bluuebunny/crossref_metadata_2025 huggingface dataset:
Four-wave mixing and direct terahertz emission with two-color semiconductor lasers
Authors: Hoffmann S. , Hofmann M. , Bründermann E. , Havenith M. , Matus M. , Moloney J. V. , Moskalenko A. S. , Kira M. , Koch S. W. , Saito S. , Sakai K.
Published: April 2004

We have observed four-wave mixing in a semiconductor laser configured to emit on two wavelengths simultaneously. The four-wave mixing sidebands exist up to 4 THz stemming from a modulation of the carrier plasma at the difference frequency of the two laser modes. In addition, we were able to generate and detect tunable THz radiation at this difference frequency from the laser device itself suggesting a scheme for a tunable THz source.
Local built-in potential on grain boundary of Cu(In,Ga)Se2 thin films
Authors: Jiang C.-S. , Noufi R. , AbuShama J. A. , Ramanathan K. , Moutinho H. R. , Pankow J. , Al-Jassim M. M.
Published: April 2004

We report on a direct measurement of two-dimensional potential distribution on the surface of photovoltaic Cu(In,Ga)Se2 thin films using a nanoscale electrical characterization of scanning Kelvin probe microscopy. The potential measurement reveals a higher surface potential or a smaller work function on grain boundaries of the film than on the grain surfaces. This demonstrates the existence of a local built-in potential on grain boundaries, and the grain boundary is positively charged. The local built-in potential on the grain boundary is expected to increase the minority-carrier collection area from one to three dimensional. In addition, a work function decrease induced by Na on the film surface was observed.
High doping incorporation on (311)B InP/InGaAs by metalorganic chemical vapor deposition and its application to tunnel junction fabrication
Authors: Okuno Yae L. , DenBaars Steven P. , Bowers John E.
Published: April 2004

We investigated the doping characteristics of InP/InGaAs on the (311)B plane by metalorganic chemical vapor deposition using metalorganic group-V regents. For both n-type Si doping and p-type Zn doping, we found that dopant incorporation is higher on the (311)B plane than the (100) plane. Applying this result, we grew a tunnel junction on (311)B InP substrates at a constant growth temperature. The junction showed good current–voltage characteristics and is promising for device applications.
Stimulated terahertz emission from arsenic donors in silicon
Authors: Hübers H.-W. , Pavlov S. G. , Riemann H. , Abrosimov N. V. , Zhukavin R. Kh. , Shastin V. N.
Published: April 2004

Stimulated emission has been obtained from intra-center donor transitions in silicon monocrystals doped by arsenic. The Si:As laser was optically excited by radiation from a CO2 laser. The emission spectrum consists of two lines corresponding to the 2p±→1s(E) and 2p±→1s(T2) intra-center arcenic transitions. The population inversion is formed due to fast 2s→1s(A1) electron relaxation assisted by intervalley longitudinal acoustic f-phonon emission. This keeps the excited donor states below the 2p± state unpopulated. Thus population inversion occurs between the 2p± state and the 1s(E), 1s(T2) states.
ZnO nanoneedles with tip surface perturbations: Excellent field emitters
Authors: Li Y. B. , Bando Y. , Golberg D.
Published: April 2004

ZnO nanoneedles were prepared on a silicon wafer through a chemical vapor deposition. The diameters of the needle tips were in a range of 20–50 nm. High-resolution transmission electron microscopy revealed that the nanoneedles were single crystals growing along the [001] direction and exhibiting multiple tip surface perturbations, just 1–3 nm in dimension. Field-emission measurements on the prepared nanostructures showed fairly low turn-on and threshold fields of 2.5 and 4.0 V/μm, respectively. The nanosize perturbations on the nanoneedle tips are assumed to cause such excellent field-emission performance.
A widely tunable refractive index in a nanolayered photonic material
Authors: Sandrock Marie , Wiggins Michael , Shirk James S. , Tai Huiwen , Ranade Aditya , Baer Eric , Hiltner Anne
Published: April 2004

A class of composite polymer films is described in which the refractive index can be varied by simple mechanical forces. The films are comprised of 1024 alternating layers of an elastomer and a glassy polymer. When the layer spacing is much less than the wavelength of the probe light, these materials behave as effective medium composites. The layer thickness of the elastomer component and thus the effective index of the composite can be varied by compressing the composite.
High-frequency small-signal conductivity of hot electrons in nitride semiconductors
Authors: Sokolov V. N. , Kim K. W. , Kochelap V. A. , Woolard D. L.
Published: April 2004

We investigate the small-signal conductivity of the electrons in group-III nitrides under a high steady-state electric field. The resulting calculation indicates a frequency dependence of the conductivity that is drastically different from that given by the Drude formula. A large and very fast response of the hot electrons in the nitrides is revealed. The complex conductivity is found to be finite up to the frequency of about 10 THz. For the fields above the threshold corresponding to the peak drift velocity, the calculation also predicts a frequency interval with a negative conductivity. A detailed analysis is provided on the field and frequency dependence of the dynamic conductivity at the high electric fields.
Deformation potentials of the E1(TO) and E2 modes of InN
Authors: Darakchieva V. , Paskov P. P. , Valcheva E. , Paskova T. , Monemar B. , Schubert M. , Lu H. , Schaff W. J.
Published: April 2004

The deformation potentials of the E1(TO) and E2 modes of InN are determined by combining infrared spectroscopic ellipsometry, Raman scattering, and x-ray diffraction measurements, and using a reported value of the mode Grüneisen parameter. The deformation potentials are obtained for two sets of stiffness constants. Strain-free values of the InN E1(TO) mode of 477.9 cm−1 and of the E2 mode of 491.1 cm−1 have been determined.
Optical coupling between a self-assembled microsphere grating and a rib waveguide
Authors: Tai Chao-Yi , Unal Bayram , Wilkinson James S. , Ghanem Mohamed A. , Bartlett Philip N.
Published: April 2004

We report the fabrication of a linear array of self-assembled polystyrene microspheres side coupled to a rib waveguide. The optical coupling between the lateral evanescent field and the periodically perturbed effective refractive index alongside the waveguide results in a transmission stopband at the Bragg wavelength. The observed transmission spectrum shows a notch centered at λ≈1590 nm, which is in close agreement with theory. The coupling coefficient, κ, and the spectral response are derived for variable cladding medium index using perturbation theory. Structures of this type are expected to find application in wavelength selection, optical sensing, and optical delays.
The Preparation and Crystal Structure of the 1 : 1 Adduct of Glycine with Urea
Authors: Smith Graham , Baldry Katherine E. , Kennard Colin H. L. , Byriel Karl A.
Published: April 2004

The 1 : 1 adduct of the a-amino acid glycine with urea has been prepared and
its crystal structure determined by X-ray crystallography and refined to a
residual R 0·028 for 776 observed reflections.
Crystals are monoclinic, pace group
P21 with two molecules in a cell
of dimensions a 7·364(1), b
4·8703(2), c 8·494(1) Å, β
98·555(7)°. The polymeric structure is based on a primary cyclic
hydrogen-bonded nine-membered ring involving both the carboxyl oxygen and an
amino hydrogen of the zwitterionic glycine molecule with the urea amine
hydrogen and oxygen respectively. These repeat down the twofold screw axis by
hydrogen bonding, with additional lateral interactions completing the
three-dimensional network structure
The Interaction of Triosmium Clusters with Pyridinethiols: the Crystal and Molecular Structures of [{Os3(µ-H)(CO)10}2(µ-S2C4H2N2)]and [Os3(µ-H)(CO)10(µ-SC5H4N)]
Authors: Ainscough Eric W. , Brodie Andrew M. , Coll Richard K. , Waters Joyce M.
Published: April 2004

Pyrimidine-2,4-dithiol [HL 1 =
(HS)2C4H2N2]
and pyridine-2-thiol [HL 2 =
(HS)C5H4N] form the osmium
clusters
[{Os3(µ-H)(CO)10}2(µ-S2C4H2N2)]
and
[Os3(µ-H)(CO)10(µ-SC5H4N)],
each of which contain chelating
µ,η1-thiolate
ligands and hydride bridges across common edges of the osmium triangles. In
the former complex two osmium triangles are linked together by the
pyrimidinedithiolato ligand.
Two New Naphthoquinones from the Roots of Conospermum sphacelatum
Authors: Butler Mark S. , Katavic Peter L. , Forster Paul I. , Guymer Gordon P.
Published: April 2004

Two new naphthoquinones,
8-[(2′E)-3′,7′-dimethylocta-2′,6′-dienyl]-2,7-dihydroxynaphthalene-1,4-dione
(1) and 2-hydroxy-6,7-dimethoxy-3-methylnaphthalene-1,4-dione (2), and one
known naphthoquinone, (+)-teretifolione-B (3), were isolated from the
roots of Conospermum sphacelatum Hook. (Proteaceae)
collected in central Queensland. The structures of compounds (1) and (2) were
determined by spectroscopic analysis.
Autocrine CSF-1R activation promotes Src-dependent disruption of mammary epithelial architecture
Authors: Wrobel Carolyn N. , Debnath Jayanta , Lin Eva , Beausoleil Sean , Roussel Martine F. , Brugge Joan S.
Published: April 2004

Elevated coexpression of colony-stimulating factor receptor (CSF-1R) and its ligand, CSF-1, correlates with invasiveness and poor prognosis of a variety of epithelial tumors (Kacinski, B.M. 1995. Ann. Med. 27:79–85). Apart from recruitment of macrophages to the tumor site, the mechanisms by which CSF-1 may potentiate invasion are poorly understood. We show that autocrine CSF-1R activation induces hyperproliferation and a profound, progressive disruption of junctional integrity in acinar structures formed by human mammary epithelial cells in three-dimensional culture. Acini coexpressing receptor and ligand exhibit a dramatic relocalization of E-cadherin from the plasma membrane to punctate intracellular vesicles, accompanied by its loss from the Triton-insoluble fraction. Interfering with Src kinase activity, either by pharmacological inhibition or mutation of the Y561 docking site on CSF-1R, prevents E-cadherin translocation, suggesting that CSF-1R disrupts cell adhesion by uncoupling adherens junction complexes from the cytoskeleton and promoting cadherin internalization through a Src-dependent mechanism. These findings provide a mechanistic basis whereby CSF-1R could contribute to invasive progression in epithelial cancers.
Core versus graded core, and global sections of line bundles
Authors: Hyry Eero , Smith Karen
Published: April 2004

We find formulas for the graded core of certainm\mathfrak {m}-primary ideals in a graded ring. In particular, ifSSis the section ring of an ample line bundle on a Cohen-Macaulay complex projective variety, we show that under a suitable hypothesis, the core and graded core of the ideal ofSSgenerated by all elements of degrees at leastNN(for some, equivalently every, largeNN) are equal if and only if the line bundle admits a non-zero global section. We also prove a formula for the graded core of the powers of the unique homogeneous maximal ideal in a standard graded Cohen-Macaulay ring of arbitrary characteristic. Several open problems are posed whose solutions would lead to progress on a non-vanishing conjecture of Kawamata.
A new variational characterization of 𝑛-dimensional space forms
Authors: Hu Zejun , Li Haizhong
Published: April 2004

A Riemannian manifold

(

M
n

,
g
)

(M^n,g)

is associated with a Schouten

(
0
,
2
)

(0,2)

-tensor

C
g

C_g

which is a naturally defined Codazzi tensor in case

(

M
n

,
g
)

(M^n,g)

is a locally conformally flat Riemannian manifold. In this paper, we study the Riemannian functional

F

k

[
g
]
=

∫
M

σ
k

(

C
g

)
d
v
o

l
g

\mathcal {F}_k[g]=\int _M\sigma _k(C_g)dvol_g

defined on

M

1

=
{
g
∈

M

|

V
o
l
(
g
)
=
1
}

\mathcal {M}_1=\{g\in \mathcal {M}|Vol(g)=1\}

, where

M

\mathcal {M}

is the space of smooth Riemannian metrics on a compact smooth manifold

M
M

and

{

σ
k

(

C
g

)
,
 
1
≤
k
≤
n
}

\{\sigma _k(C_g),\ 1\leq k\leq n\}

is the elementary symmetric functions of the eigenvalues of

C
g

C_g

with respect to

g
g

. We prove that if

n
≥
5

n\geq 5

and a conformally flat metric

g
g

is a critical point of

F

2

|

M

1

\mathcal {F}_2|_{\mathcal {M}_1}

with

F

2

[
g
]
≥
0

\mathcal {F}_2[g]\geq 0

, then

g
g

must have constant sectional curvature. This is a generalization of Gursky and Viaclovsky’s very recent theorem that the critical point of

F

2

|

M

1

\mathcal {F}_2|_{\mathcal {M}_1}

with

F

2

[
g
]
≥
0

\mathcal {F}_2[g]\geq 0

characterized the three-dimensional space forms.
Boundary correspondence of Nevanlinna counting functions for self-maps of the unit disc
Authors: Nieminen Pekka , Saksman Eero
Published: April 2004

Let

ϕ
\phi

be a holomorphic self-map of the unit disc

D

\mathbb {D}

. For every

α
∈
∂

D

\alpha \in \partial \mathbb {D}

, there is a measure

τ
α

\tau _\alpha

on

∂

D

\partial \mathbb {D}

(sometimes called Aleksandrov measure) defined by the Poisson representation
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper R e left-parenthesis alpha plus phi left-parenthesis z right-parenthesis right-parenthesis slash left-parenthesis alpha minus phi left-parenthesis z right-parenthesis right-parenthesis equals integral upper P left-parenthesis z comma zeta right-parenthesis d tau Subscript alpha Baseline left-parenthesis zeta right-parenthesis">

Re
⁡
(
α
+
ϕ
(
z
)
)

/

(
α
−
ϕ
(
z
)
)
=
∫
P
(
z
,
ζ
)

d

τ
α

(
ζ
)

\operatorname {Re}(\alpha +\phi (z))/(\alpha -\phi (z)) = \int P(z,\zeta ) \,d\tau _\alpha (\zeta )

. Its singular part

σ
α

\sigma _\alpha

measures in a natural way the “affinity” of

ϕ
\phi

for the boundary value

α
\alpha

. The affinity for values

w
w

inside

D

\mathbb {D}

is provided by the Nevanlinna counting function

N
(
w
)

N(w)

of

ϕ
\phi

. We introduce a natural measure-valued refinement

M
w

M_w

of

N
(
w
)

N(w)

and establish that the measures

{

σ
α

}

α
∈
∂

D

\{\sigma _\alpha \}_{\alpha \in \partial \mathbb {D}}

are obtained as boundary values of the refined Nevanlinna counting function

M
M

. More precisely, we prove that

σ
α

\sigma _\alpha

is the weak

∗

^*

limit of

M
w

M_w

whenever

w
w

converges to

α
\alpha

non-tangentially outside a small exceptional set

E
E

. We obtain a sharp estimate for the size of

E
E

in the sense of capacity.
Infinitely many solutions to fourth order superlinear periodic problems
Authors: Conti Monica , Terracini Susanna , Verzini Gianmaria
Published: April 2004

We present a new min–max approach to the search of multipleTT–periodic solutions to a class of fourth order equations\[<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="u Superscript i v Baseline left-parenthesis t right-parenthesis minus c u left-parenthesis t right-parenthesis equals f left-parenthesis t comma u left-parenthesis t right-parenthesis right-parenthesis comma t element-of left-bracket 0 comma upper T right-bracket comma">uiv(t)−cu(t)=f(t,u(t)),t∈[0,T],u^{iv}(t)-c u(t)=f(t,u(t)),\hspace {5mm}t\in [0,T],\]wheref(t,u)f(t,u)is continuous,TT–periodic inttand satisfies a superlinearity assumption when|u|→∞|u|\to \infty. For everyn∈Nn\in \mathbb {N}, we prove the existence of aTT–periodic solution having exactly2n2nzeroes in(0,T](0,T].
The flat model structure on 𝐂𝐡(𝐑)
Authors: Gillespie James
Published: April 2004

Given a cotorsion pair

(

A

,

B

)

(\mathcal {A},\mathcal {B})

in an abelian category

C

\mathcal {C}

with enough

A

\mathcal {A}

objects and enough

B

\mathcal {B}

objects, we define two cotorsion pairs in the category

C
h
(

C

)

\mathbf {Ch(\mathcal {C})}

of unbounded chain complexes. We see that these two cotorsion pairs are related in a nice way when

(

A

,

B

)

(\mathcal {A},\mathcal {B})

is hereditary. We then show that both of these induced cotorsion pairs are complete when

(

A

,

B

)

(\mathcal {A},\mathcal {B})

is the “flat” cotorsion pair of

R
R

-modules. This proves the flat cover conjecture for (possibly unbounded) chain complexes and also gives us a new “flat” model category structure on

C
h

(
R
)

\mathbf {Ch}(R)

. In the last section we use the theory of model categories to show that we can define

Ext
R
n

⁡
(
M
,
N
)

\operatorname {Ext}^n_R(M,N)

using a flat resolution of

M
M

and a cotorsion coresolution of

N
N

.
Translation repression by GLD-1 protects its mRNA targets from nonsense-mediated mRNA decay in C. elegans
Authors: Lee Min-Ho , Schedl Tim
Published: April 2004

Previously, we identified multiple in vivo mRNA targets of the maxi-KH/STAR domain protein GLD-1 by their ability to interact with GLD-1 in cytoplasmic extracts and, for all targets tested thus far, GLD-1 functions as a translational repressor. However, here we show that GLD-1 stabilizes the mRNAs of two targets, gna-2 (T23G11.2) and Y75B12B.1. gna-2 mRNA has two upstream open reading frames (uORF), resulting in two premature stop codons. We found that gna-2 mRNA is a naturally occurring mRNA target of nonsense-mediated mRNA decay (NMD) and that the binding of GLD-1 protects gna-2 mRNA from NMD, likely by repressing translation of the uORFs. Therefore, gna-2 mRNA comes under two posttranscriptional controls: (1) translation regulation by a specific translational repressor, GLD-1; and (2) uORF elicited regulation, mainly through NMD. As a result, these two posttranscriptional controls together provide precise temporal and spatial control of gene expression. Consistent with this novel mode of regulation, when GLD-1 mRNA targets acquire premature stop codon mutations, GLD-1 protects them from NMD. Analysis of several mRNA targets containing premature stop codons suggests that in translation repression, GLD-1 either represses ribosome assembly on the target mRNA, or subsequent ribosome elongation to the premature stop codon.
Linking preservation metadata and collection management policies
Authors: Luisa Calanag Maria , Tabata Koichi , Sugimoto Shigeo
Published: April 2004

The long‐term preservation of digital resources is one of the most important issues facing the library community. In particular, libraries need a preservation strategy for digital objects, since digitization alone provides access but not preservation. The digital library community is also focusing on the problem of designing and implementing long‐term archives or repositories. Digital repository management includes the development and enforcement of policies for tasks such as managing access to collection contents and preserving items in the collection. Comprehensive standards and best practices are currently starting to emerge, and ongoing work has deepened the understanding of the needs and requirements that must be met to carry out effective digital preservation. One of these requirements is the creation and maintenance of metadata in support of the preservation process. This paper would like to share findings from earlier and ongoing work that serve as “groundwork” for the current directions leading to the idea of making metadata a more useful and powerful tool to contribute to the technical solution of digital preservation.
Literature of disasters from the human factors point of view: a descriptive analysis
Authors: Osorio Nestor L. , Hurych Jitka
Published: April 2004

Based on information derived from bibliographic titles inErgonomic Abstracts, this paper analyzes research done on human factors in disaster management. A bibliometric analysis is done to identify the most useful material in this important and timely subject area.
User preferences in formats of print and electronic journals
Authors: Johnson Qiana
Published: April 2004

The introduction of electronic journals and electronic versions of journals has made serials collection management more complex. Libraries may want to offer a particular journal in both print and electronic formats, but find that it is often not financially feasible. More publishers are charging separately for the print or electronic versions or charging a higher price for both bundled together. As budgets become tight, librarians are having to choose between one format or another. In order to make the decision about what format to purchase, librarians need to know the format preferences of the users. To determine these preferences, library professionals can use several methods, such as user surveys, usage reports, and educated guessing.
Spanish language books: a review of print and online resources
Authors: Agee Jim , Solis Jacqueline
Published: April 2004

This paper notes that the rapid rate of demographic change in the United States of America population means that librarians must integrate Spanish language materials into their collections now if they have not already done so. It attempts to compile a current collection of high quality resources that will assist librarians in their Spanish language collection building. The paper takes an inclusive perspective and no distinction is made between Chicano, Puerto Rican, Filipino, and other geographic or cultural sub‐groups of Spanish speakers.
A simple relevancy‐ranking strategy for an interface to Boolean OPACs
Authors: Khoo Christopher S.G. , Wan Kwok‐Wai
Published: April 2004

A relevancy‐ranking algorithm for a natural language interface to Boolean online public access catalogs (OPACs) was formulated and compared with that currently used in a knowledge‐based search interface called the E‐Referencer, being developed by the authors. The algorithm makes use of seven well‐known ranking criteria: breadth of match, section weighting, proximity of query words, variant word forms (stemming), document frequency, term frequency and document length. The algorithm converts a natural language query into a series of increasingly broader Boolean search statements. In a small experiment with ten subjects in which the algorithm was simulated by hand, the algorithm obtained good results with a mean overall precision of 0.42 and mean average precision of 0.62, representing a 27 percent improvement in precision and 41 percent improvement in average precision compared to the E‐Referencer. The usefulness of each step in the algorithm was analyzed and suggestions are made for improving the algorithm.
Making Botswana an information society: current developments
Authors: Mutula Stephen M.
Published: April 2004

This paper discusses current developments in the information and communications technology (ICT) sector in Botswana and the implications for moving the country toward an information society. The paper assesses ICT infrastructure, policy and regulatory status within the frameworks of: Botswana's national development blue print, Vision 2016; Africa's Information Society Initiative (AISI); Digital Opportunity Task Force of G8 (DOT Force); and the forthcoming World Summit on Information Society (WSIS). Challenges that the country must overcome to attain information society status are discussed and the way forward charted out.
Are webliographies still in use?
Authors: Alimohammadi Dariush
Published: April 2004

Information retrieval has emerged as one of the most important areas of study in the field of information science during the past decades. Since the invention of the World Wide Web, some solutions have been planned to solve the problem of digital information retrieval, including search engines and Web directories. A webliography is a special type of Web directory and consists of an enumerative list of hypertext links to the scientific sources of information on the Net. According to the last time of updating of the webliographies, this article tries to provide an answer to this question: are webliographies still in use? In order to do this, two searches on webliography and webography made using Google. Among 357 updated and retrieved hits, 303 items have been updated at the second period of webliographies lifetime. It concludes that doing some research projects on webliographies is not only possible, but essential.
OPAC vs card catalogue: a comparative study of user behaviour
Authors: Sridhar M.S.
Published: April 2004

Even though use studies of card catalogues are quite rare, use of online public access catalogues (OPACs) has been extensively investigated since early 1980s. Yet there are not many attempts to conduct comparative studies highlighting the differences in use of card catalogues and OPACs of the same library and user population. This paper reports an attempt made to study use of the OPAC of ISRO Satellite Centre (ISAC) library and compare the results with the findings of the study of use of card catalogue of the same library conducted 17 years ago. The paper not only brings various aspects of user behaviour about OPAC but also depicts the differences in user behaviour as well as the effects of technological changes from card catalogue (manual system) to OPAC (automated system).
Numerical study of active shock control for transonic aerodynamics
Authors: Qin N. , Zhu Y. , Shaw S.T.
Published: April 2004

In this paper, the effectiveness of a number of active devices for the control of shock waves on transonic aerofoils is investigated using numerical solutions of the Reynolds‐averaged Navier‐Stokes equations. A brief description of the flow model and the numerical method is presented including, in particular, the boundary condition modelling and the numerical treatment for surface mass transfer. Comparisons with experimental data have been made where possible to validate the numerical study before some systematic numerical simulations for a parametric study. The effects of surface suction, blowing, and local modification of the surface contour (bump) on aerofoil aerodynamic performance have been studied extensively regarding the control location, the mass flow strength and the bump height. The numerical simulations highlight the benefits and drawbacks of the various control devices for transonic aerodynamic performance and identify the key design parameters for optimisation.
Dynamic modeling in large‐eddy simulation of turbulent channel flow
Authors: Gullbrand Jessica
Published: April 2004

Large‐eddy simulation (LES) of a turbulent channel flow is performed using different subfilter‐scale (SFS) models and test filter functions. The SFS models used are the dynamic Smagorinsky model (DSM) and the dynamic mixed model (DMM). The DMM is a linear combination between the scale‐similarity model and the DSM. The test filter functions investigated are the sharp cut‐off (in spectral space) and smooth filter that is commutative up to fourth‐order. The filters are applied either in the homogeneous directions or in all three spatial directions. The governing equations are discretized using a fourth‐order energy‐conserving finite‐difference scheme. The influence from the test filter function and the SFS model on the LES results are investigated and the effect of two‐dimensional versus three‐dimensional test filtering are investigated. The study shows that the combination of SFS model and filter function highly influences the computational results; even the effect on the zeroth‐order moment is large.
The role of endothermic gasification in propellant ignition
Authors: Lowe Caroline
Published: April 2004

This study explores a reactor model designed to describe the decomposition, ignition and combustion of energetic materials in combination with real experimental data for these energetic materials. Spatial uniformity is initially assumed which reduces the system of partial‐differential‐equations to a system of ordinary‐differential‐equations that can be easily solved numerically. The phase‐plane is explicitly presented and examined to illustrate how chemistry and temperature evolve in time. The computations provide an understanding of the vast different timescales that exist and illustrate the singularity structure. Following this the effect of including this chemical regime in an environment typically induced by the combustion of these materials, that is within a compressible fluid flow, is pursued.
High resolution NMR microscopy of plants and fungi
Authors: Köckenberger W. , De Panfilis C. , Santoro D. , Dahiya P. , Rawsthorne S.
Published: April 2004

Nuclear magnetic resonance (NMR) microscopy is a completely noninvasive technique that can be used to acquire images with high spatial resolution through opaque objects such as plant organs and tissue parts. The image contrast can be chosen to represent the anatomical details or to visualize the spatial distribution of a range of physico‐chemical parameters such as the apparent diffusion constant of water or the velocity of water flow within plants in vivo. In addition, images can be generated which show the spatial distribution of metabolites. Furthermore, it is possible to detect chemical compounds labelled with the stable isotope 13C and to generate images showing the spatial distribution of the 13C label in the intact plant. The ability to monitor water flow and transport of 13C‐labelled tracer in intact plants with NMR microscopy favours the use of this technique in the investigation of long‐distance transport processes in plants. A short introduction into the technical principles of NMR microscopy is provided and the problems associated with applications to plants are summarized. The potential of the technique is explained with applications to Zinnia elegans plants, wheat grains and Brassica napus siliques.
Deletion in sortase gene of Streptococcus mutans Ingbritt
Authors: Igarashi T.
Published: April 2004

Our previous studies on Streptococcus mutans have demonstrated that surface proteins containing a C‐terminal sorting signal, such as surface protein antigen (PAc), glucan‐binding protein C (GbpC) and dextranase (Dex), are anchored to the cell wall by a sortase (SrtA). In this study we found that, unlike other strains of S. mutans, strain Ingbritt did not exhibit cell wall‐anchoring of PAc, GbpC and Dex. It is speculated that the SrtA of strain Ingbritt did not function in the cell wall‐anchoring process of these surface proteins. Sequence analysis revealed a deletion of an 11‐bp nucleotide sequence in the srtA gene of strain Ingbritt, resulting in the generation of a new termination codon, resulting in production of an incomplete SrtA enzyme protein. As a result, strain Ingbritt showed a localization change of PAc, GbpC and Dex in the cell, implying that strain Ingbritt loses the biological functions mediated by the cell surface‐associated proteins of S. mutans. These results suggest that strain Ingbritt could be less cariogenic than other strains of S. mutans.
Induction of calprotectin release by Porphyromonasgingivalis lipopolysaccharide in human neutrophils
Authors: Kido J. , Kido R. , Suryono  , Kataoka M. , Fagerhol M. K. , Nagata T.
Published: April 2004

Calprotectin, a major cytosolic protein of leukocytes, is detected in neutrophils, monocytes/macrophages, and epithelial cells. This protein is known to be a marker for several inflammatory diseases and is detected in inflammatory gingival tissue with periodontal disease. Recently, we found that the calprotectin level in gingival crevicular fluid from periodontitis patients was significantly higher than that of healthy subjects. However, the regulation of calprotectin in periodontal disease is unclear. In the present study, we investigated the effect of lipopolysaccharides of periodontopathic bacteria on calprotectin release from human neutrophils. Neutrophils from healthy donors were treated with lipopolysaccharides from Porphyromonas gingivalis (P‐LPS), Actinobacillus actinomycetemcomitans, Prevotella intermedia, Fusobacterium nucleatum, and Escherichia coli. Calprotectin of neutrophil was identified by immunoblotting and calprotectin amount was determined by ELISA. Two subunits (10 and 14 kDa) of calprotectin were observed in the cell and medium fractions from neutrophils. P‐LPS increased calprotectin release from seven to 16 times the control level after 30 min and its effect appeared in a dose‐dependent manner (10–1000 ng/ml). Lipopolysaccharides from A. actinomycetemcomitans, P. intermedia, F. nucleatum, and E. coli also induced calprotectin release from neutrophils. These results suggest that lipopolysaccharides from periodontopathic bacteria induce calprotectin release from human neutrophils.
The medical treatment of Crohn's perianal fistulas
Authors: Schwartz D. A. , Herdman C. R.
Published: April 2004

Perianal fistulas are a frequent manifestation of Crohn's disease. The correct application of the newer diagnostic and therapeutic agents for treating perianal Crohn's disease are beginning to be better defined. In general, a combined medical and surgical approach is preferred. The perianal disease process should first be fully delineated with endoscopy and either MRI or EUS before treatment is begun. Patients are then stratified into one of three groups: simple fistulas and no proctitis; simple fistulas and concomitant proctitis; and complex fistulas. Patients with simple fistulas and no proctitis can be treated medically with a combination of antibiotics and an immunosuppressive agent (azathioprine or mercaptopurine). Patients with simple fistulas and concomitant proctitis should have infliximab added to their treatment plan. Complex fistulas require surgical intervention first prior to medical treatment. A combination of antibiotics, immunosuppressive therapy and infliximab are then initiated to facilitate fistula healing.
Immunological Discrimination of Phytophthora cinnamomi from other Phytophthorae Pathogenic on Chestnut
Authors: Ferraris L. , Cardinale F. , Valentino D. , Roggero P. , Tamietti G.
Published: April 2004

A polyclonal antiserum (A379) against water soluble proteins from Phytophthora cinnamomi mycelium was produced in rabbit. In ELISA, the 1 : 10 000 diluted antiserum revealed only Phytophthora isolates, not allowing a clear‐cut discrimination among congenerous species, in spite of a generally higher reactivity on P. cinnamomi proteins. The antiserum gave positive reactions in Western blot analyses against mycelial proteins from nine species of Phytophthora and Pythium sp. (grown on rich media), but not with Rhizoctonia solani, binucleate Rhizoctonia, Verticillium dahliae, Fusarium oxysporum and Cryphonectria parasitica. All Phytophthora species showed common epitopes on proteins of molecular masses 77, 66, 51 and 48 kDa. However, a species‐specific protein of 55 kDa was immunodecorated only in P. cinnamomi samples, thus allowing univocal identification of this species. When tested against total proteins from the same fungi grown on water, the antibody revealed diagnostic bands of 55 and 51 kDa in P. cinnamomi only. The antiserum is therefore suitable for the specific identification of P. cinnamomi emerging in distilled water from infected tissues of chestnut, blueberry and azalea.
Localization of Tomato spotted wilt virus in Chrysanthemum Stock Plants and Efficiency of Viral Transmission from Infected Stock Plants to Cuttings
Authors: Matsuura S. , Ishikura S. , Shigemoto N. , Kajihara S. , Hagiwara K.
Published: April 2004

Localization of Tomato spotted wilt virus (TSWV) in susceptible chrysanthemum stock plants and its efficiency of transmission from latently infected stock plants to cuttings under thrips‐free conditions were investigated using double‐antibody sandwich enzyme‐linked immunosorbent assay (DAS‐ELISA), reverse transcription polymerase chain reaction (RT‐PCR) combined with dot‐blot hybridization, and by cultivation. TSWV localized in symptomless stock plants and cuttings taken from them, and its detection frequency, was relatively high in the lower leaves and stems, but low in terminal buds of cuttings. In cv. Seinoyakata, the detection rate of TSWV in cuttings taken from infected stock plants ranged from 26.3 to 38.5% in 2002 and from 16.7 to 39.1% in 2003, and in cv. Jimba from 37.5 to 47.1% from January to May 2003. No fluctuation in detection rate by cutting generation or season was observed. The detection rate of TSWV in the roots of stock plants was >50% in most periods. These results indicate that transmission efficiency from infected chrysanthemum stock plants to cuttings is fairly high (approximately 20–50%) and thus may become a major source of secondary infection in production fields or glasshouses. Our results also suggest that several lower leaves should be combined in ELISA to detect infection in stock plants and cuttings.
The Presumption of Innocence and the Human Rights Act
Authors: Tadros Victor , Tierney Stephen
Published: April 2004

There has recently been a proliferation of case law dealing with potential inroads into the presumption of innocence in the criminal law of England and Wales, in the light of article 6(2) of the European Convention on Human Rights. This article is concerned with the nature of the presumption of innocence. It considers two central issues. The first is how the courts should address the question of when the presumption of innocence is interfered with. The second is the extent to which interference with the presumption of innocence may be justified on the grounds of proportionality. It is argued that the courts have not developed the appropriate concepts and principles properly to address these questions.
Caldwell Recklessness is Dead, Long Live Mens Rea's Fecklessness
Authors: Amirthalingam Kumaralingam
Published: April 2004

The House of Lords has recently reiterated its preference for a purely subjective doctrine of mens rea by overruling the Caldwell test of recklessness. It is argued that while the subjective basis of mens rea is essential to ensure that it is the accused's culpability that is being judged, courts must be prepared to accept that there is a residual objective element that is part of mens rea and it is that which determines whether the accused is morally blameworthy. Unless this is formally accepted, mens rea will never be restored to its proper normative role; that of determining whether the ‘mens was rea’.1
Sustained suppression of hepatitis C virus by high doses of interferon and ribavirin in adult hemophilic patients
Authors: Santagostino E. , De Filippi F. , Rumi M. G. , Rivi M. , Colombo M. , Mannucci P. M. ,   Hepatitis Study Group of the Association of Italian Hemophilia Centers
Published: April 2004

BACKGROUND: In a recent randomized controlled study, only a minority (15%) of adult hemophiliacs with chronic HCV achieved a sustained virologic response to treatment with interferon (IFN) and ribavirin given at standard doses.

STUDY DESIGN AND METHODS: Whether the therapeutic response might be improved in these patients by increasing the doses of IFN was evaluated. Thirty‐four previously untreated, adult hemophiliacs with chronic HCV but negative for HIV were investigated. There were 33 men and 1 woman, aged 21 to 60 years (mean, 36). Twenty‐three patients (68%) had genotype 1, and median serum HCV‐RNA was 473 × 103 IU per L (range, 3.6‐2145). Patients were treated with IFN at 5 million units (MU) thrice weekly for 6 months, followed by 3 mol/L for 6 additional months in combination with daily oral doses of 1 or 1.2 g of ribavirin.

RESULTS: A total of 33 patients (97%) completed the study; one patient withdrew because of treatment‐related symptoms. Treatment dosage had to be reduced in 20 patients (59%). By intention‐to‐treat analysis, 14 patients (41%) had a sustained virologic response, particularly those infected by HCV genotype 2 or 3 (70% vs. 29% with genotype 1 or 4, p < 0.05). Sustained response rates were similar in the 13 compliant patients and the 20 patients who had to reduce IFN and/or ribavirin doses (54% vs. 35%).

CONCLUSIONS: High‐dose IFN therapy plus ribavirin provided high rates of sustained virologic responses in adult hemophiliacs with chronic HCV, even if side‐effects led to dose reduction in half of these patients.
Mechanics of variable-mass systems—Part 1: Balance of mass and linear momentum
Authors: Irschik and Hans , Holl Helmut J
Published: April 2004

The equations of balance of momentum and energy usually are formulated under the assumption of conservation of mass. However, mass is not conserved when sources of mass are present or when the equations of balance are applied to a non-material volume. Mass then is said to be variable for the system under consideration. It is the scope of the present contribution to review the mechanical equations of balance for variable-mass systems. Our review remains within the framework of the classical, non-relativistic continuum mechanics of solids and fluids. We present general formulations and refer to various fields of applications, such as astronomy, machine dynamics, biomechanics, rocketry, or fluid dynamics. Also discussed are the equations for a single constituent of a multiphase mixture. The present review thus might be of interest to workers in the field of heterogeneous media as well. We first summarize the general balance law and review the Reynolds transport theorem for a non-material volume. Then the latter general formulations are used to derive and to review the equations of balance of mass and linear momentum in the presence of sources of mass in the interior of a material volume. We also discuss the appropriate modeling of such sources of mass. Subsequently, we treat the equations of balance of mass and linear momentum when mass is flowing through the surface of a non-material volume in the absence of sources of mass in the interior, and we point out some analogies to the previously presented relations. A strong emphasis is given in this article to the historical evolution of the balance equations and the physical situations to which they have been applied. The equations of balance of angular momentum and energy for variable-mass systems will be treated separately, in a second part of the review, to be published later. This review article cites 96 references.
Inhibition of Tyrosinase by Protocatechuic Aldehyde
Authors: No Jae Kyung , Kim Min Sun , Kim You Jung , Bae Song Ja , Choi Jae Sue , Chung Hae Young
Published: April 2004

The purpose of this study was to determine the inhibitory action of protocatechuic aldehyde (PCA) on tyrosinase activity. PCA is one of the compounds found in the root of Salvia miltiorrhiza. Our study documented that PCA has a potent inhibitory effect on tyrosinase, which catalyzes the rate-limiting step of melanin biosynthesis. Although melanin biosynthesis has an essential function normally in human skin for defense against ultraviolet light of the sun, its abnormal activity as seen in pigmentation disorder could lead to serious medical problems. Our data showed that PCA, with concentrations ranging from 1×10-5M to 8×10-5M , exhibited dose-dependent inhibition of the enzyme activity with 50% of inhibition at 19.92×10-6M . A further kinetic analysis on PCA inactivation of tyrosinase activity revealed a competitive inhibition of the enzyme at the L-tyrosine binding site. The findings of our present study merit further research on the applicability of PCA as a potential agent for treatment of pigmentation disorder.
B-MESON DECAY CONSTANT REVISITED AND EXTRACTION OF $|\frac{v_{td}}{v_{ts}}|$ FROM $B^0\hbox{--}{\bar B}^0$ MIXING
Authors: BHATTACHARYA A. , BANERJEE S. N. , CHAKRABARTI B. , BANERJEE S.
Published: April 2004

The ratios of Bd and Bs meson decay constant have been estimated using the variational method in conjunction with the relativistic Hamiltonian of the heavy meson in the framework of the statistical model. The ratio of CKM matrix elements [Formula: see text] has been extracted from [Formula: see text] mixing using the estimated decay constants and ratio of Bd and Bs mass differences. The results are found to be in good agreement with the existing theoretical and experimental predictions.
VLSI DESIGN OF DIGIT-SERIAL FPGA ARCHITECTURE
Authors: LEE HANHO , SOBELMAN GERALD E.
Published: April 2004

This paper presents a novel application-specific field-programmable gate array (FPGA) architecture that satisfies efficient implementation of digit-serial DSP architectures on a digit wide basis. Digit-serial DSP designs have been an effective implementation method for FPGAs. To efficiently realize a digit-serial DSP design on FPGAs, one must create an FPGA architecture optimized for those types of systems. We examine the various circuits used in digit-serial DSP designs to extract their key features that should be reflected in the new FPGA architecture. We explain the design methodology, layout and implementation of the new digit-serial FPGA architecture. Digit-serial DSP designs using the digit-serial FPGA (DS-FPGA) are compared to those implemented on Xilinx FPGAs. We have estimated that the DS-FPGA are about 2.5~3 times more efficient in area and faster than the equivalent digit-serial DSP architectures implemented using Xilinx FPGAs.
A NOVEL METHOD FOR HIGH-PERFORMANCE PHASE-LOCKED LOOP
Authors: WOO YOUNGSHIN , JANG YOUNG MIN , SUNG MAN YOUNG
Published: April 2004

In this paper, we propose a phase-locked loop (PLL) with dual PFDs and a modified loop filter in which advantages of both PFDs can be combined and the trade-off between acquisition behavior and locked behavior can be achieved. By operating the appropriate PFD connected to the well-adjusted charge pump and regulating the loop bandwidth to input frequency ratio with an input divider and a modified loop filter, an unlimited error detection range, a high frequency operation, a reduced dead zone and a higher speed lock-up time can be achieved. The proposed PLL structure is designed using 1.5 μm CMOS technology with 5 V supply voltage.
ON THE EXISTENCE OF PHYSICAL TRANSFORMATIONS BETWEEN SETS OF QUANTUM STATES
Authors: CHEFLES ANTHONY , JOZSA RICHARD , WINTER ANDREAS
Published: April 2004

Let A={ρ1,…,ρn} be a given set of quantum states. We consider the problem of finding necessary and sufficient conditions on another set B={σ1,…,σn} that guarantee the existence of a physical transformation taking ρi to σi for all i. Uhlmann has given an elegant such condition when both sets comprise pure states. We give a simple proof of this condition and develop some consequences. Then we consider multi-probabilistic transformations between sets of pure states which leads to conditions for the problem of transformability between A and B when one set is pure and the other is arbitrary.
BELL'S INEQUALITIES DETECT EFFICIENT ENTANGLEMENT
Authors: ACÍN ANTONIO , GISIN NICOLAS , MASANES LLUIS , SCARANI VALERIO
Published: April 2004

We review the status of Bell's inequalities in quantum information, stressing mainly the links with quantum key distribution and distillation of entanglement. We also prove that for all the eavesdropping attacks using one qubit, and for a family of attacks of two qubits, acting on half of a maximally entangled state of two qubits, the violation of a Bell inequality implies the possibility of an efficient secret-key extraction.
ANTINORMALLY ORDERED PHOTODETECTION OF CONTINUOUS-MODE FIELD
Authors: USAMI KOJI , TOMITA AKIHISA , NAKAMURA KAZUO
Published: April 2004

When the electromagnetic field is detected by stimulated emission, rather than by absorption, antinormally ordered photodetection can be realized. One of the distinct features of this photodetection scheme is its sensitivity to zero-point fluctuation due to the existence of the spontaneous emission. We have recently succeeded in experimentally demonstrating the antinormally ordered photodetection by exploiting nondegenerate stimulated parametric down-conversion process. To properly account for the experiment, the detection process needs to be treated with time-dependent and continuous-mode operators because of the broadband nature of the parametric down-conversion process and the wide spectrum of the pump that we used. Here, we theoretically analyze the antinormally ordered intensity correlation of the continuous-mode fields by pursuing the detection process in the Heisenberg picture. It is shown that the excess positive correlation due to zero-point fluctuation reduces because of the frequency-distinguishability of the two emitted photon pairs.