Measuring miniature eye movements by means of a SQUID magnetometer

A new technique to measure small eye movements is reported. The precise recording of human eye movements is necessary for research on visual fatigue induced by visual display units.1 So far all methods used have disadvantages: especially those which are sensitive or are rather painful.2,3 Our method is based on a transformation of mechanical vibrations into magnetic flux variations. In order to do this a small magnet is embedded in a close-fitting soft contact lens. The magnetic flux variations caused by eyeball movements during fixation are measured by means of a SQUID magnetometer. The recordings show the typical fixation pattern of a human eye. This pattern is composed of three kinds of movements: saccades, drift and microtremor. The last-mentioned type of movements are displacements in the order of 2 μm. It is possible to distinguish between movements which are perpendicular to each other

Verbreding Europees natuurbeleid

Een EU natuurbeleid heeft voordelen, maar houdt ook risico's in. Dit doordat het sectoraal, centralistisch en juridisch gericht is. De risico's kunnen worden verminderd door een verbreding van het EU natuurbelei

Stability of large vacancy clusters in silicon

Using a density-functional-based tight-binding method we investigate the stability of various vacancy clusters up to a size of 17 vacancies. Additionally, we compute the positron lifetimes for the most stable structures to compare them to experimental data. A simple bond-counting model is extended to take into account the formation of new bonds. This yields a very good agreement with the explicitly calculated formation energies of the relaxed structures for V6 to V14. The structures, where the vacancies form closed rings, such as V6 and V10, are especially stable against dissociation. For these structures, the calculated dissociation energies are in agreement with experimentally determined annealing temperatures and the calculated positron lifetimes are consistent with measurements.Peer reviewe

Costs of home care for advanced breast and cervical cancer in relation to cost-effectiveness of screening

__Abstract__ The costs of home care in the Netherlands are estimated for women with advanced breast and cervical cancer. We observe a growing role of intensive home care for the terminally ill patients. The average costs of home care are dfl 8500 per patient for breast cancer patients and dfl 7200 for cervical cancer patients. More than half of these costs are incurred in the last month before death. The level of home care in the preceding months is quite modest (dfl 120 per month for both diseases), not taking into account informal care. The costs of home care for patients with advanced cancer are only slightly related to the site of the primary tumor from which the metastases originate. Total average costs per patient during advanced disease, including hospital and nursing home care, amount to dfl 42,700 for breast cancer and dfl 29,000 for cervical cancer. This difference in costs is largely attributable to the longer duration of advanced disease for breast cancer, which substantially affects hospitalcosts. The high costs of care to patients with advanced cancer contribute to a favourable cost-effectiveness ration of those screening programmes which reduce mortality and consequently the costs of care to advanced cancer patients

Panama Viejo: an analysis of the construction of archaeological time in Eastern Panama.

The purpose of this dissertation is to demonstrate how different methods for ceramic classification can produce different chronologies, ultimately creating different historical interpretations or histories. To this end the most widespread methods for building chronology in the Americas, the "taxonomical" and the "modal" methods shall be compared using the recently excavated ceramic sample from Precolumbian Panama Viejo, one of the largest archaeological sites in Panama. It is also intended to review different conceptions of history and time because they are the theoretical background from which chronologies are built and thus have a direct impact on these archaeological histories. The site of Panama Viejo and the Eastern Region of Panama, where it is located lack a Precolumbian ceramic sequence. Building a chronology for Panama Viejo affords a good opportunity to address the problem of both the local and the regional chronologies, and also to compare both methods in every step of the chronology building process, underlining the assumptions and consequences, and the strengths and weaknesses of each method. Ultimately, it is hoped this thesis could show that both methods can be used complementarily to solve different problems, fostering a more comprehensive synchronic characterisation and a finer chronological division of ceramic assemblages. The two classifications revealed a homogeneous ceramic assemblage where continuity rather than change is the norm. It also yielded two chronologies for the site, one taxonomical with one cultural phase, and one modal with two cultural phases. These in turn gave rise to different historical accounts about the kind of behaviour that produced the pottery deposit in Panama Viejo, accounts where the difference is mostly of chronological resolution. The new ceramic data coupled with that from burial contexts helped rewrite the history of Panama Viejo, emphasising the longevity of occupation at the site by a possibly stable socio-cultural group from the mid-first millennium AD until the European Conquest

Gereformeerden en de Olympische Spelen van 1928

Religious Studie

Kroniek: Ziekmakende "spoken" in de geschiedenis van de gereformeerde kerken

Religious Studie

Hongarije als ‘troetelkind’ van Nederlandse gereformeerden

Religious Studie

De Bijbel als vrijzinnig strijdwapen en sieraad: de ontstaans- en receptiegeschiedenis van de Leidsche Vertaling (1884-1912)

Religious Studie