Differentiation between left and right wing stridulatory files in the field cricket Gryllus bimaculatus (Orthoptera: Gryllidae).

Male crickets produce acoustic signals by wing stridulation, attracting females for mating. A plectrum on the left forewing's (or tegmen) anal margin rapidly strikes along a serrated vein (stridulatory file, SF) on the opposite tegmen as they close, producing vibrations, ending in a tonal sound. The tooth strike rate of the plectrum across file teeth is equal to the sound frequency produced by the cricket (i.e., ∼5k teeth/s for ∼5 kHz in field crickets) and is specific to the forewing's resonant frequency. Sound is subsequently amplified using specialised wing cells. Anatomically, the forewings appear to mirror each other: both tegmina bear a SF and plectrum; however, most cricket species stridulate using right-over-left wing overlap making the stridulatory mechanism asymmetrical by default, rendering the left tegmen's SF unused. Therefore, we hypothesised structural differences between functional and unfunctional SFs. Three-dimensional mapping was used to accurately measure SF structures in Gryllus bimaculatus wings. We found that the left SF shows significantly greater variation in inter-tooth distance than the right, but less variation within the first sixty teeth (the functional part) than the right file. The left SF's slow evolutionary change over millions of years is discussed considering modern molecular phylogenies and fossil records.

Implications of positive urine toxicology screening in trauma patients.

BACKGROUND: Pain management in trauma patients can be difficult due to their varied injuries and presence or absence of illicit substances in their systems. Additionally, trauma patients have variable lengths of stay. Limiting length of stay to what is medically necessary and preventing long-term dependence on narcotic medications are important in trauma patient care. METHODS: We performed a retrospective review of 385 consecutive trauma activations at a Level II trauma center with urine toxicology screens from 2015. Main outcome measures recorded were urine toxicology results, average daily morphine milligram equivalents (MME), length of stay (LOS), injury severity score (ISS). We also recorded patient demographic information. Statistical analysis compared outcomes and demographics between trauma patients with positive urine toxicology screens to those with negative screens. Significance was set at p < 0.05. RESULTS: Positive urine toxicology screens were present in 230/385 (59.7%) patients. The median (interquartile range (IQR)) daily MME usage in the positive urine toxicology group was 25.2 (12.0-48.6) versus 12.4 (2.5-27.5) for those with a negative drug screen (p < 0.001). Median LOS was 3 (1-6) days versus 2 (1-4) days for the positive and negative groups, respectively (p = 0.004). There were no differences in age, gender distribution, or ISS between the two groups. Subgroup analysis showed urine toxicology positive for opiates, benzodiazepines, and tetrahydrocannabinol (THC) were associated with increased daily MME. Benzodiazepines and amphetamines were associated with increased LOS. CONCLUSION: This study identifies a positive toxicology screening as a risk factor for increased narcotic demands and longer length of stay in trauma patients. These findings may assist in developing treatment plans and setting expectations in this population. This information can also lead to proactive interventions aimed at minimizing narcotic use and shortening LOS in this population.

Relevant Insertion Site Anatomy of the Conventus Distal Radius System.

BACKGROUND: The Conventus Distal Radius System (DRS) is an intramedullary fixation scaffold inserted into the lateral aspect of the distal radius. The purpose of this study was to identify insertion site anatomy to illustrate risks associated with the minimally invasive nature of radial-sided implant application. METHODS: Ten cadavers were utilized. Using fluoroscopy, the 1.1-mm Kirschner wire and template was introduced per manufacturer's guidelines, access guide assembled, and dissection carried out to the superficial radial nerve (SRN) with preservation of the native location. The access guide marked the insertion location for the side-cut drill. This point was measured in relationship to structures nearby, including the SRN, brachioradialis (BR), lateral antebrachial cutaneous nerve (LABCN), and radial styloid (RS). RESULTS: The large guide contacted the SRN in 4 of 10 cadavers and was volar to it in 6 of 10. When volar, the mean distance was 1.7 mm. The tip of the RS to the large access guide averaged 44.5 mm. The small guide contacted the SRN in 2 of 10, was volar to it in 4 of 10, and between the bifurcation in 4 of 10. When volar, the distance averaged 3.25 mm. When bifurcated, the distance from the small guide to both the dorsal and volar branches was 3.5 mm. The distance from the RS to the small guide averaged 37.8 mm. The LABCN was found in the field of dissection in 4 of 10 cadavers. CONCLUSIONS: Several structures are at risk during insertion of the Conventus DRS; thus, knowledge of the relevant anatomy of this minimally invasive approach is crucial to optimize outcomes and patient satisfaction, and to avoid nerve injury.

A Model for Mountain Pine Beetle Outbreaks in an Age-Structured Forest: Predicting Severity and Outbreak-Recovery Cycle Period.

The mountain pine beetle (MPB, Dendroctonus ponderosae), a tree-killing bark beetle, has historically been part of the normal disturbance regime in lodgepole pine (Pinus contorta) forests. In recent years, warm winters and summers have allowed MPB populations to achieve synchronous emergence and successful attacks, resulting in widespread population outbreaks and resultant tree mortality across western North America. We develop an age-structured forest demographic model that incorporates temperature-dependent MPB infestations. Stability of fixed points is analyzed as a function of (thermally controlled) MPB population growth rates and indicates the existence of periodic outbreaks that intensify as growth rates increase. We devise analytical methods to predict outbreak severity and duration as well as outbreak return time. After incorporating a spatial aspect and controlling initial stand demographic variation, the model predicts cycle periods that fall within observed outbreak return time ranges. To assess future MPB impact on forests, we use climate model projected temperatures with our model-based approximation methods to predict potential severity of future outbreaks that reflect the effects of changing climate.