s-Hertogenbosch, Netherlands

HAS Den Bosch University of Applied Sciences

www.hasinternational.nl/
s-Hertogenbosch, Netherlands

HAS University of Applied science is an independent university of applied science, specialising in agriculture, horticulture, food, nature conservation and environment. It is located in 's-Hertogenbosch, the regional capital of North Brabant, and accredited by the Dutch Flemish Accreditation Organisation. In 2013 there were around 2400 students enrolled at HAS University of Applied science. Wikipedia.

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Winfield I.J.,Lake Ecosystems Group | van Rijn J.,HAS Den Bosch University of Applied Sciences | Valley R.D.,Navico Inc. 1229 Tyler St. NE and 120
Ecological Informatics | Year: 2015

Accurate information on the location and condition of spawning grounds of environmentally-demanding lithophilic fish species, which may use only a very small area of their habitat for spawning, is critical to their conservation and fisheries management but is frequently lacking. Here, the new hydroacoustic system BioBase, which enables the rapid characterisation of features including lake bottom hardness (with soft, medium hard and hard bottoms represented by values of 0 to 0.25, 0.25 to 0.40, and 0.40 to 0.50, respectively), was applied to known spawning grounds of Arctic charr (Salvelinus alpinus) in the north basin of the eutrophicated lake of Windermere, U.K. The output of BioBase was successfully ground-truthed using an independent video-based system (r2 =0.48, F=17.705, p<0.001) and depth and bottom hardness descriptive statistics were produced for six spawning grounds. Average depth ranged from 9.4m (North Thompson Holme) to 38.5m (Balla Wray), while average bottom hardness ranged from 0.254 (Low Wray Bay) to 0.303 (North Thompson Holme). Detailed visual outputs were also produced for contrasting shallow (North Thompson Holme) and deep (Holbeck Point) spawning grounds, both of which showed high within-site spatial variation in bottom hardness and thus in suitability for spawning. Findings were consistent with earlier, less quantitative, interpretations of the possible effects of eutrophication and associated increased deposition of fine sediments on local Arctic charr reproduction. © 2015 Elsevier B.V.


Staats W.T.,HAS Den Bosch University of Applied Sciences | Regan E.C.,National Biodiversity Data Center | Regan E.C.,World Conservation Monitoring Center
Journal of Insect Conservation | Year: 2014

The Irish Butterfly Monitoring Scheme started in 2007. The main objective of this study was to examine initial population trends from data gathered over 5 years (2008-2012) by approximately 150 volunteers across the Republic of Ireland. Nine of the 15 species analysed showed changes in population over the 5-year period; three species showed steep or moderate increases while six species showed moderate or steep declines in population. Some of these population changes are due to the highly variable weather conditions over the five years of monitoring, particularly the unusually cool, wet summer of 2012. However, factors affecting butterfly population trends are many and varied, so longer-term data are required to assess trends more reliably. A further six species had indeterminate trends over the 5-year period however, as the scheme develops, longer-term trends will have greater statistical reliability and give a clearer insight into Irish butterfly populations. The Irish Butterfly Monitoring Scheme is important in the national context, as there is little other countrywide systematic monitoring of insect populations. Furthermore, with a growing number of such standardised monitoring schemes internationally and development of bioindicators, it is now possible to monitor and track butterfly populations at larger spatial scales. We recommend that the Irish Butterfly Monitoring Scheme is continued over the long term and expanded to ensure that more Irish butterfly species are sufficiently monitored. However, in addition to monitoring population trends, basic research is still needed into the ecology and population dynamics of common butterfly species. © 2014 Springer International Publishing Switzerland.


Miller H.,UK National Oceanography Center | Winfield I.J.,UK Center for Ecology and Hydrology | Fletcher J.M.,UK Center for Ecology and Hydrology | Ben James J.,UK Center for Ecology and Hydrology | And 3 more authors.
Ecology of Freshwater Fish | Year: 2015

Spawning is a key but often fragile event in the life cycles of fish populations. Nevertheless, it has been relatively little studied for lithophilic lacustrine species requiring hard spawning substrates, such as gravels or stones, largely devoid of fine sediments. Twelve demonstrated or putative spawning grounds of Arctic charr (Salvelinus alpinus) in shallow and deep areas of the north and south basins of the eutrophicated lake of Windermere, UK, were described by hydroacoustic, physical and visual surveys. In addition, their current conditions were compared with their original qualitative descriptions made over 50 years ago. Spawning ground characteristics were found to be more complex than originally described, with considerable overlaps in depth ranges and only limited areas of appropriate hard substrates. Moreover, extensive gill netting surveys in recent years have found spawning Arctic charr at only seven of the original 12 demonstrated or putative spawning grounds, although several new spawning areas have also been found. The distribution of unsuitable fine sediments is widespread in the lake, particularly in the more eutrophicated south basin where suitable spawning habitat within the putative spawning areas is limited. Windermere faces a number of environmental problems including climate change and species introductions. However, the temporal and spatial patterns of the lake's eutrophication suggest that associated increases in fine sediments have been a major driver of the observed deterioration of Arctic charr spawning grounds and so may have also contributed to a marked decline recently observed in the local abundance of this species. © 2014 John Wiley & Sons A/S.


Rimbach R.,University of Witwatersrand | Willigenburg R.,University of Witwatersrand | Willigenburg R.,HAS Den Bosch University of Applied Sciences | Schoepf I.,University of Witwatersrand | And 4 more authors.
Ethology | Year: 2016

An individual′s survival and fitness depend on its ability to effectively allocate its time between competing behaviors. Sex, social tactic, season and food availability are important factors influencing activity budgets. However, few field studies have tested their influences. The African striped mouse (Rhabdomys pumilio) lives in highly seasonal habitats in southern Africa, and individuals can adopt different social tactics. We investigated seasonal changes in activity budgets of different tactics and predicted that individuals will reduce their activity in the non-breeding season to save energy when food availability is low and that young non-breeding adults (‘philopatrics’) invest mainly in activities related to gaining body mass to increase survival probability. We predicted old adults (‘breeders’), which bred during the previous breeding season, to invest mainly in maintenance of their social status. We conducted 90 focal observations during the non-breeding season and 73 during the breeding season. Activity budgets of striped mice were season and tactic specific, with philopatrics, but not breeders, reducing activity when food availability was low, possibly to decrease energy expenditure. Philopatrics of both sexes foraged and basked more in the breeding season than during the non-breeding season. Male philopatrics gained body mass and female philopatrics maintained their body mass in both seasons. Sex-specific differences occurred during the breeding season, when female breeders foraged more than male breeders, while male breeders chased other individuals more than female breeders. These findings indicate that individuals adopting different social tactics display distinct behaviors to fulfill tactic-specific energetic needs. © 2016 Blackwell Verlag GmbH


Tinus T.,HAS Den Bosch University of Applied Sciences | Damour M.,Institute National Dhorticulture Et Of Paysage | Van Riel V.,HAS Den Bosch University of Applied Sciences | Sopade P.A.,University of Queensland
Journal of Food Engineering | Year: 2012

The kinetics of starch and protein digestion in hammer- and cryo-milled cowpea (70-370 μm) were investigated. The pH during the protein digestion reduced with time, and both the starch and protein digestion exhibited monophasic digestograms, which were suitably (r 2 > 0.97, p < 0.001) described by a modified first-order kinetic model. The in vitro protein digestibility of the cowpea (>80%) was independent of the milling conditions. The hammer-milled cowpea digested more, but the reciprocal of its rate of protein digestion was independent of the square of the particle size. The rate of protein digestion in the cryo-milled cowpea inversely depended (p < 0.05) on the square of the particle size, with 67 × 10 -7 cm 2 s -1 as the diffusion coefficient. For the starch digestion, diffusion coefficients (cm 2 s -1) were 0.6 × 10 -7 (hammer-milled) and 0.3 × 10 -7 (cryo-milled). The protein digestion proceeded at a much faster (100×) rate than the starch digestion. © 2012 Elsevier Ltd. All rights reserved.


Sheppard L.J.,UK Center for Ecology and Hydrology | Leith I.D.,UK Center for Ecology and Hydrology | Leeson S.,UK Center for Ecology and Hydrology | Mizunuma T.,University of Edinburgh | And 3 more authors.
Biogeochemistry | Year: 2013

Wet N deposition comprises oxidised (nitrate) and reduced (ammonium) N forms in proportions that vary spatially with source and topography. Field evidence of long-term N form effects on semi-natural ecosystems and how these are modified by phosphorus and potassium availability are lacking. This study describes cover changes for some key peatland species and litter chemistry from Sphagnum capillifolium, Calluna and Eriophorum vaginatum, and peat in response to 9 years of N treatment. Ammonium and nitrate as NH4Cl or NaNO3 were provided to replicate plots in rainwater spray at +8 (low) or +56 (high) kg N ha-1 year, with and without PK via an automated system coupled to site meteorological conditions. Reduced N caused greater N accumulation in all key species than oxidised N, especially at higher doses, but cover declined more, though not significantly so, with oxidised than reduced N at the high N dose. Overall the detrimental effects of high N on Sphagnum and Calluna cover were significant but small. By comparison PK inclusion with 56 kg N ha-1 year as oxidised N, not reduced N, had devastating effects on cover, causing both S. capillifolium and Calluna to decrease 3-5-fold, facilitating invasion and expansion of nitrophiles, non-characteristic bog plants e.g. Epilobium angustifolium, Epilobium palustre, Juncus effusus, Digitalis purpurea and Dryopteris dilatata. N form appears to be significant for peatlands because of its effects on pH. The significance of changes in plant cover for peat chemistry and decomposition for biogeochemistry is discussed. © 2013 Springer Science+Business Media Dordrecht.


Winfield I.J.,UK Center for Ecology and Hydrology | van Rijn J.,HAS Den Bosch University of Applied Sciences | Valley R.D.,Navico Inc
Ecological Informatics | Year: 2015

Accurate information on the location and condition of spawning grounds of environmentally-demanding lithophilic fish species, which may use only a very small area of their habitat for spawning, is critical to their conservation and fisheries management but is frequently lacking. Here, the new hydroacoustic system BioBase, which enables the rapid characterisation of features including lake bottom hardness (with soft, medium hard and hard bottoms represented by values of 0 to 0.25, 0.25 to 0.40, and 0.40 to 0.50, respectively), was applied to known spawning grounds of Arctic charr (Salvelinus alpinus) in the north basin of the eutrophicated lake of Windermere, U.K. The output of BioBase was successfully ground-truthed using an independent video-based system (r2=0.48, F=17.705, p<0.001) and depth and bottom hardness descriptive statistics were produced for six spawning grounds. Average depth ranged from 9.4m (North Thompson Holme) to 38.5m (Balla Wray), while average bottom hardness ranged from 0.254 (Low Wray Bay) to 0.303 (North Thompson Holme). Detailed visual outputs were also produced for contrasting shallow (North Thompson Holme) and deep (Holbeck Point) spawning grounds, both of which showed high within-site spatial variation in bottom hardness and thus in suitability for spawning. Findings were consistent with earlier, less quantitative, interpretations of the possible effects of eutrophication and associated increased deposition of fine sediments on local Arctic charr reproduction. © 2015 Elsevier B.V.


Roelofs J.,Wageningen University | Roelofs J.,HAS Den Bosch University of Applied Sciences | Lopez-Gatius F.,University of Lleida | Hunter R.H.F.,Leibniz University of Hanover | And 2 more authors.
Theriogenology | Year: 2010

Good detection of estrus is critically important in dairy husbandry. Incorrect detection of estrus is related to loss of profit due to extended calving intervals, milk loss, veterinary costs, etc. Detection of estrus remains a major problem despites enormous progress in the knowledge of reproductive physiology of the cow and in development of estrus detection aids. To achieve good estrus detection, many factors have to be taken into account. On one hand a cow has to express estrus and on the other hand the farmer has to detect it. Combined action of several hormones causes physiological changes that lead to ovulation and an environment in the uterus that allows sperm to fertilize the egg. Besides these internal actions, a number of external changes can be observed. When using visual observations, time of the day and time spend on observation have a great impact on detection rates. Many devices are available to aid in estrus detection, such as pedometers, mount devices, temperature, and hormone measurements. Expression of estrus can be influenced by many factors. Heritability, number of days postpartum, lactation number, milk production, and health are known to influence estrus expression. Environmental factors like nutrition, season, housing, herd size, etc. also play a role in estrus expression. To evaluate estrus detection, record keeping is very important; a number of formulas can be used to assess detection efficiency. Besides the farmer, the veterinarian and inseminator can play an important role in estrus confirmation and good insemination strategy. In the end, the time of ovulation and the age of the egg at sperm penetration is critical for conception. Therefore, emphasis in research needs to be on the timing of insemination relative to ovulation, and thus on the detection of ovulation. © 2010 Elsevier Inc.


de Cocq P.,Wageningen University | de Cocq P.,HAS Den Bosch University of Applied Sciences | Mariken Duncker A.,VU University Amsterdam | Clayton H.M.,Michigan State University | And 3 more authors.
Journal of Biomechanics | Year: 2010

In equestrian sports, it is generally assumed that rising and sitting trot load the horse's back differently. The objective of this study was to quantify the load on the horse's back in these riding techniques. Kinematic data of 13 riders were collected in rising and sitting trot. The time-history of the position of the rider's centre of mass (CoM) was calculated, and differentiated twice to obtain the acceleration of the CoM. The reaction force between the rider and the horse's back was calculated from the acceleration. Forces were divided by the body weight of the rider to obtain dimensionless forces. As expected, the computed average vertical force did not differ between riding techniques and was not significantly different from the body weight of the riders. At trot, two force peaks were present during one stride cycle. Both peaks in rising trot were significantly lower compared to sitting trot (peak 1: 2.54±0.30 versus 2.92±0.29; p<0.001; peak 2: 1.95±0.34 versus 3.03±0.32; p<0.001). This supports the general assumption that rising trot is less demanding for the horse than sitting trot. © 2009 Elsevier Ltd.


van Beek F.E.,Wageningen University | de Cocq P.,Wageningen University | de Cocq P.,HAS Den Bosch University of Applied Sciences | Timmerman M.,Dutch Equestrian Vocational Center | Muller M.,Wageningen University
Veterinary Journal | Year: 2012

Injuries of horses might be related to the force the rider exerts on the horse. To better understand the loading of the horse by a rider, a sensor was developed to measure the force exerted by the rider on the stirrups. In the study, five horses and 23 riders participated. Stirrup forces measured in sitting trot and rising trot were synchronised with rider movements measured from digital films and made dimensionless by dividing them by the bodyweight (BW) of the rider. A Fourier transform of the stirrup force data showed that the signals of both sitting and rising trot contained 2.4 and 4.8. Hz frequencies. In addition, 1.1 and 3.7. Hz frequencies were also present at rising trot. Each stride cycle of trot showed two peaks in stirrup force. The heights of these peaks were 1.17 ± 0.28 and 0.33 ± 0.14 in rising and 0.45 ± 0.24 and 0.38 ± 0.22 (stirrup force (N)/BW of rider (N)) in sitting trot. A significant difference was found between the higher peaks of sitting and rising trot (P< 0.001) and between the peaks within a single stride for both riding styles (P< 0.001). The higher peak in rising trot occurred during the standing phase of the stride cycle. Riders imposed more force on the stirrups during rising than sitting trot. A combination of stirrup and saddle force data can provide additional information on the total loading of the horse by a rider. © 2011 Elsevier Ltd.

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