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Strong Positive (strong + positive)
Terms modified by Strong Positive Selected AbstractsConsumer,resource interactions and cyclic population dynamics of Tanytarsus gracilentus (Diptera: Chironomidae)JOURNAL OF ANIMAL ECOLOGY, Issue 5 2002Árni Einarsson Summary 1Tanytarsus gracilentus population dynamics in Lake Myvatn show a tendency to cycle, with three oscillations occurring between 1977 and 1999 having periods of roughly 7 years. The population abundance fluctuated over four orders of magnitude. 2A partial autocorrelation function (PACF) accounting for measurement error revealed a strong positive lag-1 autocorrelation and a moderate negative lag-2 partial autocorrelation. This suggests that the dynamics can be explained by a simple second-order autoregressive process. 3We tested the alternative hypotheses that the cyclic dynamics of T. gracilentus were driven by consumer,resource interactions in which T. gracilentus is the consumer, or predator,prey interactions in which T. gracilentus is the prey. We analysed autoregressive models including both consumer,resource interactions and predator,prey interactions. 4Wing length of T. gracilentus was used as a surrogate for resource abundance and/or quality, because body size is known to fluctuate with resource abundance and quality in dipterans. Furthermore, the wing lengths of Micropsectra lindrothi , a species ecologically similar to T. gracilentus , fluctuated synchronously with T. gracilentus wing lengths, thereby indicating that the shared resources of these two species were indeed cycling. Wing lengths of other chironomid species were not synchronized. 5The predators of T. gracilentus included midges in the genera Procladius and Macropelopia , and the fish Gasterosteus aculeatus (three-spined stickleback). 6The autoregressive models supported the hypothesis that T. gracilentus dynamics were driven by consumer,resource interactions, and rejected the hypothesis that the dynamics were driven by predator,prey interactions. 7The models also revealed the consequences of consumer,resource interactions for the magnitude of fluctuations in T. gracilentus abundance. Consumer,resource interactions amplified the exogenous variability affecting T. gracilentus per capita population growth rates (e.g. temperature, rainfall, etc.), leading to variability in abundance more than two orders of magnitude greater than the exogenous variability. [source] Socio-economic distance and spatial patterns in unemploymentJOURNAL OF APPLIED ECONOMETRICS, Issue 4 2002Timothy G. Conley This paper examines the spatial patterns of unemployment in Chicago between 1980 and 1990. We study unemployment clustering with respect to different social and economic distance metrics that reflect the structure of agents' social networks. Specifically, we use physical distance, travel time, and differences in ethnic and occupational distribution between locations. Our goal is to determine whether our estimates of spatial dependence are consistent with models in which agents' employment status is affected by information exchanged locally within their social networks. We present non-parametric estimates of correlation across Census tracts as a function of each distance metric as well as pairs of metrics, both for unemployment rate itself and after conditioning on a set of tract characteristics. Our results indicate that there is a strong positive and statistically significant degree of spatial dependence in the distribution of raw unemployment rates, for all our metrics. However, once we condition on a set of covariates, most of the spatial autocorrelation is eliminated, with the exception of physical and occupational distance. Racial and ethnic composition variables are the single most important factor in explaining the observed correlation patterns. Copyright © 2002 John Wiley & Sons, Ltd. [source] International equity flows and the predictability of US stock returnsJOURNAL OF FORECASTING, Issue 8 2007Daniel Hartmann Abstract We examined the link between international equity flows and US stock returns. Based on the results of tests of in-sample and out-of-sample predictability of stock returns, we found evidence of a strong positive (negative) link between international equity flows and contemporaneous (one-month-ahead) stock returns. Our results also indicate that an investor, in real time, could have used information on the link between international equity flows and one-month-ahead stock returns to improve the performance of simple trading rules.,,Copyright © 2007 John Wiley & Sons, Ltd. [source] Contact calls of common marmosets (Callithrix jacchus): influence of age of caller on antiphonal calling and other vocal responsesAMERICAN JOURNAL OF PRIMATOLOGY, Issue 2 2009H.-C. Chen Abstract Marmosets, as do many other primates, live in forest environments, are group living and constantly at risk of predation. Retaining contact with one another is therefore a matter of survival. We ask here whether their contact calls (phee and twitter vocalizations) are in some way ordered acoustically by sex or age and whether the calls of older marmosets elicit different responses than those of younger marmosets. In our study, marmosets (2,14 years) were visually isolated from conspecifics and the vocal responses to each isolated caller by other marmosets in the colony were recorded. Vocal responses to phee calls largely consisted of phee calls and, less commonly, twitter calls. No differences between the responses to calls by males and females were apparent. However, we found a strong positive and significant correlation between the caller's age and the percentage of its phee calls receiving a phee response, and a significant negative correlation between the caller's age and the percentage of its phee calls receiving a twitter response. The older the marmoset, the more antiphonal calling occurred. Two-syllable phee calls were emitted more often by older marmosets (10,14 years) than by younger ones (2,6 years). Hence, we have found age-dependent differences in phee-call production and a consistent change in the response received across the adult life-span. This age-dependent effect was independent of kinship relations. This is the first evidence that marmosets distinguish age by vocal parameters alone and make social decisions based on age. Am. J. Primatol. 71:165,170, 2009. © 2008 Wiley-Liss, Inc. [source] Osteopontin expression correlates with invasiveness in cervical cancerAUSTRALIAN AND NEW ZEALAND JOURNAL OF OBSTETRICS AND GYNAECOLOGY, Issue 4 2009Jae Yun SONG Aim: Osteopontin is a secreted, integrin-binding glycophosphoprotein that is overexpressed in many types of cancers and appears to be involved in carcinogenesis and cancer progression. To understand the role of osteopontin in carcinogenesis of cervical cancer, this study was designed to determine whether osteopontin is expressed in cervical cancer and carcinoma in situ (CIS) tissue as well as in normal cervical tissue. Methods: The expression of osteopontin was immunohistochemically analysed from 68 normal cervix, 55 CIS and 52 invasive cervical cancer tissues using a paraffin-embedded tissue array. Immunostaining was evaluated by intensity and the percentage of stained cells. Results: Osteopontin expression in normal, CIS and cervical cancer tissues was two of 68 (2.9%), 43 of 55 (78.2%) and 46 of 52 (88.4%), respectively (P < 0.01). High intensity (strong positive)/high proportion (more than 50%) staining seen in CIS and cervical cancer tissue samples was 45 of 55 (81.8%)/22 of 55 (40.0%) and 50 of 52 (96.2%)/31 of 52 (59.7%), respectively (P = 0.029 and P = 0.054). There was no significant correlation between the immunostaining score and stage and the immunostaining score and survival. Conclusion: Osteopontin may have a potential use as a diagnostic factor for cervical cancer and osteopontin expression is closely correlated with carcinogenesis and invasion of cervical cancer. 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