Search

Context: Dispersal of individuals contributes to long-term population persistence, yet requires a sufficient degree of landscape connectivity. To date, connectivity has mainly been investigated using least-cost analysis and circuit theory, two methods that make assumptions that are hardly applicable to dispersal. While these assumptions can be relaxed by explicitly simulating dispersal trajectories across the landscape, a unified approach for such simulations is lacking. Objectives: Here, we propose and apply a simple three-step approach to simulate dispersal and to assess connectivity using empirical GPS movement data and a set of habitat covariates. Methods: In step one of the proposed approach, we use integrated step-selection functions to fit a mechanistic movement model describing habitat and movement preferences of dispersing individuals. In step two, we apply the parameterized model to simulate dispersal across the study area. In step three, we derive three complementary connectivity maps; a heatmap highlighting frequently traversed areas, a betweenness map pinpointing dispersal corridors, and a map of inter-patch connectivity indicating the presence and intensity of functional links between habitat patches. We demonstrate the applicability of the proposed three-step approach in a case study in which we use GPS data collected on dispersing African wild dogs (Lycaon pictus) inhabiting northern Botswana. Results: Using step-selection functions we successfully parametrized a detailed dispersal model that described dispersing individuals' habitat and movement preferences, as well as potential interactions among the two. The model substantially outperformed a model that omitted such interactions and enabled us to simulate 80,000 dispersal trajectories across the study area. Conclusion: By explicitly simulating dispersal trajectories, our approach not only requires fewer unrealistic assumptions about dispersal, but also permits the calculation of multiple connectivity metrics that together provide a comprehensive view of landscape connectivity. In our case study, the three derived connectivity maps revealed several wild dog dispersal hotspots and corridors across the extent of our study area. Each map highlighted a different aspect of landscape connectivity, thus emphasizing their complementary nature. Overall, our case study demonstrates that a simulation-based approach offers a simple yet powerful alternative to traditional connectivity modeling techniques. It is therefore useful for a variety of applications in ecological, evolutionary, and conservation research. [ABSTRACT FROM AUTHOR]

The development and use of cost-effective and appropriate survey methods to assess species distribution and to monitor range expansion and contraction of wild populations is crucial due to the limited financial resources for conservation. Of particular importance, yet little studied, is the ability to collect information before a wild population is well established, i.e. at the early stages of recolonisation. During 2018 and 2019, we used camera traps, audio recorders, and scat detection dogs simultaneously to investigate composition, detection probability, and territorial extent of a pack of wolves in the Swiss Alps. We compared the efficacy of these survey methods by assessing sampling effort, data obtained, and costs. We show that, under the presented setup, camera traps and scat detection dogs substantially outperformed audio recorders in detecting wolves, representing the packs' territorial extent, and revealing the number of adult wolves. The detection dogs did not detect pups but, unlike the other methods, allowed the identification of single individuals. The use of four camera traps during 13 weeks, a 24-km-long transect walked with the detection dog, or the use of one audio recorder during 148 weeks were necessary to obtain a comparable wolf detection probability. Our results show that no single method was able to return all information that we hoped to collect. Comprehensive and cost-effective information was best obtained by combining data from camera traps and detection dogs. We suggest both methods to be simultaneously used to successfully investigate wolf recolonisation into historical range. [ABSTRACT FROM AUTHOR]

Purpose: The body mass index (BMI) may be associated with an increased incidence and aggressiveness of urological cancers. In this study, we aimed to evaluate the impact of the BMI on survival in patients with T1G3 non-muscle-invasive bladder cancer (NMIBC).Methods: A total of 1155 T1G3 NMIBC patients from 13 academic institutions were retrospectively reviewed and patients administered adjuvant intravesical Bacillus Calmette-Guérin (BCG) immunotherapy with maintenance were included. Multivariable Cox regression analysis was performed to identify factors predictive of recurrence and progression.Results: After re-TURBT, 288 patients (27.53%) showed residual high-grade NMIBC, while 867 (82.89%) were negative. During follow-up, 678 (64.82%) suffered recurrence, and 303 (30%) progression, 150 (14.34%) died of all causes, and 77 (7.36%) died of bladder cancer. At multivariate analysis, tumor size (hazard ratio [HR]:1.3; p = 0.001), and multifocality (HR:1.24; p = 0.004) were significantly associated with recurrence (c-index for the model:55.98). Overweight (HR: 4; p < 0.001) and obesity (HR:5.33 p < 0.001) were significantly associated with an increased risk of recurrence. Addition of the BMI to a model that included standard clinicopathological factors increased the C-index by 9.9. For progression, we found that tumor size (HR:1.63; p < 0.001), multifocality (HR:1.31; p = 0.01) and concomitant CIS (HR: 2.07; p < 0.001) were significant prognostic factors at multivariate analysis (C-index 63.8). Overweight (HR: 2.52; p < 0.001) and obesity (HR: 2.521 p < 0.001) were significantly associated with an increased risk of progression. Addition of the BMI to a model that included standard clinicopathological factors increased the C-index by 1.9.Conclusions: The BMI could have a relevant role in the clinical management of T1G3 NMIBC, if associated with bladder cancer recurrence and progression. In particular, this anthropometric factor should be taken into account at initial diagnosis and in therapeutic strategy decision making. [ABSTRACT FROM AUTHOR]

Purpose: To use triphasic multi-detector computed tomography (MDCT) to study the renal segmental arterial anatomy and its relationship with the urinary tract to plan nephron-sparing surgery (NSS). Methods: One hundred and fifty nine patients underwent abdominal contrast-enhanced MDCT. We evaluated renal arteries and parenchymal vasculature. In 61 patients, the arteries and the urinary tract were represented simultaneously. Results: 86.60 % presented a single renal artery; 13.4 %, multiple arteries. All single renal arteries divided into anterior and posterior branch before the hilum. The anterior artery branched into a superior, middle, and inferior branch. In 43.14 %, the inferior artery arose before the others; in 45.75 %, the superior artery arose before the others; in 9.80 %, the branches shared a common trunk. In 26.80 %, the posterior artery supplies the entire posterior surface; in 73.20 %, it ends along the inferior calyx. In 96.73 %, the upper pole was vascularized by the anterior superior branch and the posterior artery: the 'tuning fork'. MDCT showed four vascular segments in 96.73 % and five in 3.27 %. MDCT showed two avascular areas: the first along the projection of the inferior calyx on the posterior aspect, the second between the branches of the 'tuning fork'. Conclusions: The arterial phase provides the arterial tree representation; the delayed phase shows arteries and urinary tract simultaneously. MDCT provides a useful representation of the renal anatomy prior to intervascular-intrarenal NSS. [ABSTRACT FROM AUTHOR]

Radiation therapy (RT) is one of the treatment options for prostate cancer (PCa). Transperineal low-dose rate brachytherapy (BT) is another safe and effective technique for low-risk PCa. Recurrence after RT for localized PCa can be defined by a PSA value of 2 ng/mL above the nadir after RT, and biochemical recurrence (BCR) rate after RT is 40-60 %. In case of radiorecurrent PCa, treatment options include salvage radical prostatectomy (RP), cryotherapy, high-intensity focused ultrasound (HIFU), and salvage BT. Only salvage RP has cancer control results for over 10-year follow-up in a substantial portion of patients (30-40 %). However, salvage RP is technically demanding, and experienced surgeons are needed; in fact, RT-induced cystitis, fibrosis, and tissue plane obliteration can lead to significant complications, such as rectal injuries, anastomotic stricture, and urinary incontinence. This review describes indications, oncologic and functional outcomes, surgical techniques, and complications of salvage robot-assisted RP. [ABSTRACT FROM AUTHOR]

Habitat fragmentation, patch quality and landscape structure are important predictors for species richness. However, conservation strategies targeting single species mainly focus on habitat patches and neglect possible effects of the surrounding landscape. This project assesses the impact of management, habitat fragmentation and landscape structure at different spatial scales on the distribution of three endangered butterfly species, Boloria selene, Boloria titania and Brenthis ino. We selected 36 study sites in the Swiss Alps differing in (1) the proportion of suitable habitat (i.e., wetlands); (2) the proportion of potential dispersal barriers (forest) in the surrounding landscape; (3) altitude; (4) habitat area and (5) management (mowing versus grazing). Three surveys per study site were conducted during the adult flight period to estimate occurrence and density of each species. For the best disperser B. selene the probability of occurrence was positively related to increasing proportion of wetland on a large spatial scale (radius: 4,000 m), for the medium disperser B. ino on an intermediate spatial scale (2,000 m) and for the poorest disperser B. titania on a small spatial scale (1,000 m). Nearby forest did not negatively affect butterfly species distribution but instead enhanced the probability of occurrence and the population density of B. titania. The fen-specialist B. selene had a higher probability of occurrence and higher population densities on grazed compared to mown fens. The altitude of the habitat patches affected the occurrence of the three species and increasing habitat area enhanced the probability of occurrence of B. selene and B. ino. We conclude that, the surrounding landscape is of relevance for species distribution, but management and habitat fragmentation are often more important. We suggest that butterfly conservation should not focus only on a patch scale, but also on a landscape scale, taking into account species-specific dispersal abilities. [ABSTRACT FROM AUTHOR]