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ABSTRACT Aquatic invasive species have negative impacts on native biodiversity and pose a significant threat to overall ecosystem health. Successfully established non‐native species possess life history traits that are advantageous for colonization and expansion into novel environments. The reproductive traits and strategies of fish are often good predictors of invasion success. Thus, understanding reproductive dynamics of non‐native species in their introduced environments is an important component for predicting expansion and effectively managing invasive populations. The Weather Loach Misgurnus anguillicaudatus is a recently discovered introduced species in Georgia, USA, and little is known about its life history attributes where it is not native. Thus, the objectives of this study were to: (1) estimate mean batch fecundity of female Weather Loach; (2) determine timing and periodicity of spawning; and (3) evaluate whether the gonadosomatic index (GSI) is a reliable indicator of reproductive status in this species. Based on observed peaks in eggs larger than 500 µm, we identified the presumed spawning season for Weather Loach to be occurring from April through August. The highest average fecundity observed was during July (10,539 eggs) and the lowest average fecundity observed was during April (3083 eggs). The GSI was a strong predictor of fecundity and tracked the number of mature eggs present in each month of the year. Our estimates of batch fecundity and determination of the annual spawning season can help managers better understand reproductive dynamics and develop predictive population models aimed at evaluating management activities.

BackgroundSegmental rib fractures in blunt thoracic trauma present with increased morbidity and mortality with an association of increased pulmonary insult and concomitant injuries. There is a paucity within the literature regarding the necessity of fixation of one or both segments of rib fractures in a flail chest. This study aimed to analyze surgical rib fixation and assess outcomes for non-fixed fractured rib ends in segmental rib fractures.MethodsThis is a retrospective review of 125 patients who underwent open reduction internal fixation of flail segmental rib fractures at our urban Level 1 trauma center. Initial plain films and CT were compared with follow-up plain film imaging at 3 months to assess radiographic outcomes, fracture healing, fixation failure, or residual deformity. Clinical outcomes such as length of intensive care unit (ICU) stay, length of ventilatory support, associated pneumonia, duration until chest tube removal, and need for additional rib surgery were analyzed.ResultsFixation of a single end of segmental rib fractures and flail segments was associated with decreased incidence of fracture union at 3 months postoperatively (43/55 vs 65/70, respectively; p=0.018) but failed to show any difference in fracture collapse (50/55 vs 67/70, respectively; p=0.223). There were no differences between postoperative ICU length of stay (4.18±5.54 vs 4.62±4.48 days, respectively; p=0.690), postoperative ventilatory status (29/55 vs 38/70, respectively; p=0.840), duration of ventilatory support (3.52±4.69 vs 4.34±5.87, respectively; p=0.430), or associated pneumonia (7/55 vs 8/70, respectively; p=0.770).ConclusionsThese data support that fixation of both sides of flail segment rib fractures results in improved rib fracture union at 3 months postoperatively. However, fixation of both sides of flail segments does not appear to result in any difference in fracture collapse or clinical perioperative outcomes.Level of EvidenceTherapeutic Level III

Background: Pilon fractures are associated with high-energy injuries, and there is presently much debate as to optimal fixation strategies and timing of intervention. There is little evidence comparing the type of fibular fixation during pilon fracture fixation. The purpose of this study was to compare fibular fixation methods in complex pilon injuries as it relates to pilon union rates and development of post-traumatic arthritis. Methods: This was a retrospective review from an urban Level 1 trauma center from January 2009 to May 2019, including patients age ≥ 18 who sustained a pilon fracture with an associated fibula fracture. Patients were allocated into one of three groups based on fibular fracture treated with plating, intramedullary device, or no fixation. Radiographic analysis was performed postoperatively and at final follow up to evaluate for tibial or fibular nonunion, malunion, talocrural angle, and ankle Kellgren–Lawrence grade. Results: Of the 107 patients in this study, 42 underwent surgical fixation of their fibular fracture. There were no differences with respect to tibial or fibular union rates amongst the three groups. Furthermore, there were no differences in the presence of radiographic ankle arthritis at final follow up. However, Kellgren–Lawrence arthritis grading did appear to be a more severe grade in patients who did not undergo fibular fixation (p = 0.001). Conclusions: Fibular intramedullary fixation does not appear to influence tibial or fibular nonunion rates as compared to plating in complex pilon injuries.

Morbidity and Mortality Weekly Report (MMWR)

We present the joint astrometric and direct imaging discovery, mass measurement, and orbital analysis of HD 63754 B (HIP 38216 B), a companion near the stellar-substellar boundary orbiting ~20 AU from its Sun-like host. HD 63754 was observed in our ongoing high-contrast imaging survey targeting stars with significant proper-motion accelerations between Hipparcos and Gaia consistent with wide-separation substellar companions. We utilized archival HIRES and HARPS radial velocity (RV) data, together with the host star's astrometric acceleration extracted from the Hipparcos-Gaia Catalog of Accelerations (HGCA), to predict the location of the candidate companion around HD 63754 A. We subsequently imaged HD 63754 B at its predicted location using the Near Infrared Camera 2 (NIRC2) in the \\(L'\\) band at the W. M. Keck Observatory. We then jointly modeled the orbit of HD 63754 B with RVs, Hipparcos-Gaia accelerations, and our new relative astrometry, measuring a dynamical mass of \\({81.9}_{-5.8}^{+6.4} M_{jup}\\), an eccentricity of \\({0.260}_{-0.059}^{+0.065}\\), and a nearly face-on inclination of \\(174.81_{-0.50}^{+0.48}\\) degrees. For HD 63754 B, we obtain an L' band absolute magnitude of \\(L' = 11.39\\pm0.06\\) mag, from which we infer a bolometric luminosity of \\(log(L_{bol}/L_{\\odot})= -4.55 \\pm0.08\\) dex using a comparison sample of L and T dwarfs with measured luminosities. Although uncertainties linger in age and dynamical mass estimates, our analysis points toward HD 63754 B's identity as a brown dwarf on the L/T transition rather than a low-mass star, indicated by its inferred bolometric luminosity and model-estimated effective temperature. Future RV, spectroscopic, and astrometric data such as those from JWST and Gaia DR4 will clarify HD 63754 B's mass, and enable spectral typing and atmospheric characterization.