Colocation and role of polyphosphates and alkaline phosphatase in apatite biomineralization of elasmobranch tesserae

AbstractElasmobranchs (e.g. sharks and rays), like all fishes, grow continuously throughout life. Unlike other vertebrates, their skeletons are primarily cartilaginous, comprising a hyaline cartilage-like core, stiffened by a thin outer array of mineralized, abutting and interconnected tiles called tesserae. Tesserae bear active mineralization fronts at all margins and the tesseral layer is thin enough to section without decalcifying, making this a tractable but largely unexamined system for investigating controlled apatite mineralization, while also offering a potential analog for endochondral ossification. The chemical mechanism for tesserae mineralization has not been described, but has been previously attributed to spherical precursors, and alkaline phosphatase (ALP) activity. Here, we use a variety of techniques to elucidate the involvement of phosphorus-containing precursors in the formation of tesserae at their mineralization fronts. Using Raman spectroscopy, fluorescence microscopy and histological methods, we demonstrate that ALP activity is located with inorganic phosphate polymers (polyP) at the tessera–uncalcified cartilage interface, suggesting a potential mechanism for regulated mineralization: inorganic phosphate (Pi) can be cleaved from polyP by ALP, thus making Pi locally available for apatite biomineralization. The application of exogenous ALP to tissue cross-sections resulted in the disappearance of polyP and the appearance of Pi in uncalcified cartilage adjacent to mineralization fronts. We propose that elasmobranch skeletal cells control apatite biomineralization by biochemically controlling polyP and ALP production, placement and activity. Previous identification of polyP and ALP shown previously in mammalian calcifying cartilage supports the hypothesis that this mechanism may be a general regulating feature in the mineralization of vertebrate skeletons

Phonons in potassium doped graphene: the effects of electron-phonon interactions, dimensionality and ad-atom ordering

Graphene phonons are measured as a function of electron doping via the addition of potassium adatoms. In the low doping regime, the in-plane carbon G-peak hardens and narrows with increasing doping, analogous to the trend seen in graphene doped via the field-effect. At high dopings, beyond those accessible by the field-effect, the G-peak strongly softens and broadens. This is interpreted as a dynamic, non-adiabatic renormalization of the phonon self-energy. At dopings between the light and heavily doped regimes, we find a robust inhomogeneous phase where the potassium coverage is segregated into regions of high and low density. The phonon energies, linewidths and tunability are remarkably similar for 1-4 layer graphene, but significantly different to doped bulk graphite.Comment: Accepted in Phys. Rev. B as a Rapid Communication. 5 pages, 3 figures, revised text with additional dat

Randomized Composable Core-sets for Distributed Submodular Maximization

An effective technique for solving optimization problems over massive data sets is to partition the data into smaller pieces, solve the problem on each piece and compute a representative solution from it, and finally obtain a solution inside the union of the representative solutions for all pieces. This technique can be captured via the concept of {\em composable core-sets}, and has been recently applied to solve diversity maximization problems as well as several clustering problems. However, for coverage and submodular maximization problems, impossibility bounds are known for this technique \cite{IMMM14}. In this paper, we focus on efficient construction of a randomized variant of composable core-sets where the above idea is applied on a {\em random clustering} of the data. We employ this technique for the coverage, monotone and non-monotone submodular maximization problems. Our results significantly improve upon the hardness results for non-randomized core-sets, and imply improved results for submodular maximization in a distributed and streaming settings. In summary, we show that a simple greedy algorithm results in a $1/3$-approximate randomized composable core-set for submodular maximization under a cardinality constraint. This is in contrast to a known $O({\log k\over \sqrt{k}})$ impossibility result for (non-randomized) composable core-set. Our result also extends to non-monotone submodular functions, and leads to the first 2-round MapReduce-based constant-factor approximation algorithm with $O(n)$ total communication complexity for either monotone or non-monotone functions. Finally, using an improved analysis technique and a new algorithm $\mathsf{PseudoGreedy}$, we present an improved $0.545$-approximation algorithm for monotone submodular maximization, which is in turn the first MapReduce-based algorithm beating factor $1/2$ in a constant number of rounds

Detection of the Red Giant Branch Stars in M82 Using the Hubble Space Telescope

We present color-magnitude diagrams and luminosity functions of stars in two halo regions of the irregular galaxy in M82, based on F555W and F814W photometry taken with the Hubble Space Telescope and Wide Field Planetary Camera 2. The I-band luminosity function shows a sudden jump at I~23.95 mag, which is identified as the tip of the red giant branch (TRGB). Adopting the Lee et al. (1993) calibration of the TRGB based on the RR Lyrae distances to Galactic globular clusters, we obtain the distance modulus of (m-M)_0=27.95 +- 0.14 (random) +- 0.16 (systematic) mag. This corresponds to a linear distance of 3.9 +- 0.3 (random) +- 0.3 (systematicf) Mpc, which agrees well with the distance of M81 deteremined from the HST observations of the Cepheid variable stars. In addition, we observe a significant number of stars apparently brighter than the TRGB. However, with the current data, we cannot rule out whether these stars are blends of fainter stars, or are indeed intermediate-age asymptotic giant branch stars.Comment: 8 figure

Study protocol: addressing evidence and context to facilitate transfer and uptake of consultation recording use in oncology: a knowledge translation implementation study

Background: The time period from diagnosis to the end of treatment is challenging for newly diagnosed cancer patients. Patients have a substantial need for information, decision aids, and psychosocial support. Recordings of initial oncology consultations improve information recall, reduce anxiety, enhance patient satisfaction with communication, and increase patients' perceptions that the essential aspects of their disease and treatment have been addressed during the consultation. Despite the research evidence supporting the provision of consultation recordings, uptake of this intervention into oncology practice has been slow. The primary aim of this project is to conduct an implementation study to explicate the contextual factors, including use of evidence, that facilitate and impede the transfer and uptake of consultation-recording use in a sample of patients newly diagnosed with breast or prostate cancer. Methods: Sixteen oncologists from cancer centres in three Canadian cities will participate in this three-phase study. The preimplementation phase will be used to identify and address those factors that are fundamental to facilitating the smooth adoption and delivery of the intervention during the implementation phase. During the implementation phase, breast and prostate cancer patients will receive a recording of their initial oncology consultation to take home. Patient interviews will be conducted in the days following the consultation to gather feedback on the benefits of the intervention. Patients will complete the Digital Recording Use Semi-Structured Interview (DRUSSI) and be invited to participate in focus groups in which their experiences with the consultation recording will be explored. Oncologists will receive a summary letter detailing the benefits voiced by their patients. The postimplementation phase includes a conceptual framework development meeting and a seven-point dissemination strategy. Discussion: Consultation recording has been used in oncology, family medicine, and other medicine specialties, and despite affirming evidence and probable applications to a large number of diseases and a variety of clinical contexts, clinical adoption of this intervention has been slow. The proposed study findings will advance our conceptual knowledge of the ways to enhance uptake of consultation recordings in oncology

CHARACTERISTICS OF NATURE-BASED TOURISM ENTERPRISES IN NORTH DAKOTA

Recreational activities related to North Dakota's wealth of natural resources are well-established in North Dakota. In recent years, North Dakota's abundant resources have attracted visitors from around the country and the world. In addition to providing recreational activities for residents and visitors alike, natural resource-based tourism is a basic sector that may have considerable potential for creating economic opportunities in rural areas. Recognition of the potential importance of resource-based tourism to rural economies is well-advanced in other parts of the United States. However, little attention has historically been paid to tourism in North Dakota. While much anecdotal evidence exists suggesting that natural resource-based tourism is growing in North Dakota, no basic research on the sector has to date been completed. The goal of this study is to identify and analyze existing agricultural and natural resource-based tourism enterprises in North Dakota.nature-based tourism, outdoor recreation, enterprise characteristics, rural businesses, economic development, Resource /Energy Economics and Policy,

RURAL ECONOMIC EFFECTS OF THE CONSERVATION RESERVE PROGRAM IN NORTH DAKOTA

The Conservation Reserve Program (CRP), enacted in 1985, provides conservation benefits and agricultural supply control through voluntary, long-term retirement of crop land. Large-scale, long-term land retirement programs produce, in varying degrees, negative effects on those businesses and economic sectors that provide agricultural inputs and services. While the effects of the CRP on agriculture are well understood, economic assessments of the market-value of conservation benefits from the program accruing to rural economies remains largely undocumented. One of the conservation benefits of the program is wildlife habitat, which has bolstered upland bird, waterfowl, and big game populations. Growing wildlife populations have contributed to increased consumptive and non-consumptive wildlife-based recreation. This study addressed the net economic effects of decreased agricultural activity and increased recreational activity associated with the CRP in six rural areas of North Dakota from 1996 through 2000. The negative effects of the CRP on agricultural revenues were based on the level of economic activity that would have occurred in the absence of the program. The net change in revenues from CRP land returning to agricultural production in the six study areas was estimated at $76 million or about$56 per CRP-acre. However, returning CRP lands to agricultural production was estimated to lower commodity prices and reduce agricultural revenues on non-CRP lands by $25.9 million. The combined effect was estimated at$50.2 million annually or $37 per CRP-acre in the study areas. The CRP affects many types of outdoor recreation; however, hunting was identified as the most influenced type of recreation in North Dakota. Recreational impacts were determined by comparing pheasant, waterfowl, and deer hunter numbers before and after the CRP, assigning the relative role the CRP has played in the change in hunter numbers, allocating a percentage of the change in hunter numbers to each study area, and applying seasonal hunter expenditure patterns to the change in hunter numbers. Average annual CRP-related hunter expenditures in the six study areas were estimated at$12.8 million or $9.45 per CRP-acre. Overall, recreational revenues averaged 26 percent of the agricultural losses. The degree to which CRP-based hunting revenues in rural areas offset agricultural losses varied throughout the state. In several cases, hunting expenditures offset a substantial portion of the agricultural losses, while in other areas, the net economic loss from the program remains high. The net economic effects of the program in western and central North Dakota were the most favorable, whereas the effects were least favorable in eastern areas of the state. In North Dakota, the net economic effect of losses in agricultural revenues and gains in hunting-based recreational expenditures indicated that several areas of the state are not as economically burdened by the CRP as previous research has suggested.Conservation Reserve Program, Economic Impacts, Rural Economies, Land Economics/Use,

PERCEPTIONS OF LEAFY SPURGE AND EVALUATION OF THE TEAM LEAFY SPURGE PROJECT, BY PUBLIC LAND MANAGERS, LOCAL DECISION MAKERS, AND RANCH OPERATORS

Leafy spurge is an exotic, noxious, perennial weed which is widely established in the north central United States and is an especially serious problem in the northern Great Plains (Bangsund et al. 1999). In 1997, the Agriculture Research Service and Animal Plant Health Inspection Service, U.S. Department of Agriculture, initiated a major Integrated Pest Management (IPM) research and demonstration project to develop and demonstrate ecologically based IPM strategies that can produce effective, affordable leafy spurge control. In 1998 and 1999, a survey of ranchers and public land managers was conducted to evaluate managerial, institutional, and social factors that might affect the rate and extent of implementation of various control strategies. In 2001, a second survey of the same ranchers and public land managers was conducted to (1) assess any changes in land managers' perceptions of weed problems, control alternatives, and related issues, and (2) evaluate the impact of the TEAM Leafy Spurge project on the respondent's weed control practices. The impacts of noxious weeds on grazing operations, specifically leafy spurge, are not abating, and ranchers seem more aware than ever of the severity of the problem. A slightly larger percentage of respondents in 2001 view leafy spurge as a major problem and the most serious problem for grazing operations than in 1998 and 1999. Heightened awareness among landowners may also be linked to TEAM Leafy Spurge's efforts to inform landowners of the problem and offer affordable, effective weed management techniques. While the use of biological control methods, specifically flea beetles, has grown, herbicides continue to be the control practice of choice. While slightly fewer respondents reported using herbicides in 2001 than in 1998 and 1999, the vast majority of landowners plan to continue to use herbicides. Over 50 percent of respondents are using biological control, and over 76 percent of respondents indicated flea beetles were either somewhat or very effective in controlling leafy spurge. Nearly half of the respondents had heard of TEAM Leafy Spurge, and all TEAM Leafy Spurge demonstration sites, events, and publications were favorably rated. A large majority of the respondents agreed that the program had been effective in demonstrating and communicating leafy spurge treatment and control options. Based on the results of the 2001 survey, it would appear that the program has indeed made progress in communicating the type of information landowners need to address what continues to be a significant issue for grazing operations in the Midwest.leafy spurge, noxious weeds, weed management, rancher opinion, Land Economics/Use,

LOCAL SOCIOECONOMIC IMPACTS OF THE CONSERVATION RESERVE PROGRAM

The Conservation Reserve Program (CRP), first enacted in 1985, seeks to achieve both conservation and agricultural supply control objectives through voluntary, long-term (10 year contracts) retirement of cropland. By fall 2000, the program had enrolled about 31.4 million acres nationwide, and North Dakota ranked third among the states, with 3.2 million contracted acres, or 11 percent of the state's total cropland. Although long-term land retirement offers a variety of environmental benefits, as well as providing a stable income to participating landowners, large-scale land retirement can pose adverse economic impacts for nearby communities, primarily because agricultural supply and service sector businesses may be adversely affected. This study was undertaken to examine the local socioeconomic effects of the Conservation Reserve Program in rural areas of North Dakota. Interviews with agricultural and community leaders in six rural areas of North Dakota revealed that the CRP was perceived to have both positive and negative effects. The program was considered a substantial benefit to landowners, providing them with a guaranteed income from some of their least productive land. In addition, the environmental benefits of the program, including reduced soil erosion, improved water quality, and enhanced wildlife populations, were widely recognized. Negative effects cited by the leaders focused on the adverse impacts of cropland retirement on the farm supply and service sector and the role of the CRP in declining farm numbers and rural depopulation. A survey of more than 1,000 CRP contract holders provided additional perspective regarding the program's effects. Leading reasons for enrolling land in the CRP were to reduce erosion/increase soil fertility (24%), reduce income risk (23%), CRP was economically attractive (22%), and provide a transition to retirement (11%). The contract holders also reported that the land they enrolled in the CRP had lower yields than other land in the area, by an average of 5 percent. Forty-two percent of the respondents had enrolled 150 acres or less and only 21 percent had enrolled more than 450 acres. Of the contract holders who had once farmed but were no longer farming, only 23 percent indicated that the CRP influenced their decision to quit farming. On the other hand, of the respondents who were currently farming, 31 percent indicated that the CRP had been instrumental in keeping them on the farm. When the leaders were asked for suggestions to improve the program, their responses reflected three major themes. One group felt that the CRP should focus on highly erodible land and that recent changes in enrollment criteria have allowed too much productive farmland to be enrolled. Another group of respondents argued for periodic haying of the CRP land (e.g., every third or fourth year), a measure they thought that would both improve the wildlife habitat value of the land and provide a feed base for livestock producers. Finally, a number of leaders in each study area suggested options to increase recreational access to CRP land. They believe that increased economic activity associated with recreational activities (primarily hunting) may offer their communities a means to offset some of the economic losses associated with land retirement.Conservation Reserve Program (CRP), cropland retirement, socioeconomic impacts, costs and benefits, Land Economics/Use,

RANCH OPERATORS' PERCEPTIONS OF LEAFY SPURGE MANAGEMENT AND EVALUATION OF THE TEAM LEAFY SPURGE PROJECT

Leafy spurge is an exotic, noxious, perennial weed which is widely established in the north central United States and is an especially serious problem in the northern Great Plains (Bangsund et al. 1999). In 1997, the Agriculture Research Service and the Animal and Plant Health Inspection Service, U.S. Department of Agriculture, initiated a major Integrated Pest Management (IPM) research and demonstration project to develop and demonstrate ecologically based IPM strategies that can produce effective, affordable leafy spurge control. In 1998 and 1999, a survey of ranchers and public land managers was conducted to evaluate managerial, institutional, and social factors that might affect the rate and extent of implementation of various control strategies. In 2001, a second survey of the same ranchers and public land managers was conducted to (1) assess any changes in land managers' perceptions of weed problems, control alternatives, and related issues, and (2) evaluate the impact of the TEAM Leafy Spurge project on the respondent's weed control practices. The impacts of noxious weeds on grazing operations, specifically leafy spurge, are not abating, and ranchers seem more aware than ever of the severity of the problem. A slightly larger percentage of respondents in 2001 view leafy spurge as a major problem and the most serious problem for grazing operations than in 1998 and 1999. Heightened awareness among landowners may also be linked to TEAM Leafy Spurge's efforts to inform landowners of the problem and offer affordable, effective weed management techniques. While the use of biological control methods, specifically flea beetles, has grown, herbicides continue to be the control practice of choice. While slightly fewer respondents reported using herbicides in 2001 than in 1998 and 1999, the vast majority of landowners plan to continue to use herbicides. Over 50 percent of respondents are using biological control and over 76 percent of respondents indicated flea beetles were either somewhat or very effective in controlling leafy spurge. Nearly half of the respondents had heard of TEAM Leafy Spurge, and all TEAM Leafy Spurge demonstration sites, events, and publications were favorably rated. A large majority of the respondents agreed that the program had been effective in demonstrating and communicating leafy spurge treatment and control options. Based on the results of the 2001 survey, it would appear that the program has indeed made progress in communicating the type of information landowners need to address what continues to be a significant issue for grazing operations in the Midwest.leafy spurge, noxious weeds, weed management, rancher opinion, Crop Production/Industries,