Evidence of increasing juvenile white sharks' (Carcharodon carcharias) habitat use at the Northern Channel Islands.

Juvenile white sharks (Carcharodon carcharias) typically aggregate along coastal beaches; however, high levels of recruitment and shifting oceanographic conditions may be causing habitat use expansions. Telemetry data indicate increased habitat use at the Northern Channel Islands (California, USA) by juvenile white shark that may be in response to increased population density at aggregation locations, or anomalous oceanographic events that impact habitat use or expand available habitat. Findings illustrate the need for long-term movement monitoring and understanding drivers of habitat use shifts and expansion to improve ecosystem management.

High resolution acoustic telemetry reveals swim speeds and inferred field metabolic rates in juvenile white sharks (Carcharodon carcharias).

White sharks (Carcharodon carcharias) are the largest shark species to display regional endothermy. This capability likely facilitates exploitation of resources beyond thermal tolerance thresholds of potential sympatric competitors as well as sustained elevated swim speeds, but results in increased metabolic costs of adults, which has been documented in different studies. Little, however, is known of the metabolic requirements in free-swimming juveniles of the species, due to their large size at birth and challenges in measuring their oxygen consumption rates in captivity. We used trilateration of positional data from high resolution acoustic-telemetry to derive swim speeds from speed-over-ground calculations for eighteen free-swimming individual juvenile white sharks, and subsequently estimate associated mass-specific oxygen consumption rates as a proxy for field routine metabolic rates. Resulting estimates of mass-specific field routine metabolic rates (368 mg O2 kg-1 h-1 ± 27 mg O2 kg-1 h-1 [mean ± S.D.]) are markedly lower than those reported in sub-adult and adult white sharks by previous studies. We argue that median cruising speeds while aggregating at nearshore nursery habitats (0.6 m s-1 [mean ± S.E = 0.59 ± 0.001], 0.3 TL s-1) are likely a feature of behavioral strategies designed to optimize bioenergetic efficiency, by modulating activity rates in response to environmental temperature profiles to buffer heat loss and maintain homeostasis. Such behavioral strategies more closely resemble those exhibited in ectotherm sharks, than mature conspecifics.

Parcellation of Human Amygdala Subfields Using Orientation Distribution Function and Spectral K-means Clustering.

Amygdala plays an important role in fear and emotional learning, which are critical for human survival. Despite the functional relevance and unique circuitry of each human amygdaloid subnuclei, there has yet to be an efficient imaging method for identifying these regions in vivo. A data-driven approach without prior knowledge provides advantages of efficient and objective assessments. The present study uses high angular and high spatial resolution diffusion magnetic resonance imaging to generate orientation distribution function, which bears distinctive microstructural features. The features were extracted using spherical harmonic decomposition to assess microstructural similarity within amygdala subfields are identified via similarity matrices using spectral k-mean clustering. The approach was tested on 32 healthy volunteers and three distinct amygdala subfields were identified including medial, posterior-superior lateral, and anterior-inferior lateral.

Simplified management of post-prostate biopsy rectal bleeding.

Transrectal ultrasound-guided biopsy of the prostate is a common urologic procedure associated with low morbidity and mortality. On occasion, rectal bleeding occurs and can be effectively managed by temporarily inserting a tampon into the rectum.

Comparison of local anesthesia techniques during transrectal ultrasound-guided biopsies.

OBJECTIVES: To compare the effectiveness of periprostatic nerve blockade versus intrarectal lidocaine during transrectal ultrasound-guided biopsies. METHODS: A prospective randomized study was performed on 150 men requiring biopsy of the prostate. Patients were assigned to three groups: group 1 received no anesthetic, group 2 received 10 mL of 2% lidocaine gel intrarectally, and group 3 received a periprostatic injection of 5 mL of 1% lidocaine solution before undergoing prostate biopsy. Patients were asked to respond to a preprocedural and postprocedural questionnaire that consisted of four questions designed to evaluate pain perception and pain experienced, respectively, during the entire procedure. RESULTS: The mean pain scores, comparing responses from groups 2 (topical lidocaine) and 3 (periprostatic) individually with those from group 1 (control), were not statistically different for any of the preprocedural questions. The postprocedural pain scores were significantly lower in groups 2 and 3 compared with those from group 1 (control) for overall procedure impression (3.1 +/- 1.7 and 2.6 +/- 1.8 versus 3.8 +/- 1.8, respectively; P <0.05 for both). The postprocedural scores for probe insertion were significantly lower for the topical group than for the control group (2.2 +/- 1.7 versus 3.7 +/- 2.1, P <0.05) but not for the periprostatic group compared with the control group (3.0 +/- 1.9, P = 0.14). The biopsy postprocedural scores were significantly lower for the periprostatic group than for the control group (2.8 +/- 1.9 versus 4.3 +/- 1.7, P <0.05). CONCLUSIONS: Our data confirm that both techniques of local anesthesia are effective in reducing patient discomfort; however, periprostatic nerve blockade using injectable lidocaine appears to be more specific in reducing pain during the biopsy portion of the procedure.