping characteristics is “Incompleteness” or a sense of things feeling “not just right”. Incompleteness has been related to a constellation of symptoms in OCD, but its association with ASD has not yet been examined. In this study parents with two or more children with ASD (P-MC) ( n =115) were compared to an independent sample of parents having a single child with an ASD (P-SC), matched by age and gender, on level of Incompleteness. Results indicate that P-MC parents scored significantly higher in Incompleteness than P-SC parents. Incompleteness scores were also associated with a profile of behaviors in their children with ASD ( n =357) characterized by high scores on the empirically derived repetitive sensory motor actions and resistance to change domains of the Autism Diagnostic Interview-Revised ( Cuccaro et al., 2003 ). We discuss the implications of Incompleteness found in parents of children with an ASD, as well as its utility as a possible endophenotype for both ASD and OCD.

This study examined the associations between clinical anxiety, domains of emotional intelligence (EI), and three clinician-rated indices of maladjustment. Of key interest was whether social phobia (SP) is unique among anxiety disorders in being characterized by lower levels of Interpersonal and, particularly, Intrapersonal EI, and whether these differentially predict maladjustment. Individuals with SP (n = 169) obsessive-compulsive disorder (n = 65) and panic disorder (n = 64), and nonclinical controls (n = 169) completed the short form self-report Emotional Quotient Inventory (EQ-i: S). All anxiety disorder groups showed lower total EI than controls, and differed among themselves with the SP group displaying the lowest levels of total EI and lower scores on two EQ-i:S subscales (Interpersonal and, more robustly, Intrapersonal). The Intrapersonal dimension alone predicted all indices of greater maladjustment in the SP group. These findings indicate a negative relationship between anxiety disorders and EI, and reaffirm the foremost link between Intrapersonal EI and SP and its functional outcomes.

There has been no published investigation made of the relationship between social anxiety and emotional intelligence (EI), or of their shared impact upon interpersonal adjustment. This study examined these questions using structural equation modeling with self-report data from a large nonclinical sample (N = 2629). EI was found to be highly related to social interaction anxiety, but not performance anxiety. A model permitting these three predictors to inter-correlate indicated that the EI factor was the dominant predictor of interpersonal adjustment, substantially reducing the unique contribution made by interaction anxiety. This pattern reflected the principal contributions made to interaction anxiety by the interpersonal and, particularly, intrapersonal domains of EI.

The present study examined the link between problematic gambling and gambling related cognitions (GRCs) in a large sample of adolescents with (N = 266) and without (N = 1,738) special education needs (SEN) between the ages of 14 and 18 years attending several high schools in eastern central Ontario. The adolescents with SENs were identified as having various learning disorders and/or internalizing and externalizing problems [e.g., attention deficit hyperactivity disorder (ADHD)]. All adolescents completed a self-report questionnaire package that included the GRC Scale (GRCS; Raylu and Oei in Addiction 99:757-769, 2004), as well as measures of problem gambling, negative affect, and ADHD symptomatology. Results showed that adolescents with SEN hold more erroneous beliefs about gambling and had a higher risk of developing problematic patterns of gambling behaviour than their typically developing peers. Moreover, the GRCS subscales were found to be strong predictors of problem gambling among adolescents both with and without SEN, accounting for a substantial amount of the variance even when controlling for the effects of age, gender, ADHD, and negative affect. It is suggested that intervention and prevention programs aimed at adolescent gambling need to give particular attention to those with SEN.

The present study examined the factor structure of the Gambling Related Cognitions Scale (GRCS); (Raylu and Oei in Addiction 99:757–769, 2004) in a large sample of adolescents (N = 1,490) between the ages of 16 and 18 years (630 males, 860 females) attending several high schools in central Ontario. Problem gambling was measured using the DSM-IV-J (Fisher in J Gambl Stud 8:263–285, 1992). A 5-factor GRCS model was found to have the best fit to the data, and gambling-related cognitions were found to be powerful predictors of disordered gambling among adolescents. However, strong associations among GRCS subscales, as well as the small amount of variance in problem gambling accounted for by specific GRCS subscales, call into question the multidimensionality of the GRCS when used with adolescents.

The present study examined the prevalence of disordered gambling behaviours in a community-based sample of adolescents (N = 532) living in eastern central Ontario. Of particular interest was examining the hypothesis that adolescents with learning disorders are at elevated risk for disordered gambling. Rates of disordered gambling in male adolescents with learning disorders were found to be significantly higher than adolescents without learning problems, even after controlling for negative affectivity and ADHD symptomatology. The implications for treatment and intervention of gambling problems in adolescence are discussed.

Two issues regarding academic and intellectually gifted children are debated to this day. The first concerns the social-emotional competency of gifted children and the second focuses on the question of what is the most appropriate educational setting to support the academic and personal development of these children. Self, teacher and parent ratings of emotional intelligence (EI) were obtained from samples of gifted children in both special and regular class programs and a group of matched average ability and average achieving students in grades 4-8. While a number of small but statistically significant differences were obtained between the groups on the various EI subscales, gifted children tended to show well developed EI competencies, whether in regular or segregated classes, and compared with average ability students.

We report the case of a 56-year-old postmenopausal woman who was referred to our Endocrinology Outpatient Clinic because of severe hyperhidrosis. She had a four-year history of excessive sweating of her face and upper body. On presentation no sweating could be documented. Physical examination was also unremarkable. It appeared that five days earlier her general practitioner had prescribed oxybutynin for urge incontinence and this accidentally cured her hyperhidrosis. She was diagnosed with idiopathic hyperhidrosis. We advised her to continue the oxybutynin and six months later, she was still symptom-free. Oral anticholinergic drugs are known to be effective for hyperhidrosis, but only anecdotal reports on oxybutynin can be found in the literature. Oxybutynin is not approved for hyperhidrosis, explaining the unfamiliarity with this medicine. This case shows that oxybutynin can be a very effective and simple treatment with only mild side effects. Therefore, oxybutynin merits consideration in patients with idiopathic hyperhidrosis. This report includes a concise review of the causes and treatment options of hyperhidrosis.

In 1986 the International Association of Hydrological Sciences published a volume on “Developments in the analysis of groundwater flow systems” (Engelen & Jones eds., 1986). That volume presented an overview of concepts and case studies evolving from the fundamental ideas of Toth on the hierarchical nesting of gravity-driven groundwater flow systems.

Groundwater conditions in extensive humid tropical coastal lowlands such as found along the northern side of the island of Java, are closely related to the overall clayey and silty character of the sediments. The ample supply of suspended sediments in the present-day tropical humid and monsoonal setting is sufficient to result in a net outbuilding of coastal lowlands in a shallow marine and deltaic environment. Hydraulic gradients are far too small and permeabilities are usually too low, to ensure adequate flushing by groundwater flows of the recently deposited marine and deltaic sediments. In general, when marine and deltaic sediments predominate, fairly unfavourable groundwater conditions are met. Shallow and deep groundwaters may be highly mineralised (TDS up to several grams per litre) and mostly unfit for human or livestock consumption, even at great distances from a present-day coastline.

The study “Optimisation of water management in the Wierden area” by Hoogendoorn & Te Stroet (1993) represents the most detailed and applied step in the (eco-)hydrological systems analysis of the region Twente. The area of 20 × 20 = 400 km2 is located in the Regge valley, east of the city of Almelo, between the eastern and western complexes of ice-pushed ridges of the province Overijssel (see figure 14.1).

Toth has gradually extended his concept of a hierarchy of flow systems, originally developed for small drainaige basins, to large sedimentary basins with large width-, depth- and time scales, for instance the study of gravity-induced cross-formational flow of formation fluids in the Red Earth Region of Alberta, Canada (Toth, 1978) and the study of oil deposits in the Upper Rhine Graben (Toth and Otto, 1989)

The Netherlands are tectonically positioned at the southern end of the North Sea Basin (see figure 7.1). This Basin dates from Cenozoic times. Near the area of the Netherlands it becomes narrow and grades into the NW-SE trending Ruhr Graben structures which in turn are connected to the Rhine Graben. South of the Netherlands the stable Brabant Massif forms a border of the North Sea Basin. Graben and horst structures, some of which are still tectonically active, are frequently found in the subsoil. During the Quaternary the fault systems have been very active. Thicknesses of the Quaternary series are therefore characterised by strong differences especially in the southern parts.

The man-made fresh Lake IJssel resulted in 1932 from barring the inland branch Zuyder Sea from the North Sea basin by a barrier dam. It covers a large part of the central area of the Netherlands (see figure 10.1).

Water resources management, nature conservation and environmental legislation in general have become very complex in recent years, in particular in industrialised countries. Environmental legislation has developed into a difficult and unpleasant task to many planners at national, regional and local governmental levels, because of the need to reconcile the interests of different users with the functions of certain elements of the hydrological cycle. Groundwater supply for industries and drinking water, nature conservation, recreation, agriculture, pollution control, etc. are examples of such rivalling users with often strongly conflicting interests. Planners, managers and legislators are faced with the difficult task of finding both realistic and economically feasible solutions which hopefully satisfy the needs and demands of all involved parties. Furthermore, thanks to the publicity on ecology and environment, the general public has become aware of the ongoing deterioration of ecosystems and of groundwater quality and is urging policy makers to take firm action.

In Poland a fairly complete sequence of Late Precambrian to Cenozoic sediments has been deposited on two fringing cratons. In the Northeast the sediments are underlain by the ancient stable East European Platform and in the Southwest by the Variscan Central European Platform. In the south, bordering the Czech republic, the Carpathian Mountain range is found forming the frontier of the Alpine Orogeny in this region. Post-Cambrian tectonic movements in Poland were largely confined to a narrow rifting zone along the bordering margins of the East and Central European crustal Platforms which gave rise to the long NE-SW trending Mid-Polish Trough. From Permian until Late Cretaceous times the trough became filled with a thick pile of sediments. Afterwards in early Tertiary times inversion took place and folding of the 10 km thick sedimentary fill occurred forming the Mid-Polish Anticlinorium.

In descriptions of indigenous flora of the Netherlands special codes have been attributed to all plant species. These codes refer to the preference of species for specific ecosystems. Initially (Van der Maarel, 1971), the coding system was strongly related to the position of the plant species in the plant-sociological classification system (Westhoff & Den Held, 1969). In the 1970’s the coding system was revised and more ecologically oriented (Arnolds & Van der Meijden, 1976). Still objections to this system were voiced concerning the ecological amplitude and the poor relation with abiotic factors. In 1982 the Centre for Environmental Studies (CML) of the State University of Leiden designed a preliminary structure for a national ecotope system (Everts et al., 1982). In 1987 the new ecotope typology was extended (Stevers et al., 1987). CML and the National Herbarium of the State University of Leiden used this new system to generate new codes for wild plant species in the Netherlands (Runhaar et al., 1987).

The ever increasing use of water by competing users leads more and more to shortages of water. Insufficient water at the right time in the right place and with the right quality necessitates increasing sophistication in water resources management world-wide. Depending upon the natural availability of water and the socioeconomic development of a region or country different stages in analysis, planning, use and management can be discerned.

The report deals with reconnaissance survey of the hydrological systems at the scale 1:100,000 in the region Twente in the province of Overijssel in the eastern part of the Netherlands (see figure 11.1). The region of approximately 50 × 25 km has a diversified topography of glacial, eolian and fluvial origin with a number of existing and potential nature reserves. National, provincial and local authorities, public companies and private organisations and landowners have an interest in an integrated approach to water management from regional, down to local scales. The main focus of the report is on background information for policy formulation and management of existing and designated or potential nature reserves.

In “Effects of interventions in the groundwater systems in the Regge valley” by Gieske (1990) the first part of the second phase in the eco-hydrological systems analysis of the region Twente is presented. After the regional reconnaissance of the hydrological systems of the region Twente at the scale 1:100,000 in the first phase, in the second phase the Regge valley was studied more in detail by flow systems modelling at the scale 1:50,000. The Regge valley is located in the western part of the region Twente within the province of Overijssel. The modelled area has a size of 16,5 × 24 km.

In “Hydrological systems analysis of the Dinkel valley/Borne creek area” by Hoogendoorn (1992) the second part of the second phase in the eco-hydrological systems analysis of the region Twente is presented. The area was studied, as a follow up to the reconnaissance study of the first phase, by flow systems modelling at the scale 1:50,000.

Water is one of the key factors for a sustainable development in Europe (OECD, 1989; Van der Ven and Kohsiek, 1991; United Nations, 1991; Fried 1992; Engelen, 1992). The complex of relations requires an integrated, holistic approach (IIASA, 1991). There are many different sources of supply with time-dependent quantity- and quality characteristics on the one hand and many demand and use sectors, nature conservation, agriculture, industry, public water supply and navigation, on the other hand.

The provincial government of Drenthe needed a clarification on the desired (“optimal”) groundwater levels in the province for its provincial water management plan, given the national and provincial policy to combat damage to nature from decreasing groundwater levels. The purpose of the study was: 1. to establish the present groundwater situation; 2. to search for trends in the groundwater situation; 3. to substantiate which human factors cause the groundwater situation and how those factors could be modified to improve the situation.

In 1989 TNO-IAG published the last sheet of the “National Groundwater Map of the Netherlands” at a scale 1:50,000. This large project was initiated by the institute in the 1960’s and financed by: Ministry of Transport, Public Works and Water Management; Ministry of Housing, Physical Planning and Environment; Ministry of Agriculture, Nature Management and Fisheries.

In the south and south-eastern parts of the Netherlands, situated on the Pleistocene coversands much groundwater is abstracted for drinking water and industrial purposes. Just across the border in neighbouring Germany lignite is being mined in huge open pits, measuring depths up to 400 m below ground level. The amount of groundwater which has to be pumped to allow mining of the Miocene lignite layers at the bottom of the pits equals about 1000 million m3 per year. This huge amount of pumped groundwater matches the total annual production of drinking water in the Netherlands. It is not surprising that the influences of the strongly depressed piezometric heads around the open lignite mines are also noticeable in the southern part of the Netherlands, in particular in the Central Graben. The Central Graben forms the tectonic continuation of the Ruhr Graben in Germany, developed from Miocene times onwards, in which the lignites were deposited in thick layers following the tectonic subsidence (see figure 7.1 in chapter 7).

An enquiry using a structured questionnaire was conducted among all 6300 GPs in the Netherlands in order to assess the distribution of HIV-related problems over general practices in the Netherlands and the influence on it of the use of the 'HIV-wijzer voor de huisarts', a loose-leaf handbook on HIV, distributed since 1988 among all Dutch general practitioners. The enquiry was conducted one year after its publication. The 2156 respondents (34%) appeared to be reasonably representative of all GPs. The results show minor imperfections because a small proportion of the questionnaires was filled out incompletely. Almost 90% of respondents mentioned HIV-related consultations, 24% had HIV-seropositive patients and 18% had AIDS patients. These numbers were correlated mainly with municipality size, less with region. The use of the 'HIV-wijzer' was related to occurrence of HIV-related consultations and AIDS patients in a practice. GPs who do not encounter these problems are little motivated to read the 'HIV-wijzer'. For them, other means of education have to be developed or HIV has to be included in existing education programmes on other subjects.

Signals from an explosive source backscattered from the seafloor and received at long range by hydrophones of a towed array are processed to estimate the directional distribution of energy for a given time increment. As assembly of these data shows the time and amplitude of scattering features, and after conversion to distance, the geographic location of the return. A frequency-domain beam-forming procedure is used in which beam levels are averaged over a given band of a broad-band source. The processing is applied to experimental data obtained in the southern Tyrrhenian Sea. The major backscattering occurred at the Baconi Seamounts and the coastal margin of Sardinia.