bluuebunny/crossref_metadata_2025 huggingface dataset:
The action of waving cylindrical tails with noncircular cross-section in propelling microrobots
Authors: Kósa Gábor , Shoham Moshe , Haber Shimon
Published: August 2010

With the advent of microtechnologies, manufacturing of swimming microrobots that mimic the motion of micro-organisms has become feasible. Based upon the work of Taylor [“The action of waving cylindrical tails in propelling microscopic organisms,” Proc. R. Soc. London, Ser. A 209, 225 (1951)], the creeping flow induced by a noncircular swimming tail waving in a plane or in spirals was investigated. Tails with rectangular, elliptic, and trapezoidal cross-sections were examined, the latter being the most commonly fabricated microtail. It was observed that for a given cross-section area and propagating wave velocity the trapezoidal cross-section yields the highest tail velocity, whereas the elliptic tail results in the lowest one. Generally, it was obtained that if the cross-section deviation from circularity is expressed by a Fourier series expansion only the symmetric second harmonic affects the propulsion of the tail provided that the wave amplitude is smaller than the cross-section mean radius and of the order of the deviation from circularity. It was also shown that for a planar wave propagating velocity, a higher swimming velocity is obtained if the wider side of the noncircular cross-section faces the waving motion. For helical tails, first order effects of noncircularity on the swimming velocity vanish.
Analytic treatment of vortex states in cylindrical superconductors in applied axial magnetic field
Authors: Ludu A. , Van Deun J. , Milošević M. V. , Cuyt A. , Peeters F. M.
Published: August 2010

We solve the linear Ginzburg–Landau (GL) equation in the presence of a uniform magnetic field with cylindrical symmetry and we find analytic expressions for the eigenfunctions in terms of the confluent hypergeometric functions. The discrete spectrum results from an implicit equation associated to the boundary conditions and it is resolved in analytic form using the continued fractions formalism. We study the dependence of the spectrum and the eigenfunctions on the sample size and the surface conditions for solid and hollow cylindrical superconductors. Finally, the solutions of the nonlinear GL formalism are constructed as expansions in the linear GL eigenfunction basis and selected by minimization of the free energy. We present examples of vortex states and their energies for different samples in enhancing/suppressing superconductivity surroundings.
Mimicking coarse-grained simulations without coarse-graining: Enhanced sampling by damping short-range interactions
Authors: Wei Dongshan , Wang Feng
Published: August 2010

The damped-short-range-interaction (DSRI) method is proposed to mimic coarse-grained simulations by propagating an atomistic scale system on a smoothed potential energy surface. The DSRI method has the benefit of enhanced sampling provided by a typical coarse-grained simulation without the need to perform coarse-graining. Our method was used to simulate liquid water, alanine dipeptide folding, and the self-assembly of dimyristoylphosphatidylcholine lipid. In each case, our method appreciably accelerated the dynamics without significantly changing the free energy surface. Additional insights from DSRI simulations and the promise of coupling our DSRI method with Hamiltonian replica-exchange molecular dynamics are discussed.
Marginal turbulent magnetohydrodynamic flow in a square duct
Authors: Shatrov Victor , Gerbeth Gunter
Published: August 2010

Direct numerical simulations using a high-order finite-difference method were performed of the turbulent flow in a straight square duct in a transverse magnetic field. Without magnetic field the turbulence can be maintained for values of the bulk Reynolds number above approximately Re=1077 [M. Uhlmann et al., “Marginally turbulent flow in a square duct,” J. Fluid Mech. 588, 153 (2007)]. In the magnetohydrodynamic case this minimal value of the bulk Reynolds number increases with the Hartmann number. The flow is laminar at Re=3000 when the Hartmann number is larger than Ha=12.5 and the flow is turbulent for Ha≦12.0. The secondary mean flow structure at Re=3000 consists of eight vortices located mainly at the Hartmann walls.
GaN-based light emitting diodes with embedded SiO2 pillars and air gap array structures
Authors: Lai Wei-Chih , Yang Ya-Yu , Peng Li-Chi , Yang Shih-Wei , Lin Yu-Ru , Sheu Jinn-Kong
Published: August 2010

We demonstrated GaN-based light emitting diodes (LEDs) with different embedded heights of SiO2 pillars and air gap array structures. The air gap on top of the SiO2 pillars were also realized using the enhanced epitaxial lateral overgrowth mode. With the embedded SiO2 pillars and air gap array structures, we achieved a smaller reverse leakage current due to the lateral growth-induced crystal quality improvement. Moreover, under 20 mA current injections, the output powers were 3.04, 4.23, 4.66, and 4.44 mW for conventional LED, LEDs with embedded 200 and 500 nm height of SiO2 pillars and air gaps, 500 nm height of SiO2 pillars and air gaps, and 700 and 400 nm height of SiO2 pillars and air gaps, respectively. We found that the embedded 500 nm height SiO2 pillars and 500 nm height air gap array structures could enhance LED output power by more than 50% due to the enhanced guided-light scattering efficiency in our study.
Visual Strategies Used for Time-to-Arrival Judgments in Driving
Authors: van Loon Editha M , Khashawi Fadhel , Underwood Geoffrey
Published: August 2010

To investigate the sources of visual information that are involved in the anticipation of collisions we recorded eye movements while participants made relative timing judgments about approaching vehicles at a junction. The avoidance of collisions is a critical aspect in driving, particularly where cars enter a line of traffic from a side road, and the present study required judgments about animations in a virtual driving environment. In two experiments we investigated the effects of (i) the angle of approach of the vehicle and the type of path (straight or curved) of the observer, and (ii) the speed of both the observer and the approaching car. Relative timing judgments depend on the angle of approach of the other vehicle (judgments are more accurate for perpendicular than for obtuse angles). Eye-movement analysis shows that visual strategies in relative timing judgments are characterised by saccadic eye movements back and forth between the approaching car and the road ahead, particularly the side line which may serve as a spatial reference point. Results suggest that observers use the distance of the car from this reference point for their timing judgments.
Martin Hetzer: Taking the nuclear membrane beyond the barrier
Authors: Short Ben
Published: August 2010

Hetzer investigates how the nuclear envelope and nuclear pores organize chromatin and regulate gene expression.
How cyclin A destruction escapes the spindle assembly checkpoint
Authors: Di Fiore Barbara , Pines Jonathon
Published: August 2010

The anaphase-promoting complex/cyclosome (APC/C) is the ubiquitin ligase essential to mitosis, which ensures that specific proteins are degraded at specific times to control the order of mitotic events. The APC/C coactivator, Cdc20, is targeted by the spindle assembly checkpoint (SAC) to restrict APC/C activity until metaphase, yet early substrates, such as cyclin A, are degraded in the presence of the active checkpoint. Cdc20 and the cyclin-dependent kinase cofactor, Cks, are required for cyclin A destruction, but how they enable checkpoint-resistant destruction has not been elucidated. In this study, we answer this problem: we show that the N terminus of cyclin A binds directly to Cdc20 and with sufficient affinity that it can outcompete the SAC proteins. Subsequently, the Cks protein is necessary and sufficient to promote cyclin A degradation in the presence of an active checkpoint by binding cyclin A–Cdc20 to the APC/C.
SNX27 mediates PDZ-directed sorting from endosomes to the plasma membrane
Authors: Lauffer Benjamin E.L. , Melero Cristina , Temkin Paul , Lei Cai , Hong Wanjin , Kortemme Tanja , von Zastrow Mark
Published: August 2010

Postsynaptic density 95/discs large/zonus occludens-1 (PDZ) domain–interacting motifs, in addition to their well-established roles in protein scaffolding at the cell surface, are proposed to act as cis-acting determinants directing the molecular sorting of transmembrane cargo from endosomes to the plasma membrane. This hypothesis requires the existence of a specific trans-acting PDZ protein that mediates the proposed sorting operation in the endosome membrane. Here, we show that sorting nexin 27 (SNX27) is required for efficient PDZ-directed recycling of the β2-adrenoreceptor (β2AR) from early endosomes. SNX27 mediates this sorting function when expressed at endogenous levels, and its recycling activity requires both PDZ domain–dependent recognition of the β2AR cytoplasmic tail and Phox homology (PX) domain–dependent association with the endosome membrane. These results identify a discrete role of SNX27 in PDZ-directed recycling of a physiologically important signaling receptor, and extend the concept of cargo-specific molecular sorting in the recycling pathway.
HDM2 ERKs PCNA
Authors: Nguyen Hai Dang , Bielinsky Anja-Katrin
Published: August 2010

In this issue, a study by Groehler and Lannigan (2010. J. Cell Biol. doi:10.1083/jcb.201002124) sheds light on the regulation of proliferating cell nuclear antigen (PCNA) turnover and how it is counteracted by the small chromatin-bound kinase ERK8 (extracellular signal-regulated kinase 8). Importantly, inactivation of ERK8 results in genome instability and is associated with cell transformation.
Weighted-𝐿² interpolation on non-uniformly separated sequences
Authors: Ostrovsky Stanislav
Published: August 2010

We define a weighted-

ℓ
2

\ell ^2

-norm associated to a discrete sequence

Γ
\Gamma

in

C

\mathbb {C}

and a weight function

φ
\varphi

. We then give a sufficient condition which ensures that we can always extend weighted-

ℓ
2

\ell ^2

data to global holomorphic functions which are also weighted-

L
2

L^2

. The condition is such that the so-called upper density of

Γ
\Gamma

is strictly less than one.
On Corson compacta and embeddings of 𝐶(𝐾) spaces
Authors: Marciszewski Witold , Plebanek Grzegorz
Published: August 2010

We investigate properties of those compact spacesKKfor which the Banach spaceC(K)C(K)can be isomorphically embedded into a spaceC(L)C(L), whereLLis Corson compact. We show that in such a caseKKmust be Corson compact providedKKhas some additional measure–theoretic property. The result is applicable to Rosenthal compacta and several other classes of compact spacesKK.
Symbolic dynamics for nonhyperbolic systems
Authors: Richeson David , Wiseman Jim
Published: August 2010

We introduce index systems, a tool for studying isolated invariant sets of dynamical systems that are not necessarily hyperbolic. The mapping of the index systems mimics the expansion and contraction of hyperbolic maps on the tangent space, and they may be used like Markov partitions to generate symbolic dynamics. Every continuous dynamical system satisfying a weak form of expansiveness possesses an index system. Because of their topological robustness, they can be used to obtain rigorous results from computer approximations of a dynamical system.
The distribution of zeros of a class of Jacobi polynomials
Authors: Charalambides Marios , Csordas George
Published: August 2010

Polynomials whose coefficients are successive derivatives of a class of generalized Laguerre polynomials evaluated atx=0x=0are shown to be stable. These polynomials can be expressed in terms of Jacobi polynomials. The authors also prove that a related family of polynomials, depending on a parameter, possess only real and negative zeros. A special class of stability-preserving operators is also investigated.
Sub-Bergman spaces in the unit ball of ℂⁿ
Authors: Symesak Frédéric
Published: August 2010

Let
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="normal upper Phi left-parenthesis z right-parenthesis equals left-parenthesis phi 1 left-parenthesis z right-parenthesis comma midline-horizontal-ellipsis comma phi Subscript l Baseline left-parenthesis z right-parenthesis right-parenthesis">

Φ
(
z
)
=
(

φ
1

(
z
)
,
⋯
,

φ
l

(
z
)
)

\Phi (z)=( \varphi _1(z),\cdots ,\varphi _l(z))

be holomorphic from the unit ball of

C

n

\mathbb C^n

into the unit ball of

C

l

\mathbb C^l

. We denote by

B

α

(
z
,
w
)

B_{\alpha }(z,w)

the weighted Bergman kernel. We give a condition for the kernel
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="left-parenthesis 1 minus normal upper Phi left-parenthesis z right-parenthesis ModifyingAbove normal upper Phi left-parenthesis w right-parenthesis With bar right-parenthesis upper B Subscript alpha Baseline left-parenthesis z comma w right-parenthesis">

(
1
−
Φ
(
z
)

Φ
(
w
)

¯

)

B

α

(
z
,
w
)

(1-\Phi (z){\overline {\Phi (w)}}\,)B_{\alpha }(z,w)

to be a reproducing kernel and we study the related Hilbert space.
An octonion algebra originating in combinatorics
Authors: Đoković Dragomir , Zhao Kaiming
Published: August 2010

C.H. Yang discovered a polynomial version of the classical Lagrange identity expressing the product of two sums of four squares as another sum of four squares. He used it to give short proofs of some important theorems on composition of

δ
\delta

-codes (now known as

T
T

-sequences). We investigate the possible new versions of his polynomial Lagrange identity. Our main result shows that all such identities are equivalent to each other.
One-parameter families of smooth interval maps: Density of hyperbolicity and robust chaos
Authors: van Strien Sebastian
Published: August 2010

In this paper we will discuss the notion of robust chaos and show that (i) there are natural one-parameter families of interval maps with robust chaos and (ii) hyperbolicity is dense within generic one-parameter families (and so these families are not robustly chaotic).
An inductive proof of the Feinstein-Heath Swiss cheese “Classicalisation” theorem
Authors: Mason J.
Published: August 2010

A theory of allocation maps has been developed by J. F. Feinstein and M. J. Heath in order to prove a theorem, using Zorn’s lemma, concerning the compact plane sets known as Swiss cheese sets. These sets are important since, as domains, they provide a good source of examples in the theory of uniform algebras and rational approximation. In this paper we take a more direct approach when proving their theorem by using transfinite induction and cardinality. An explicit reference to a theory of allocation maps is no longer required. Instead we find that the repeated application of a single operation developed from the final step of the proof by Feinstein and Heath is enough.
A probabilistic approach to the Liouville property for Schrödinger operators with an application to infinite configurations of balls
Authors: Hess-Green Rachel , Pinsky Ross
Published: August 2010

Consider the equation

(*)

1
2

Δ
u
−
V
u
=
0
 
in
 

R
d

,

\begin{equation}\frac 12\Delta u-Vu=0\ \text {in}\ R^d,\tag {*} \end{equation}

for

d
≥
3

d\ge 3

, where

V
⪈
0

V\gneq 0

. One says that the Liouville property holds if the only bounded solution to (*) is 0. Under a certain growth condition on

V
V

, we give a necessary and sufficient analytic condition for the Liouville property to hold. We then apply this to the case that

V
V

is the indicator function of an infinite collection of small balls.
Indispensable binomials in semigroup ideals
Authors: Ojeda Ignacio , Vigneron-Tenorio Alberto
Published: August 2010

In this paper, we deal with the problem of the uniqueness of a minimal system of binomial generators of a semigroup ideal. Concretely, we give different necessary and/or sufficient conditions for the uniqueness of such a minimal system of generators. These conditions come from the study and combinatorial description of the so-called indispensable binomials in the semigroup ideal.
Divisibility theory of semi-hereditary rings
Authors: Ánh P. , Siddoway M.
Published: August 2010

The semigroup of finitely generated ideals partially ordered by inverse inclusion, i.e., the divisibility theory of semi-hereditary rings, is precisely described by semi-hereditary Bezout semigroups. A Bezout semigroup  is a commutative monoid

S
S

with 0 such that the divisibility relation

a
|
b
⟺
b
∈
a
S

a\vert b \Longleftrightarrow b\in aS

is a partial order inducing a distributive lattice on

S
S

with multiplication distributive on both meets and joins, and for any

a
,

b
,

d
=
a
∧
b
∈
S
,

a
=
d

a
1

a,\, b,\, d=a\wedge b\in S,\, a=da_1

there is

b
1

∈
S

b_1\in S

with

a
1

∧

b
1

=
1
,

b
=
d

b
1

a_1\wedge b_1=1,\, b=db_1

.

S
S

is semi-hereditary if for each

a
∈
S

a\in S

there is

e
2

=
e
∈
S

e^2=e\in S

with

e
S
=

a

⊥

=
{
x
∈
S

|

a
x
=
0
}

eS=a^{\perp }=\{x\in S\,\vert \, ax=0\}

. The dictionary is therefore complete: abelian lattice-ordered groups and semi-hereditary Bezout semigroups describe divisibility of Prüfer (i.e., semi-hereditary) domains and semi-hereditary rings, respectively. The construction of a semi-hereditary Bezout ring with a pre-described semi-hereditary Bezout semigroup is inspired by Stone’s representation of Boolean algebras as rings of continuous functions and by Gelfand’s and Naimark’s analogous representation of commutative

C
∗

C^*

-algebras.
Rings of coinvariants and 𝑝-subgroups
Authors: Lin Tzu-Chun
Published: August 2010

Let

ϱ
:
G
↪
G
L
(
n
,

F

)

\varrho :G\hookrightarrow GL(n, \mathbb {F})

be a faithful representation of a finite group

G
G

over the field

F

\mathbb {F}

and let

V
≅

F

n

V \cong \mathbb {F}^n

be an

F

(
G
)

\mathbb {F}(G)

-module. It has been shown by L. Smith that if

n
=
3

n=3

and the order of

G
G

is divisible by the positive characteristic

p
p

of

F

\mathbb {F}

, then

F

[
V

]
G

\mathbb {F} [V]^G

is Cohen-Macaulay. Under the condition

n
=
3

n=3

we prove the following conjecture through this remarkable result: If

F

[
V

]
G

\mathbb {F} [V]_G

is a Poincaré duality algebra, then

F

[
V

]

Syl

p

⁡
(
G
)

\mathbb {F} [V]_{\operatorname {Syl}_{p}(G)}

is a complete intersection, where

Syl

p

⁡
(
G
)

\operatorname {Syl}_{p}(G)

is a Sylow

p
p

-subgroup of

G
G

.
Remarks on global a priori estimates for the nonlinear Schrödinger equation
Authors: Colliander J. , Grillakis M. , Tzirakis N.
Published: August 2010

We present a unified approach for obtaining global a priori estimates for solutions of nonlinear defocusing Schrödinger equations with defocusing nonlinearities. The estimates are produced by contracting the local momentum conservation law with appropriate vector fields. The corresponding law is written for defocusing equations of tensored solutions. In particular, we obtain a new estimate in two dimensions. We bound the restricted

L
t
4

L

γ

4

L_t^4L_{\gamma }^4

Strichartz norm of the solution on any curve

γ
\gamma

in

R

2

\mathbb R^2

. For the specific case of a straight line we upgrade this estimate to a weighted Strichartz estimate valid in the full plane.
Uniqueness of the maximum likelihood estimator for 𝑘-monotone densities
Authors: Seregin Arseni
Published: August 2010

We prove uniqueness of the maximum likelihood estimator for the class of

k
−

k-

monotone densities.
Mapping class groups of medium distance Heegaard splittings
Authors: Johnson Jesse
Published: August 2010

We show that if the Hempel distance of a Heegaard splitting is larger than three, then the mapping class group of the Heegaard splitting is isomorphic to a subgroup of the mapping class group of the ambient 3-manifold. This implies that given two handlebody sets in the curve complex for a surface that are distance at least four apart, the group of automorphisms of the curve complex that preserve both handlebody sets is finite.
Geometric properties of points on modular hyperbolas
Authors: Ford Kevin , Khan Mizan , Shparlinski Igor
Published: August 2010

Given an integer

n
≥
2

n\ge 2

, let

H

n

\mathcal {H}_n

be the set
\[
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="script upper H Subscript n Baseline equals left-brace left-parenthesis a comma b right-parenthesis colon a b identical-to 1 left-parenthesis mod n right-parenthesis comma 1 less-than-or-equal-to a comma b less-than-or-equal-to n minus 1 right-brace">

H

n

=
{
(
a
,
b
)
 
:
 
a
b
≡
1

(
mod

n
)
,
 
1
≤
a
,
b
≤
n
−
1
}

\mathcal {H}_n= \{(a,b) \ : \ ab \equiv 1 \pmod n,\ 1\le a,b \le n-1\}

\]
and let

M
(
n
)

M(n)

be the maximal difference of

b
−
a

b-a

for

(
a
,
b
)
∈

H

n

(a,b) \in \mathcal {H}_n

. We prove that for almost all

n
n

,

n
−
M
(
n
)
=
O

(

n

1

/

2
+
o
(
1
)

)

.

n-M(n)=O\left (n^{1/2+o(1)}\right ).

We also improve some previously known upper and lower bounds on the number of vertices of the convex closure of

H

n

\mathcal {H}_n

.
On a series representation for Carleman orthogonal polynomials
Authors: Dragnev Peter , Miña-Díaz Erwin
Published: August 2010

Let

{

p
n

(
z
)

}

n
=
0

∞

\{p_n(z)\}_{n=0}^\infty

be a sequence of complex polynomials (

p
n

p_n

of degree

n
n

) that are orthonormal with respect to the area measure over the interior domain of an analytic Jordan curve. We prove that each

p
n

p_n

of sufficiently large degree has a primitive that can be expanded in a series of functions recursively generated by a couple of integral transforms whose kernels are defined in terms of the degree

n
n

and the interior and exterior conformal maps associated with the curve. In particular, this series representation unifies and provides a new proof for two important known results: the classical theorem by Carleman establishing the strong asymptotic behavior of the polynomials

p
n

p_n

in the exterior of the curve, and an integral representation that has played a key role in determining their behavior in the interior of the curve.
Heinz type estimates for graphs in Euclidean space
Authors: Fontenele Francisco
Published: August 2010

Let

M
n

M^n

be an entire graph in the Euclidean

(
n
+
1
)

(n+1)

-space

R

n
+
1

\mathbb R^{n+1}

. Denote by

H
H

,

R
R

and

|

A

|

|A|

, respectively, the mean curvature, the scalar curvature and the length of the second fundamental form of

M
n

M^n

. We prove that if the mean curvature

H
H

of

M
n

M^n

is bounded, then

inf
M

|

R

|

=
0

\inf _M|R|=0

, improving results of Elbert and Hasanis-Vlachos. We also prove that if the Ricci curvature of

M
n

M^n

is negative, then

inf
M

|

A

|

=
0

\inf _M|A|=0

. The latter improves a result of Chern as well as gives a partial answer to a question raised by Smith-Xavier. Our technique is to estimate

inf

|

H

|

,

inf

|

R

|

\inf |H|,\;\inf |R|

and

inf

|

A

|

\inf |A|

for graphs in

R

n
+
1

\mathbb R^{n+1}

of

C
2

C^2

real-valued functions defined on closed balls in

R

n

\mathbb R^n

.
On the spatial asymptotics of solutions of the Ablowitz–Ladik hierarchy
Authors: Michor Johanna
Published: August 2010

We show that for decaying solutions of the Ablowitz–Ladik system, the leading asymptotic term is time independent. In addition, two arbitrary bounded solutions of the Ablowitz–Ladik system which are asymptotically close at the initial time stay close. All results are also derived for the associated hierarchy.
Physicochemical Evaluation and Optimization of Enriched Expanded Pellets with Milk Protein Concentrate
Authors: Limón‐Valenzuela V. , Martínez‐Bustos F. , Aguilar‐Palazuelos E. , Caro‐Corrales J. J. , Zazueta‐Morales J. J.
Published: August 2010

The objective of this work was to study the effect of addition of milk protein concentrate (MPC, 0–10%) and feed moisture (FM, 20–30%) in a blend of corn starch (CS, 80%) and quality protein maize (QPM, 20%) on different physicochemical characteristics of third‐generation (3G) snack foods using extrusion technology. A laboratory single‐extruder with a 3:1 compression ratio, a rectangular die, and a central composite nonroutable model with two variables were used. The physicochemical characteristics evaluated were expansion index (EI), bulk density (BD), penetration force (PF), and color parameters L*a*b*. EI decreased with the increase of MPC and FM, whereas BD and color parameters (a* and b*) increased; PF showed a minimum point (MPC = 5% and FM = 25%). EI, BD, and PF were selected for the optimization process in an area of superposition of 1.5–4.1% of MPC and 20.0–24.1% of FM. A validation of the optimal area was performed on samples with average values of 4.64 (±0.28) for EI, 141.02 (±7.29) kg m–3 for BD, and 0.0033 (±0.00065) for N m PF. It is feasible to obtain a functional 3G snack food with good expansion characteristics using a microwave oven, and this snack has health benefits due to the addition of MPC and QPM.
Core–shell La

1−
x

Sr

x

MnO
3
nanoparticles as colloidal mediators for magnetic fluid hyperthermia
Authors: Pollert E. , Kaman O. , Veverka P. , Veverka M. , Maryško M. , Závěta K. , Kačenka M. , Lukeš I. , Jendelová P. , Kašpar P. , Burian M. , Herynek V.
Published: August 2010

Core–shell nanoparticles consisting of La
0.75
Sr
0.25
MnO
3
cores covered by silica were synthesized by a procedure consisting of several steps, including the sol–gel method in the presence of citric acid and ethylene glycol, thermal and mechanical treatment, encapsulation employing tetraethoxysilane and final separation by centrifugation in order to get the required size fraction. Morphological studies revealed well-separated particles that form a stable water suspension. Magnetic studies include magnetization measurements and investigation of the ferromagnetic–superparamagnetic–paramagnetic transition. Magnetic heating experiments in ‘calorimetric mode’ were used to determine the heating efficiency of the particles in water suspension and further employed for biological studies of extracellular and intracellular effects analysed by tests of viability.
Growth of nanocrystals and thin films at the water–oil interface
Authors: Stansfield G. L. , Vanitha P. V. , Johnston H. M. , Fan D. , AlQahtani H. , Hague L. , Grell M. , John Thomas P.
Published: August 2010

The use of the water–oil interface provides significant advantages in the synthesis of inorganic nanostructures. Employing the water–toluene interface, luminescent CdS nanocrystals have been obtained at a relatively modest temperature of 35
°
C. The diameters of the particulates can be varied between 1.0 and 5.0 nm. In addition, we have devised a new method for transferring thin films at the water–toluene interface onto solid substrates. Using this method, thin films consisting of Au and Ag nanocrystals spread over very large areas (square centimetres) are obtained in a single step. These films are directly usable as ingredients of functional devices. We show this by constructing a working amine sensor based on films of Au nanocrystals. The materials obtained have been characterized by X-ray diffraction, scanning and transmission electron microscopy, absorption and emission spectroscopy and charge transport measurements.
Detection of endogenous magnetic nanoparticles with a tunnelling magneto resistance sensor
Authors: Ionescu A. , Darton N. J. , Vyas K. , Llandro J.
Published: August 2010

The magnetotactic bacterium
Magnetospirillum
sp. has been cultured and the properties of its endogenous magnetic nanoparticles characterized. Electron-microscopic analyses indicate that the endogenous magnetite nanoparticles in
Magnetospirillum
sp. are coated with a 3–4 nm thick transparent shell, forming a magnetosome. These magnetite nanoparticles had diameters of 50.9±13.3 nm, in good agreement with the diameter of 40.6±1.2 nm extracted from magnetometry. Each
Magnetospirillum
sp. bacterium contained chains of 5–25 magnetosomes. Superconducting quantum interference device magnetometry results indicate that the extrinsic superparamagnetic response of the bacterial solution at room temperature can be attributed to the reversal of the magnetization by physical rotation of the nanoparticles. The intrinsic blocking temperature of a sample of freeze-dried bacteria was estimated to be 282±13 K. A tunnelling magneto resistance sensor was used to detect the stray fields of endogenous magnetic nanoparticles in static and quasi-dynamic modes. Based on the tunnelling magneto resistance sensor results, the magnetic moment per bacterium was estimated to be approximately 2.6×10
−13
 emu. The feasibility of this detection method either as a mass-coverage device or as part of an integrated microfluidic circuit for detection and sorting of magnetosome-containing cells was demonstrated.
Multi-layer films of block copolymer micelles adsorbed to colloidal templates
Authors: Addison Timothy , Cayre Olivier J. , Biggs Simon , Armes Steven P. , York David
Published: August 2010

Alternating layers of cationic and anionic block copolymer micelles have been deposited onto colloidal silica particles using a layer-by-layer approach. The resulting films have been investigated using a number of characterization techniques including zeta potential measurements, dynamic light scattering, thermo-gravimetric analysis and microscopy. The micelles used here demonstrate pH-responsive behaviour both in solution and when adsorbed at interfaces. It has been shown that block copolymer micelles can selectively encapsulate and release hydrophobic materials; therefore, the incorporation of such responsive species within films has the potential to offer increased functionality. The formation of films onto colloidal particles is of great interest as it can provide pathways to direct encapsulation of materials along with surface modification. This study aims to provide new insights into the nature and properties of responsive films. Such studies will allow for the future development of novel delivery systems that have potential application within a number of industrial sectors including personal care products, pharmaceuticals and agro-chemicals.
On the Anatomical Differences in the three Species of Rhea.
Authors: Gadow Hans
Published: August 2010

The chief differences between the three species are the following:—

This tabular arrangement shows that Darwin's Rhea differs considerably from the other two species, whilst the latter offer apparently few important characters for separation. However, no matter if the number of the neck‐vertebræ of Rh. macrorhyncha (the best name for which would be that of the long‐necked or slender‐headed Rhea) be a constant character or not, the differences in the proportions of the skulls afford an anatomical character just as good as those which induce us to consider Rh. darwini a so‐called good species. If we thus consider the three forms of Rhea as three equivalent species, their present geographical distribution becomes less puzzling; otherwise we should expect à priori that the eastern form would differ more from the two others than these do from each other. Moreover, since it rarely happens that two large species of a certain order or family of creatures inhabit the same tracts of country unless they do so through immigration, it is probable that the original home of Rh. americana was Central South America, and that it spread from there into regions occupied by Rh. darwini.
On the Structure and Development of the Hyobranchial Skeleton of the Parsley‐Frog (Pelodytes punctatus).
Authors: Eidewood W. G.
Published: August 2010

The almost complete closure of the hyoglossal sinus of Pelodytes (Jgs., fig. 9) is due to the extensive development and inward slope of the processus anteriores (pa., fig. 9).

The lateral foramina of Pelodytes (fl., fig. 9) are not primary fenestrations of the basal plate, but are formed by the enclosure of the foremost lateral sinus by the confluence of the expanded end of the processus antero‐lateralis with the cartilage of the hyoidean cornu.

Although in Pelodytes the hyoidean cornu (h, h‘, h“, fig. 9) is broken, the portion missing is comparatively insignificant.

The spicula (sp., fig. 1) are larVal structures of no morphological significance. They are processes of cartilage developed from the proximal ends of the ceratohranchials to support the horizontal pharyngeal velum.

The processus postero‐lateralis (ppl., fig. 9) ia the persistent proximal portion of the first ceratobranchial.

The processus antero‐lateralis (pal., figs. 8& 9) is a secondary outgrowth of the basal plate or body of the hyoid having no relation whatever to the larval branchial bars.

The thyrohyal (t., fig. 9) is the part of the hypobranchial plate of the larva which forms the inner boundary of the thyroid foramen (tf., fig. 4). Its posterior end becomes free on the absorption of the ceratohranchials and the consequent conversion of the foramen into a sinus.
On the Development of the Hyobranchial Skeleton of the Midwife‐Toad (Alytes obstetricans).
Authors: Ridewood W. G.
Published: August 2010

In the hyobranchial skeleton of the early larva of Alytes there is an anterior copula which subsequently disappears and forms no part of the adult hyoid.

The posterior copula extends backward to the laryngeal sinus, and thus completely separates the two hypobranchial plates. It persists as the central part of the body of the hyoid.

The postero‐lateral process of the adult hyoid cannot be identified with the base of the first ceratobranchial as it can in Pelodytes, but both the antero‐lateral and postero‐lateral processes are new formations, as in Rana.

The branchial bars or ceratobranchials of the larva form no part of the adult hyoid, but are entirely resorbed.

The thyrohyal is developed from that part of the hypobranchial cartilage of the larva which constitutes the inner boundary of the thyroid foramen.
The Growth of the Shell of Patella vulgata L
Authors: Russell E. S.
Published: August 2010

The breeding‐season extends from July to January.

Sexual maturity is reached at a length of 20–25 mni.

An merage size for a limpet of the last season's brood in Janiinry or February is 10 mm. A t the end of the first year it mag be 29 mm. long. Probable sizes at the end of the second and subsequent years are 38 mm., 44 mni., 48 mm., 53 mm. Shells over 50 mm. may be considerably more than five years old.

Sexual maturity is reached in the first year, and when the linipet is only half‐grown.

The rate of growth decreases with age and maturity. It is slower during the colder months of the year.

Considerable changes take place in the ratios of the shelldimensions during growth.

These changes are probably in large part the expression of laws of growth, and not due to natural selection,
30. Observations on the Life‐History, Biology, and Genetics of the Lady‐bird Beetle, Adalia bipunctata (Mulsant)
Authors: Hawkes Onèra A. Merritt
Published: August 2010

Adalia bipunctata has so many varieties that it is highly suitable for the needed study of inheritance of normally occurring variations.

Adalia can be mated in captivity with ease, but their cannibalistic habit makes it very difficult to rear them satisfactorily in large numbers.

The time passed in the various stages is variable, depending not only on the food, hut also on the temperature, to which all stages, but especially the pupal, make a rapid response.

Little is known of either hibernation or migration, but apparently both septempunctata and bipunctata tend to collect in numbers in the spring and autumn, and may at times be found hibernating, piled upon one another, similar to the “masses” of Hippodamia found in the western U.S.A.

There is no evidence of dominance in crosses between the two main forms–the Red “type” and the Black (var. 4‐maculata and var. 6‐pustulata).

Eleven ma tings of Red produced only the Red type.

Black and Red forms also occur in G. variabilis, and, as in bipunctata, neither is dominant.

The pronotum of the Black form is darker than that of the Red, but there is no progressive blackening of the pronotum of the Red coincidentally with the increase in the size of the black spots of the elytra.

Although it is possible to make a series from pure red elytra on the one hand through various patterns to pure black on the other, this cannot be regarded as proof that the variations are merely fluctuating. The percentages of the variations is, as far as is known, approximately stable, and certain types are far more common than others. These facts, combined with the observation that the children tend to show the variations of the parents, strongly suggest that there are probably certain points of genetic stability, and that only analysis is needed to show that there is some regular method of inheritance.
27. The Chondrocranium of the Teleostean Fish Sebastes marinus.
Authors: Mackintosh N. A.
Published: August 2010

Summary.

There is a precocious development of the visceral skeleton.

In at least the earlier stages there is no sign of a fenestra hypophyseos.

The cranial flexure is retained for a considerable period after hatching.

In the 5·5 mm. stage the hyomandibular, symplectic, and quadrate are represented by a simple temporal cartilage. This appears also to be a single piece of cartilage in the earlier stages.

The upper jaw does not appear until a comparatively late stage, and there is evidence that it arises independently and grows back to meet the quadrate.

The anterior part of the trabeculæ gives rise to an interorbital septum of rather limited area.

There is a free rostral cartilage situated above the nasal septum.

The lower jaw is long and exhibits prominent coronoid and retro‐articular processes.

The hyomandibular is club‐shaped and very long. Its length is correlated with the special depth of the head.
Some Notes on the African Squirrels of the Genus Heliosciurus
Authors: Ingoldby C. M.
Published: August 2010

Summary.

H. gembianus Of the only species of this genus as at present restricted, inhabits the whole of Equatorial Africa. Its Iiuinerous forms are climatic phases.

It would follow from this t h a t while some forms iniglit be restricted to a de6nite single area, others would be found patchily in various and often widelyseparate areas. 'Phis proves to be the case, and the same form has been described by various names according to the particular area in which i t was discovered. So that within a relatively small area which happens to include a variety of environmental conditions, “high‐rain forest,”“clearings,”“orchard bush” and other types of Savannah forest and grassland, such as Nigeria, or that area usually known as “Congo‐Poko‐Uele,” several races of this species occur in close proxiniity, euch of wliich races may crop of again and again

in other siinilar but perhaps distant and quite unconnected localities.

The importance of this from the point of view of systematic zoology needs no emphasis. It is perhaps not too much to hope that work on soinetliiiig like these lines will eventually throw light on the physiological basis of reaction to climatic conditions, and so on the whole question of the formation of new species.
The Zoological Society's Expedition to the Zambesi, 1927: No. 2. Observations on the Natural History of the Land‐Crab Sesarma meinerti, from Beira, with special reference to the Theory of Warning Colours.*
Authors: COTT HUGH B.
Published: August 2010

The crabs belonging to the genus Sesarma show a wide range of variation in habits and in the conditions under which they live. S. meinerti is a species that has largely adopted terrestrial habits. A colony of the crabs was found at Beira, living on dry ground near mangrove‐swamps. The habits of the species are described.

An attempt has been made to show that the colour of S. meinerti has an aposematic function. The vivid colour of the crab, its aggressive behaviour and power of self‐defence, its tough physique and well‐developed power of regeneration, and the relative freedom from the persecution of enemies in which it lives, all point to this conclusion.

The boldness of the species and its ability to defend itself from attack have been adopted in response to the requirements of a more or less terrestrial mode of life, and the aposematic coloration is correlated with the exigencies of this habitat; conspicuousness being useful to the ciabs. the origin and development of the warning colours are to be explained by the operation of natural selection.
19. On the Genus Polypoctphalus Braun 1878 (Cestoda)
Authors: WOODLAND W. N. F.
Published: August 2010

.I have confirmed in the main the accounts of Braun, Linton, and Southwell of the two remarkable species, ľolypocephalus medusia and P. radiatus, and have contributed some additions. The chief of these are the presence in P. medusia, as in P. radiatus, of an opening (borne on a central column) from a glandular mass situated under the floor of the tentacle‐containing hollow or cavity, the alternation of the dorsal and ventral surfaces of proglottis with genital pores on opposite sides, the quadripartite form of the ovary, and of the columns of vitellaria, which are continuous, anteriorly and posteriorly, with it. Comparison of the strobilæ of the two species shows that they undoubtedly belong to the same genus–the general disposition of the organs, number of testes, and origin of the uterus being the same in both, –a, conclusion obviously suggested by the similar form of the scoleees. The two species, on the other hand, are very distinct from each other. The arrangement of the vitellaria in four columns (if the vitellaria be represented by these extensions of the ovary) is, so far as I know, unparalleled among Cestoda, The genus Polypocephalus is re‐defined and the two species diagnosed.
27. The Interpretation of the Embryonic and Post‐larval Characters of certain Tetraxonid Sponges, with Observations on Post‐larval Growth‐stages in some Species
Authors: Burton Maurice
Published: August 2010

Summary.

In certain species of Tetraxonida the period of adult life may, in some cases, be subdivided into as many as three distinct growth stages, each characterized by some evident change in the form of the spicules, coupled with changes in the arrangement of the skeleton, or even with differences in the gross morphology.

A tangential skeleton is a primitive character, and species in which this persists throughout adult life may be regarded as having undergone little specialization.

Extrusion of spicules takes place either continuously or at definite periods in the life cycle. This has been assumed by previous authors, but without definite reason for so doing, and the proof now forthcoming enables us to explain the absence of particular categories of spicules from certain individuals of a species, the disorganization of the skeleton SO often seen, and the differences in the arrangement of the dermal skeleton in different individuals of the same species.

In the identification of species not only must the normal fluctuating variations and those due to ecological, geographical, and environmental factors be considered, but also those due to age.

The order in which different forms of spicules appear in the life cycle indicates the order of their appearance in the evolution of the species, anti probably, although this yet remains to be proved, when reduction of the skeleton takes place the last spicules to appear are the first to disappear.
41. The Development of the Kidney in Ampullaria (Pila) gigas
Authors: Fernando Wilfred
Published: August 2010

Summary.

The right kidney and left kidney in the embryo arise as evaginations of the pericardium. Mesodermal cells from the neighbourhood adhere to these evaginations.

While the left kidney disappears, the right kidney enlarges and comes into contact with the invagination of the ectoderm which later forms the mantle‐cavity in the posterior region.

The right kidney then opens into the mantle‐cavity.

That portion of the mantle‐cavity with which the kidney comes into contact becomes a tubular organ distinct from the mantle‐cavity, and is called the “ureter.”

As a result of torsion, the right kidney of the embryo becomes the left, posterior kidney of the adult.

The ureter becomes dorsal and lies anterior to the left, posterior kidney. It becomes the anterior kidney of the adult.

In the adult the glandular posterior kidney, which opens internally into the pericardium, discharges its products into the anterior kidney, and thence to the exterior.

The anterior kidney of the adult Ampullaría is a modified and enlarged ureter, homologous with the ureter of Vivipara.
48. The Bionomics and Comparative Morphology of the Early Stages of certain Chrysondidz (Coleoptera, Phytophaga).
Authors: Paterson Nellie F.
Published: August 2010

Summary.

The immature stages of Chrysomelidae fall into five natural groups—Tricho‐stomata, Cyclica, Eupoda, Camptosomata, and Cryptostomata, which coincide with the recognized divisions of imagines.

An account is given of the biology and external morphology of the early stages of thirty‐five species.

The principal systematic characters are the chatotaxy, mouth‐parts, and number of ocelli in the larva, and the chaetotaxy in the pupa.

The larval mouth‐parts are remarkably constant, but the numbers and disposition of the primary setae afford characters of taxonomic importpnce.

The hypothetical segment possesses sixteen pairs of setæ, arranged into two transverse rows.

The Trichostomata are considered to be the least modified forms, and of the Chrysomelince thePhœdoninaare the most generalized. The Eupoda, Campto‐somata, and Cryptostomata are somewhat divergent forms which appear to have developed along their own paths of specialization.
52. The Anatomy and Histology of the Alimentary Canal in the Common Wasp (Vespa vulgaris).
Authors: Green T. L.
Published: August 2010

Summary.

The mouth‐parts of the wasp are designed for biting, licking, and mastication; they are well developed in all castes; their musculature is fully described and compared with larva, and also with the bee and Dytiseus.

The pharynx is a large sac with complicated muscles designed for pumping and swallowing. The elasticity of chitin is used to antagonize certain muscles; it co‐operates with others, and these show reduced size.

Certain direct homologies of larval and adult muscles are defined, and the significance of this possibility discussed.

The esophagus and crop are typical.

The proventriculus is well developed and acts as a pump in conjunction with the pharynx.

The ventriculus is typical and is built upon a definite, geometric pattern which conditions the features seen in sections cut in known planes. The replacement cells are few and lie within the basement‐membrane; any idea that they exist external to this is due to confusing them with a layer of fine longitudinal muscle‐fibres whose presence confirms White's record of a third layer of ventricular muscles.

The peritrophic membrane arises by “delamination,” probably as the result of condensation of cell‐secretions, and not from the striated border nor the esophageal valve. It may represent a partially chitinous intima of the mid‐gut.

The small intestine has two well‐marked histological areas and a local anterior muscle concentration acting as a sphincter or as a means of hastening peristalsis.

The Malpighian tubules show well‐marked secretion phases.

The rectum has a general syncytium, with characteristic rectal pads. The interpretation of these structures awaits the further study of their development.

The intrinsic muscles of the gut are attached to the basement‐membrane lying below the digestive epithelium.