A greener Arctic does not benefit caribou; the shift in tundra vegetation due to warming is associated with declining caribou herds.

Abstract:In this study, individual tree height (TH), crown base height (CBH), crown area (CA) and crown volume (CV), which were considered as essential parameters for individual stem volume and biomass estimation, were estimated by both an airborne laser scanner (ALS) and a terrestrial laser scanner (TLS). These ALS-and TLS-derived tree parameters were compared because TLS has been introduced as an instrument to measure objects more precisely. ALS-estimated TH was extracted from the highest value within a crown boundary delineated with the crown height model (CHM). The ALS-derived CBH of individual trees was estimated by k-means clustering method using the ALS data within the boundary. The ALS-derived CA was calculated simply with the crown boundary, after which CV was computed automatically using the crown geometric volume (CGV). On the other hand, all TLS-derived parameters were detected manually and precisely except the TLS-derived CGV. As a result, the ALS-extracted TH, CA, and CGV values were underestimated whereas CBH was overestimated when compared with the TLS-derived parameters. The coefficients of determination (R

Forest canopy height is an important biophysical variable for quantifying carbon storage in terrestrial ecosystems. Active light detection and ranging (lidar) sensors with discrete-return or waveform lidar have produced reliable measures of forest canopy height. However, rigorous procedures are required for an accurate estimation, especially when using waveform lidar, since backscattered signals are likely distorted by topographic conditions within the footprint. Based on extracted waveform parameters, we explore how well a physical slope correction approach performs across different footprint sizes and study sites. The data are derived from airborne (Laser Vegetation Imaging Sensor; LVIS) and spaceborne (Geoscience Laser Altimeter System; GLAS) lidar campaigns. Comparisons against field measurements show that LVIS data can satisfactorily provide a proxy for maximum forest canopy heights (n = 705, RMSE = 4.99 m, and R 2 = 0.78), and the simple slope correction grants slight accuracy advancement in the LVIS canopy height retrieval (RMSE of 0.39 m improved). In the same vein of the LVIS with relatively smaller footprint size (~20 m), substantial progress resulted from the physically-based correction OPEN ACCESS Remote Sens. 2014, 6 6567 for the GLAS (footprint size = ~50 m). When compared against reference LVIS data, RMSE and R 2 for the GLAS metrics (n = 527) are improved from 12.74-7.83 m and from 0.54-0.63, respectively. RMSE of 5.32 m and R 2 of 0.80 are finally achieved without 38 outliers (n = 489). From this study, we found that both LVIS and GLAS lidar campaigns could be benefited from the physical correction approach, and the magnitude of accuracy improvement was determined by footprint size and terrain slope.

Rationale:Lymphangiomas develop in the head, neck, and axilla of patients <2 years old in more than 90% of cases. They are rarely reported in adults.Patient concerns:Here, we report on a 37-year-old woman with a firm, hypoechoic 3.3 cm mass in the right upper, outer quadrant of the breast with discomfort, and swelling of the right axillary region.Diagnosis and interventions:She underwent wide excision of the right breast and axillary lesion and the lesion pathologic finding is lymphangioma of the breast.Outcomes:She was in good condition with no signs of postoperative complications and no evidence of recurrence at 6 months postsurgery.Lessons:Despite the rarity of breast cystic lymphangioma, its evaluation should be considered for prompt diagnosis and definitive treatment to prevent recurrence and complications. Furthermore, this is the first case of concomitant lymphangioma of the breast parenchyma and axillary region.