High Frequency Of Contact Research Articles

Contact expectation based routing for delay tolerant networks

In conventional networks, routing problem can be modeled as the design of an efficient source-to-destination route based on persistent end-to-end paths. However, in a delay tolerant network (DTN), nodes are intermittently connected and thus, the end-to-end paths will not always exist, in which routing is a challenging issue. Previous DTN routing protocols tend to make routing decision based on the nodes’ contact information. In this paper, we observe that considering both the nodes’ contact information and message property such as the time-to-live (TTL) would help to improve the performance. Embedded this idea, we first propose an expected encounter based routing protocol (EER) which distributes multiple replicas of a message proportionally between two encounters according to their expected encounter values. In case of a single replica of a message, EER makes the routing decision by comparing two encountering nodes’ minimum expected meeting delays to destination. We further propose a community aware routing protocol (CAR) which takes advantages of the high contact frequency property of the nodes within the same community. We also propose the buffer management strategies corresponding for the two protocols. We conduct simulations to evaluate our proposed protocols and some existing ones on three metrics: delivery ratio, latency and goodput. The simulation results illustrate that our proposed EER and CAR protocols outperform other existing ones.

Abstract LB-161: Frequent somatic transfer of mitochondrial DNA into the nuclear genome of human cancer cells

Abstract Mitochondrial genomes are separated from the nuclear genome for most of the cell cycle by the nuclear double membrane, intervening cytoplasm and the mitochondrial double membrane. Despite these physical barriers we show that somatically acquired mitochondrial-nuclear genome fusion sequences are present in cancer cells. Most occur in conjunction with intranuclear genomic rearrangements and the features of the fusion fragments indicate that non-homologous end joining and/or replication-dependent DNA double strand break repair are the dominant mechanism involved. Remarkably, mitochondrial-nuclear genome fusions occur at a similar rate per base pair of DNA as interchromosomal nuclear rearrangements, indicating the presence of a high frequency of contact between mitochondrial and nuclear DNA in some somatic cells. Transmission of mitochondrial DNA to the nuclear genome occurs in neoplastically transformed cells, but we do not exclude the possibility that some mitochondrial-nuclear DNA fusions observed in cancer occurred years earlier in normal somatic cells. Citation Format: Young Seok Ju, Jose Tubio, William Mifsud, Beiyuan Fu, ICGC Prostate Cancer, Bone Cancer, Breast Cancer Working Groups, Fengtang Yang, Peter Campbell, Michael Stratton. Frequent somatic transfer of mitochondrial DNA into the nuclear genome of human cancer cells. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr LB-161. doi:10.1158/1538-7445.AM2015-LB-161

Incorporating the human-Aedes mosquito interactions into measuring the spatial risk of urban dengue fever

To block human–mosquito interactions by eliminating dengue vectors, Aedes aegypti L. and Aedes albopictus Skuse have been considered the main strategies for dengue prevention. Spatial targeting of dengue risk areas is the highest priority for implementing control measures. However, the frequency of human-Aedes mosquito contacts as human factors for assessing the risk of dengue has not been taken into account by past studies. The objective of this study is to clarify the geographic effects of crowd-gathering places on the frequency of dengue vector for assessing the spatial risk of exposure to dengue in Kaohsiung City, Taiwan. A geographic information system (GIS) was used to integrate crowd-gathering places and ovitrap locations for investigating potential human–mosquito contacts. A negative binominal regression was used to estimate the spatial risk of dengue by integrating vector mosquitoes from the ovitrap survey, urban environmental risk factors and human crowd-gathering places as the surrogate of human activities. We also compared the estimated spatial risk of exposure to dengue with traditional approaches. Our results indicated that the spatial distribution of the residential populations is not consistent with the locations of social activities. Additionally, people closer to crowd-gathering places have a higher frequency of contact with Ae. aegypti than with Ae. albopictus larvae. The dengue risk is caused by the human-Aedes aegypti contacts concentrated around city centers, while the risk caused by the human-Aedes albopictus contacts is distributed around the city boundary. Our study concluded that only relying on infected human cases or the abundance of vector mosquitoes is not enough for assessing the spatial risk of dengue. This reliance could ignore the areas with frequent vector existence and; therefore, result in the underestimated risk of dengue transmission. This study demonstrates the methodological framework for estimating the potential dengue risk and identifies the crowd-gathering places that facilitate dengue transmission.

Frequent somatic transfer of mitochondrial DNA into the nuclear genome of human cancer cells.

Mitochondrial genomes are separated from the nuclear genome for most of the cell cycle by the nuclear double membrane, intervening cytoplasm, and the mitochondrial double membrane. Despite these physical barriers, we show that somatically acquired mitochondrial-nuclear genome fusion sequences are present in cancer cells. Most occur in conjunction with intranuclear genomic rearrangements, and the features of the fusion fragments indicate that nonhomologous end joining and/or replication-dependent DNA double-strand break repair are the dominant mechanisms involved. Remarkably, mitochondrial-nuclear genome fusions occur at a similar rate per base pair of DNA as interchromosomal nuclear rearrangements, indicating the presence of a high frequency of contact between mitochondrial and nuclear DNA in some somatic cells. Transmission of mitochondrial DNA to the nuclear genome occurs in neoplastically transformed cells, but we do not exclude the possibility that some mitochondrial-nuclear DNA fusions observed in cancer occurred years earlier in normal somatic cells.

Effectiveness of peer support for improving glycaemic control in patients with type 2 diabetes: a meta-analysis of randomized controlled trials.

BackgroundTo assess the effects of peer support at improving glycemic control in patients with type 2 diabetes.MethodsRelevant electronic databases were sought for this investigation up to Dec 2014. Randomized controlled trials involving patients with type 2 diabetes that evaluated the effect of peer support on glycated hemoglobin (HbA1c) concentrations were included. The pooled mean differences (MD) between intervention and control groups with 95% confidence interval (CI) were calculated using random-effects model. The Cochrane Collaboration’s tool was used to assess the risk of bias.ResultsThirteen randomized controlled trials met the inclusion criteria. Peer support resulted in a significant reduction in HbA1c (MD −0.57 [95% CI: −0.78 to −0.36]). Programs with moderate or high frequency of contact showed a significant reduction in HbA1c levels (MD −0.52 [95% CI: −0.60 to −0.44] and −0.75 [95% CI: −1.21 to −0.29], respectively), whereas programs with low frequency of contact showed no significant reduction (MD −0.32 [95% CI: −0.74 to 0.09]). The reduction in HbA1c were greater among patients with a baseline HbA1c ≥ 8.5% (MD −0.78 [95% CI: −1.06 to −0.51]) and between 7.5 ~ 8.5% (MD −0.76 [95% CI: −1.05 to −0.47]), than patients with HbA1c < 7.5% (MD −0.08 [95% CI: −0.32 to 0.16]).ConclusionsPeer support had a significant impact on HbA1c levels among patients with type 2 diabetes. Priority should be given to programs with moderate or high frequency of contact for target patients with poor glycemic control rather than programs with low frequency of contact that target the overall population of patients.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-015-1798-y) contains supplementary material, which is available to authorized users.

OA53 "dementia friendly pharmacies" a community based health promotion project.

Inspired by the Ottawa Charter for Health Promotion, which is a major point of reference also for the "Compassionate Communities", we would like to propose that communities consolidate various settings like schools, workplaces, and health care organisations like community pharmacies, all of which might be included in a compassionate communities approach. We aim at enabling community pharmacies to offer informal consulting and support for people with dementia and their informal caregivers. Furthermore we want to support pharmacies to reach out in the community through various activities. By this means the project seeks to contribute to de-stigmatising dementia. The project is based on the approach "Participatory Health Research" (Hockley, Froggatt, Heimerl 2013; Wright et al . 2010). The core elements of the approach are participation, action and reflection. Approximately 40 staff (almost exclusively women) in 18 community pharmacies actively participates in the project, i.e. needs assessment, interactive workshops, practice projects and evaluation. People with dementia and their informal care givers are included in the needs assessment and in different steps of the programme. Community pharmacy staff raised several issues, closely related to communication, counselling and providing advice in a community pharmacy setting: They believe further development of professional practice to be important, since dementia care will become a more prominent issue for the community pharmacy. Moreover, a high frequency of contact with people living with dementia and their caregivers was reported by the majority of staff. Professional competencies related to dementia care are a key issue, and community pharmacy personnel viewed their practice with a critical eye: Communicating with disoriented persons poses some challenges, as does communicating with caregivers. In the still ongoing project the raised issues are being dealt with in practice projects that are performed by the pharmacies with the support of the project staff. Several projects reach out to the community through self-help groups, cinema performances, public presentations and discussions. Informal care givers have engaged in direct contact with the included pharmacies and become part of selected practice projects. People with dementia have been included in the needs assessment and the design of the project logo.

English

This study was conducted in Northern Ethiopia, Adwa district. The main objective of the study was to examine factors influencing allocation of land for improved wheat variety by smallholder farmers of the study area. Descriptive, inferential and econometric methods were used to analyze data. Results of descriptive and inferential analyses showed that; adopters had high family size in adult-equivalent, high number of tropical livestock unit, large land size, high frequency of extension contact, access to credit service, they were followed formal schooling, and they were nearest to main road and market as compared to non-adopters. Tobit model was used to analyze factors influencing adoption of improved wheat technology econometrically. A total of thirteen explanatory variables were included in the model. From the tested variables only eight variables (education level of household head, family size, tropical livestock unit, distance from main road and nearest market, access to credit service, extension contact and perception of household towards cost of the technology) were found to be the significant factors affecting adoption of improved wheat variety. Implication of results of this study is that any development intervention through improved wheat technologies should consider the aforementioned socioeconomic characteristics and determinants of adoption for success. Key words: Adoption of Improved wheat variety, Adwa, smallholder farmers, Topit model.

Hand-touch contact assessment of high-touch and mutual-touch surfaces among healthcare workers, patients, and visitors

Unlike direct contact with patients' body, hand hygiene practice is often neglected by healthcare workers (HCWs) and visitors after contact with patients' environment. Contact with hospital environmental items may increase risk of pathogen transmission. To enumerate the number of hand-touch contacts by patients, HCWs and visitors with any hospital environmental items. All contact-episodes between person and item were recorded by direct observation in a six-bed cubicle of acute wards for 33 working days. High-touch and mutual-touch items with high contact frequencies by HCWs, patients, and visitors were analysed. In total, 1107 person-episodes with 6144 contact-episodes were observed in 66 observation hours (average: 16.8 person-episodes and 93.1 contact-episodes per hour). Eight of the top 10 high-touch items, including bedside rails, bedside tables, patients' bodies, patients' files, linen, bed curtains, bed frames, and lockers were mutually touched by HCWs, patients, and visitors. Bedside rails topped the list with 13.6 contact-episodes per hour (mean), followed by bedside tables (12.3 contact-episodes per hour). Using patients' body contacts as a reference, it was found that medical staff and nursing staff contacted bedside tables [rate ratio (RR): 1.741, 1.427, respectively] and patients' files (RR: 1.358, 1.324, respectively) more than patients' bodies, and nursing staff also contacted bedside rails (RR: 1.490) more than patients' bodies. Patients' surroundings may be links in the transmission of nosocomial infections because many are frequently touched and mutually contacted by HCWs, patients, and visitors. Therefore, the focus of hand hygiene education, environmental disinfection, and other system changes should be enhanced with respect to high-touch and mutual-touch items.

Social support exchanges in a social media community for people living with HIV/AIDS in China

In recent years, social media has become an important source of social support. People living with HIV/AIDS in China created an online support group (the HIV/AIDS Weibo Group) on Weibo, the Chinese version of Twitter, in January 2011. The current study examined how social support transmitted in this social media community. First, messages over five successive weeks (2 May 2011 to 13 June 2011) were randomly selected from the HIV/AIDS Weibo Group on Weibo. Next, we employed social network analysis to map the HIV/AIDS Weibo Group’s structure and to measure the study variables. After that, a multivariate analysis of variance was applied to examine the influence of frequency of contact and reciprocity on informational and emotional social support exchanged in each dyad. The results revealed that pairs with a high level of contact frequency or reciprocity exchanged more informational support than do pairs with a low level of contact frequency or reciprocity. Moreover, dyadic partners with high frequency of contact exchanged a larger amount of emotional support than those with a low level frequency of contact; but strongly reciprocal dyads did not exchange significantly more emotional social support than their counterparts with a low level of reciprocity.

Determining the frequency, kinds and cues of violence displayed by patients in an acute older person ward environment: findings from an observational study.

Workplace violence is one of the most complex and significant occupational hazards experienced by nurses in healthcare settings. Verbal abuse and physical violence are particularly prevalent in older person assessment wards, owing to the prevalence of illnesses involving cognitive dysfunction; the high frequency and nature of contact with staff; and the frustration caused by high levels of disability. To determine the frequency, kinds and cues of violence displayed by patients towards nurses in an acute older person assessment ward environment using a structured observational tool - the Violence Assessment Tool (VAT). Observational study. Non-participant structured observations of behavioural cues for violence towards nurses in an acute older person hospital ward were gathered and analysed. One hundred and twelve hours of observations were undertaken, resulting in 95 behavioural cues for violence in 19 patients. Four of these patients subsequently escalated to physical violence. Pacing around the bed was the only commonality in the behavioural cues of patients who became violent. All patients who became violent had previously demonstrated showing. To date, the assessment of potentially violent older patients has not been adequately addressed. The VAT may be one way of addressing this challenge through early identification of the more subtle behavioural cues that could indicate potential for violence. Further research on the VAT using a larger data set could determine its predictability for physically violent acts displayed by older people.

Limited Potential for Prevention of Emergency Surgery for Femoral Hernia

Femoral hernias are frequently operated on as an emergency. Emergency procedures for femoral hernia are associated with an almost tenfold increase in postoperative mortality, while no increase is seen for elective procedures, compared with a background population. The aim of this study was to compare whether symptoms from femoral hernias and healthcare contacts prior to surgery differ between patients who have elective and patients who have emergency surgery. A total of 1,967 individuals operated on for a femoral hernia over 1997-2006 were sent a questionnaire on symptoms experienced and contact with the healthcare system prior to surgery for their hernia. Answers were matched with data from the Swedish Hernia Register. A total of 1,441 (73.3%) patients responded. Awareness of their hernia prior to surgery was denied by 53.3% (231/433) of those who underwent an emergency procedure. Of the emergency operated patients, 31.3% (135/432) negated symptoms in the affected groin prior to surgery and 22.2% (96/432) had neither groin nor other symptoms. Elective patients had a considerably higher contact frequency with their general practitioner, as well as the surgical outpatient department, prior to surgery compared with patients undergoing emergency surgery (p < 0.001). Patients who have elective and patients who have emergency femoral hernia surgery differ in previous symptoms and healthcare contacts. Patients who need emergency surgery are often unaware of their hernia and frequently completely asymptomatic prior to incarceration. Early diagnosis and expedient surgery is warranted, but the lack of symptoms hinders earlier detection and intervention in most cases.

Binomial Random Parameters Logistic Regression Model of Housing Satisfaction

Lifecycle events strongly influence the long term dynamics of activity-travel behavior. Moving house, as an example of a lifecycle event, triggers households to reconsider their activity-travel choices and possibly to adapt to the new house-job relationship. In turn, the decision to move house is a function of housing satisfaction, which depends on factors such as socio-demographic and economic characteristics of individuals, physical aspects of the dwellings, accessibility to different places in the city, etc. The main goal of this paper, which has been written as part of a project about residential mobility in Rotterdam, a metropolitan area in the Netherlands, is to understand some determinants of housing satisfaction. The model results represent the odds that a respondent with a particular profile is satisfied with his/her current housing situation. Differences in these odds are found to be associated with individuals’ profiles and housing characteristics. In general, these differences can be explained by household needs, constraints or preferences, which are strongly related to lifecycle phase. Satisfaction is found to decrease with increasing levels of urbanization, indicating that housing satisfaction is influenced by negative externalities such as pollution, congestion, noise, etc. Higher contact frequency with relatives, friends and club activities, has a positive effect on housing satisfaction. Finally, distance to work was found not significantly related to housing satisfaction.

Schistosomiasis infection among primary school students in a war zone, Southern Kordofan State, Sudan: a cross-sectional study

BackgroundSchistosomiasis is a major health problem adversely affecting the health of vulnerable populations in Sudan.MethodsWe conducted a school-based survey to estimate the prevalence of schistosomiasis in 36 villages in Southern Kordofan (SK) State. A total of 2,302 primary school students were recruited. Each student completed a questionnaire and submitted one urine and one stool sample.ResultsThe prevalence of schistosomiasis haematobium was 23.7%, while schistosomiasis mansoni was not detected among the study participants. S. haematobium infection was identified in all areas, with the highest prevalence in the western locality of SK State. The infection was associated with the distance between home/school and open water sources. In addition, S. haematobium infection was associated with the existence of and distance to open water sources, higher frequency of contact with open water, absence of a health advocacy group in the school and history of schistosomiasis treatment.ConclusionsThis study highlights schistosomiasis as a public health problem in SK State. The findings will guide the schistosomiasis Control Program of the State Ministry of Health in developing and applying treatment plans for schistosomiasis in SK State.

High and low contact frequency cardiac rehabilitation programmes elicit similar improvements in cardiorespiratory fitness and cardiovascular risk factors

Cardiac rehabilitation (CR) is a proven intervention that substantially improves physical health and decreases death and disability following a cardiovascular event. Traditional CR typically involves 36 on-site exercise sessions spanning a 12-week period. To date, the optimal dose of CR has yet to be determined. This study compared a high contact frequency CR programme (HCF, 34 on-site sessions) with a low contact frequency CR programme (LCF, eight on-site sessions) of equal duration (4 months). A total of 961 low-risk cardiac patients (RARE score <4) self-selected either a HCF (n = 469) or LCF (n = 492) CR programme. Cardiorespiratory fitness and cardiovascular risk factors were measured on admission and discharge. Similar proportions of patients completed HCF (n = 346) and LCF (n = 351) (p = 0.398). Patients who were less fit (<8 METs) were more likely to drop out of the LCF group, while younger patients (<60 years) were more likely to drop out of the HCF group. Both groups experienced similar reductions in weight (-2.3 vs. -2.4 kg; p = 0.779) and improvements in cardiorespiratory fitness (+1.5 vs. +1.4 METs; p = 0.418). Patients in the LCF programme achieved equivalent results to those in the HCF programme. Certain subgroups of patients, however, may benefit from participation in a HCF programme, including those patients who are predisposed to prematurely discontinuing the programme and those patients who would benefit from increased monitoring. The LCF model can be employed as an alternative option to widen access and participation for patients who are unable to attend HCF programmes due to distance or time limitations.

어린이집 주요 바닥마감재의 경제성 및 LCCO2분석에 관한 연구

As the construction industry develops, environmental pollution gets increasingly serious, giving damage including the increase of incidence of respiratory diseases and skin diseases among children with weakened immune systems, rather than adults. In daycare centers, infants and children spending much of their time, have high frequency of contact with the interior floor finish material. However, the majority of the child care centers don not use eco-friendly flooring but ordinary monorium flooring, because the initial investment cost of the eco-friendly flooring is higher than ordinary monorium flooring. Therefore, in this study, life cycle costs including the initial investment cost of the eco-friendly flooring and ordinary monorium flooring were calculated, demonstrating that the eco-friendly flooring is more economical than ordinary monorium flooring in terms of life-cycle cost. In addition, the analysis of the environmental performance also showed the excellence of the eco-friendly floor finishes. It is expected that the use of the eco-friendly floor finishes will increase due to their excellence in the aspect of life cycle cost and eco-friendly performance, through this study.

Structural and functional characteristics of the social networks of people with mild intellectual disabilities

In the research on people with intellectual disabilities and their social networks, the functional characteristics of their networks have been examined less often than the structural characteristics. Research on the structural characteristics of their networks is also usually restricted to the size and composition of the networks, moreover, with little attention to such characteristics as the variety, accessibility, length and origin of the relationships or the frequency and initiation of the contacts. A comprehensive examination of both the structural and functional characteristics of the social networks of 33 people with intellectual disabilities was therefore undertaken. The social networks of the individuals who all lived in the community varied from 4 to 28 members (mean 14.21); 42.65% of the network members were family members, 32.84% acquaintances and 24.51% professionals. Remarkable is the high frequency of contact with network members; the finding that the participants considered themselves to be the main initiator of contact more often than the other members of their networks as the main initiators; the high scores assigned to neighbours and professionals for functional characteristics; and the relatively low scores assigned to network members for the connection characteristic of the social networks. The important role of professionals in the social networks of people with mild intellectual disabilities and practical implications to facilitate their social inclusion are discussed.

Pocketcheck: updating the HLA class I peptide specificity roadmap

The structural determination of peptide:HLA (human leucocyte antigen) class I complexes by X-ray crystallography has provided valuable information for understanding how peptides bind to individual HLA class I molecules and how this may influence the immune response. We compared 101 crystal structures of 9-mer peptide:HLA class I complexes available in the protein data bank (PDB) by performing a contact analysis using the Contact Map Analysis webserver http://ligin.weizmann.ac.il/cma. An InterSystems Caché 'post-relational' database containing residue position, amino acid (AA) and buried surface that contact a particular peptide position was then created allowing data comparison for all the structures (Pocketcheck). The analysis illustrates that the HLA class I residues 24, 45, 63 and 67 show high contact frequencies to both the p1 and/or p2 position of bound peptides, indicating that they might influence the nature of a peptide anchor. To determine the influence of these residues we utilized soluble HLA technology and mass spectrometry to analyze peptides derived from HLA-B*44:06 since it differs from the previously described allele B*44:02 by seven AA exchanges located in the alpha 1 domain (residues 24, 32, 41, 45, 63, 67 and 80). HLA-B*44:06 features an anchor motif of P or A at p2 and Y or W at the C-terminal. Additionally B*44:06-derived peptides feature an auxiliary anchor motif at p1, comprising D or E. Our results illustrate that structural analysis can provide valuable information to understand allogenicity and provides a further step towards intelligent HLA mismatching.

Challenges Relating to the Interface Between Crisis Mental Health Clinicians and Police When Engaging with People with a Mental Illness

Symptoms of mental illness can increase the risk of disturbed behaviour. Joint intervention between police and mental health services is therefore sometimes needed to manage crisis events safely, and to divert people with a mental illness from further criminal justice system contact. This study explored how crisis mental health clinicians and police officers experience the service interface to identify perceived challenges tocollaboration and possible solutions. This was explored through circulation of a developed questionnaire to staff of the Crisis Assessment Team of Alfred Psychiatry and police officers from three Melbourne police stations. In addition to identifying the high frequency of contact between interfacing services, a number of challenges to effective interface were identified. These included: inefficient communication before or following a joint event; difficulty accessing support from the interfacing service and delays in handing over care in hospital emergency departments; and staff occasionally not respecting the professional abilities of staff from interfacing services.

High Frequency of Leaf Swallowing and its Relationship to Intestinal Parasite Expulsion in “Village” Chimpanzees at Bulindi, Uganda

Self-medication by great apes to control intestinal parasite infections has been documented at sites across Africa. Chimpanzees (Pan troglodytes) swallow the leaves of certain plant species whole, without chewing. Previous studies demonstrated a relationship between chimpanzee leaf swallowing and expulsion of nematode worms (Oesophagostomum sp.) and tapeworms (Bertiella sp.) in dung. We investigated the relationship between leaf swallowing and parasite expulsion in chimpanzees inhabiting a fragmented forest-farm mosaic at Bulindi, Uganda. During 13 months whole undigested leaves occurred in chimpanzee dung at a considerably higher frequency (10.4% of dungs) than at other sites (0.4-4.0%). Leaf swallowing occurred year-round and showed no pronounced seasonality. Chimpanzees egested adults of multiple species of Oesophagostomum (including O. stephanostomum) and proglottids of two tapeworms-Bertiella sp. and probably Raillietina sp. The latter may not be a true infection, but the byproduct of predation on domestic fowl. Compared to previous studies, the co-occurrence of whole leaves and parasites in chimpanzee dung was low. Whereas the presence of leaves in dung increased the probability of adult nematode expulsion, no association between leaf swallowing and the shedding of tapeworm proglottids was apparent. Anthropogenic habitat changes have been linked to alterations in host-parasite interactions. At Bulindi, deforestation for agriculture has increased contact between apes and people. Elevated levels of leaf swallowing could indicate these chimpanzees are especially vulnerable to parasite infections, possibly due to environmental changes and/or increased stress levels arising from a high frequency of contact with humans. Frequent self-medication by chimpanzees in a high-risk environment could be a generalized adaptation to multiple parasite infections that respond differently to the behavior. Future parasitological surveys of apes and humans at Bulindi are needed for chimpanzee health monitoring and management, and to investigate the potential for disease transmission among apes, people, and domestic animals.

Agricultural information exchange and organizational ties: The effect of network topology on managing agrodiversity

Increasing agricultural diversity, particularly perennial based agroforestry systems, is re-emerging as a mechanism for ecological and economic benefits through the mitigation of environmental risks. By and large, rural producer social networks are important to the exchange of information on such complex systems and associated agrarian management practices. These information networks are not restricted to producers as other agrarian-based organizations are active within the larger agricultural innovation system. However, little is known about the effects of such organizational ties on the emergent properties of producer network structures, which play a critical role in the successful exchange of complex agrarian information and the adoption of management practices that result in higher agrodiversity. Accordingly, this study investigates information network structures within the agrarian environment in order to understand the barriers to, and development of, effective farm management, specifically the management of agrodiversity. Network data was collected from producers in two geographically separate areas in the economically important cocoa (Theobroma cacao) growing region of Ghana [Site A, located close to an urban centre, had high frequency of contact with agro-environmental organizations and Site B, in a remote location, had a low frequency of contact] on the exchange of agroforestry management practices. Results showed that although 31% of producers in Site A relied exclusively on fellow producers for agroecological information, the majority of producers formed ties to one or more of the rural organizations operating within these communities. And producers with greater access to organizations were situated in agrarian information networks with lower density, thus more diffuse networks. Furthermore, producers with ties to organizations were likely to be positioned in more efficient information networks as identified by a low level of redundant ties and this efficiency was positively correlated to higher reported on-farm agrodiversity. The success of information exchange on agro-environmental practices, such as managing agrodiversity, within producer networks may be distinctly coupled with the presence of organizational ties. Unlike common-pooled resources that may require highly dense networks for trust-based collective action, diverse agricultural systems that are innovation driven arguably require diffuse networks for efficient exchange of complex information. Policy that promotes appropriate network structures for the exchange of such information is strategic for persistent cocoa production systems. This study provides further evidence of the role of information networks on the exchange and practice of innovation in agricultural systems, particularly in developing country agriculture.