4,232 research outputs found
What happened to the knowledge economy? ICT, intangible investment and Britain's productivity record revisited
A major puzzle is that despite the apparent importance of innovation around the "knowledge economy", UK macro performance appears unaffected: investment rates are flat, and productivity has slowed down. We investigate whether measurement issues might account for the puzzle. The standard National Accounts treatment of most spending on "knowledge" or "intangible" assets is as intermediate consumption. Thus they do not count as either GDP or investment. We ask how treating such spending as investment affects some key macro variables, namely, market sector gross value added (MGVA), business investment, capital and labour shares, growth in labour and total factor productivity, and capital deepening. We find (a) MGVA was understated by about 6% in 1970 and 13% in 2004 (b) instead of the nominal business investment/MGVA ratio falling since 1970 it is has been rising (c) instead of the labour compensation/MGVA ratio being flat since 1970 it has been falling (d) growth in labour productivity and capital deepening has been understated and growth in total factor productivity overstated (e) total factor productivity growth has not slowed since 1990 but has been accelerating
How Fine should Grain be Ground for Milk Cows?
IntroductionThe ground beef bin on the Jones farm was empty. Mr. Jones pulled the switch and soon the little mill was humming a song that scarcely changed a note as the first few shovels of grain disappeared down its mouth. Mr. Jones noted that the grain was scarcely more than cracked. He readjusted the mill to grind it finer, and soon it was spewing out an entirely different product. Did Mr. Jones make a mistake when he readjusted his mill to grind the feed finer for his dairy cows?Results of an experiment conducted at the South Dakota Agricultural Experiment Station would indicate that Jones did make a mistake by grinding the grain fine – one that is common in the dairy industry. These are a few results of the experiment:1. It made little difference in the case of milk cows whether grain was ground coarse or fine in relation to the food value obtained by the cow from the entire ration. Feeds need only to be cracked sufficiently to expose the kernel interiors to digestive juices.2. More benefit was derived from grinding corn than from grinding oats. A total of 110 pounds of alfalfa hay and whole corn ration was required to equal 100 pounds of an alfalfa hay and medium-ground corn ration in food value. For whole oats the comparison was 102 pounds to 100 pounds.3. After subtracting the food value of the alfalfa hay, it was found 119 pounds of whole corn were required to equal 100 pounds of medium ground corn in food value, and 105 pounds of whole oats were required to equal 100 pounds of medium ground oats. These figures may be used when combining these grains with o�her roughages in a ration. Little difference was noted in the food value of either grain when ground medium or fine.4. Greater benefits were derived from grinding corn largely because greater amounts pass through the animal undigested when whole corn is fed. Nearly one-fifth (19.9 percent) of the whole corn fed was recovered from the feces (solid manure). For whole oats, recoveries in the feces ranged from 10.8 to 14.8 percent.5. Ground grain rations were much more palatable than whole grain, and were more convenient for mixing with other ingredients in the ration.Futhermore, it is generally understood that it costs more in time and money for fine grinding than for medium coarse grinding. The power cost is greater chiefly because of the greater length of time that the power must be used in grinding fine as compared with coarse. Calculations made from figures obtained from the South Dakota, Indiana and Ohio Stations indicate that it would take about 2 or 2Yz times as much power to grind the finely ground grain as for the medium coarse as used in this experiment. For instance, Indiana reported that it took 0.21 kilowatt hours (K.W.H. electrical power) for coarse grinding of 100 pounds of corn and oats and 0.57 kilowatt hours for fine grinding. If one were paying for electrical power from a highline the cost would be directly proportional to the kilowatt hours used. Essentially the same relationships would exist if tractors or gas engines were used as a source of power
Rotational predissociation of extremely weakly bound atom-molecule complexes produced by Feshbach resonance association
We study the rotational predissociation of atom - molecule complexes with
very small binding energy. Such complexes can be produced by Feshbach resonance
association of ultracold molecules with ultracold atoms. Numerical calculations
of the predissociation lifetimes based on the computation of the energy
dependence of the scattering matrix elements become inaccurate when the binding
energy is smaller than the energy width of the predissociating state. We derive
expressions that represent accurately the predissociation lifetimes in terms of
the real and imaginary parts of the scattering length and effective range for
molecules in an excited rotational state. Our results show that the
predissociation lifetimes are the longest when the binding energy is positive,
i.e. when the predissociating state is just above the excited state threshold.Comment: 17 pages, 5 figure
Does preoperative axillary staging lead to overtreatment of women with screen detected breast cancer?
Aim
To determine the impact of pre-operative axillary ultrasound staging in a screen detected breast cancer population
Materials and Method
Ultrasound and needle biopsy staging results alongside reference standard sentinel lymph node biopsy and axillary lymph node dissection were retrospectively extracted from the unit's computer records between 01/04/2008 and 31/03/2015. Axillary staging was compared with final pathology and treatment.
Results
Of the 215,661 screening examinations performed, 780 invasive cancers were diagnosed which had pre-operative axillary staging data, of which 162 (20.7%) were node positive. 36 (4.6%) had a heavy nodal burden (3 or more nodes). 90 (11.5%) had an abnormal axillary ultrasound and axillary biopsy of which 54 were positive for cancer (33.3% of the node positive cases) and triaged to axillary lymph node dissection avoiding a sentinel lymph node biopsy. Of these 22 (40.7%) had neoadjuvant treatment, and 32 (59.3%) proceeded directly to axillary lymph node dissection. The sensitivity of axillary ultrasound and biopsy to detect women with aheavy nodal burden (3 or more nodes) was 41.7% (15 of 36). However, 17 (53%) of the 32 women with a positive axillary biopsy had a low burden of axillary disease (≤2 positive nodes) at axillary lymph node dissection, the mean number of nodes obtained was 14.6.
Conclusion
Significant numbers of women are being potentially overtreated or denied entry into Positive Sentinel Node: adjuvant therapy only vs adjuvant therapy and clearance or axillary radiotherapy (POSNOC) because of routine pre-operative axillary staging
Behavioural evolution in penguins does not reflect phylogeny
Over the past two decades, behavioural biologists and ecologists have made effective use of the comparative method, but have often stopped short of adopting an explicitly phylogenetic approach. We examined 68 behaviour and life history (BLH) traits of 15 penguin species to: (i) infer penguin phylogeny, (ii) assess homology of behavioural characters, and (iii) evaluate hypotheses about character evolution and ancestral states. Parsimony analysis of the BLH dataset found either two shortest trees (characters coded as unordered) or a single shortest tree (characters coded as a combination of unordered and Dollo). The BLH data had significant structure. Kishino-Hasegawa tests indicated that BLH trees were significantly different from most previous estimates of penguin phylogeny. The BLH phylogeny generated from Dollo characters appeared to be less accurate than the tree derived from the completely unordered dataset. Dividing BLH data into display and non-display traits resulted in no significant differences in level of homoplasy and no difference in the accuracy of phylogeny. Tests for homology of BLH traits were performed by mapping the characters onto a molecular tree. Assuming that independent gains are less likely than losses of character states, 65 of the 68 characters were likely to be homologous across taxa, and at least several characters appeared to have been stable since the origin of modern penguins around 30 Myr. Finally, the likely BLH traits of the most recent common ancestor of extant penguins were reconstructed from character states along the internal branch leading to the penguins. This analysis suggested that the "proto-penguin" probably had a similar life history to current temperate penguins but few ritualized behaviours. A southern, cool-temperate origin of penguins is suggested
A method for exploratory repeated-measures analysis applied to a breast-cancer screening study
When a model may be fitted separately to each individual statistical unit,
inspection of the point estimates may help the statistician to understand
between-individual variability and to identify possible relationships. However,
some information will be lost in such an approach because estimation
uncertainty is disregarded. We present a comparative method for exploratory
repeated-measures analysis to complement the point estimates that was motivated
by and is demonstrated by analysis of data from the CADET II breast-cancer
screening study. The approach helped to flag up some unusual reader behavior,
to assess differences in performance, and to identify potential random-effects
models for further analysis.Comment: Published in at http://dx.doi.org/10.1214/11-AOAS481 the Annals of
Applied Statistics (http://www.imstat.org/aoas/) by the Institute of
Mathematical Statistics (http://www.imstat.org
Developing Intensity-Duration-Frequency (IDF) Curves From Satellite-Based Precipitation: Methodology and Evaluation
Given the continuous advancement in the retrieval of precipitation from satellites, it is important to develop methods that incorporate satellite-based precipitation data sets in the design and planning of infrastructure. This is because in many regions around the world, in situ rainfall observations are sparse and have insufficient record length. A handful of studies examined the use of satellite-based precipitation to develop intensity-duration-frequency (IDF) curves; however, they have mostly focused on small spatial domains and relied on combining satellite-based with ground-based precipitation data sets. In this study, we explore this issue by providing a methodological framework with the potential to be applied in ungauged regions. This framework is based on accounting for the characteristics of satellite-based precipitation products, namely, adjustment of bias and transformation of areal to point rainfall. The latter method is based on previous studies on the reverse transformation (point to areal) commonly used to obtain catchment-scale IDF curves. The paper proceeds by applying this framework to develop IDF curves over the contiguous United States (CONUS); the data set used is Precipitation Estimation from Remotely Sensed Information Using Artificial Neural Networks – Climate Data Record (PERSIANN-CDR). IDFs are then evaluated against National Oceanic and Atmospheric Administration (NOAA) Atlas 14 to provide a quantitative estimate of their accuracy. Results show that median errors are in the range of (17–22%), (6–12%), and (3–8%) for one-day, two-day and three-day IDFs, respectively, and return periods in the range (2–100) years. Furthermore, a considerable percentage of satellite-based IDFs lie within the confidence interval of NOAA Atlas 14
Pasts and pagan practices: moving beyond Stonehenge
Theorizing the past is not restricted to archaeology and interpretations of 'past' both influence and are themselves constituted within politicized understandings of self, community and in certain instances, spirituality. 'The past in the imagination of the present' is appropriated, variously, to give meaning to the present or to justify actions and interpret experiences. Summer solstice at Stonehenge, with an estimated 21,000 celebrants in 2005, is only the most publicized appropriation (by pagans and other adherents of alternative spirituality and partying) of a 'sacred site'; and conflicts and negotiations occurring throughout Britain are represented in popular and academic presentations of this 'icon of Britishness'. This paper presents work from the Sacred Sites, Contested Rites/Rights Project (http://www.sacredsites.org.uk) project, a collaboration of archaeology and anthropology informed by pagan and alternative approaches and standpoints investigating and theorizing discourse and practice of heritage management and pagan site users. Whether in negotiations around the Stonehenge solstice access or in dealing with numerous other sites, boundaries between groups or discourses are not clearly drawn - discursive communities merge and re-emerge. But clearly 'past' and 'site' are increasingly important within today's Britain, even as television archaeology increases its following, and pagan numbers continue to grow.</p
- …