Sexual Dimorphism, Allometry and Vertebral Scute Morphology in Notochelys platynota (Gray, 1834)

Sexual dimorphism, allometry, and vertebral scute morphology were studied in the Malayan flat-shelled turtle, Notochelys platynota (Gray, 1834). Adult males (mean CL = 238.29 ± 50.68 mm, range 130.5-282.0, n = 16) were, on average, larger than adult females (mean CL = 203.48 ± 52.50 mm, range 125.3-330.0, n = 44). The five largest individuals in the study, however, were females (283-330 mm CL). The SDI value for this species was calculated as -1.17. Sexual dimorphism of the shell was not evident when examined by ANCOVA. The regression slopes of males and females differed significantly (P \u3c 0.05) in only one of 26 characters examined. Allometric growth of the shell, however, was evident in N. platynota. Shell shape changed as CL increased proportionally more than shell width, shell height and plastral length (18/26 characters). This allometric growth pattern yields adults with relatively narrower and flatter shells than juveniles. Of 127 specimens examined, 3.9% (n = 5) had five vertebral scutes, 85.0% (n = 108) had six, 10.2 % (n = 13) had seven and 0.8% (n = 1) had eight vertebrals. In specimens with five vertebrals (presumably the ancestral condition), all scutes were large, broader than long, and of similar length. In specimens with six or seven vertebrals, the first four and last vertebrals (Vert6 or 7) were large and broader than long. The smaller supernumerary scutes characteristic of this species were usually found between the fourth and last vertebrals and were occasionally longer than broad (5% of specimens, n = 5). The presence of supernumerary scutes does not affect the relative length of the entire vertebral series, as evidenced by a lack of variation in this character among specimens with five, six and seven vertebrals. Instead, as suggested by an increased width to length ratio of several normal scutes in specimens with six or seven vertebrals, there is a shortening of several normal scutes to accommodate the additional ones. In specimens with six or seven vertebral scutes, the relative lengths of most normal vertebrals (all except Vert1) were noticeably shorter than in specimens with five vertebral scutes. The fourth and last (Vert6 or 7) vertebrals were the shortest of these normal scutes

Reproduction and Health of a Beaver (Castor canadensis) Population in Prince William County, Virginia

Reproduction and health were studied in a beaver (Castor canadensis) population from Prince William County, Virginia during 1998. Copulating beavers were observed in Quantico Creek at Prince William Forest Park on 22 January. Seven females from Quantico Marine Base were trapped between January and May, sacrificed, and dissected. Those reproductively active weighed over 39 pounds (17.7 kg) and were trapped before 1 March. Mean litter size based on counts of corpora lutea was 4.80 young (3-7); however, litter size based on the number of embryos present was only 2.75 (1-3), comparable to most others reported in the literature. Five of the seven dissected females had prime pelts, one an average pelt, and one a poor quality pelt. Subcutaneous fat deposits and those at the base of the tail were moderate to high in all females. Four contained moderate mesenteric deposits, while three had low to no mesenteric fat present. No abnormalities were found in the heart, lungs, liver, kidneys, or bladder. Four females had suffered wounds to either the tail and/or body, possibly from male courtship. The females harbored two of the most common beaver helminths: the stomach nematode, Travassosizts america1711S (100% incidence) and the cecal trematode, Stichorchis subtriquetnis (86% incidence). Compared to other reported studies, these worm burdens were moderate to average

The effect of Fe atoms on the adsorption of a W atom on W(100) surface

We report a first-principles calculation that models the effect of iron (Fe) atoms on the adsorption of a tungsten (W) atom on W(100) surfaces. The adsorption of a W atom on a clean W(100) surface is compared with that of a W atom on a W(100) surface covered with a monolayer of Fe atoms. The total energy of the system is computed as the function of the height of the W adatom. Our result shows that the W atom first adsorbs on top of the Fe monolayer. Then the W atom can replace one of the Fe atoms through a path with a moderate energy barrier and reduce its energy further. This intermediate site makes the adsorption (and desorption) of W atoms a two-step process in the presence of Fe atoms and lowers the overall adsorption energy by nearly 2.4 eV. The Fe atoms also provide a surface for W atoms to adsorb facilitating the diffusion of W atoms. The combination of these two effects result in a much more efficient desorption and diffusion of W atoms in the presence of Fe atoms. Our result provides a fundamental mechanism that can explain the activated sintering of tungsten by Fe atoms.Comment: 9 pages, 2 figure

Supported Decision-Making: The Expectations Held by People With Experience of Mental Illness

Supported decision-making (SDM) is a principle guiding mental health service provision, which aims to improve people’s ability to make informed decisions about their care. Understanding diverse individual needs is vital to its success. Based on 29 narrative interviews with people diagnosed with mental illness in Australia, we examine how participants reflected on their own experiences of SDM. We find that participants’ conceptualization of mental health expertise, their own lived experiences and sense of agency, and their varying needs for dependence and independence influenced their relations with mental health practitioners. These factors in turn shaped their expectations about SDM. Four narrative positions emerged: the ‘Inward Expert’, the ‘Outward Entrustor’, the ‘Self-Aware Observer’ and the ‘Social Integrator’. These positionings influenced the type or style of support that participants expected and considered most useful. Our findings are relevant to developing effective approaches to SDM that take into account service users’ needs and preferences

Stress radiography Is a reliable method to quantify posterior cruciate ligament insufficiency: A systematic review

PURPOSE: To perform a systematic review of posterior tibial stress radiography techniques and radiographic measurement methods to compare their accuracy and efficacy to aid clinicians in quantifying posterior cruciate ligament laxity. METHODS: Electronic databases, including PubMed, MEDLINE, Embase.com 1947- , Ovid Medline 1946- , Scopus 1823- , Cochrane Central Register of Controlled Trials (CENTRAL), and Clinicaltrials.gov 1997- were queried in December 2020. The abstracts of articles were reviewed by 2 authors for published studies comparing posterior tibial stress radiography techniques, describing, and comparing radiographic measurement methods, and comparing stress radiographs with instrumented knee testing. RESULTS: The systematic review included 13 studies that satisfied the inclusion and exclusion criteria. There were 3 studies comparing stress radiography with instrumented knee devices, 6 studies comparing stress radiography techniques, and 5 studies evaluating the reliability of radiographic measurements. Stress radiography was more sensitive for detecting posterior tibial translation than KT-1000 and KT-2000 and was similar to the Rolimeter knee arthrometer. The majority of studies found TELOS stress radiography to be more sensitive than gravity or hamstring contraction stress views. Kneeling stress radiographs were found to be equivalent to TELOS in one study and superior in another. All reported methods of radiographic measurement for posterior tibial translation showed good-to-excellent intraobserver and interobserver reliability, and no single technique demonstrated clear superiority. CONCLUSIONS: The results of this systematic review indicate that posterior stress radiography with TELOS and kneeling stress radiography are the most reliable methods to evaluate posterior cruciate ligament laxity. Gravity stress and hamstring contraction can be used but may underestimate posterior tibial translation. Radiographic measurement methods are reliable and no single method is clearly superior. CLINICAL RELEVANCE: This information will allow clinicians to use various radiographic methods to objectively measure posterior tibial translation to formulate a treatment plan

Association of Meniscal Status, Lower Extremity Alignment, and Body Mass Index With Chondrosis at Revision Anterior Cruciate Ligament Reconstruction

BACKGROUND: Knees undergoing revision anterior cruciate ligament reconstruction (rACLR) have a high prevalence of articular cartilage lesions. HYPOTHESIS: The prevalence of chondrosis at the time of rACLR is associated with meniscal status and lower extremity alignment. STUDY DESIGN: Cross-sectional study; Level of evidence, 3. METHODS: Data from the prospective Multicenter ACL Revision Study (MARS) cohort were reviewed to identify patients with preoperative lower extremity alignment films. Lower extremity alignment was defined by the weightbearing line (WBL) as a percentage of the tibial plateau width, while the chondral and meniscal status of each weightbearing compartment was recorded at the time of surgery. Multivariable proportional odds models were constructed and adjusted for relevant factors to examine which risk factors were independently associated with the degree of medial and lateral compartment chondrosis. RESULTS: The cohort included 246 patients with lower extremity alignment films at the time of rACLR. Mean (+/-SD) patient age was 26.9 +/- 9.5 years and body mass index (BMI) was 26.4 +/- 4.6. The medial compartment had more chondrosis (grade 2/3, 42%; grade 4, 6.5%) than did the lateral compartment (grade 2/3, 26%; grade 4, 6.5%). Disruption of the meniscus was noted in 35% of patients on the medial side and 16% in the lateral side. The mean WBL was 0.43 +/- 0.13. Medial compartment chondrosis was associated with BMI (P = .025), alignment (P = .002), and medial meniscal status (P = .001). None of the knees with the WBL lateral to 0.625 had grade 4 chondrosis in the medial compartment. Lateral compartment chondrosis was significantly associated with age (P = .013) and lateral meniscal status (P \u3c .001). Subjects with intact menisci were found to decrease their odds of having chondrosis by 64% to 84%. CONCLUSION: The status of articular cartilage in the tibiofemoral compartments at the time of rACLR is related to meniscal status. Lower extremity alignment and BMI are associated with medial compartment chondrosis

Effect of Limb Lengthening on Internodal Length and Conduction Velocity of Peripheral Nerve

The influences of axon diameter, myelin thickness, and internodal length on the velocity of conduction of peripheral nerve action potentials are unclear. Previous studies have demonstrated a strong dependence of conduction velocity on internodal length. However, a theoretical analysis has suggested that this relationship may be lost above a nodal separation of ∼0.6 mm. Here we measured nerve conduction velocities in a rabbit model of limb lengthening that produced compensatory increases in peripheral nerve growth. Divided tibial bones in one hindlimb were gradually lengthened at 0.7 mm per day using an external frame attached to the bone. This was associated with a significant increase (33%) of internodal length (0.95–1.3 mm) in axons of the tibial nerve that varied in proportion to the mechanical strain in the nerve of the lengthened limb. Axonal diameter, myelin thickness, and g-ratios were not significantly altered by limb lengthening. Despite the substantial increase in internodal length, no significant change was detected in conduction velocity (∼43 m/s) measured either in vivo or in isolated tibial nerves. The results demonstrate that the internode remains plastic in the adult but that increases in internodal length of myelinated adult nerve axons do not result in either deficiency or proportionate increases in their conduction velocity and support the view that the internodal lengths of nerves reach a plateau beyond which their conduction velocities are no longer sensitive to increases in internodal length