Leaving the door open for fish pain: Evolutionary convergence and the utility of ‘just-so stories’

Key argues that fish do not experience pain because they lack the necessary (but not necessarily sufficient) brain structures and associated functional circuitry to engender such conscious percepts. I propose that fish pain may be dependent on neuroanatomical regions and pathways that are structurally and/or functionally analogous — but not strictly homologous — to well-characterized mammalian substrates of pain. An example is the convergent appearance of the complex, single-compartment eye across invertebrate and vertebrate phylogeny. Structural-functional convergence is ubiquitous in evolution. Comparative inferences and correlative lines of evidence play an important role in building evolutionary arguments. The dismissal of the perception of pain in fish may be premature at best

Land Use Conflict: When City and Country Clash

Urban sprawl is not a new phenomenon. Metropolitan areas have been growing and expanding for the past century, pushing development into rural areas. History has shown that rural-urban conflicts are often the result. During the second half of the twentieth century, the migration to the central city has been reversed, as people pour out of cities and into the suburbs. Today, increasingly complex rural-urban land use issues have continued to generate controversy

Effects of Buoyancy on Laminar, Transitional, and Turbulent Gas Jet Diffusion Flames

Gas jet diffusion flames have been a subject of research for many years. However, a better understanding of the physical and chemical phenomena occurring in these flames is still needed, and, while the effects of gravity on the burning process have been observed, the basic mechanisms responsible for these changes have yet to be determined. The fundamental mechanisms that control the combustion process are in general coupled and quite complicated. These include mixing, radiation, kinetics, soot formation and disposition, inertia, diffusion, and viscous effects. In order to understand the mechanisms controlling a fire, laboratory-scale laminar and turbulent gas-jet diffusion flames have been extensively studied, which have provided important information in relation to the physico-chemical processes occurring in flames. However, turbulent flames are not fully understood and their understanding requires more fundamental studies of laminar diffusion flames in which the interplay of transport phenomena and chemical kinetics is more tractable. But even this basic, relatively simple flame is not completely characterized in relation to soot formation, radiation, diffusion, and kinetics. Therefore, gaining an understanding of laminar flames is essential to the understanding of turbulent flames, and particularly fires, in which the same basic phenomena occur. In order to improve and verify the theoretical models essential to the interpretation of data, the complexity and degree of coupling of the controlling mechanisms must be reduced. If gravity is isolated, the complication of buoyancy-induced convection would be removed from the problem. In addition, buoyant convection in normal gravity masks the effects of other controlling parameters on the flame. Therefore, the combination of normal-gravity and microgravity data would provide the information, both theoretical and experimental, to improve our understanding of diffusion flames in general, and the effects of gravity on the burning process in particular

Neuromodulation and Mitochondrial Transport: Live Imaging in Hippocampal Neurons over Long Durations

To understand the relationship between mitochondrial transport and neuronal function, it is critical to observe mitochondrial behavior in live cultured neurons for extended durations1-3. This is now possible through the use of vital dyes and fluorescent proteins with which cytoskeletal components, organelles, and other structures in living cells can be labeled and then visualized via dynamic fluorescence microscopy. For example, in embryonic chicken sympathetic neurons, mitochondrial movement was characterized using the vital dye rhodamine 1234. In another study, mitochondria were visualized in rat forebrain neurons by transfection of mitochondrially targeted eYFP5. However, imaging of primary neurons over minutes, hours, or even days presents a number of issues. Foremost among these are: 1) maintenance of culture conditions such as temperature, humidity, and pH during long imaging sessions; 2) a strong, stable fluorescent signal to assure both the quality of acquired images and accurate measurement of signal intensity during image analysis; and 3) limiting exposure times during image acquisition to minimize photobleaching and avoid phototoxicity

HDAC6 Regulates Mitochondrial Transport in Hippocampal Neurons

Background: Tubulin is a major substrate of the cytoplasmic class II histone deacetylase HDAC6. Inhibition of HDAC6 results in higher levels of acetylated tubulin and enhanced binding of the motor protein kinesin-1 to tubulin, which promotes transport of cargoes along microtubules. Microtubule-dependent intracellular trafficking may therefore be regulated by modulating the activity of HDAC6. We have shown previously that the neuromodulator serotonin increases mitochondrial movement in hippocampal neurons via the Akt-GSK3b signaling pathway. Here, we demonstrate a role for HDAC6 in this signaling pathway. Methodology/Principal Findings: We found that the presence of tubacin, a specific HDAC6 inhibitor, dramatically enhanced mitochondrial movement in hippocampal neurons, whereas niltubacin, an inactive tubacin analog, had no effect. Compared to control cultures, higher levels of acetylated tubulin were found in neurons treated with tubacin, and more kinesin-1 was associated with mitochondria isolated from these neurons. Inhibition of GSK3b decreased cytoplasmic deacetylase activity and increased tubulin acetylation, whereas blockade of Akt, which phosphorylates and down-regulates GSK3b, increased cytoplasmic deacetylase activity and decreased tubulin acetylation. Concordantly, the administration of 5-HT, 8-OH-DPAT (a specific 5-HT1A receptor agonist), or fluoxetine (a 5-HT reuptake inhibitor) increased tubulin acetylation. GSK3b was found to co-localize with HDAC6 in hippocampal neurons, and inhibition of GSK3b resulted in decrease

Is there a nonadherent subtype of hypertensive patient? A latent class analysis approach

To determine subtypes of adherence, 636 hypertensive patients (48% White, 34% male) reported adherence to medications, diet, exercise, smoking, and home blood pressure monitoring. A latent class analysis approach was used to identify subgroups that adhere to these five self-management behaviors. Fit statistics suggested two latent classes. The first class (labeled “more adherent”) included patients with greater probability of adhering to recommendations compared with the second class (labeled “less adherent”) with regard to nonsmoking (97.7% versus 76.3%), medications (75.5% versus 49.5%), diet (70.7% versus 46.9%), exercise (63.4% versus 27.2%), and blood pressure monitoring (32% versus 3.4%). Logistic regression analyses used to characterize the two classes showed that “more adherent” participants were more likely to report full-time employment, adequate income, and better emotional and physical well-being. Results suggest the presence of a less adherent subtype of hypertensive patients. Behavioral interventions designed to improve adherence might best target these at-risk patients for greater treatment efficiency

Supersymmetric Vacua in Random Supergravity

We determine the spectrum of scalar masses in a supersymmetric vacuum of a general N=1 supergravity theory, with the Kahler potential and superpotential taken to be random functions of N complex scalar fields. We derive a random matrix model for the Hessian matrix and compute the eigenvalue spectrum. Tachyons consistent with the Breitenlohner-Freedman bound are generically present, and although these tachyons cannot destabilize the supersymmetric vacuum, they do influence the likelihood of the existence of an `uplift' to a metastable vacuum with positive cosmological constant. We show that the probability that a supersymmetric AdS vacuum has no tachyons is formally equivalent to the probability of a large fluctuation of the smallest eigenvalue of a certain real Wishart matrix. For normally-distributed matrix entries and any N, this probability is given exactly by P = exp(-2N^2|W|^2/m_{susy}^2), with W denoting the superpotential and m_{susy} the supersymmetric mass scale; for more general distributions of the entries, our result is accurate when N >> 1. We conclude that for |W| \gtrsim m_{susy}/N, tachyonic instabilities are ubiquitous in configurations obtained by uplifting supersymmetric vacua.Comment: 26 pages, 6 figure

Group Versus Individual Physical Therapy for Veterans With Knee Osteoarthritis: Randomized Clinical Trial

BACKGROUND: Efficient approaches are needed for delivering nonpharmacological interventions for management of knee osteoarthritis (OA). OBJECTIVE: This trial compared group-based versus individual physical therapy interventions for management of knee OA. DESIGN AND METHODS: Three hundred twenty patients with knee OA at the VA Medical Center in Durham, North Carolina, (mean age=60 years, 88% male, 58% nonwhite) were randomly assigned to receive either the group intervention (group physical therapy; six 1-hour sessions, typically 8 participants per group) or the individual intervention (individual physical therapy; two 1-hour sessions). Both programs included instruction in home exercise, joint protection techniques, and individual physical therapist evaluation. The primary outcome measure was the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC; range=0-96, higher scores indicate worse symptoms), measured at baseline, 12 weeks, and 24 weeks. The secondary outcome measure was the Short Physical Performance Battery (SPPB; range=0-12, higher scores indicate better performance), measured at baseline and 12 weeks. Linear mixed models assessed the difference in WOMAC scores between arms. RESULTS: At 12 weeks, WOMAC scores were 2.7 points lower in the group physical therapy arm compared with the individual physical therapy arm (95% confidence interval [CI]-5.9, 0.5; P=.10), indicating no between-group difference. At 24 weeks, WOMAC scores were 1.3 points lower in the group physical therapy arm compared with the individual physical therapy arm (95% CI-4.6, 2.0; P=.44), indicating no significant between-group difference. At 12 weeks, SPPB scores were 0.1 points lower in the group physical therapy arm compared with the individual physical therapy arm (95% CI-0.5, 0.2; P=.53), indicating no difference between groups. LIMITATIONS: This study was conducted in one VA medical center. Outcome assessors were blinded, but participants and physical therapists were not blinded. CONCLUSIONS: Group physical therapy was not more effective than individual physical therapy for primary and secondary study outcomes. Either group physical therapy or individual physical therapy may be a reasonable delivery model for health care systems to consider