Space-time modelling of emerging infectious diseases: Assessing leptospirosis risk in Sri Lanka

In this research, models were developed to analyze leptospirosis incidence in Sri Lanka and its relation to rainfall. Before any leptospirosis risk models were developed, rainfall data were evaluated from an agro-ecological monitoring network for producing maps of total monthly rainfall in Sri Lanka. Four spatial interpolation techniques were compared: inverse distance weighting, thin-plate splines, ordinary kriging, and Bayesian kriging. Error metrics were used to validate interpolations against independent data. Satellite data were used to assess the spatial pattern of rainfall. Results indicated that Bayesian kriging and splines performed best in low and high rainfall, respectively. Rainfall maps generated from the agro-ecological network were found to have accuracies consistent with previous studies in Sri Lanka. These rainfall data were then used as the primary predictor in a family of time series leptospirosis forecasting models at varying spatial scales across Sri Lanka. Several modelling scenarios were evaluated using proper scoring rules and numerous other metrics to assess model fit and calibration. A negative binomial integer-valued autoregressive conditional heteroscedasticity (INGARCH) model that included current and previous rainfall covariates, as well as regression on previous cases of leptospirosis at a local and seasonal time scale was selected as the best performing model. It was found that rainfall did not have a significant correlation with leptospirosis incidence in Sri Lanka, but the family of INGARCH models developed was able to forecast leptospirosis incidence and effectively provide early warning for leptospirosis outbreaks at the district level across Sri Lanka

A Partial Bison (Bison cf. B. latifrons) Skeleton from Chuchi Lake, and its Implications for the Middle Wisconsinan Environment of Central British Columbia

Fragmentary but massive left and right horncores, found with eight post-cranial bones, from a clay unit underlying a diamicton of the last (Fraser) glaciation at Chuchi Lake, British Columbia probably represents an individual giant bison (Bison cf. B. latifrons). A sample of bone from one of the horncores yielded an accelerator mass spectrometry (AMS) radiocarbon date of 30 740 ± 220 BP, whereas overlapping dates from two other laboratories on an associated humerus are 34 800 ± 420 BP and 35 480 ± 1080 BP. Despite the discrepancy between horncore and humerus dates, they are in accord with the suspected stratigraphie age of the clay unit whence they came. Analysis of pollen from that clay unit indicates that bison with massive horns once occupied an open forest in the vicinity. Probably giant bison and Columbian mammoths (incorporating paleoenvironmental evidence found with the nearby, penecontemporaneous Babine Lake mammoth) shared lake-dotted open forest to shrub tundra range in what is now central British Columbia toward the close of the Middle Wisconsinan (Olympia Nonglacial Interval). The Chuchi Lake specimen is important because it is the first indication of giant bison from British Columbia, and it appears to be one of the latest known survivors of this species.On a trouvé au lac Chuchi dans une unité d'argile recouverte d'un diamicton de la dernière glaciation (Fraser), des fragments de noyaux de cornes droite et gauche et des ossements postcrâniens qui pourraient provenir du bison géant (Bison cf. B. latifrons). Un échantillon d'un des noyaux de corne a été daté au radiocarbone par spectrométrie de masse par accélérateur à 30 740 ± 220 BP, alors qu'un humérus du même horizon a été daté dans deux différents laboratoires à 34 800 ± 420 BP et 35 480 ± 1080 BP. Malgré la différence entre les dates du noyau de corne et de l'humérus, celles-ci concordent avec l'âge stratigraphique présumé de l'unité d'argile où les ossements ont été trouvés. L'analyse du pollen de la même unité d'argile indique que le bison vivait dans une forêt ouverte. Selon les données paléoenvironnementales du Babine Lake, où on a trouvé un mammouth du même âge, il est probable que le bison et le mammouth colombien partageaient un milieu variant entre la forêt ouverte et la toundra arbustive parsemée de lacs, au centre de la Colombie-Britannique, pendant le Wisconsinien moyen (intervalle non glaciaire de l'Olympia). La découverte du spécimen du Chuchi Lake est d'autant plus importante qu'il constitue le premier indice de la présence du bison géant en Colombie-Britannique; il pourrait être parmi les derniers survivants de cette espèce.Fragmentarische aber massive linke und rechte Hornkerne zusammen mit acht Hinterschâdelknochen, die man in einer Lehm-Einheit unter einem Diamikton der letzten Vereisung (Fraser) am See Chuchi, British Columbia, gefunden hat, kônnten wohl von einem einzelnen Riesenbison stammen (Bison ci. B. latifrons). Fur eine Knochenprobe von einem der Hornkerne wurde mittels Massenspek-trometrie durch Beschleuniger ein Radiokarbondatum von 30 740 ± 220 v.u.Z. ermittelt, wâhrend zwei andere Labore sich ùberschneidende Daten auf einem damit in Verbindung gebrachten Oberarmknochen ermittelten: 34 800 ± 420 v.u.Z. und 35 480 ± 1080 v.u.Z. Trotz der Diskrepanz zwischen den Hornkern- und Oberarmknochendaten, stimmen sie mit dem vermuteten stratigraphischen Alter der Lehmeinheit, aus der sie stammen, ûberein. Die Pollen-Analyse von dieser Lehmeinheit zeigt, daf3 ehemals Bisons mit massiven Hôrnern in einem offenen WaId in der Nàhe lebten. Gegen Ende des mittleren Wisconsiniums (nichtglaziales Intervall von Olympia) teilten sich wahrscheinlich Riesenbisons und kolumbianische Mammuts (wenn man die Palàoumweltbelege von Babine Lake berùcksichtigt, wo man ein Mammut des gleichen Alters gefunden hat) ein Gebiet, das von Seen durchsetzten offenen WaId bis zur Buschtundra enthielt und dem heutigen Zentrum von British Columbia entspricht. Das Exemplar von Chuchi Lake ist wichtig, weil es der erste Hinweis auf Riesenbison von British Columbia ist, und es scheint eines der letzten bekannten Ùberlebenden dieser Art zu sein

Cluster Perturbation Theory for Hubbard models

Cluster perturbation theory is a technique for calculating the spectral weight of Hubbard models of strongly correlated electrons, which combines exact diagonalizations on small clusters with strong-coupling perturbation theory at leading order. It is exact in both the strong- and weak-coupling limits and provides a good approximation to the spectral function at any wavevector. Following the paper by S\'en\'echal et al. (Phys. Rev. Lett. {\bf 84}, 522 (2000)), we provide a more complete description and derivation of the method. We illustrate some of its capabilities, in particular regarding the effect of doping, the calculation of ground state energy and double occupancy, the disappearance of the Fermi surface in the $t-t'$ Hubbard model, and so on. The method is applicable to any model with on-site repulsion only.Comment: 11 pages, 10 figures (RevTeX 4

Telehealth experiences in Canadian veterans: associations, strengths and barriers to care during the COVID-19 pandemic.

INTRODUCTION: Identifying barriers to care in veteran populations is critical, as veterans face increased social isolation, relationship strains and financial insecurities. For Canadian veterans experiencing barriers to accessing healthcare, telehealth may be a promising alternative with comparable effectiveness to in-person services; however, the potential benefits and limitations of telehealth require further examination to determine its long-term utility, and to inform health policy and planning. The goal of the present research was to identify predictors and barriers to telehealth usage in Canadian veterans in the context of the COVID-19 pandemic. METHODS: Data were drawn from baseline data of a longitudinal survey examining the psychological functioning of Canadian veterans during the COVID-19 pandemic. Participants were 1144 Canadian veterans aged 18-93 years (M RESULTS: Findings suggest that sociodemographic factors and previous telehealth use were significantly associated with telehealth use during the COVID-19 pandemic. Qualitative evidence highlighted both the benefits (eg, reducing barriers of access) and drawbacks (eg, not all services can be delivered) of telehealth services. CONCLUSIONS: This paper provided a deeper understanding of Canadian veterans\u27 experiences with accessing telehealth care during the COVID-19 pandemic. While for some, the use of telehealth mitigated perceived barriers (eg, safety concerns of leaving home), others felt that not all health services could be appropriately carried out through telehealth. Altogether, findings support the use of telehealth services in increasing care accessibility for Canadian veterans. Continued use of quality telehealth services may be a valuable form of care that extends the reach of healthcare professionals

Physical and psychological challenges faced by military, medical and public safety personnel relief workers supporting natural disaster operations: a systematic review

Natural disasters, including floods, earthquakes, and hurricanes, result in devastating consequences at the individual and community levels. To date, much of the research reflecting the consequences of natural disasters focuses heavily on victims, with little attention paid to the personnel responding to such disasters. We conducted a systematic review of the challenges faced by military, medical and public safety personnel supporting natural disaster relief operations. Specifically, we report on the current evidence reflecting challenges faced, as well as positive outcomes experienced by military, medical and public safety personnel following deployment to natural disasters. The review included 382 studies. A large proportion of the studies documented experiences of medical workers, followed by volunteers from humanitarian organizations and military personnel. The most frequently reported challenges across the studies were structural (i.e., interactions with the infrastructure or structural institutions), followed by resource limitations, psychological, physical, and social challenges. Over 60% of the articles reviewed documented positive or transformative outcomes following engagement in relief work (e.g., the provision of additional resources, support, and training), as well as self-growth and fulfillment. The current results emphasize the importance of pre-deployment training to better prepare relief workers to manage expected challenges, as well as post-deployment supportive services to mitigate adverse outcomes and support relief workers’ well-being