Power-law scaling in dimension-to-biomass relationship of fish schools

Motivated by the finding that there is some biological universality in the relationship between school geometry and school biomass of various pelagic fishes in various conditions, I here establish a scaling law for school dimensions: the school diameter increases as a power-law function of school biomass. The power-law exponent is extracted through the data collapse, and is close to 3/5. This value of the exponent implies that the mean packing density decreases as the school biomass increases, and the packing structure displays a mass-fractal dimension of 5/3. By exploiting an analogy between school geometry and polymer chain statistics, I examine the behavioral algorithm governing the swollen conformation of large-sized schools of pelagics, and I explain the value of the exponent.Comment: 25 pages, 6 figures, to appear in J. Theor. Bio

Observation of Very High Energy Gamma Rays from HESS J1804-216 with CANGAROO-III Telescopes

We observed the unidentified TeV gamma-ray source HESS J1804-216 with the CANGAROO-III atmospheric Cerenkov telescopes from May to July in 2006. We detected very high energy gamma rays above 600 GeV at the 10 sigma level in an effective exposure of 76 hr. We obtained a differential flux of (5.0+/-1.5_{stat}+/-1.6_{sys})\times 10^{-12}(E/1 TeV)^{-\alpha} cm^{-2}s^{-1}TeV^{-1} with a photon index \alpha of 2.69 +/- 0.30_{stat} +/- 0.34_{sys}, which is consistent with that of the H.E.S.S. observation in 2004. We also confirm the extended morphology of the source. By combining our result with multi-wavelength observations, we discuss the possible counterparts of HESS J1804-216 and the radiation mechanism based on leptonic and hadronic processes for a supernova remnant and a pulsar wind nebula.Comment: 11 pages, 12 figures, Accepted in Ap

Ensiling of soybean curd residue and wet brewers grains with or without other feeds as a total mixed ration

Wet brewers grains and soybean curd residue were stored in laboratory-scale silos without (BG and SC silages, respectively) or with other ingredients as total mixed rations (BGT and SCT silages, respectively). Silages were opened after 14 and 56 d, and microbial counts, fermentation products, and aerobic stability were determined. Denaturing gradient gel electrophoresis was carried out to examine bacterial communities, and several bacteria that appeared to be involved in fermentation were identified. Lactic acid content was greater in SCT than in BGT silage, but lower in SC than in BG silage. Ethanol content was greater in BG than in SC regardless of silage type. Aerobic deterioration occurred promptly in ensiling materials (nonensiled by-products and total mixed ration mixtures) and in silages stored alone; however, SCT and BGT silages resisted deterioration and no heating was found for more than 5.5 d regardless of storage period. Silages were stable even with high yeast populations at silo opening, whereas prolonged ensiling decreased yeast counts in the 2 total mixed ration silages. The denaturing gradient gel electrophoresis profiles appeared similar between SCT and BGT silages but not between SC and BG silages. Weissella spp. and Lactobacillus brevis were common in aerobically stable SCT and BGT silages, and Lactobacillus buchneri was detected only in BGT silage. Both L. brevis and L. buchneri were found in silage but not in ensiling materials. Several other lactic acid bacteria were also identified in SCT and BGT silages, but did not appear to be related to fermentation and aerobic stability.</p

Efficient delivery of radical cystectomy after neoadjuvant chemotherapy for muscle‐invasive bladder cancer

BACKGROUND: Cystectomy delay >90 days after a diagnosis of muscle‐invasive bladder cancer (MIBC) adversely affects pathologic stage and survival outcomes in patients who undergo primary surgery. After neoadjuvant chemotherapy (NAC), the impact of the timing of cystectomy delivery on these outcomes is uncertain. Poor communication between urologic and medical oncologists can result in cystectomy delay after systemic treatment. The authors of this report hypothesized that a delay in cystectomy delivery after NAC is associated with adverse survival outcomes. METHODS: An eligible cohort of 153 patients with MIBC received NAC and underwent radical cystectomy between 1990 and 2007. At the authors' institution, the genitourinary team strives to schedule patients for surgery at the time of initial evaluation or after their first chemotherapy cycle. Clinicopathologic characteristics, including timing of cystectomy, chemotherapy delivery, vital status, and reasons for excessive surgical delay, were analyzed retrospectively using an institutional database. A Cox proportional regression model was used to test the association between the timing of cystectomy delivery and survival. RESULTS: The median follow‐up for all patients was 3.6 years. The median time to cystectomy was 16.6 weeks and 6.9 weeks from the first and last day of NAC, respectively. In multivariate analyses, the timing of cystectomy delivery from the termination of NAC did not significantly alter the risk of survival. The most common reason for cystectomy delivery beyond 10 weeks (28 patients; 18%) was procedural scheduling. CONCLUSIONS: Cystectomy delivery within 10 weeks after NAC did not compromise patient survival and, thus, provided a reasonable window for patient recovery and surgical intervention. Cancer 2012;. © 2011 American Cancer Society. The authors analyzed the timing between the termination of neoadjuvant chemotherapy and cystectomy and assessed its impact on the survival of patients with muscle‐invasive bladder cancer. By using a multidisciplinary approach, the authors determined that the median time to cystectomy was 6.9 weeks. The results indicated that undergoing cystectomy within 10 weeks after the completion of neoadjuvant chemotherapy did not compromise cancer‐specific or overall survival.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/89461/1/26240_ftp.pd

Be[com]ing a Teacher in Neoliberal Times: Visioning as Resistance in Teacher Education

Teacher education is under assault from the corporatization of public education. There is evidence that reductive, essentialized/ing discourses of standardization and compliance exert intense pressures on teacher education, and a market-based, audit culture constricts conceptions of the “good teacher”. Despite the pervasiveness of neoliberal discourses, little is known about how student teachers experience increased corporatization in education, or about how they act rather than are acted upon in this context. In examining these dynamics, we explore the following research questions: (a) How do student teachers make sense of neoliberal discourses in teaching? (b) How do student teachers experience the process of what Hammerness describes as “teacher visioning” in the context of neoliberal discourses? (c) What, if any, effect does visioning have on their responses to these discourses? We draw on qualitative data including focus groups, interviews, and document analysis from a group of early childhood student teachers enrolled in a public teacher education program and placed in field sites around eastern Massachusetts. Based on our findings, we argue that teacher visioning can, under certain circumstances, serve as an impetus for student teacher resistance to neoliberal pressures

Assessing Communities of Practice in health policy : A conceptual framework as a first step towards empirical research

Peer reviewe

Diaoyu Dao, Diaoyutai or Senkaku? Creative solutions to a festering dispute in the East China Sea from an 'Island Studies' perspective

This paper draws on extensive island examples with a view to offer ‘creative’ solutions to the ongoing dispute over the Diaoyu/Diaoyutai/ Senkaku Islands between China (and Taiwan) and Japan in the East China Sea. In spite of the rhetoric and apparent intractability of island conflicts, there are various examples from the past (and the present) that suggest how island disputes may be decided, and in ‘win–win’ ways, to the satisfaction of the different parties involved. The resolution of island territorial problems can benefit greatly from a critical appreciation of how other small islands, also contested, have had their situation resolved in non-zero-sum ways. In such cases, sovereignty has been shared, split/divided or expunged; in other cases, sovereignty disputes have been put aside in order to co-develop and co-exploit natural resources. There is also one example of a UNESCO World Heritage Site consisting of a string of small islands and surrounding waters whose management is shared between three countries.peer-reviewe

Actin behavior in bulk cytoplasm is cell cycle regulated in early vertebrate embryos

The mechanical properties of cells change as they proceed through the cell cycle, primarily owing to regulation of actin and myosin II. Most models for cell mechanics focus on actomyosin in the cortex and ignore possible roles in bulk cytoplasm. We explored cell cycle regulation of bulk cytoplasmic actomyosin in Xenopus egg extracts, which is almost undiluted cytoplasm from unfertilized eggs. We observed dramatic gelation-contraction of actomyosin in mitotic (M phase) extract where Cdk1 activity is high, but not in interphase (I-phase) extract. In spread droplets, M-phase extract exhibited regular, periodic pulses of gelation-contraction a few minutes apart that continued for many minutes. Comparing actin nucleation, disassembly and myosin II activity between M-phase and I-phase extracts, we conclude that regulation of nucleation is likely to be the most important for cell cycle regulation. We then imaged F-actin in early zebrafish blastomeres using a GFP–Utrophin probe. Polymerization in bulk cytoplasm around vesicles increased dramatically during mitosis, consistent with enhanced nucleation. We conclude that F-actin polymerization in bulk cytoplasm is cell cycle regulated in early vertebrate embryos and discuss possible biological functions of this regulation

On the relationship between mass and diameter distributions in tree communities

It has been suggested that frequency distributions of individual tree masses in natural stands are characterized by power-law distributions with exponents near -3/4, and that therefore tree communities exhibit energetic equivalence among size classes. Because the mass of trees is not measured directly, but estimated from diameter, this supposition is based on the fact that the observed distribution of tree diameters is approximately characterized by a power-law with an exponent -2. Here we show that diameter distributions of this form are not equivalent to mass distributions with exponents of -3/4, but actually to mass distributions with exponents of -11/8. We discuss the implications of this result for the metabolic theory of ecology and for understanding energetic equivalence and the processes structuring tree communities

Mechanisms of amino acid sensing in mTOR signaling pathway

Amino acids are fundamental nutrients for protein synthesis and cell growth (increase in cell size). Recently, many compelling evidences have shown that the level of amino acids is sensed by extra- or intra-cellular amino acids sensor(s) and regulates protein synthesis/degradation. Mammalian target of rapamycin complex 1 (mTORC1) is placed in a central position in cell growth regulation and dysregulation of mTOR signaling pathway has been implicated in many serious human diseases including cancer, diabetes, and tissue hypertrophy. Although amino acids are the most potent activator of mTORC1, how amino acids activate mTOR signaling pathway is still largely unknown. This is partly because of the diversity of amino acids themselves including structure and metabolism. In this review, current proposed amino acid sensing mechanisms to regulate mTORC1 and the evidences pro/against the proposed models are discussed