A preliminary study on the affinities of Philippine, Bornean and New Guinean hepatics

The generic and specific affinities of the Philippine, Bornean and New Guinean hepatic floras were analyzed by calculating the Kroeber's percentage of similarity on the basis of recently published checklists. It is observed that the overall affinities parallel that exhibited by local moss floras except for one important difference. For the three areas, the number and distribution of species of large, actively evolving hepatic genera are noted to be disparate and with few shared taxa. Contrastingly, the large and actively evolving moss genera produce consistently large number of species in all three areas with an equally large number of shared taxa. The strong dependence of many hepatic taxa on asexual reproduction and the poor spore dispersability are accepted as the best explanation to this phenomenon

Aggregate Employment Dynamics: Building From Microeconomic Evidence

This paper studies quarterly employment flows of approximately 10,000 large U.S. manufacturing establishments during 1972:1-1980:4.After estimating the extent of short run microeconomic substitution between employment and hours per worker (hours-week), we construct measures of the path of the deviation between actual and desired employment based on the observed behavior of establishments' hours-week. These deviations are then used as the state variables upon which units decide their employment adjustments (microeconomic policy). Using this framework we find that: (i) Microeconomic employment adjustment policies are non-linear, with firms adjusting to large deviations proportionally more than to small ones; (ii) Employment adjustments are often either large or nil, suggesting the presence of non-convexities in the adjustment cost technologies; (iii) 60 to 90 % of aggregate employment fluctuations is due to changes in the cross sectional distribution of employment deviations, while the rest is due to microeconomic policy changes; (iv) Most of the net aggregate employment fluctuations from changes in the cross sectional distribution are accounted for by aggregate shocks, despite significant fluctuations in the distribution of idiosyncratic shocks and the marked countercyclical nature of their second moment(i.e. reallocation shocks) (v) Similarly, most of the net aggregate employment fluctuations due to microeconomic policy changes are accounted for by aggregate shocks; (vi) Aggregate shocks are also the dominant source of job destruction, but account for less than half of fluctuations in job creation; (vii) A simple parametric version of the aggregate model suggested by the microeconomic nonlinearities shown above has a mean square error 50% lower than its linear counterpart's.

Plant-Level Adjustment and Aggregate Investment Dynamics

macroeconomics, Plant-Level Adjustment, Aggregate Investment Dynamics

Possible origin of the 0.5 plateau in the ballistic conductance of quantum point contacts

A non-equilibrium Green function formalism (NEGF) is used to study the conductance of a side-gated quantum point contact (QPC) in the presence of lateral spin-orbit coupling (LSOC). A small difference of bias voltage between the two side gates (SGs) leads to an inversion asymmetry in the LSOC between the opposite edges of the channel. In single electron modeling of transport, this triggers a spontaneous but insignificant spin polarization in the QPC. However, the spin polarization of the QPC is enhanced substantially when the effect of electron-electron interaction is included. The spin polarization is strong enough to result in the occurrence of a conductance plateau at 0.5G0 (G0 = 2e2/h) in the absence of any external magnetic field. In our simulations of a model QPC device, the 0.5 plateau is found to be quite robust and survives up to a temperature of 40K. The spontaneous spin polarization and the resulting magnetization of the QPC can be reversed by flipping the polarity of the source to drain bias or the potential difference between the two SGs. These numerical simulations are in good agreement with recent experimental results for side-gated QPCs made from the low band gap semiconductor InAs

A tiny taxonomic thorn: Brevianthus hypocanthidium and Aponardia huerlimannii are one and the same.

Brevianthus hypocanthidium and Aponardia huerlimannii are found to be synonymous and the new combination Brevianthus huerlimannii is made

Neutrino-Induced Giant Air Showers in Large Extra Dimension Models

In models based on large extra dimensions where massive spin 2 exchange can dominate at high energies, the neutrino-proton cross section can rise to typical hadronic values at energies above 10^20 eV. The neutrino then becomes a candidate for the primary that initiates the highest energy cosmic ray showers. We investigate characteristics of neutrino-induced showers compared to proton-induced showers. The comparison includes study of starting depth, profile with depth, lateral particle distribution at ground and muon lateral distribution at ground level. We find that for cross sections above 20 mb there are regions of parameter space where the two types of showers are essentially indistinguishable. We conclude that the neutrino candidate hypothesis cannot be ruled out on the basis of shower characteristics.Comment: 24 pages, latex, 19 figures; text discussion and references added, typos corrected; figures and conclusions unchange

Plant-Level Adjustment and Aggregate Investment Dynamics

From pages 3-4 -- 'This paper integrates the organizing framework of the aggregation literature and the microeconomic data of the LRD [Longitudinal Research Database]. It organizes data from a large sample of continuously operating plants in the U.S. manufacturing sector for the period 1972-88 (that is very similar to the sample used by Doms and Dunne) in a way that is useful for understanding aggregate investment dynamics. Indeed, the final product is an aggregate investment equation that has aggregate equipment investment on the left-hand side and not only aggregate, but also microeconomic variables on the right-hand side. Throughout the paper we attempt to explain equipment investment.

Optical resonance imaging: An optical analog to MRI with sub-diffraction-limited capabilities

We propose here optical resonance imaging (ORI), a direct optical analog to magnetic resonance imaging (MRI). The proposed pulse sequence for ORI maps space to time and recovers an image from a heterodyne-detected third-order nonlinear photon echo measurement. As opposed to traditional photon echo measurements, the third pulse in the ORI pulse sequence has significant pulse-front tilt that acts as a temporal gradient. This gradient couples space to time by stimulating the emission of a photon echo signal from different lateral spatial locations of a sample at different times, providing a widefield ultrafast microscopy. We circumvent the diffraction limit of the optics by mapping the lateral spatial coordinate of the sample with the emission time of the signal, which can be measured to high precision using interferometric heterodyne detection. This technique is thus an optical analog of MRI, where magnetic-field gradients are used to localize the spin-echo emission to a point below the diffraction limit of the radio-frequency wave used. We calculate the expected ORI signal using 15 fs pulses and 87° of pulse-front tilt, collected using f/2 optics and find a two-point resolution 275 nm using 800 nm light that satisfies the Rayleigh criterion. We also derive a general equation for resolution in optical resonance imaging that indicates that there is a possibility of superresolution imaging using this technique. The photon echo sequence also enables spectroscopic determination of the input and output energy. The technique thus correlates the input energy with the final position and energy of the exciton

Relativistic Point-Coupling Models as Effective Theories of Nuclei

Recent studies have shown that concepts of effective field theory such as naturalness can be profitably applied to relativistic mean-field models of nuclei. Here the analysis by Friar, Madland, and Lynn of naturalness in a relativistic point-coupling model is extended. Fits to experimental nuclear data support naive dimensional analysis as a useful principle and imply a mean-field expansion analogous to that found for mean-field meson models.Comment: 26 pages, REVTeX 3.0 with epsf.sty, plus 5 figure

Austral hepaticae 53. unraveling hidden diversity: a novel species of Frullania Raddi from New Zealand

Frullania crassissima J.J.Engel, von Konrat and Glenny, a member of the genus Frullania Raddi, is described and illustrated. It is morphologically most similar to F. setchellii, F. svihlana and F. falciloba, of New Zealand and F. vittiana of Lord Howe Island. The new species is also sister to F. squarrosula, F. nicholsonii, F. vittiana and F. falcilobaina previously published phylogenetic analysis. It shares with those species a falcate asymmetrical leaf lobule that is truncate at its apex. It differs from those species principally in the surface ornamentation of the perianth and leaf cell wall thickenings. It is currently only known from the type material, but is likely to be more widespread