This paper describes advancements in recreation management using new technology that couples Geographic Information Systems (GIS) with Intelligent Agents to simulate recreation behaviour in real world settings. RBSim 2 (Recreation Behaviour Simulator) is a computer simulation program that enables recreation managers to explore the consequences of change to any one or more variables so that the goal of accommodating increasing visitor use is achieved while maintaining the quality of visitor experience. RBSim provides both a qualitative understanding of management scenarios by the use of map graphics from a GIS as well as a quantitative understanding of management consequences by generating statistics during the simulation. Managers are able to identify points of over crowding, bottlenecks in circulation systems, and conflicts between different user groups.
RBSim 2 is a tool designed specifically for the purposes of simulating human recreation behaviour in outdoor environments. The software is designed to allow recreation researchers and managers to simulate any recreation environment where visitors are restricted to movement on a network (roads, trails, rivers, etc.). The software architecture is comprised of the following components:
• GIS module to enter travel network, facilities, and elevation data
• Agent module to specify tourist personality types, travel modes, and agent rules
• Typical Trip planner to specify trips as an aggregation of entry/exit nodes, arrival curves, destinations and agents.
• Scenario designer to specify combinations of travel networks, and typical trip plans.
• Statistical module to specify outputs and summarise simulation results
This paper describes the RBSim software architecture with specific reference to the trip planning algorithms used by the recreation agents. An application of the simulator at Port Campbell National Park, Victoria Australia is described. 相似文献
The polytetrapeptide repeat of tropoelastin, Val1-Pro2-Gly3-Gly4, coacervates from aqueous solution as temperature increases. The coacervation is a cooperative process which is concentration dependent, moving the temperature profile of coacervation curves to lower temperature with high concentrations. Electron micrographs of uranyl acetate or uranyl acetate-oxalic acid negatively stained coacervated samples are characterized by filamentous structures whose center-to-center diameter is approximately 50 Å as measured with optical diffraction. Coacervation thus results in increased intermolecular order. Circular dichroism spectra in methanol and trifluoroethanol solutions are significantly different from the spectrum in water. Once coacervated, though, the polytetrapeptide gave a CD spectrum very similar to that seen in these organic solvents. The data support the point of view that coacervation is the result of hydrophobic association attending an inverse temperature transition. 相似文献
This paper describes the most common cytogenetic techniques we routinely adopt in our laboratories for producing high-resolution
banding on prometaphase stage chromosomes, from synchronized or nonsynchronized blood cultures. Special emphasis is given
to the FISH procedures applied to prometaphase chromosomes for mapping purposes. Each section includes historical information,
basic principles for the given technique, its primary use in veterinary cytogenetics, and major limitations. Supplementary
material (protocols and chemicals used) are available on our website. Even though these techniques mainly refer to the Bovidae,
they can be easily extended and adapted to members of other taxa. 相似文献
The biomechanics of body contraction in Porifera is almost unknown, although sponge contraction has been observed already in ancient times. Some members of the genus Tethya represent the most contractile poriferan species. All of them show a highly ordered skeleton layout. Based on three main spicule types, functional units are assembled, termed skeleton superstructures here. Using synchrotron radiation based x-ray microtomography and quantitative image analysis with specially developed particle and structure recognition algorithms allowed us to perform spatial allocation and 3D-morphometric characterizations of single spicules and skeleton superstructures in T. minuta. We found and analyzed three skeleton superstructures in the investigated specimen: (1) 85 megasclere bundles, (2) a megaster sphere, composed by 16,646 oxyasters and (3) a pinacoderm–tylaster layer composed by micrasters. All three skeleton superstructures represent composite materials of siliceous spicules and extracellular matrix. From structure recognition we developed an abstracted mathematical model of the bundles and the sphere. In addition, we analyzed the megaster network interrelation topology and found a baso-apical linear symmetry axis for the megaster density inside the sphere. Based on our results, we propose a hypothetical biomechanical contraction model for T. minuta and T. wilhelma, in which the skeleton superstructures restrain physical stress generated by contraction in the tissue. While skeletal structures within the genus Tethya have been explained using R. Buckminster Fullers principle of tensegrity by other authors, we prefer material science based biomechanical approaches, to understand skeletal superstructures by referring to their composite material properties.Electronic Supplementary Material Supplementary material is available to authorised users in the online version of this article at . 相似文献
Adoptive tumour infiltrating lymphocytes (TIL) in combination with a modulated dosage of interleukin-2 (IL-2) can be used
with acceptable toxicity in the treatment of immunogenic tumours. Following an experience of reinfusion in advanced melanoma,
colorectal and renal cancer patients, treatment was given to disease-free patients after metastasectomy. The high risk of
relapse and favourable ratio between reinfused TIL and possible microscopic residual disease determined this choice of adjuvant
treatment. A group of 12 patients with advanced disease (7 melanoma, 4 colorectal carcinoma, 1 kidney carcinoma) were treated
with TIL (median 5.8×1010 cells) and IL-2 (West’s schedule) modulated towards a lower dosage (from 12 to 6 MIU/day) in order to maintain an acceptable
level of toxicity. As treatment was well tolerated, it was offered to another 22 patients in an adjuvant setting after metastasectomy
(11 melanoma, 10 colorectal carcinoma, 1 renal cancer), the median dose of TIL reinfused being 4.95×1010 cells. No objective response was observed in advanced patients: all patients progressed after a median of 1.5 months (0–8
months) and median survival was 8 months (3–22+ months). Thirteen patients from the second group are still disease-free after
a median of 23+ months (9+–47+ months). The remaining 9 patients relapsed after a median of 5 months (3–18 months). Toxicity
was moderate as clinical and hepatic/renal function parameters were used to assess the need for dose reductions. Consequently,
there was great diversity in IL-2 dosages administered. In particular, there seemed to be a difference in IL-2 doses administered
between disease-free cases and those who progressed (17.5 MIU/day versus 7 MIU/day in melanoma patients; 11.2 MIU/day versus
7.1 MIU/day in colorectal cancer patients). By contrast, no differences were observed between number of TIL reinfused and
clinical response. Phenotypical characteristics of reinfused TIL were similar to those reported in the literature: 97% were
CD3 and 92% were CD8. Aspecific cytolytic activity was evaluated on 12 cases whereas, in 2 melanoma cases, autologous tumour
tissue was available for the specific cytotoxicity test. Perforin levels in TIL measured at the end of culture were generally
high or very high. Cytokine levels were measured on the supernatant at the end of culture, with an estreme variability in
results. Finally, ζ chain and p56lck were histologically assessed on the resected tissue from which TIL were cultivated. There were virtually none of the former
and a complete absence of the latter, which concurs with data reported in the literature. The same immunocytochemical analysis
was carried out on TIL at the end of culture. This time an almost complete restoration of both functions was seen, especially
in melanoma patients, who are still free from disease. The study is on-going and it has been decided to focus on disease-free
patients after metastasectomy in order to increase the number and possibility of clinical and histological correlations. 相似文献
To investigate the molecular mechanism of gastric carcinogenesis, we analyzed genetic instability and p53 gene mutations in 40 primary gastric carcinomas. Tumor samples were from untreated patients with no family history suggestive
of genetic predisposition to cancer. We screened six microsatellite loci by the polymerase chain reaction (PCR) method, and
exons 5–8 of the p53 gene by the PCR-based denaturing gradient gel electrophoresis and sequencing techniques. Microsatellite instability was detected
in 32.5% (13/40), and gene mutations in 40% (16/40), of the tumors analyzed. No statistically significant associations were
found between genetic alterations and clinico-pathological variables (with the exception of diffusion of lymph node metastases,
which was inversely associated with the presence of microsatellite alterations; P < 0.01). Interestingly, a negative association was found between genetic instability and p53 gene mutations: 11 out of 13 tumors showing instability proved to carry a nonmutated p53 gene versus 2/13 carrying a mutated gene (P = 0.03). These observations suggest that genetic instability and p53 gene mutations play a crucial role in the gastric carcinogenic process, but likely act through distinct pathways during cancer
development. However, genetic instability is not in and of itself neoplastic. Therefore, we investigated whether insertion/deletion
mutations of the polyadenine tract within the transforming growth factor-β type II receptor gene (TGF-βRII) were frequently present in gastric tumors with an RER+ (replication error) phenotype. We found RII mutations in 8/40 (20%) samples: mutations were present in 7/13 (54%) RER+ tumors versus 1/27 (4%) RER– cases (P < 0.001).
Received: 14 May 1996 / Revised: 13 June 1996 相似文献
The planthopper Prokelisia marginata VanDuzee (Homoptera: Delphacidae) has beenconsidered for the biological control of theweed Spartina alterniflora Loisel(Poaceae) in Willapa Bay, Washington, U.S.A. Prokelisia marginata is a stenophagousphloem-feeding insect with the potential totransmit bacterial plant diseases that could bemoved by less-specific vectors to other plantspecies. Initial assays with PCR primers thatare putatively specific for phytoplasmas gavepositive results in Spartina. However,subsequent analyses did not indicate thetransmission of the pathogen by theplanthopper. We sequenced the 16S ribosomalRNA (rRNA) gene of the bacterial species thatgave positive results in PCR. Comparisons withsequences available in GenBank suggested thatthe positive results using the putativelyspecific PCR primers were due to the presenceof such bacteria as Pseudomonas, Holomonas, Vibrio, and Acinetobacter. We did not find phytoplasmasin either Spartina or the planthopperP. marginata. 相似文献