bluuebunny/crossref_metadata_2025_split huggingface dataset:
A weak discrete maximum principle and stability of the finite element method in 𝐿_{∞} on plane polygonal domains. I
Authors: Schatz Alfred H. 
Published: June 2010

Let

Ω
\Omega

be a polygonal domain in the plane and

S
r
h

(
Ω
)

S_r^h(\Omega )

denote the finite element space of continuous piecewise polynomials of degree

⩽
r
−
1

(
r
⩾
2
)

\leqslant r - 1\;(r \geqslant 2)

defined on a quasi-uniform triangulation of

Ω
\Omega

(with triangles roughly of size h). It is shown that if

u
h

∈

S
r
h

(
Ω
)

{u_h} \in S_r^h(\Omega )

is a "discrete harmonic function" then an a priori estimate (a weak maximum principle) of the form
\[

‖

u
h

‖

L
∞

(
Ω
)

⩽
C

‖

u
h

‖

L
∞

(
∂
Ω
)

{\left \| {{u_h}} \right \|_{{L_\infty }(\Omega )}} \leqslant C{\left \| {{u_h}} \right \|_{{L_\infty }(\partial \Omega )}}

\]
holds. Now let u be a continuous function on

Ω
¯

\bar \Omega

and

u
h

{u_h}

be the usual finite element projection of u into

S
r
h

(
Ω
)

S_r^h(\Omega )

(with

u
h

{u_h}

interpolating u at the boundary nodes). It is shown that for any

χ
∈

S
r
h

(
Ω
)

\chi \in S_r^h(\Omega )

\[

‖

u
−

u
h

‖

L
∞

(
Ω
)

⩽
c

(

ln
⁡

1
h

)

r
¯

‖

u
−
χ

‖

L
∞

(
Ω
)

,

where

r
¯

=

{

1

a
m
p
;

if

r
=
2
,

0

a
m
p
;

if

r
⩾
3.

{\left \| {u - {u_h}} \right \|_{{L_\infty }(\Omega )}} \leqslant c{\left ( {\ln \frac {1}{h}} \right )^{\bar r}}{\left \| {u - \chi } \right \|_{{L_\infty }(\Omega )}},\quad {\text {where}}\;\bar r = \left \{ {\begin {array}{*{20}{c}} 1 & {{\text {if}}\;r = 2,} \\ 0 & {{\text {if}}\;r \geqslant 3.} \\ \end {array} } \right .

\]
This says that (modulo a logarithm for

r
=
2

r = 2

) the finite element method is bounded in

L
∞

{L_\infty }

on plane polygonal domains.
On the differential-difference properties of the extended Jacobi polynomials
Authors: Lewanowicz S. 
Published: June 2010

We discuss differential-difference properties of the extended Jacobi polynomials
\[

P
n

(
x
)

=

p
+
2

F
q

(
−
n
,
n
+
λ
,

a
p

;

b
q

;
x
)

(
n
=
0
,
1
,
…
)
.

{P_n}(x){ = _{p + 2}}{F_q}( - n,n + \lambda ,{a_p};{b_q};x)\quad (n = 0,1, \ldots ).

\]
The point of departure is a corrected and reformulated version of a differential-difference equation satisfied by the polynomials

P
n

(
x
)

{P_n}(x)

, which was derived by Wimp (Math. Comp., v. 29, 1975, pp. 577-581).
A note on asymptotic evaluation of some Hankel transforms
Authors: Frenzen C. L. , Wong R. 
Published: June 2010

Asymptotic behavior of the integral
\[

I
f

(
w
)
=

∫
0
∞

e

−

x
2

J
0

(
w
x
)
f
(

x
2

)

x

d
x

{I_f}(w) = \int _0^\infty {{e^{ - {x^2}}}{J_0}(wx)f({x^2})\;x\;dx}

\]
is investigated, where

J
0

(
x
)

{J_0}(x)

is the Bessel function of the first kind and w is a large positive parameter. It is shown that

I
f

(
w
)

{I_f}(w)

decays exponentially like

e

−
γ

w
2

{e^{ - \gamma {w^2}}}

,

γ
>
0

\gamma > 0

, when

f
(
z
)

f(z)

is an entire function subject to a suitable growth condition. A complete asymptotic expansion is obtained when

f
(
z
)

f(z)

is a meromorphic function satisfying the same growth condition. Similar results are given when

f
(
z
)

f(z)

has some specific branch point singularities.
Computing when multiplications cost nothing
Authors: Newman D. J. 
Published: June 2010

A (rather strange) computer is considered which costs 1 cent to perform each addition but costs nothing to perform a multiplication. It is shown that the addition chain from 1 to n cost maximally

(
Log
⁡
n

)

1

/

2
+
o
(
1
)

{(\operatorname {Log} n)^{1/2 + o(1)}}

rather than the classical

∼
Log
⁡
n

\sim \operatorname {Log} n

.
Perfect multiple error-correcting arithmetic codes
Authors: Gordon Daniel M. 
Published: June 2010

An arithmetic code is a subgroup of

Z

r
n

±
1

{{\mathbf {Z}}_{{r^n} \pm 1}}

, with the arithmetic distance

d
(
x
,
y
)
=

min
t

x
−
y
≡

Σ

i
=
1

t

c
i

r

n
(
i
)

(
mod

r
n

±
1
)

d(x,y) = {\min _t}x - y \equiv \Sigma _{i = 1}^t{c_i}{r^{n(i)}}\;(\bmod {r^n} \pm 1)

, for

|

c
i

|

>
r

|{c_i}| > r

,

n
(
i
)
⩾
0

n(i) \geqslant 0

for

1
⩽
i
⩽
t

1 \leqslant i \leqslant t

. A perfect e-error-correcting code is one from which all

x
∈

Z

r
n

±
1

x \in {{\mathbf {Z}}_{{r^n} \pm 1}}

, are within distance e of exactly one codeword. Necessary and sufficient (assuming the Generalized Riemann Hypothesis) conditions for the existence of infinitely many perfect single error-correcting codes for a given r are known. In this paper some conditions for the existence of perfect multiple error-correcting codes are given, as well as the results of a computer search for examples.
An algebraic study of Gauss-Kronrod quadrature formulae for Jacobi weight functions
Authors: Gautschi Walter , Notaris Sotirios E. 
Published: June 2010

We study Gauss-Kronrod quadrature formulae for the Jacobi weight function

w

(
α
,
β
)

(
t
)
=

(
1
−
t

)
α

(
1
+
t

)
β

{w^{(\alpha ,\beta )}}(t) = {(1 - t)^\alpha }{(1 + t)^\beta }

and its special case

α
=
β
=
λ
−

1
2

\alpha = \beta = \lambda - \frac {1}{2}

of the Gegenbauer weight function. We are interested in delineating regions in the

(
α
,
β
)

(\alpha ,\beta )

-plane, resp. intervals in

λ
\lambda

, for which the quadrature rule has (a) the interlacing property, i.e., the Gauss nodes and the Kronrod nodes interlace; (b) all nodes contained in

(
−
1
,
1
)

( - 1,1)

; (c) all weights positive; (d) only real nodes (not necessarily satisfying (a) and/or (b)). We determine the respective regions numerically for

n
=
1
(
1
)
20
(
4
)
40

n = 1(1)20(4)40

in the Gegenbauer case, and for

n
=
1
(
1
)
10

n = 1(1)10

in the Jacobi case, where n is the number of Gauss nodes. Algebraic criteria, in particular the vanishing of appropriate resultants and discriminants, are used to determine the boundaries of the regions identifying properties (a) and (d). The regions for properties (b) and (c) are found more directly. A number of conjectures are suggested by the numerical results. Finally, the Gauss-Kronrod formula for the weight

w

(
α
,
1

/

2
)

{w^{(\alpha ,1/2)}}

is obtained from the one for the weight

w

(
α
,
α
)

{w^{(\alpha ,\alpha )}}

, and similarly, the Gauss-Kronrod formula with an odd number of Gauss nodes for the weight function

w
(
t
)
=

|

t

|

γ

(
1
−

t
2

)
α

w(t) = |t{|^\gamma }{(1 - {t^2})^\alpha }

is derived from the Gauss-Kronrod formula for the weight

w

(
α
,
(
1
+
γ
)

/

2
)

{w^{(\alpha ,(1 + \gamma )/2)}}

.
Numerical approximation of minimum norm solutions of 𝐾𝑓=𝑔 for special 𝐾
Authors: Luecke Glenn R. 
Published: June 2010

Let

K
:

L
2

(
Y
,
μ
)
→

L
2

(
X
,
ν
)

K:{L_2}(Y,\mu ) \to {L_2}(X,\nu )

be continuous and linear and assume

(
K
f
)
(
x
)
=

∫
Y

k
(
x
,
y
)
f
(
y
)

d
μ
(
y
)

(Kf)(x) = \smallint _Y^{} {k(x,y)f(y)\,d\mu (y)}

. Define

k
x

{k_x}

by

k
x

(
y
)
=
k
(
x
,
y
)

{k_x}(y) = k(x,y)

. Assume K has the property that (a)

k
x

∈

L
2

(
Y
,
μ
)

{k_x} \in {L_2}(Y,\mu )

for all

x
∈
X

x \in X

and (b) if

K
f
=
0

ν

Kf = 0\;\nu

-a.e., then

(
K
f
)
(
x
)
=
0

(Kf)(x) = 0

for all

x
∈
X

x \in X

. For example, if

X
=
Y
=
[
0
,
1
]

X = Y = [0,1]

,

μ
=
ν

\mu = \nu

is Lebesgue measure and if

k
(
x
,
y
)

k(x,y)

satisfies a Lipschitz condition in x, then K has the above property. Assume K satisfies this property and

f
0

{f_0}

is a minimum

L
2

{L_2}

norm solution of the first-kind integral equation

(
K
f
)
(
x
)
=
g
(
x
)

(Kf)(x) = g(x)

for all

x
∈
X

x \in X

. It is shown that

f
0

{f_0}

is the

L
2

{L_2}

-norm limit of linear combinations of the

k

x
i

{k_{{x_i}}}

’s. It is then shown how to choose constants

c
1

,
…
,

c
n

{c_1}, \ldots ,{c_n}

to minimize

‖

f
0

−

∑

j
=
1

n

c
j

k

x
j

‖

\left \| {{f_0} - \sum \nolimits _{j = 1}^n {{c_j}{k_{{x_j}}}} } \right \|

without knowing what

f
0

{f_0}

is. This paper also contains results on how to choose the

k

x
j

{k_{{x_j}}}

’s as well as numerical examples illustrating the theory.
Long‐term proliferation and characterization of human spermatogonial stem cells obtained from obstructive and non‐obstructive azoospermia under exogenous feeder‐free culture conditions
Authors: Lim J. J. , Sung S.‐Y. , Kim H. J. , Song S.‐H. , Hong J. Y. , Yoon T. K. , Kim J. K. , Kim K.‐S. , Lee D. R. 
Published: June 2010

AbstractObjectives:  The aim of the present study was to improve efficiency of isolation and to optimize proliferative potential of human spermatogonial stem cells (SSCs) obtained from obstructive azoospermic (OA) and non‐obstructive azoospermic (NOA) patients, and further, to characterize these cells for potential use in infertility treatment or study of reproductive biology.Materials and methods:  We have applied a cell‐sorting method, using collagen and magnetic activated cell separation to overcome obstacles, developing a collection system, and simple long‐term proliferation system, that yields large numbers of high‐purity SSCs from obstructive OA and NOA patients.Results:  SSCs derived from OA and NOA patients proliferated and maintained their characteristics for more than 12 passages (>6 months) in vitro. Moreover, the population of cells positive for the SSC‐specific markers GFRα‐1 and integrin α6, increased to more than 80% at passage 8.Conclusion:  These finding may support the idea that in vitro propagation of SSCs could be a useful tool for infertility treatment and study of reproductive biology.
Demographic characteristics, patterns and risk factors for retinal vein occlusion in Nepal: a hospital‐based case–control study
Authors: Thapa Raba , Paudyal Govinda , Bernstein Paul S 
Published: June 2010

AbstractPurpose:  Retinal vein occlusion (RVO) is an increasing problem leading to visual impairment in Nepal. Our study investigates the demographic characteristics, patterns and risk factors for RVO in this developing Asian country.Methods:  This is a hospital‐based case–control study conducted at the Tilganga Institute of Ophthalmology of Nepal during the period of January 2007 to January 2008. All consecutive new cases of RVO diagnosed at the Institute were included. Cases with intraocular inflammation or a prior history of intraocular injections, laser therapy or vitrectomy for RVO were excluded from the study. Age, sex and geographically matched subjects were recruited as a control group from patients who presented for regular eye examinations at the same hospital during the study period.Results:  A total of 218 patients with RVO presented during the study period. The mean age of the patients was 61.1 ± 12.3 years with more men (58.3%) than women. The mean age for control groups was 61.3 ± 13.0 years. Seventy per cent of subjects had branch retinal vein occlusion, whereas central retinal vein occlusion was present in 26.6%. 63.9% of branch retinal vein occlusion was found in the superotemporal branch. Hypermetropia, primary open angle glaucoma, hypertension, mixed diabetes and hypertension, and heart disease were significantly higher in RVO cases as compared with the control group.Conclusion:  The demographic characteristics, patterns and risk factors of RVO in Nepal can help guide interventions against these blinding diseases in similar developing countries.
Interventions for apnoea of prematurity: a personal view
Authors: Poets CF 
Published: June 2010

AbstractAim:  To review treatments for apnoea of prematurity (AOP).Methods:  Literature Review and description of personal practice.Results:  Provided that symptomatic apnoea has been ruled out, interventions to improve AOP can be viewed as directed at one of three underlying mechanisms: (i) a reduced work of breathing [e.g. prone positioning, nasal continuous positive airway pressure (CPAP)], (ii) an increased respiratory drive (e.g. caffeine), and (iii) an improved diaphragmatic function (e.g. branched‐chain amino acids). Most options currently applied, however, have not yet been shown to be effective and/or safe, except for prone, head‐elevated positioning, synchronized nasal ventilation/CPAP, and caffeine.Conclusion:  Treatment usually follows an incremental approach, starting with positioning, followed by caffeine (which should be started early, at least in infants <1250 g), and nasal ventilation or CPAP via variable flow systems that reduce work of breathing. From a research point of view, we most urgently need data on the frequency and severity of bradycardia and intermittent hypoxia that can yet be tolerated without putting an infant at risk of impaired development or retinopathy of prematurity.
Seroepidemiology of Helicobacter pylori infection and hepatitis A in a rural area: evidence against a common mode of transmission
Authors: Luzza F , Imeneo M , Maletta M , Paluccio G , Giancotti A , Perticone F , Focà A , Pallone F 
Published: June 2010

Background and aims—Recent studies have shown that the age-specific seroprevalence of H pylori infection parallels hepatitis A (HAV), suggesting similar modes of transmission. The aim of this study was to investigate the seroepidemiology ofH pylori and HAV in the same setting.Patients—A sample of 705 resident subjects (273 men, age range 1–87 years, median 50) who attended the outpatient medical centre of the rural town of Cirò, Southern Italy (11 000 inhabitants) for blood testing were recruited.Methods—All subjects completed a structured questionnaire. A serum sample was drawn from each subject and assayed for H pylori IgG by a validated in house enzyme linked immunosorbent assay. Antibodies to HAV were determined in 466 subjects (163 men, age range 1–87 years, median 49). A measure of agreement between H pylori and HAV seropositivity, the κ statistic, was used.Results—Overall, 446 (63%) subjects were seropositive for H pylori. Of the 466 subjects screened for both H pylori and HAV, 291 (62%) were seropositive for H pylori and 407 (87%) for HAV. Cross-tabulation of these data showed that 275 (59%) were seropositive and 43 (9%) seronegative for both H pylori and HAV, 16 (3%) were seropositive for H pylori, and 132 (28%) were seropositive for HAV (OR = 5.6, CI 3 to 10). There was a parallel, weakly correlated (r = 0.287) rise in the seroprevalence of the two infections with increasing age. However, the agreement between H pylori and HAV seropositivity was little better than chance (κ = 0.21) and in those aged less than 20 years it was worse than chance (κ = –0.064). Furthermore, multiple logistic regression analysis did not show any risk factor shared by both infections.Conclusions—The correlation between H pylori and HAV reflects the age-specific seroprevalence of both infections rather than a true association. This study provides evidence against a common mode of transmission of H pylori and HAV.
Energy expenditure and body composition in children with Crohn’s disease: effect of enteral nutrition and treatment with prednisolone
Authors: Azcue M , Rashid M , Griffiths A , Pencharz P B 
Published: June 2010

Background—Malnutrition and growth retardation are common complications of Crohn’s disease in children. The contribution of resting energy expenditure (REE) to malnutrition is unclear.Aims—To characterise the REE and body composition in children with Crohn’s disease and compare them with normal controls and patients with anorexia nervosa; to compare the effects of prednisolone and enteral nutrition on energy expenditure and body composition.Subjects—Twenty four children with Crohn’s disease, 19 malnourished females with anorexia nervosa, and 22 healthy control subjects were studied.Methods—In children with Crohn’s disease measurements were done when the disease was acute and repeated at one and three months after treatment with either prednisolone or enteral nutrition. Resting energy expenditure was measured by indirect calorimetry and body composition by anthropometry, bioelectrical impedance analysis, total body potassium, H218O, and bromide space studies.Results—Body weight and ideal body weight were significantly lower in patients with Crohn’s disease than in healthy controls. Lean tissue was depleted and there was an increase in extracellular water. Per unit of lean body mass, there was no difference between REE in patients with Crohn’s disease and controls, whereas patients with anorexia nervosa had significantly reduced REE. With enteral nutrition all body compartments and REE increased significantly (p<0.001). In a subgroup of age-matched men there was a significant increase in height after three months of enteral nutrition compared with prednisolone (p<0.01). Those treated with steroids did not show a significant change in height but did show an increase in all body compartments. However, intracellular water as well as lean body mass accretion were significantly higher in the enteral nutrition group than in the prednisolone group.Conclusions—Despite being malnourished, children with Crohn’s disease fail to adapt their REE per unit of lean body mass. This might be a factor contributing to their malnutrition. Lean tissue accretion is higher in patients treated with enteral nutrition than in those treated with prednisolone.
Contribution of acid and duodenogastrooesophageal reflux to oesophageal mucosal injury and symptoms in partial gastrectomy patients
Authors: Vaezi M F , Richter J E 
Published: June 2010

Background—The role of acid and pepsin in causing symptoms and oesophagitis is well established; however, the significance of duodenogastro-oesophageal reflux (DGOR) in this disorder is unclear.Aims—To understand the role of acid and DGOR in causing upper gastrointestinal (GI) symptoms and oesophageal mucosal injury in partial gastrectomy (PG) patients.Methods—Thirty two PG patients with upper GI symptoms were studied. Twenty four hour ambulatory acid and bilirubin measurements were obtained with Bilitec 2000 using glass electrode and fibreoptic sensor. Upper GI symptoms and oesophagitis were correlated with either acid or DGOR.Results—The PG patients were a heterogeneous group: 28% (9/32) had mixed reflux (acid+/DGOR+); 50% (16/32) had only DGOR (acid−/DGOR+); and 22% (7/32) had neither (acid−/DGOR−). Upper GI symptoms were associated with both mixed reflux (69%) and DGOR (24%). Six patients (67%) in the acid+/DGOR+ group had oesophagitis; no acid−/DGOR+ or acid−/DGOR− patients had oesophagitis. Mixed reflux showed a significant (p<0.0001) association with oesophagitis, while DGOR did not (p=0.3).Conclusions—(1) The majority of upper GI symptoms and all cases of oesophagitis in the PG patients occurred in patients who had mixed refluxate (acid and DGOR); (2) DGOR without simultaneous acid reflux may cause symptoms, but was not associated with oesophagitis in this patient group.
Red kidney bean lectin is a potent cholecystokinin releasing stimulus in the rat inducing pancreatic growth
Authors: Herzig K-H , Bardocz S , Grant G , Nustede R , Fölsch U R , Pusztai A 
Published: June 2010

Background—Lectins are proteins capable of specific binding to carbohydrates without altering their covalent structure. As an essential part of plants they are ingested in our daily diet. By binding to glycosyl side chains of receptors lectins can mimic or inhibit the action of the ligand. Oral administration of phytohaemagglutinin (PHA) in rats dose dependently induces growth of the small intestine and the pancreas by an unknown mechanism.Aims—To investigate the mechanism of PHA induced intestinal and pancreatic growth.Methods—Thirty day old male rats were pairfed for 10 days with lactalbumin as a control diet or lactalbumin plus PHA or purified soybean trypsin inhibitor (STI) as a positive control (42 mg/rat/day) with or without 20 μg of the cholecystokinin A (CCK-A) antagonist MK 329. To investigate further the effect of PHA on CCK release intestinal mucosal cells were isolated from rats which were continuously perfused in a perfusion apparatus. CCK release into the medium was assayed.Results—PHA and STI significantly stimulated growth of the pancreas and the small intestine. MK 329 blocked this growth effect in the pancreas but not in the small intestine. In vivo, PHA significantly increased CCK plasma levels from 0.75 to 6.67 (SEM 2.23) compared with 2.3 (0.35) pM in the control group. In addition, in vitro PHA dose dependently stimulated CCK release with a maximal effect at 100 ng/ml.Conclusion—In vivo and in vitro PHA is a potent stimulus for CCK release in the rat, thereby inducing pancreatic growth, whereas intestinal growth is stimulated by a CCK independent mechanism.
Induction of various cytokines and development of severe mucosal inflammation by cagA gene positive Helicobacter pylori strains
Authors: Yamaoka Y , Kita M , Kodama T , Sawai N , Kashima K , Imanishi J 
Published: June 2010

Background—Helicobacter pyloristrains possessing the cagA gene are thought to induce interleukin 8 (IL-8) in gastric mucosa. However, it is still unclear whether a relation exists between the cagA gene and the expression patterns of cytokines other than IL-8.Aims—To investigate the relation between the cagA gene and the production of various cytokine proteins using an enzyme linked immunosorbent assay (ELISA).Patients and methods—In 184 patients, the cagA gene was detected by polymerase chain reaction (PCR), and levels of production of IL-1β, IL-6, IL-7, IL-8, IL-10, and tumour necrosis factor α (TNF-α) in antral biopsy specimens were measured by ELISA.Results—Mucosal levels of IL-1β, IL-6, IL-8, and TNF-α were significantly higher in H pyloripositive than in H pylori negative patients. Furthermore, the mucosal levels of IL-1β and IL-8 were significantly higher in specimens infected with cagApositive strains than in those infected with cagAnegative strains. In H pylori positive patients, the mucosal level of IL-8 was closely correlated with that of IL-1β (p<0.0001), and the mucosal level of IL-6 was closely correlated with that of TNF-α (p<0.0001).Conclusion—These findings suggest that the ability to induce cytokines differs among the strains;cagA+ strains induce various kinds of cytokines and may cause severe inflammation, whereascagA− strains induce IL-8 and IL-1β only weakly and may cause only mild inflammation. However, as most patients infected with the cagA+ strains have gastritis, these strains may not be equivalent to ulcerogenic strains.
Incidence of Crohn’s disease in Stockholm County 1955–1989
Authors: Lapidus A , Bernell O , Hellers G , Persson P-G , Löfberg R 
Published: June 2010

Aim—To evaluate the incidence of Crohn’s disease in Stockholm County between 1955 and 1989.Methods—A cohort of 1936 patients with Crohn’s disease was retrospectively assembled. Incidence rates and changes in disease distribution were assessed.Results—The mean increase in incidence was 15% (95% confidence intervals 12% to 18%) per five year period with a mean annual incidence rate at 4.6/105during the last two decades. The mean incidence for the entire study period was similar for men and women. The mean age at diagnosis increased from 25 years in 1960–64 to 32 years in 1985–89, partly because of an increasing proportion of patients aged at least 60 years at diagnosis. The proportion of patients with colonic Crohn’s disease at the time of diagnosis increased from 15% to 32% (17% difference; 95% confidence intervals 12% to 23%) whereas the proportion of patients with ileocaecal disease decreased from 58% to 41% (17% difference; 95% confidence intervals 10% to 24%) during the study period. Elderly patients had a higher proportion of small bowel disease and a lower proportion of ileocolonic disease compared with the younger patients.Conclusion—The incidence rate of Crohn’s disease in Stockholm has stabilised at 4.6/105 and the proportion of elderly patients has increased during a 35 year period. Colonic Crohn’s disease has increased in frequency with a reciprocal decrease in ileocaecal disease.