bluuebunny/crossref_metadata_2025 huggingface dataset:
Jordan rings with nonzero socle
Authors: Osborn J. Marshall , Racine M. L.
Published: July 2010

Let

J

\mathcal {J}

be a nondegenerate Jordan algebra over a commutative associative ring

Φ
\Phi

containing

1
2

\tfrac {1}{2}

. Defining the socle

G

\mathcal {G}

of

J

\mathcal {J}

to be the sum of all minimal inner ideals of

J

\mathcal {J}

, we prove that

G

\mathcal {G}

is the direct sum of simple ideals of

J

\mathcal {J}

. Our main result is that if

J

\mathcal {J}

is prime with nonzero socle, then either (i)

J

\mathcal {J}

is simple unital and satisfies DCC on principal inner ideals, (ii)

J

\mathcal {J}

is isomorphic to a Jordan subalgebra

J

′

\mathcal {J}’

of the plus algebra

A
+

{A^ + }

of a primitive associative algebra A with nonzero socle S, and

J

′

\mathcal {J}’

contains

S
+

{S^ + }

, or (iii)

J

\mathcal {J}

is isomorphic to a Jordan subalgebra

J

\mathcal {J}

of the Jordan algebra of all symmetric elements H of a. primitive associative algebra A with nonzero socle S, and

J

\mathcal {J}

contains

H

∩

S

H\, \cap \,S

. Conversely, any algebra of type (i), (ii), or (iii) is a prime Jordan algebra with nonzero socle. We also prove that if

J

\mathcal {J}

is simple then

J

\mathcal {J}

contains a completely primitive idempotent if and only if either

J

\mathcal {J}

is unital and satisfies DCC on principal inner ideals or

J

\mathcal {J}

is isomorphic to the Jordan algebra of symmetric elements of a

∗
*

-simple associative algebra A with involution 

∗
*

containing a minimal one-sided ideal.
Maximal inequalities related to generalized a.e. continuity
Authors: Jurkat W. B. , Troutman J. L.
Published: July 2010

An integral inequality of the classical Hardy-Littlewood type is obtained for the maximal function of positive convolution operators associated with approximations of the identity in

R
n

{R^n}

. It is shown that the (formally) rearranged maximal function can in general be estimated by an elementary integral involving the decreasing rearrangements of the kernel of the approximation and the function being approximated. (The estimate always holds when the kernel has compact support or a decreasing radial majorant integrable in a neighborhood of infinity; a one-dimensional counterexample shows that integrability alone may not suffice.) The finiteness of the integral determines a Lorentz space of functions which are a.e. continuous in the generalized sense of the approximation. Conversely, in dimension one it is established that this space is the largest strongly rearrangement invariant Banach space of such functions. In particular, the new inequality provides access to the study of Cesàro continuity of order less than one.
The free boundary for elastic-plastic torsion problems
Authors: Caffarelli Luis A. , Friedman Avner
Published: July 2010

Consider the variational inequality: find

u

∈

K

u\, \in \,K

such that
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="integral Underscript upper Q Endscripts nabla u dot nabla left-parenthesis v minus u right-parenthesis greater-than-or-slanted-equals mu integral Underscript upper Q Endscripts left-parenthesis v minus u right-parenthesis left-parenthesis mu greater-than 0 right-parenthesis">

∫
Q

∇
u

⋅

∇

(

v

−

u

)

⩾

μ

∫
Q

(

v

−

u

)

(

μ

>

0

)

\int _Q {\nabla u\, \cdot \,\nabla \left ( {v\, - \,u} \right )} \, \geqslant \,\mu \,\int _Q {\left ( {v\, - \,u} \right )} \,\left ( {\mu \, > \,0} \right )

for any

v

∈

K

v\, \in \,K

, where

K

=

{

w

∈

H
0
1

(
Q
)

,

|

∇
w

|

⩽

1

}

K\, = \,\left \{ {w\, \in \,H_0^1\left ( Q \right ),\,\left | {\nabla w} \right |\, \leqslant \,1\,} \right \}

and Q is a simply connected domain whose boundary is piecewise

C
3

{C^3}

. The solution u represents the stress function in a torsion problem of an elastic bar with cross section Q; the sets
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="upper E equals left-brace x element-of upper Q semicolon StartAbsoluteValue nabla u left-parenthesis x right-parenthesis EndAbsoluteValue greater-than 1 right-brace comma upper P equals left-brace x element-of upper Q semicolon StartAbsoluteValue nabla u left-parenthesis x right-parenthesis EndAbsoluteValue equals 1 right-brace">

E

=

{

x

∈

Q
;

|

∇
u

(
x
)

|

>

1

}

,

P

=

{

x

∈

Q
;

|

∇
u

(
x
)

|

=

1

}

E\, = \,\left \{ {x\, \in \,Q;\,\left | {\nabla u\left ( x \right )} \right |\, > \,1} \right \},\,\,P\, = \,\left \{ {x\, \in \,Q;\,\left | {\nabla u\left ( x \right )} \right | = \,1} \right \}

are the elastic and plastic subsets of Q. The ridge R of Q is, by definition, the set of points in Q where dist

(

x
,

∂
Q

)

\left ( {x,\,\partial Q} \right )

is not

C

1
,
1

{C^{1,1}}

. The paper studies the location and shape of E, P and the free boundary

Γ

=

∂
E

∩

Q

\Gamma \, = \,\partial E\, \cap \,Q

. It is proved that the ridge is elastic and that E is contained in a

(

c

/

μ

)

\left ( {c/\mu } \right )

-neighborhood of R, as

μ

→

∞

(

c

>

0

)

\mu \, \to \,\infty \,\left ( {c\, > \,0} \right )

. The behavior of E and P near the vertices of

∂
Q

\partial Q

is studied in detail, as well as the nature of

Γ
\Gamma

away from the vertices. Applications are given to special domains. The case where Q is multiply connected is also studied; in this case the definition of K is somewhat different. Some results on the “upper plasticity” and “lower plasticity” and on the behavior as

μ

→

∞

\mu \, \to \,\infty

are obtained.
Continuity of the density of a gas flow in a porous medium
Authors: Caffarelli Luis A. , Friedman Avner
Published: July 2010

The equation of gas in a porous medium is a degenerate nonlinear parabolic equation. It is known that a unique generalized solution exists. In this paper it is proved that the generalized solution is continuous.
Sur les germes d’applications differentiables à singularités isolées
Authors: Bochnak Jacek , Kucharz Wojciech
Published: July 2010

Le but de cet article est d’étudier les germes d’applications différentiables

(

R

n

,
0
)

→

(

R

p

,
0
)

({{\textbf {R}}^n},0)\, \to \,({{\textbf {R}}^p},0)

, ou plus généralement les familles de telles applications, ayant en 0 une singularité isolée. Nous formulerons certains critères de

C
0

{C^0}

-suffisance de jets et nous démontrerons quelques théorèmes sur le nombre de types topologiques de germes qui apparaissent dans des familles de germes à singularité isolée.
Single-valued representation of set-valued mappings
Authors: Ioffe A. D.
Published: July 2010

It is shown that the graph of a set-valued mapping satisfying typical conditions which guarantee the existence of measurable selections can be represented as the union of graphs of measurable single-valued mappings depending continuously on a parameter running through some Polish space.
Zeros of Stieltjes and Van Vleck polynomials
Authors: Alam Mahfooz
Published: July 2010

The study of the polynomial solutions of the generalized Lamé differential equation gives rise to Stieltjes and Van Vleck polynomials. Marden has, under quite general conditions, established varied generalizations of the results proved earlier by Stieltjes, Van Vleck, Bocher, Klein, and, Pólya, concerning the location of the zeros of such polynomials. We study the corresponding problem for yet another form of the generalized Lamé differential equation and generalize some recent results due to Zaheer and to Alam. Furthermore, applications of our results to the standard form of this differential equation immediately furnish the corresponding theorems of Marden. Consequently, our main theorem of this paper may be considered as the most general result obtained thus far in this direction.
Theorems of Fubini type for iterated stochastic integrals
Authors: Berger Marc A. , Mizel Victor J.
Published: July 2010

An extension of the Itô calculus which treats iterated Itô integration, as applied to a class of two-parameter processes, is introduced. This theory includes the integration of certain anticipative integrands and introduces a notion of stochastic differential for such integrands. Among the key results is a version of Fubini’s theorem for iterated stochastic integrals, in which a “correction” term appears. Applications to stochastic integral equations and to the Itô calculus are given, and the relation of the present development to recent work of Ogawa is described.
Toeplitz operators and related function algebras on certain pseudoconvex domains
Authors: Jewell Nicholas P. , Krantz Steven G.
Published: July 2010

Toeplitz operators are defined on pseudoconvex domains in

C

n

{{\textbf {C}}^n}

and their spectral properties are studied. In addition, the linear space

H
∞

+

C

{H^\infty }\, + \,C

is discussed and is seen to be a closed algebra on a variety of domains.
Expansive homeomorphisms and topological dimension
Authors: Mañé Ricardo
Published: July 2010

Let K be a compact metric space. A homeomorphism

f
:

K
∣

f:\,K\mid

is expansive if there exists

ε

>

0

\varepsilon \, > \,0

such that if

x
,
y

∈

K

x, y\, \in \,K

satisfy

d

(

f
n

(
x
)

,

f
n

(
y
)

)

>

ε

d\left ( {{f^n}\left ( x \right ),\,{f^n}\left ( y \right )} \right )\, > \,\varepsilon

for all

n

∈

Z

n\, \in \,{\textbf {Z}}

(where

d

(

⋅
,

⋅

)

d\left ( { \cdot ,\, \cdot } \right )

denotes the metric on K) then

x

=

y

x\, = \,y

. We prove that a compact metric space that admits an expansive homeomorphism is finite dimensional and that every minimal set of an expansive homeomorphism is 0-dimensional.
Codimension one isometric immersions between Lorentz spaces
Authors: Graves L. K.
Published: July 2010

The theorem of Hartman and Nirenberg classifies codimension one isometric immersions between Euclidean spaces as cylinders over plane curves. Corresponding results are given here for Lorentz spaces, which are Euclidean spaces with one negative-definite direction (also known as Minkowski spaces). The pivotal result involves the completeness of the relative nullity foliation of such an immersion. When this foliation carries a nondegenerate metric, results analogous to the Hartman-Nirenberg theorem obtain. Otherwise, a new description, based on particular surfaces in the three-dimensional Lorentz space, is required.
Compactifications of the generalized Jacobian variety
Authors: Oda Tadao , Seshadri C. S.
Published: July 2010

The generalized Jacobian variety of an algebraic curve with at most ordinary double points is an extension of an abelian variety by an algebraic torus. Using the geometric invariant theory, we systematically compactify it in finitely many different ways and describe their structure in terms of torus embeddings. Our compactifications include all known good ones.
An algebraic determination of closed orientable 3-manifolds
Authors: Jaco William , Myers Robert
Published: July 2010

Associated with each polyhedral simple closed curve j in a closed, orientable 3-manifold M is the fundamental group of the complement of j in M,

π
1

(
M
−
j
)

{\pi _1}(M - j)

. The set,

K

(
M
)

\mathcal {K}(M)

, of knot groups of M is the set of groups

π
1

(
M
−
j
)

{\pi _1}(M - j)

as j ranges over all polyhedral simple closed curves in M. We prove that two closed, orientable 3-manifolds M and N are homeomorphic if and only if

K

(
M
)
=

K

(
N
)

\mathcal {K}(M) = \mathcal {K}(N)

. We refine the set of knot groups to a subset

F

(
M
)

\mathcal {F}(M)

of fibered knot groups of M and modify the above proof to show that two closed, orientable 3-manifolds M and N are homeomorphic if and only if

F

(
M
)
=

F

(
N
)

\mathcal {F}(M) = \mathcal {F}(N)

.
The atomic decomposition for parabolic 𝐻^{𝑝} spaces
Authors: Latter Robert H. , Uchiyama Akihito
Published: July 2010

The theorem of A. P. Calderón giving the atomic decomposition for certain parabolic

H
p

{H^p}

spaces is extended to all such spaces. The proof given also applies to Hardy spaces defined on the Heisenberg group.
Rational inner functions on bounded symmetric domains
Authors: Korányi Adam , Vági Stephen
Published: July 2010

It is shown that the rational inner functions on any bounded symmetric domain are given by a generalized version of a formula found by Rudin and Stout in the case of the polydisc. In particular, it is shown that all rational inner functions are constant on symmetric domains which have no irreducible factor of tube type.
Local 𝐻-maps of classifying spaces
Authors: Lance Timothy
Published: July 2010

Let BU denote the localization at an odd prime p of the classifying space for stable complex bundles, and let

f
:
B
U
→
B
U

f:BU \to BU

be an H-map with fiber F. In this paper the Hopf algebra

H

∗

(
F
,

Z

/

P
)

{H^{\ast }}(F,\textbf {Z}/P)

is computed for any such f. For certain H-maps f of geometric interest the p-local cohomology of F is given by means of the Bockstein spectral sequence. A direct description of

H

∗

(
F
,

Z

(
P
)

)

{H^ {\ast } }(F,{{\textbf {Z}}_{(P)}})

is also given for an important special case. Applications to the classifying spaces of surgery will appear later.
Morse and generic contact between foliations
Authors: Walker Russell B.
Published: July 2010

Motivated by the recent work of J. Franks and C. Robinson, the study of the contact between two foliations of equal codimension is begun. Two foliations generically contact each other in certain dimensional sub-manifold complexes. All but a finite number of these contact points are “Morse". In a recent paper by the author, a complete large isotopy “index of contact” is specified for two foliations of

T
2

{T^2}

. If contact is restricted to index 0 ("domed contact"), some sharp conclusions are made as to the topology of the manifold and isotopy classes of the two foliations. It is hoped that this work will lead to the construction of new quasi-Anosov diffeomorphisms and possibly to a new Anosov diffeomorphism.
A new characterization of amenable groups
Authors: Sherman Jon
Published: July 2010

Paradoxical sets, which are a natural generalization of the type of sets made famous as Hausdorff-Banach-Tarski paradoxes, are defined in terms of piecewise translations. Piecewise translations are the generalization to arbitrary discrete groups of the maps used in the Banach-Tarski paradoxes as congruences by finite decomposition. A subset of a group is defined to be large if finitely many translates of it can cover the group. The main result of this paper is that a group is amenable if and only if it does not contain a large paradoxical set.
Adding and subtracting jumps from Markov processes
Authors: Bass Richard F.
Published: July 2010

If

X
t

{X_t}

is a continuous Markov process with infinitesimal generator A, if n is a kernel satisfying certain conditions, and if B is an operator given by
\[

B
g
(
x
)

=

∫

[

g
(
y
)

−

g
(
x
)

]

n
(

x
,

d
y

)
,

Bg(x)\, = \,\int {[ {g( y)\, - \,g(x)}]} \,n({x,\,dy}),

\]
then

A

+

B

A\, + \,B

will be the generator of a Markov process that has Lévy system

(
n
,

d
t
)

(n,\,dt)

. Conversely, if

X
t

{X_t}

has Lévy system

(
n
,

d
t
)

(n,\,dt)

, n satisfies certain conditions, and B is defined as above, then

A

−

B

A\, - \,B

will be the generator of a continuous Markov process.
Diffeomorphisms and volume-preserving embeddings of noncompact manifolds
Authors: Greene R. E. , Shiohama K.
Published: July 2010

The theorem of J. Moser that any two volume elements of equal total volume on a compact manifold are diffeomorphism-equivalent is extended to noncompact manifolds: A necessary and sufficient condition (equal total and same end behavior) is given for diffeomorphism equivalence of two volume forms on a noncompact manifold. Results on the existence of embeddings and immersions with the property of inducing a given volume form are also given. Generalizations to nonorientable manifolds and manifolds with boundary are discussed.
Continuous functions on countable compact ordered sets as sums of their increments
Authors: Moran Gadi
Published: July 2010

Every continuous function from a countable compact linearly ordered set A into a Banach space V (vanishing at the least element of A ) admits a representation as a sum of a series of its increments (in the topology of uniform convergence). This series converges to no other sum under rearrangements of its terms. A uniqueness result to the problem of representation of a regulated real function on the unit interval as a sum of a continuous and a steplike function is derived.
Subnormal operators quasisimilar to an isometry
Authors: Hastings William W.
Published: July 2010

Let

V
=

V
0

⊕

V
1

V = {V_0} \oplus {V_1}

be an isometry, where

V
0

{V_0}

is unitary and

V
1

{V_1}

is a unilateral shift of finite multiplicity n. Let

S
=

S
0

⊕

S
1

S = {S_0} \oplus {S_1}

be a subnormal operator where

S
0

⊕

S
1

{S_0} \oplus {S_1}

is the normal decomposition of S into a normal operator

S
0

{S_0}

and a completely nonnormal operator

S
1

{S_1}

. It is shown that S is quasisimilar to V if and only if

S
0

{S_0}

is unitarily equivalent to

V
0

{V_0}

and

S
1

{S_1}

is quasisimilar to

V
1

{V_1}

. To prove this, a standard representation is developed for n-cyclic subnormal operators. Using this representation, the class of subnormal operators which are quasisimilar to

V
1

{V_1}

is completely characterized.
On natural radii of 𝑝-adic convergence
Authors: Dwork B. , Robba P.
Published: July 2010

We study the radius of p-adic convergence of power series which represent algebraic functions. We apply the p-adic theory of ordinary linear differential equations to show that the radius of convergence is the natural one, provided the degree of the function is less than p. The study of similar questions for solutions of linear differential equations is indicated.
Reparametrization of 𝑛-flows of zero entropy
Authors: Feldman J. , Nadler D.
Published: July 2010

Let

ϕ
\phi

,

ψ
\psi

be two ergodic n-parameter flows which preserve finite probability measures on their spaces X, Y. Let T be a nullset-preserving map:

X

→

Y

X\, \to \,Y

sending each

ϕ
\phi

-orbit homeomorphically to a

ϕ
\phi

-orbit. Then

ϕ
\phi

,

ψ
\psi

are called homeomorphically orbit-equivalent. For

n

=

1

n\, = \,1

, there has been developed a theory of such equivalence: “Loosely Bernoulli” theory. A completely parallel theory exists for higher dimensions, except that it is necessary to impose a certain natural “growth” restriction on T, a restriction which is vacuous in the case

n

=

1

n\, = \,1

. In this paper we carry out this program, but only for the case of zero entropy.
An equivariant Wall obstruction theory
Authors: Baglivo Jenny A.
Published: July 2010

Let G be a finite group. For a certain class of CW-complexes with a G-action which are equivariantly dominated by a finite complex we define algebraic invariants to decide when the space is equivariantly homotopy or homology equivalent to a finite complex.
Some Ramsey-type numbers and the independence ratio
Authors: Staton William
Published: July 2010

If each of k, m, and n is a positive integer, there is a smallest positive integer

r

=

r
k

(
m
,

n
)

r\, = \,{r_k}\,(m,\,n)

with the property that each graph G with at least r vertices, and with maximum degree not exceeding k, has either a complete subgraph with m vertices, or an independent subgraph with n vertices. In this paper we determine

r
3

(
3
,

n
)

=

r
(
n
)

{r_3}(3,\,n)\, = \,r(n)

, for all n. As a corollary we obtain the largest possible lower bound for the independence ratio of graphs with maximum degree three containing no triangles.
Geometric properties of a class of support points of univalent functions
Authors: Brown Johnny E.
Published: July 2010

Let S denote the set of functions

f
(
z
)

f(z)

analytic and univalent in

|

z

|

>

1

|z|\, > \,1

, normalized by

f
(
0
)

=

0

f(0)\, = \,0

and

f
′

(
0
)

=

1

f’(0)\, = \,1

. A function f is a support point of S if there exists a continuous linear functional L, nonconstant on S, for which f maximizes Re

Re

L
(
g
)

\operatorname {Re} \,L(g)

,

g
∈
S

g \in S

. The support points corresponding to the point-evaluation functionals are determined explicitly and are shown to also be extreme points of S. New geometric properties of their omitte

arcs

Γ

\operatorname {arcs}\,\Gamma

are found. In particular, it is shown that for each such support point

Γ
\Gamma

lies entirely in a certain half-strip,

Γ
\Gamma

has monotonic argument, and the angle between radius and tangent vectors increases from zero at infinity to a finite maximum value at the tip of the

arc

Γ

\operatorname {arc}\,\Gamma

. Numerical calculations appear to indicate that the known bound

π

/

4

\pi /4

for the angle between radius and tangent vectors is actually best possible.
Approximation theory in the space of sections of a vector bundle
Authors: Handel David
Published: July 2010

Let

p
:

E

→

B

p:\,E\, \to \,B

be a real m-plane bundle and S an n-dimensional subspace of the space of sections

Γ
(
E
)

\Gamma (E)

of E. S is said to be k-regular if whenever

x
1

,

…
,

x
k

{x_1},\, \ldots ,\,{x_k}

are distinct points of B and

υ
i

∈

p

−
1

(

x
i

)

{\upsilon _i}\, \in \,{p^{ - 1}}({x_i})

,

1

⩽

i

⩽

k

1\, \leqslant \,i\, \leqslant \,k

, there exists a

σ

∈

S

\sigma \, \in \,S

such that

σ
(

x
i

)

=

υ
i

\sigma ({x_i})\, = \,{\upsilon _i}

for

1

⩽

i

⩽
k

1\, \leqslant \,i\, \leqslant k

. It is proved that if E has a Riemannian metric and B is compact Hausdorff with at least

k

+

1

k\, + \,1

points, then S is k-regular if and only if for each

φ

∈

Γ
(
E
)

\varphi \, \in \,\Gamma (E)

, the set of best approximations to

φ
\varphi

by elements of S has dimension at most n - km. This extends a classical theorem of Haar, Kolmogorov, and Rubinstein (the case of the product line bundle). Complex and quaternionic analogues of the above are obtained simultaneously. Existence and nonexistence of k-regular subspaces of a given dimension are obtained in special cases via cohomological methods involving configuration spaces. For example, if E is the product real

(
2
m

−

1
)

(2m\, - \,1)

-plane bundle over a 2-dimensional disk, then

Γ
(
E
)

\Gamma (E)

contains a k-regular subspace of dimension

2
k
m

−

1

2km\, - \,1

, but not one of dimension

2
k
m

−

1

α
(
k
)

2km\, - \,1\,\alpha (k)

, where

α
(
k
)

\alpha (k)

denotes the number of ones in the dyadic expansion of k.
Identification of Species in the Botryosphaeriaceae Family Causing Stem Blight on Southern Highbush Blueberry in Florida
Authors: Wright A. F. , Harmon P. F.
Published: July 2010

Stem blight of southern highbush blueberry (SHB) results in premature plant mortality and has been identified by Florida blueberry growers as the economically most important disease for the industry. In 2007, plants with stem blight and dieback symptoms were sampled at 4-month intervals from two farms located in Alachua and Polk Co., FL. In all, 30 cane samples (stem blight) and 30 crown segments (dieback) were collected at each sample date and each location. In total, 360 samples were collected; fungal species in the family Botryosphaeriaceae were isolated from 85% of the samples. Based on morphology and phylogenetic analysis of the internal transcribed spacer region and elongation factor 1-α (EF1-α) sequences, two dominant species recovered from SHB in Florida were identified: Lasiodiplodia theobromae and Neofusicoccum ribis. Species isolation was independent of location, symptom type, and time of year. Additional samplings are needed to investigate population change over multiple years and in the rest of the southeastern United States. Breeding for resistance and management of stem blight and dieback in Florida should focus on these two fungal species.
Efficacy of Natural Plant Products on the Control of Aggregate Sheath Spot of Rice
Authors: Chaijuckam Patcharavipa , Davis R. Michael
Published: July 2010

Aqueous extracts from ginger, pepper, basil, and garlic plants and essential oils from neem, garlic, lemongrass, and cinnamon were evaluated for their antagonistic effects against Rhizoctonia oryzae-sativae, the cause of aggregate sheath spot of rice. The compounds in 5% concentrations in water or agar were tested on several R. oryzae-sativae isolates. Cinnamon oil, the most efficacious plant product in vitro, was further tested in the greenhouse for the control of the disease on two rice cultivars inoculated with R. oryzae-sativae. One milliliter of each of four cinnamon oil concentrations (12.5, 37.5, 62.5, or 87.5%) diluted in vegetable oil was applied to the surface of the water in constantly flooded pots. Cinnamon oil failed to reduce the disease caused by one of the isolates at any concentration. Cinnamon oil suppressed the disease caused by the other isolate on one of the cultivars at a concentration of 37.5%, and on both cultivars at a concentration of 62.5 and 87.5%. However, cinnamon oil at 87.5% was phytotoxic. Cinnamon oil has potential to control aggregate sheath spot but relatively high concentrations were required for disease suppression.
Grafting Tomato with Interspecific Rootstock to Manage Diseases Caused by Sclerotium rolfsii and Southern Root-Knot Nematode
Authors: Rivard C. L. , O'Connell S. , Peet M. M. , Louws F. J.
Published: July 2010

Southern blight (Sclerotium rolfsii) and root-knot nematodes (Meloidogyne spp.) cause severe damage to fresh-market tomato (Solanum lycopersicum) throughout the southeastern United States. Grafting is an emerging technology in U.S. tomato production, and growers require information regarding the resistance characteristics conferred by rootstocks. In this study, southern blight (SB) and root-knot nematodes (RKN) were effectively managed using interspecific hybrid rootstocks. During 2007 and 2008, field trials were carried out at two locations that had soils naturally infested with S. rolfsii. At the end of the growing seasons, the mean SB incidence of nongrafted plants was 27 and 79% at the two sites. SB incidence among plants grafted onto rootstock cultivars Big Power (one location only), Beaufort, and Maxifort ranged from 0 to 5%, and area under the disease progress curve (AUDPC) values were lower than for nongrafted and self-grafted controls (P < 0.01). At one location, soils were naturally infested with RKN, and all three rootstocks reduced RKN AUDPC and RKN soil populations at first harvest (P < 0.01). Big Power was particularly effective at reducing RKN galling and RKN soil populations at final fruit harvest (P < 0.01). Fruit yield was higher when resistant rootstocks were utilized (P < 0.05), and in our study grafting was effective at maintaining crop productivity in soils infested with S. rolfsii and M. incognita.
Scarification and Environmental Factors that Enhance Carpogenic Germination of Sclerotia of Sclerotinia sclerotiorum
Authors: Garg Harsh , Sivasithamparam Krishnapillai , Barbetti Martin J.
Published: July 2010

Ascospores of Sclerotinia sclerotiorum are the primary source of inoculum for disease epidemics in many economically important crops. Mass production of ascospores under laboratory conditions is required to prepare inoculum for use in selection of genotypes with resistance against Sclerotinia diseases. A study was undertaken, first, to investigate the effect on carpogenic germination of scarifying sclerotia from two S. sclerotiorum isolates taken from canola (Brassica napus) and, second, to identify environmental factors that enhance carpogenic germination. Seven different environmental treatments were applied to scarified and unscarified sclerotia: (i) sterilized distilled water for 4 months at 15°C, (ii) aerated water for 4 months at 4°C, (iii) constant rinsing with tap water for 8 weeks at 4°C, (iv) cold-conditioning for 4 weeks at 4°C and subsequent transfer into moist unsterilized compost at 15°C, (v) incubation in sterilized river sand at 15°C, (vi) air drying for 2 weeks followed by subsequent transfer into sterilized moist river sand at 15°C, or (vii) placed into 0.5% water agar and incubated at 15°C. Carpogenic germination of scarified sclerotia was significantly greater (P < 0.05) than for unscarified sclerotia. There was significant interaction (P < 0.001) between scarification and the different environmental treatments in relation to the carpogenic germination. Carpogenic germination of scarified sclerotia was enhanced by incubation of sclerotia in compost or in sterilized river sand. Further, overall carpogenic germination of both scarified and unscarified sclerotia occurred to the greatest extent when sclerotia of either of the two isolates were subjected to constant rinsing with tap water. We believe this to be the first report of both the enhanced carpogenic germination by scarification in S. sclerotiorum and the environmental factors we report that enhance carpogenic germination of scarified sclerotia. The progression of carpogenic germination in all the environmental treatments was also monitored as a part of this study across the two consecutive years for the same two isolates. The majority of sclerotia of both isolates germinated between the months of June and September in both years, a period which coincides with the main part of the cropping season when Sclerotinia stem rot is normally observed in rainfed canola in Western Australia. These data suggested the existence of a seasonal rhythm-like pattern in relation to the carpogenic germination of this pathogen.
First Report of Turnip mosaic virus on Watercress in Brazil
Authors: Costa H. , Ventura J. A. , Jadão A. S. , Rezende J. A. M. , Mello A. P. O. A.
Published: July 2010

Watercress (Nasturtium officinale L.), a member of the family Brassicaceae, is consumed mainly as salad. Medicinal properties have also been attributed to this species. In Brazil, watercress is grown mainly by very small farmers. The crop is primarily seed propagated and growers can harvest several times per year in an established planting. Very few diseases have been reported in this crop worldwide. In Brazil, watercress infection by Cauliflower mosaic virus (CaMV) (3), Cucumber mosaic virus (CMV) (1), and an unidentified potyvirus (2) were previously reported. In January 2009, 80% of watercress plants, cv. Gigante Redondo, exhibiting severe mosaic, leaf size reduction, and plant stunting were observed in a crop in Marechal Floriano Municipality, State of Espírito Santo, Brazil. Preliminary leaf dip analysis by transmission electron microscopy revealed the presence of potyvirus-like particles. Sap from five infected plants reacted in plate-trapped antigen (PTA)-ELISA with polyclonal antiserum against Turnip mosaic virus (TuMV), but not with antiserum against CMV. Both antisera were produced in the Plant Virology Laboratory, ESALQ/USP. Mechanically inoculated watercress plants developed similar systemic mosaic symptoms. The virus was also transmitted to Nicotiana benthamiana, which exhibited severe mosaic and stunting. The presence of TuMV on these inoculated plants was confirmed by PTA-ELISA and reverse transcription (RT)-PCR. Total RNA extracted from infected and healthy watercress and infected N. benthamiana was analyzed by RT-PCR using specific pairs of primers flanking the coat protein gene of TuMV. Degenerated anti-sense (5′-t/caacccctt/gaacgcca/cagt/ca-3′) and sense (5′-gcaggtgaa/gacg/acttgat/ca/gc-3′) primers were designed after analysis to an alignment of the nucleotide sequences for five isolates of TuMV available in the GenBank (Accession Nos. NC_002509, D10927, EU680574, AB362513, and D88614). One fragment of 838 bp was amplified from samples in the infected plants, but not in the healthy controls. Two amplicons were purified and directly sequenced in both directions. Comparisons of the 731-bp consensus nucleotide sequence (Accession No. HM008961) to several other isolates of TuMV revealed 94 to 95% identity in the coat protein region. To our knowledge, this is the first report of TuMV in watercress in Brazil. Management of the disease should include propagation by seeds instead of vegetative parts of the plants and rouging of diseased plants to prevent mechanical transmission during successive harvestings.

References: (1) A. J. Boari et al. Fitopatol. Bras. 25:438, 2000. (2) A. J. Boari et al. Fitopatol. Bras. 27:S200, 2002. (3) M. L. R. Z. C. Lima et al. Fitopatol. Bras. 9:403, 1984.
First Report of Iris yellow spot virus on Garlic in India
Authors: Gawande S. J. , Khar A. , Lawande K. E.
Published: July 2010

Garlic (Allium sativum) is a spice crop of prime importance in India as well as other parts of the world. Iris yellow spot virus (IYSV; genus Tospovirus, family Bunyaviridae) is an important pathogen of onion bulb and seed crops in many parts of the world (3). The virus is also known to infect garlic and other Allium spp. (2–4). IYSV infection of garlic was reported from Reunion Island (4) and the United States (1). In February 2010, straw-colored, spindle-shaped spots with poorly defined ends were observed on the leaves of a garlic crop at the research farm of the Directorate of Onion and Garlic Research in the Pune District of Maharashtra State, India, 105 days after planting. The spots coalesced to form larger patches on the leaves, suggesting possible IYSV infection. Symptoms were visible on older leaves and more prevalent on cv. G-41, G-282, AC50, AC200, AC283, and Godavari than on other cultivars. The incidence of symptomatic plants was estimated at 5% for G-41 and AC-200, 8% for G-282 and AC283, and 10% for AC50. Leaves were sampled from 40 symptomatic plants per cultivar with each sample composited from young, middle, and older (basal) leaves of the plant. Samples were assayed by double-antibody sandwich-ELISA (Loewe Biochemica GmbH, Sauerlach, Germany) and each tested positive for the virus. Total RNA was extracted from the leaves of ELISA-positive plants using the RNAeasy Plant Mini kit (Qiagen GmbH, Hilden, Germany) and tested by reverse transcription-PCR assay using primers IYSV-F (5′-TCAGAAATCGAGAAACTT-3′) and IYSV-R (5′-TAATTATATCTATCTTTCTTGG-3′) (2) designed to amplify 797 bp of the nucleocapsid (N) gene of IYSV. Amplicons of expected size were obtained and cloned into a pDrive vector (Qiagen GmbH). The recombinant clone was sequenced (GenBank Accession No. HM173691). Sequence comparisons showed 98 to 100% nt identity with other IYSV N gene sequences in GenBank (Nos. EU310294 and EU310286). A phylogenetic analysis of the deduced amino acid sequences of the N gene showed that the garlic isolate of IYSV grouped most closely with onion IYSV isolates from India (GenBank Nos. EU310294, EU310286, EU310300, and EU310296). To our knowledge, this is the first report of natural infection of garlic by IYSV in India. Additional surveys and evaluations are needed to obtain a better understanding of the potential impact of IYSV on garlic production in India.

References: (1) S. Bag et al. Plant Dis. 93:839, 2009. (2) A. Bulajic et al. Plant Dis. 93:976, 2009. (3) D. Gent et al. Plant Dis. 90:1468, 2006. (4) I. Robène-Soustrade et al. Plant Pathol. 55:288, 2006.
First Report of Xanthomonas hortorum pv. carotae Causing Bacterial Leaf Blight of Carrot in Mauritius
Authors: Pruvost O. , Boyer C. , Robène-Soustrade I. , Jouen E. , Saison A. , Hostachy B. , Benimadhu S.
Published: July 2010

Bacterial blight of carrot (Daucus carota) is caused by Xanthomonas hortorum pv. carotae (4). The pathogen is seed transmitted and carrot seeds can be an important source of primary inoculum (2). A 2008–2009 outbreak of a disease resembling bacterial blight was observed in Mauritius in 10 ha of carrot crops, primarily in humid areas of the island, at an estimated incidence of 10%. Carrot leaves with angular, water-soaked leaf spots that turned necrotic were collected at Plaine Sophie, Mauritius in December 2008. Yellow, Xanthomonas-like colonies were isolated onto KC agar medium (3). MultiLocus sequence analysis (MLSA) with four genes (atpD, dnaK, efp, and gyrB) was performed as described previously (1) on five carrot strains together with two reference strains of X. hortorum pv. carotae (LMG 8643 and LMG 8644). The reference strains were identical. Of the five Mauritius strains, two (LG1-1 and LG1-4) were identical, and most closely related to, but distinct from, the reference strains (genetic distance of 0.02). The other three strains represented two sequence types identified as Xanthomonas sp. based on a phylogenetic tree derived from concatenated sequences, but were not related to any type strain. PCR assays with a 3S primer pair specific for X. hortorum pv. carotae (2) produced an amplicon of approximately 350 bp from isolates LG1-1, LG1-4, and each of the reference strains. A PCR assay with a 9B primer pair (2) yielded an amplicon of 0.9 kb for strains LG1-1, LG1-4, and LMG 8644, whereas LMG 8643 yielded an amplicon of approximately 2.0 kb (2). Foliage of 4-week-old plants (36 plants per strain) of the carrot cv. Senator F1 were spray inoculated with a suspension of each strain using an 18-h culture in sterile 0.01 M tris buffer (pH 7.2) with approximately 1 × 108 CFU/ml. Plants sprayed with tris buffer were used as a negative control treatment. Plants were incubated in a growth chamber at 26 ± 1°C at a relative humidity of 95 ± 5% and a photoperiod of 16 h. Water-soaked lesions that developed into necrotic areas were observed 12 to 15 days after inoculation of LG1-1, LG1-4, and the two reference strains. Bacteria were recovered from lesions onto KC medium (3) 3 weeks after inoculation with mean Xanthomonas populations of at least 1 × 107 CFU/lesion. Colonies with morphology typical of Xanthomonas were recovered and typed using atpD sequencing to fulfill Koch's postulates. Although Xanthomonas-like bacteria were isolated from symptomatic carrot leaves in Mauritius in 1989, the results of that study were not published. To our knowledge, this is the first report of molecular and pathological characterization of this pathogen in carrot crops in Mauritius.

References: (1) L. Bui Thi Ngoc et al. Int. J. Syst. Evol. Microbiol. 60:515, 2010. (2) X. Q. Meng et al. Plant Dis. 88:1226, 2004. (3) O. Pruvost et al. J. Appl. Microbiol. 99:803, 2005. (4) L. Vauterin et al. Int. J. Syst. Bacteriol. 45:472, 1995.
Identification of Iris yellow spot virus on Leek (Allium porrum) in Sri Lanka
Authors: Widana Gamage S. M. K. , Hassani-Mehraban A. , Peters D.
Published: July 2010

Leek (Allium porrum) has become one of the major leafy vegetable export crops in Sri Lanka during last few years. This year-round crop is cultivated in open fields at elevations between 1,000 and 2,000 m on approximately 1,600 ha with a production of 27,000 t per year (2). In August 2009, straw-colored spots (2 to 3 mm in diameter), surrounded by a greenish halo and a necrotic area, resembling symptoms to those caused by Iris yellow spot virus (IYSV) were observed on leek in Kandapola in the Nuwara Eliya District. Additional thrips damage consisting of silver-colored spots was observed on all plants. IYSV (family Bunyaviridae, genus Tospovirus) was first described and characterized in the Netherlands in 1998 (1). During the last few years, this virus was reported from Australia, Brazil, Chile, France, Germany, Guatemala, India, Israel, New Zealand, Peru, Reunion Island, Serbia, South Africa, Spain, the United States (4), and Japan. Collected samples were initially analyzed for IYSV infections using antisera raised against nucleocapsid (N) protein in a double-antibody sandwich (DAS)-ELISA. The presence of IYSV was confirmed by a reverse transcription (RT)-PCR using IYSV-F-373 (5′CTGCGGGCTTCTCTGG3′) and IYSV-R-779 (5′GACTCACCAATGTCTTCAAC3′) primers that amplify a 400-bp fragment of the N gene. The entire N gene was not obtained when specific primers were used to retrieve the complete N gene. Four nucleotides of the reverse primer GAAAGATAGATATAATTAA (indicated in bold) did not match with sequence at the 3′end of the N gene. Hence, to obtain the remaining parts of the N gene, the primers UHP (5′CACTGGATCCTTTTGTTTTTGTTTTTTG3′) and Asian Termini (5′CCCGGATCCAGAGCAATCGAGGY3′) (3) were combined with IYSV-F and IYSV-R. The obtained amplicons were cloned into pGEM-T easy vector and sequenced. The N gene sequence has been deposited at the NCBI/GenBank (Accession No. GU901211). The deduced N protein sequence(s) were compared with other IYSV N protein sequences available in the GenBank and showed a 92% protein identity with the Brazilian strain (IYSV-BR) and 97% with the Dutch strain (IYSV-NL) with Accession Nos. AAF04199 and AAB61923, respectively. No data on the thrips vector species or on the disease incidence have been collected. The presence of IYSV in Sri Lanka can potentially be considered as a threat for the export of leek. To our knowledge, this is the first report that IYSV occurs in Sri Lanka.

References: (1) I. Cortêz et al. Phytopathology 88:1276, 1998. (2) Department of Census and Statistics Sri Lanka. Retrieved from http://www.statistics.gov.lk , 2009. (3) A. Hassani-Mehraban et al. Phytopathology 95:852, 2005. (4) H. R. Pappu et al. Virus Res. 141:219, 2009.
First Report of Citrus exocortis viroid from Grapevine in China
Authors: Shu J. , Wang G. P. , Xu W. X. , Hong N.
Published: July 2010

Citrus exocortis viroid (CEVd) can induce bark scaling, dwarfing, leaf epinasty, and fruit yield loss in susceptible hosts. In citrus, CEVd is reported from around the world, but in grape, it is reported from fewer locations (Australia, Brazil, California, and Spain [1]). In 2009, leaves were collected from 40 grapevines (of several different cultivars and species) from Henan, Hubei, Shandong, and Liaoning provinces, China. Total RNA or double-stranded RNA was extracted from the leaves by a described method (3) and subjected to reverse transcription with a random primer (Takara, Dalian, China) and then PCR with primer CEV-AM3 and CEV-AP3 (2). Results showed that the target DNA fragments of 372 bp long were amplified only from the symptomless leaves collected from two grapevines of cv. White Rose grown for approximately 26 years within a small garden in Hubei Province. Amplified products were recovered and cloned into pMD18-T (Takara) and 10 positive clones of each isolate were sequenced and aligned. For both isolates, 20% of the clones represented the same variant (CEVd-hn-g-1; GenBank Accession No. GU592444). It showed a max identity of 94 to 99% with the variants (GenBank Accession Nos. Y00328.1 and DQ471996.1) from grape registered in NCBI, 91 to 100% (GenBank Accession Nos. DQ431993.1 and DQ831485.1) from citrus, 91 to 98% (GenBank Accession Nos. EF488068.1 and EF488050.1) from broad bean, and 89 to 94% (GenBank Accession Nos. AY671953.1 and S67446.1) from tomato. To our knowledge, this is the first report of CEVd from grape in China.

References: (1) M. Eiras et al. Fitopatol. Bras. 31:440, 2006. (2) H. J. Gross et al. Eur. J. Biochem. 121:249, 1982. (3) W. X. Xu et al. J. Virol. Methods 135:276, 2006.
First Report of Blueberry red ringspot virus in Highbush Blueberry in the Czech Republic
Authors: Přibylová J. , Špak J. , Kubelková D. , Petrzik K.
Published: July 2010

A collection of highbush blueberry (Vaccinium corymbosum L.) cultivars planted in the field for propagation in South Bohemia was surveyed in May and July of 2009 for the occurrence of detrimental viruses. A total of 67 plants of 10 cultivars (Berkeley, Burlington, Blue Crop, Bluetta, Darrow, Duke, Gila, Jersey, Late Blue, and Northland), were observed for typical Blueberry red ringspot virus (BRRV) symptoms that appear as reddish ring spots and blotches on stems and fruits, exclusively on the upper surface of the older leaves but not the underside. Samples of leaves were collected and maintained at –20°C until used for DNA extraction, then assayed for BRRV infection using PCR. Controls originated from the same blueberry cultivars in vitro. DNA was extracted from leaf tissue with a NucleoSpin Plant II kit for isolating genomic DNA according to the manufacturer's instructions (Macherey-Nagel, Düren, Germany). Primer pair BRRV15/16, which amplified fragments of the reverse transcriptase gene (1), was used in PCR for BRRV detection. The program used for PCR amplification was 94°C for 2 min, followed by 35 cycles at 94°C for 30 s, 49°C for 30 s, and 70°C for 45 s, followed by a final extension at 70°C for 5 min. The total PCR volume of 25 μl contained 20 ng of DNA, 200 μmol liter–1 dNTPs, 0.5 μl of each primer BRRV15 and BRRV16 (20 pmol μl–1), 75 mM Tris-HCl pH 8.8, 20 mM (NH4)2SO4, 0.01% Tween 20, 2.5 mM MgCl2, 2.5 U of Taq Purple DNA polymerase, and stabilizers (Top-Bio Ltd., Prague, Czech Republic). Amplifications were conducted in an MJ Research (Waltham, MA) thermocycler. Aliquots (4 μl) of each PCR product were analyzed by electrophoresis in tris-acetate-EDTA buffer. No BRRV symptoms were observed on the plants in early spring, yet BRRV was detected in one symptom-free bush of cv. Darrow by PCR. In July, typical symptoms developed on that and another cv. Darrow bush that was also positive by PCR. DNA fragments of the expected sizes were amplified from total nucleic acid samples of both infected blueberry bushes using primers BRRV15/16, while no amplification products were detected in plants without symptoms. The amplicons obtained with primers BRRV15/BRRV16 were sequenced and revealed 97.5%-nt identity to the BRRV putative reverse transcriptase gene (GenBank Accession No. AF404509). The 845 nt of the amplicon has been deposited at GenBank under Accession No. HM107773. The disease was likely introduced in infected planting material, since no highbush blueberry plantations exist in the vicinity and V. corymbosum is not native to the Czech Republic. In conclusion, to our knowledge, this is the first report of Blueberry red ringspot virus (genus Soymovirus, family Caulimoviridae) in V. corymbosum L. in the Czech Republic. Symptom observation and PCR testing for BRRV should therefore, be incorporated into the certification scheme for highbush blueberry in the Czech Republic.

Reference: (1) J. J. Polashock et al. Plant Dis. 93:727, 2009.
An experimental charge density of HEPES
Authors: Śledź Paweł , Kamiński Radosław , Chruszcz Maksymilian , Zimmerman Matthew D. , Minor Wladek , Woźniak Krzysztof
Published: July 2010

We report the experimental charge density of HEPES [4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid], which is a common buffering agent. The structure was refined using the Hansen–Coppens formalism. The ability of the HEPES molecule to form stable intermolecular interactions and intermolecular hydrogen bonds in the crystal structure is discussed in terms of its buffering properties. The protonation mode observed in the crystal structure is different from that expected in solution, suggesting that additional factors must be taken into consideration in order to explain the solution properties of the compound. As ordered HEPES molecules are found in the active sites of proteins in several protein crystal structures, our results will allow for quantitative analysis of the electrostatic potential of the interacting surfaces of those proteins.