bluuebunny/crossref_metadata_2025 huggingface dataset:
Nyström methods for Fredholm integral equations using equispaced points
Authors: Occorsio Donatella , Russo Maria
Published: April 2014

In this paper we investigate some Nystr?m methods for Fredholm integral
equations in the interval [0, 1]. We give an overview of the order of
convergence, which depends on the smoothness of the involved functions. In
particular, we consider the Nystr?m methods based on the so called
Generalized Bernstein quadrature rule, on a Romberg scheme and on the
so-called IMT rule. We prove that the proposed methods are convergent, stable
and well conditioned. Also, we give several numerical tests for comparing
these three methods.
Approximation of analytic functions by sequences of linear operators
Authors: Gadjiev Akif , Çetіn Nursel
Published: April 2014

In the present paper, we investigate approximation of analytic functions and
their derivatives in a bounded simply connected domain by the sequences of
linear operators without the properties of k?positivity.
Degree hypergroupoids associated with hypergraphs
Authors: Farshi Mehdi , Davvaz Bijan , Mirvakili Saeed
Published: April 2014

In this paper, we present some connections between graph theory and
hyperstructure theory. In this regard, we construct a hypergroupoid by
defining a hyperoperation on the set of degrees of vertices of a hypergraph
and we call it a degree hypergroupoid. We will see that the constructed
hypergroupoid is always anHv-group. We will investigate some conditions on a
degree hypergroupoid to have a hypergroup. Further, we study the degree
hypergroupoid associated with Cartesian product of hypergraphs. Finally, the
fundamental relation and complete parts of a degree hypergroupoid are
studied.
A p-adic Montel Theorem and locally polynomial functions
Authors: Almira J.M. , Abu-Helaiel Kh.F.
Published: April 2014

We prove a version of Montel?s Theorem for the case of continuous functions
defined over the field Qp of p-adic numbers. In particular, we prove that,
if ?m+1 h0 f (x) = 0 for all x ? Qp, and h0 satisfies |h0|p = p?N0, then,
for all x0 ? Qp, the restriction of f over the set x0 + pN0Zp coincides with
a polynomial px0 (x) = a0(x0) + a1(x0)x +...+ am(x0)xm. Motivated by
this result, we compute the general solution of the functional equation with
restrictions given by ?m+1 h f (x) = 0 (x ? X and h ? BX(r) = {x ? X : ?x? ?
r}), whenever f : X ? Y, X is an ultrametric normed space over a
non-Archimedean valued field (K, |?|) of characteristic zero, and Y is a
Q-vector space. By obvious reasons, we call these functions uniformly
locally polynomial.
A conjecture on equitable vertex arboricity of graphs
Authors: Zhang Xin , Wu Jian-Liang
Published: April 2014

Wu, Zhang and Li [4] conjectured that the set of vertices of any simple graph
G can be equitably partitioned into ?(?(G) + 1)=2? subsets so that each of
them induces a forest of G. In this note, we prove this conjecture for
graphs G with ?(G) ? |G|=2.
Hermite-Hadamard inequalities for relative semi-convex functions and applications
Authors: Noor Muhammad , Noor Khalida , Awan Muhammad
Published: April 2014

In this paper, we prove some Hermite-Hadamard inequalities for the class of
relative semiconvex functions. Several special cases are also discussed.
Thus it is worth mentioning that our results can be viewed as a
generalization of previous results. Some applications to special means are
also presented. Ideas and techniques of this paper may inspire further
research in various branches of pure and applied sciences.
The reciprocal reverse Wiener index of unicyclic graphs
Authors: Li Jianping , Zhou Bo
Published: April 2014

The reciprocal reverse Wiener index R?(G) of a connected graph G is defined
in mathematical chemistry as the sum of weights 1/d(G)?dG(u,v) of all
unordered pairs of distinct vertices u and v with dG(u, v) < d(G), where
dG(u, v) is the distance between vertices u and v in G and d(G) is the
diameter of G. We determine the minimum and maximum reciprocal reverse Wiener
indices in the class of n-vertex unicyclic graphs and characterize the
corresponding extremal graphs.
Convenient adjacencies on Z2
Authors: Slapal Josef
Published: April 2014

We discuss graphs with the vertex set Z2 which are subgraphs of the
8-adjacency graph and have the property that certain natural cycles in these
graphs are Jordan curves, i.e., separate Z2 into exactly two connected
components. After considering graphs with the usual connectedness, we
concentrate on a graph with a special one.
Some new fixed point theorems for contractive and nonexpansive mappings
Authors: Pant Rajendra
Published: April 2014

In the present paper, we obtain some new fixed point theorems for set-valued
contractive and nonexpansive mappings in the setting of ultrametric spaces.
Our theorems complement, generalize and extend some well known results of
Petalas and Vidalis [A fixed point theorem in non-Archimedean vector spaces,
Proc. Amer. Math. Soc 118(1993), 819-821.], Suzuki [A new type of fixed point
theorem in metric spaces, Nonlinear Anal. 71(2009), 5313-5317.] and others.
Explicit formulas for computing Bernoulli numbers of the second kind and Stirling numbers of the first kind
Authors: Qi Feng
Published: April 2014

In the paper, by establishing a new and explicit formula for computing the
n-th derivative of the reciprocal of the logarithmic function, the author
presents new and explicit formulas for calculating Bernoulli numbers of the
second kind and Stirling numbers of the first kind. As consequences of these
formulas, a recursion for Stirling numbers of the first kind and a new
representation of the reciprocal of the factorial n! are derived. Finally,
the author finds several identities and integral representations relating to
Stirling numbers of the first kind.
The normalized Laplacian Estrada index of a graph
Authors: Li Jianxi , Guo Ji-Ming , Shiu Wai
Published: April 2014

In this paper, we define and investigate the normalized Laplacian Estrada
index of a graph. Some bounds for the normalized Laplacian Estrada index of a
graph in term of its vertex number, maximum (or minimum) degree are obtained,
some inequalities between the normalized Laplacian Estrada and the normalized
Laplacian energy are also obtained.
An analogue of the Ostrowski inequality and applications
Authors: Masjed-Jamei Mohammad , Dragomir Sever
Published: April 2014

A new analogue of the Ostrowski inequality is introduced in three different
cases for functions in L1[a; b] and L?[a; b] spaces and its application is
given for deriving error bounds of some quadrature rules.
Minimal properties of the Drazin-inverse solution of a matrix equation
Authors: Miladinovic Marko , Miljkovic Sladjana , Stanimirovic Predrag
Published: April 2014

We present the Drazin-inverse solution of the matrix equation AXB = G as a
least-squares solution of a specified minimization problem. Some important
properties of the Moore-Penrose inverse are extended on the Drazin inverse
by exploring the minimal norm properties of the Drazin-inverse solution of
the matrix equation AXB = G. The least squares properties of the
Drazin-inverse solution lead to new representations of the Drazin inverse of
a given matrix, which are justified by illustrative examples.
Duality for mixed second-order programs with multiple arguments
Authors: Kailey N. , Gupta S.K.
Published: April 2014

The duality theory is well-developed for non linear programs. Technically, a
major part of such broad framework possibly be extended to mixed non linear
programs, however this has demonstrated complicated, in minority as the
duality theory does not integrate well with modern computational practice. In
this paper, we constructed a new pair of second-order multiobjective mixed
dual problems over arbitrary cones with multiple arguments, with an eye
towards developing a more practical framework. Weak, strong and converse
duality theorems are then established under K-?-bonvexity assumptions.
Several known results are obtained as special cases.
The Laplacian eigenvalues and invariants of graphs
Authors: Pan Rong-Ying , Yan Jing , Zhang Xiao-Dong
Published: April 2014

In this paper, we investigate some relations between the invariants
(including vertex and edge connectivity and forwarding indices) of a graph
and its Laplacian eigenvalues. In addition, we present a sufficient condition
for the existence of Hamiltonicity in a graph involving its Laplacian
eigenvalues.
Effect of sintering temperature on electrical and microstructure properties of hot pressed Cu-TiC composites
Authors: Islak S. , Kır D. , Buytoz S.
Published: April 2014

In this study, Cu-TiC composites were successfully produced using hot
pressing method. Cu-TiC powder mixtures were hot-pressed for 4 min at 600,
700 and 800?C under an applied pressure of 50 MPa. Phase composition and
microstructure of the composites hot pressed at different temperatures were
characterized by X-ray diffraction, scanning electron microscope, and optic
microscope techniques. Microstructure studies revealed that TiC particles
were distributed uniformly in the Cu matrix. With the increasing sintering
temperature, hardness of composites changed between 64.5 HV0.1 and 85.2
HV0.1. The highest electrical conductivity for Cu-10 wt.% TiC composites was
obtained for the sintering temperature of 800?C, with approximately 68.1%
IACS.
Densification and volumetric change during supersolidus liquid phase sintering of prealloyed brass Cu28Zn powder: Modeling and optimization
Authors: Mohammadzadeh A. , Azadbeh M. , Namini Sabahi
Published: April 2014

An investigation has been made to use response surface methodology and
central composite rotatable design for modeling and optimizing the effect of
sintering variables on densification of prealloyed Cu28Zn brass powder
during supersolidus liquid phase sintering. The mathematical equations were
derived to predict sintered density, densification parameter, porosity
percentage and volumetric change of samples using second order regression
analysis. As well as the adequacy of models was evaluated by analysis of
variance technique at 95% confidence level. Finally, the influence and
interaction of sintering variables, on achieving any desired properties was
demonstrated graphically in contour and three dimensional plots. In order to
better analyze the samples, microstructure evaluation was carried out. It
was concluded that response surface methodology based on central composite
rotatable design, is an economical way to obtain arbitrary information with
performing the fewest number of experiments in a short period of time.
Kinetics of multi-step processes of thermal degradation of Co(II) complex with N-benzyloxycarbonylglycinato ligand. Deconvolution of DTG curves
Authors: Sumar-Ristovic M. , Minic D.M. , Blagojevic V. , Andjelkovic K.
Published: April 2014

Thermal decomposition of Co(II) complex with N-benzyloxycarbonylglycinato
ligand, [Co(N-Boc-gly)2(H2O)4]?2H2O, in non-isothermal conditions occurs in
three complex steps. In order to investigate detail kinetics of first two
steps, dehydration and ligand degradation, DTG curves were deconvoluted using
product of Gaussian and Lorentzian function. It was shown that process of
complex dehydration consists of three, while process of ligand fragmentation
consist of five elementary steps. For elementary steps the kinetic triplet
(Ea, Z and f(?)) was determinated. Kinetic parameters were obtained by
application of IKP method. On the basis of M?lek?s criteria and
Sest?k-Berggren's method, Sest?k-Berggren's model, f(?)=?M(1-?)N was
suggested for all elementary steps, while Master plot method and Perez-
Maqueda criteria confirmed suggested reaction models. The thermodynamic
activation parameters were calculated for process of complex dehydration, and
lifetime for first elementary step of the dehydration and ligand degradation
processes was estimated.
Formation of porous clay ceramic using sago waste ash as a prospective additive material with controllable milling
Authors: Aripin H. , Mitsudo S. , Rahmat B. , Tani S. , Sako K. , Fujii Y. , Kikuchi K. , Saito T. , Idehara T. , Sabchevski S.
Published: April 2014

A novel type of ceramic material was produced by mixing sago waste ash from
the sago processing industry in Indonesia with clay. The composition was
prepared by adding 50 %wt amount of sago waste into the clay, then a series
of samples was milled for 6 h, 12 h, 24 h and 48 h, respectively. The samples
were dry pressed and sintered at temperatures ranging from 800?C to 1200?C.
The influence of the sintering temperature and the milling time on bulk
density, firing shrinkage, water adsorption, and hardness was studied in
detail. The results demonstrate that the low water absorption of less than
0.5% and the highest hardness of 5.82 GPa were obtained for the sample
sintered at 1100?C and milled for 48 h. The investigation of the absorptive
properties of such ceramics indicates that they could be recommended as a
promising material for manufacturing of unglazed floor tiles.
The Development of Reporting Norms without Explicit Guidance: An Example from Accounting for Gift Cards
Authors: Hennes Karen M. , Schenck Kristy M.
Published: April 2014

SYNOPSIS

This study examines the evolution of retail firms' financial reporting for unused gift cards (i.e., breakage) as an example of how reporting norms develop in the absence of explicit authoritative guidance. We find that firms exhibit a wide range of accounting and reporting choices but show significant increases in the quantity and detail of disclosure over time. Consistent with our predictions, these changes in disclosure are positively related to initial disclosure levels below the average of industry peers, the receipt of a related SEC comment letter, and specific external auditors (especially those with a high frequency of related comment letters in their client portfolio). Overall, the evolution of reporting norms for gift card breakage demonstrates the role the SEC, peers, and auditors have in quickly shaping U.S. reporting norms in the absence of formal disclosure requirements.
Technology-Facilitated Contribution Behavior: An Experimental Investigation
Authors: Du Hui , Lehmann Constance M. , Willson Victor L.
Published: April 2014

Contribution behavior is described as voluntarily providing assistance or sharing knowledge when a colleague makes a request for assistance (Olivera, Goodman, and Tan 2008). The purpose of this paper is to investigate factors that lead to contribution behavior through collaboration technology. We engaged 183 participants over a collaboration platform to work on an accounting task and interrupted them with a request for help on a similar task. The participants could respond to the request using communication tools embedded in the collaboration application if they wanted to help. Post-experimental survey data were collected to measure the participants' motivations to contribute and analyze the quality of their contributions. The results indicate that participants are more motivated to contribute when they know the individual requesting assistance and have positive prior experience with the individual. Furthermore, having a higher level of domain knowledge in the area of the request and specificity of the request are associated with higher contribution quality. We discuss implications to accounting firms for providing an environment conducive to contribution behavior.

Data Availability: Data are available from the first author.
Mandatory Adoption of XBRL and Foreign Institutional Investors' Holdings: Evidence from China
Authors: Wang Tawei , Seng Jia-Lang
Published: April 2014

This paper investigates the association between the mandatory adoption of the eXtensible Business Reporting Language (XBRL) in China and foreign institutional investors' interest. Based on a sample from the Shanghai Stock Exchange and the Shenzhen Stock Exchange in the period from 2004 to 2009, our results demonstrate that the adoption of XBRL is positively related to foreign institutional investors' holdings. In addition, although state-owned enterprises (SOEs), compared to non-SOEs, have fewer foreign institutional investors' holdings in our sample period, the adoption of XBRL reduces such differences for non-tradable shares. As China is one of the world's largest and growing economic entities and an early adopter of XBRL, our findings shed light on the role played by XBRL as a global standard and how it facilitates business information exchange around the world.
The Impact of XBRL Reporting on Market Efficiency
Authors: Cong Yu , Hao Jia , Zou Lin
Published: April 2014

This paper examines the impact of XBRL reporting required by the U.S. Securities and Exchange Commission (SEC) on market efficiency. Based on the disclosure theories about imperfect markets, we hypothesize that XBRL reporting facilitates the generation and infusion of idiosyncratic information into the market and thus improves market efficiency. Our findings show a synchronous increase of information asymmetry and trading volume as posited in the disclosure theory and our hypotheses.
How Do Somatosensory Deficits in the Arm and Hand Relate to Upper Limb Impairment, Activity, and Participation Problems After Stroke? A Systematic Review
Authors: Meyer Sarah , Karttunen Auli H. , Thijs Vincent , Feys Hilde , Verheyden Geert
Published: April 2014

Background

The association between somatosensory impairments and outcome after stroke remains unclear.

Purpose

The aim of this study was to systematically review the available literature on the relationship between somatosensory impairments in the upper limb and outcome after stroke.

Data Sources

The electronic databases PubMed, CINAHL, EMBASE, Cochrane Library, PsycINFO, and Web of Science were systematically searched from inception until July 2013.

Study Selection

Studies were included if adult patients with stroke (minimum n=10) were examined with reliable and valid measures of somatosensation in the upper limb to investigate the relationship with upper limb impairment, activity, and participation measures. Exclusion criteria included measures of somatosensation involving an overall score for upper and lower limb outcome and articles including only lower limb outcomes.

Data Extraction

Eligibility assessment, data extraction, and quality evaluation were completed by 2 independent reviewers. A cutoff score of ≥65% of the maximal quality score was used for further inclusion in this review.

Data Synthesis

Six articles met all inclusion criteria. Two-point discrimination was shown to be predictive for upper limb dexterity, and somatosensory evoked potentials were shown to have predictive value in upper limb motor recovery. Proprioception was significantly correlated with perceived level of physical activity and social isolation and had some predictive value in functional movements of the upper limb. Finally, the combination of light touch and proprioception impairment was shown to be significantly related to upper limb motor recovery as well as handicap situations during activities of daily living.

Limitations

Heterogeneity of the included studies warrants caution when interpreting results.

Conclusions

Large variation in results was found due to heterogeneity of the studies. However, somatosensory deficits were shown to have an important role in upper limb motor and functional performance after stroke.
Relationships Between Balance and Cognition in Patients With Subjective Cognitive Impairment, Mild Cognitive Impairment, and Alzheimer Disease
Authors: Tangen Gro Gujord , Engedal Knut , Bergland Astrid , Moger Tron Anders , Mengshoel Anne Marit
Published: April 2014

Background

Balance impairments are common in patients with Alzheimer disease (AD), but which aspects of balance are affected, at which stage of cognitive impairment, and their associations with cognitive domains remain unexplored.

Objectives

The aims of this study were: (1) to explore differences in balance abilities among patients with subjective cognitive impairment (SCI) or mild cognitive impairment (MCI), mild AD, and moderate AD and (2) to examine the relationship between the various aspects of balance and cognitive domains.

Design

This was a cross-sectional study.

Methods

Home-dwelling patients with SCI or MCI (n=33), mild AD (n=99), and moderate AD (n=38) participated in this study. The Balance Evaluation Systems Test (BESTest), comprising 6 subscales—“Biomechanical Constraints,” “Stability Limits/Verticality,” “Anticipatory Postural Adjustments,” “Postural Responses,” “Sensory Orientation,” and “Stability in Gait”—was used to assess balance. Cognitive domains were assessed using the following measures: Mini-Mental Status Examination, Word-List Learning Test from the Consortium to Establish a Registry for Alzheimer's Disease (CERAD), Verbal Fluency Test, Clock Drawing Test, and Trail Making Test, parts A and B (TMT-A and TMT-B, respectively). Two-way between-group analyses of variance, adjusted for age, were used to analyze differences among the groups. Multiple linear regression analysis was used to explore the associations between balance and cognition.

Results

Differences were found between the groups on all BESTest subscales; the moderate AD group had the worst scores. The TMT-B (measuring executive function) was associated with all of the BESTest subscales after controlling for demographic factors.

Limitations

The cross-sectional design hampered interpretation of the development of balance impairments.

Conclusions

The study findings indicate that all aspects of balance control deteriorate with increasing severity of cognitive impairment and that executive function plays an important role in balance control. Physical therapists should pay attention to these findings both in clinical practice and in future research.
AM-PAC “6-Clicks” Functional Assessment Scores Predict Acute Care Hospital Discharge Destination
Authors: Jette Diane U. , Stilphen Mary , Ranganathan Vinoth K. , Passek Sandra D. , Frost Frederick S. , Jette Alan M.
Published: April 2014

Background

Physical therapists and occupational therapists practicing in acute care hospitals play a crucial role in discharge planning. A standardized assessment of patients' function could be useful for discharge recommendations.

Objectives

The study objective was to determine the accuracy of “6-Clicks” basic mobility and daily activity measures for predicting discharge from an acute care hospital to a home or institutional setting.

Design

The study was retrospective and observational.

Methods

“6-Clicks” scores obtained at initial visits by physical therapists or occupational therapists and patients' discharge destinations were used to develop and validate receiver operating characteristic curves for predicting discharge destination. Positive predictive values (PPV), negative predictive values (NPV), and likelihood ratios were calculated.

Results

Areas under the receiver operating characteristic curves for basic mobility scores were 0.857 (95% confidence interval [CI]=0.852, 0.862) and 0.855 (95% CI=0.850, 0.860) in development and validation samples, respectively. Areas under the curves for daily activity scores were 0.846 (95% CI=0.841, 0.851) and 0.845 (95% CI=0.840, 0.850) in development and validation samples, respectively. Cutoff scores providing the best accuracy for determining discharge destination were 42.9 for basic mobility and 39.4 for daily activity. For basic mobility, the PPV was 0.748 and the NPV was 0.801 in both development and validation samples. For daily activity, the PPVs were 0.787 and 0.784 and the NPVs were 0.748 and 0.746 in development and validation samples, respectively.

Limitations

Limitations included lack of information on the rater reliability of “6-Clicks” instruments, use of surrogate data for some discharge designations, and use of a clinical database for research purposes.

Conclusions

This study provides evidence of the accuracy of “6-Clicks” scores for predicting destination after discharge from an acute care hospital.
Smoking and older age associated with mumps in an outbreak in a group of highly-vaccinated individuals attending a youth club party, the Netherlands, 2012
Authors: Ladbury G , Ostendorf S , Waegemaekers T , van Binnendijk R , Boot H , Hahné S
Published: April 2014

Binary file ES_Abstracts_Final_ECDC.txt matches
West Nile virus surveillance in mosquitoes, April to October 2013, Vojvodina province, Serbia: implications for the 2014 season
Authors: Kemenesi G , Krtinić B , Milankov V , Kutas A , Dallos B , Oldal M , Somogyi N , Németh V , Bányai K , Jakab F
Published: April 2014

After the West Nile virus (WNV) outbreak in 2012, we collected mosquito samples from Vojvodina province, Serbia, in 2013. We found high WNV infection rate in two species, Culex pipiens and Anopheles maculipennis. Phylogenetic analysis showed that Serbian WNV strains from 2013 were most closely related to Italian and Greek strains isolated in 2012 and 2010, respectively. Public health authorities should be aware of a potentially increased risk of WNV activity during the 2014 season.
Seasonal influenza immunisation in Europe. Overview of recommendations and vaccination coverage for three seasons: pre-pandemic (2008/09), pandemic (2009/10) and post-pandemic (2010/11)
Authors: Mereckiene J , Cotter S , Nicoll A , Lopalco P , Noori T , Weber J T , D'Ancona F , Lévy-Bruhl D , Dematte L , Giambi C , Valentiner-Branth P , Stankiewicz I , Appelgren E , O’Flanagan D , the VENICE project gatekeepers group Collective
Published: April 2014

Since 2008, annual surveys of influenza vaccination policies, practices and coverage have been undertaken in 29 European Union (EU)/ European Economic Area (EEA) countries. After 2009, this monitored the impact of European Council recommendation to increase vaccination coverage to 75% among risk groups. This paper summarises the results of three seasonal influenza seasons: 2008/09, 2009/10 and 2010/11. In 2008/09, 27/29 countries completed the survey; in 2009/10 and 2010/11, 28/29 completed it. All or almost all countries recommended vaccination of older people (defined as those aged ≥50, ≥55, ≥59, ≥60 or ≥65 years), and people aged ≥6 months with clinical risk and healthcare workers. A total of 23 countries provided vaccination coverage data for older people, but only 7 and 10 had data for the clinical risk groups and healthcare workers, respectively. The number of countries recommending vaccination for some or all pregnant women increased from 10 in 2008/09 to 22 in 2010/11. Only three countries could report coverage among pregnant women. Seasonal influenza vaccination coverage during and after the pandemic season in older people and clinical groups remained unchanged in countries with higher coverage. However, small decreases were seen in most countries during this period. The results of the surveys indicate that most EU/EEA countries recommend influenza vaccination for the main target groups; however, only a few countries have achieved the target of 75% coverage among risk groups. Coverage among healthcare workers remained low.
A new type of reconstruction of the hemipelvis after Type 3 amputative sacrectomy using pedicled fibula
Authors: Starantzis Konstantinos A. , Sakellariou Vasileios I. , Rose Peter S. , Yaszemski Michael J. , Papagelopoulos Panayiotis J.
Published: April 2014

This is a technical note of pelvic reconstruction performed by an advanced multidisciplinary team. The authors report a new 3-stage reconstruction of the hemipelvis after Type 3 sacrectomy involving instrumented spinoiliac arthrodesis and pedicled fibula grafting in 2 patients.

The anterior stage of the procedure begins with a transabdominal approach to mobilize the viscera and to free up the tumor from the vessels. The posterior divisions of internal iliac vessels, the middle sacral vessels, and the lateral sacral vessels are then ligated. An anterior vertebrectomy is done at the appropriate level, followed by an anterior osteotomy through the lateral planed surgical margin of the sacrum close to the salvaged sacroiliac joint. The second stage includes a major sacral resection with lower-extremity amputation from the pubic symphysis through the intact side of the sacrum, ipsilateral pedicled fibula harvesting, and closure with an ipsilateral pedicled quadriceps flap. The final stage involves reconstruction with lumboiliac instrumentation. The pedicled fibular graft left from the second stage is then placed distally within the previously created iliopectineal docking site and proximally within the L-5 docking site.

The authors believe that this is a feasible and reproducible technique with theoretical advantages that have to be proved in the long-term follow-up.
Stereotactic radiosurgery at a low marginal dose for the treatment of pediatric arteriovenous malformations: obliteration, complications, and functional outcomes
Authors: Potts Matthew B. , Sheth Sunil A. , Louie Jonathan , Smyth Matthew D. , Sneed Penny K. , McDermott Michael W. , Lawton Michael T. , Young William L. , Hetts Steven W. , Fullerton Heather J. , Gupta Nalin
Published: April 2014

Object

Stereotactic radiosurgery (SRS) is an established treatment modality for brain arteriovenous malformations (AVMs) in children, but the optimal treatment parameters and associated treatment-related complications are not fully understood. The authors present their single-institution experience of using SRS, at a relatively low marginal dose, to treat AVMs in children for nearly 20 years; they report angiographic outcomes, posttreatment hemorrhage rates, adverse treatment-related events, and functional outcomes.

Methods

The authors conducted a retrospective review of 2 cohorts of children (18 years of age or younger) with AVMs treated from 1991 to 1998 and from 2000 to 2010.

Results

A total of 80 patients with follow-up data after SRS were identified. Mean age at SRS was 12.7 years, and 56% of patients had hemorrhage at the time of presentation. Median target volume was 3.1 cm3 (range 0.09–62.3 cm3), and median prescription marginal dose used was 17.5 Gy (range 12–20 Gy). Angiograms acquired 3 years after treatment were available for 47% of patients; AVM obliteration was achieved in 52% of patients who received a dose of 18–20 Gy and in 16% who received less than 18 Gy. At 5 years after SRS, the cumulative incidence of hemorrhage was 25% (95% CI 16%–37%). No permanent neurological deficits occurred in patients who did not experience posttreatment hemorrhage. Overall, good functional outcomes (modified Rankin Scale Scores 0–2) were observed for 78% of patients; for 66% of patients, functional status improved or remained the same as before treatment.

Conclusions

A low marginal dose minimizes SRS-related neurological deficits but leads to low rates of obliteration and high rates of hemorrhage. To maximize AVM obliteration and minimize posttreatment hemorrhage, the authors recommend a prescription marginal dose of 18 Gy or more. In addition, SRS-related symptoms such as headache and seizures should be considered when discussing risks and benefits of SRS for treating AVMs in children.
Choroid plexus coagulation in infants with extreme hydrocephalus or hydranencephaly
Authors: Shitsama Sylvia , Wittayanakorn Nunthasiri , Okechi Humphrey , Albright A. Leland
Published: April 2014

Object

Severe hydrocephalus and hydranencephaly are common congenital conditions in Kenya. In patients with these conditions, ventriculoperitoneal (VP) shunts are associated with appreciable complications and endoscopic third ventriculostomies (ETVs) have limited success. Endoscopic choroid plexus coagulation (CPC) to diminish CSF production is a potential treatment option. The purpose of this study was to evaluate the effect of CPC without ETV in infants with severe hydrocephalus or hydranencephaly.

Methods

Medical records of infants with severe congenital hydrocephalus or hydranencephaly who underwent CPC in Kijabe Hospital from November 2010 to April 2013 were reviewed retrospectively. Thirty-three patients with complete medical records and preoperative radiographic images were identified. After CPC, the infants were followed in the Kijabe Hospital outpatient department, in mobile clinics, or by telephone. Success of the CPC was defined as resolution of preoperative symptoms, stabilization of head size, and avoidance of VP shunt placement.

Results

Patients were followed from 30 to 608 days (median of 120 days). Three patients were lost to follow-up. Of the 30 evaluable patients, CPC was considered to be successful in 13 (43.3%), including 8 of 20 patients with severe hydrocephalus and 5 of 10 with hydranencephaly. Failure of CPC was evident from increased head circumference in 14 (82%) of 17 patients and from CSF leakage in 3. Of the 17 failures, 13 occurred within 3 months of surgery. Six patients died: 3 whose CPC procedures were failures, 2 whose CPC was successful, and 1 postoperatively. Of the 17 in whom CPC failed, 10 subsequently underwent VP shunt insertion.

Conclusions

CPC stabilizes macrocephaly in approximately 40% of infants with severe congenital hydrocephalus and hydranencephaly and can be considered as an alternative to VP shunt placement.
Quality measurement in the shunt treatment of hydrocephalus: analysis and risk adjustment of the Revision Quotient
Authors: Piatt Joseph H. , Freibott Christina E.
Published: April 2014

Object

The Revision Quotient (RQ) has been defined as the ratio of the number of CSF shunt revisions to the number of new shunt insertions for a particular neurosurgical practice in a unit of time. The RQ has been proposed as a quality measure in the treatment of childhood hydrocephalus. The authors examined the construct validity of the RQ and explored the feasibility of risk stratification under this metric.

Methods

The Kids' Inpatient Database for 1997, 2000, 2003, 2006, and 2009 was queried for admissions with diagnostic codes for hydrocephalus and procedural codes for CSF shunt insertion or revision. Revision quotients were calculated for hospitals that performed 12 or more shunt insertions annually. The univariate associations of hospital RQs with a variety of institutional descriptors were analyzed, and a generalized linear model of the RQ was constructed.

Results

There were 12,244 admissions (34%) during which new shunts were inserted, and there were 23,349 admissions (66%) for shunt revision. Three hundred thirty-four annual RQs were calculated for 152 different hospitals. Analysis of variance in hospital RQs over the 5 years of study data supports the construct validity of the metric. The following factors were incorporated into a generalized linear model that accounted for 41% of the variance of the measured RQs: degree of pediatric specialization, proportion of initial case mix in the infant age group, and proportion with neoplastic hydrocephalus.

Conclusions

The RQ has construct validity. Risk adjustment is feasible, but the risk factors that were identified relate predominantly to patterns of patient flow through the health care system. Possible advantages of an alternative metric, the Surgical Activity Ratio, are discussed.
Grounding-zone ice thickness from InSAR: Inverse modelling of tidal elastic bending
Authors: Marsh Oliver J. , Rack Wolfgang , Golledge Nicholas R. , Lawson Wendy , Floricioiu Dana
Published: April 2014

Ice-thickness measurements in Antarctic ice-shelf grounding zones are necessary for calculating the mass balance of individual catchments, but remain poorly constrained for most of the continent. We describe a new inverse modelling optimization approach to estimate ice thickness in the grounding zone of Antarctic outlet glaciers and ice shelves using spatial patterns of tide-induced flexure derived from differential interferometric synthetic aperture radar (InSAR). We demonstrate that the illposedness of the inverse formulation of the elastic-plate equations for bending can be controlled by regularization. In one dimension, the model recreates smooth, synthesized profiles of ice thickness from flexure information to within 1–2%. We test the method in two dimensions and validate it in the grounding zone of Beardmore Glacier, a major outlet glacier in the Transantarctic Mountains, using interferograms created from TerraSAR-X satellite imagery acquired in 2012. We compare our results with historic and modern ice-thickness data (radio-echo sounding from 1967 and ground-penetrating radar from 2010). We match both longitudinal and transverse thickness transects to within 50 m root-mean-square error using an effective Young’s modulus of 1.4 GPa. The highest accuracy is achieved close to the grounded ice boundary, where current estimates of thickness based on surface elevation measurements contain a systematic bias towards thicker ice.
Continuous snowpack monitoring using upward-looking ground-penetrating radar technology
Authors: Schmid Lino , Heilig Achim , Mitterer Christoph , Schweizer Jürg , Maurer Hansruedi , Okorn Robert , Eisen Olaf
Published: April 2014

Snow stratigraphy and water percolation are key contributing factors to avalanche formation. So far, only destructive methods can provide this kind of information. Radar technology allows continuous, non-destructive scanning of the snowpack so that the temporal evolution of internal properties can be followed. We installed an upward-looking ground-penetrating radar system (upGPR) at the Weissfluhjoch study site (Davos, Switzerland). During two winter seasons (2010/11 and 2011/12) we recorded data with the aim of quantitatively determining snowpack properties and their temporal evolution. We automatically derived the snow height with an accuracy of about ± 5 cm, tracked the settlement of internal layers (± 7 cm) and measured the amount of new snow (± 10 cm). Using external snow height measurements, we determined the bulk density with a mean error of 4.3% compared to manual measurements. Radar-derived snow water equivalent deviated from manual measurements by 5%. Furthermore, we tracked the location of the dry-to-wet transition in the snowpack until water percolated to the ground. Based on the transition and an independent snow height measurement it was possible to estimate the volumetric liquid water content and its temporal evolution. Even though we need additional information to derive some of the snow properties, our results show that it is possible to quantitatively derive snow properties with upGPR.
Interannual changes of the floating ice shelf of Petermann Gletscher, North Greenland, from 2000 to 2012
Authors: Münchow Andreas , Padman Laurie , Fricker Helen A.
Published: April 2014

Petermann Gletscher, northwest Greenland, drains 4% of the Greenland ice sheet into Nares Strait. Its floating ice shelf retreated from 81 to 48 km in length during two large calving events in 2010 and 2012. We document changes in the three-dimensional ice-shelf structure from 2000 to 2012, using repeated tracks of airborne laser altimetry and ice radio-echo sounding, ICESat laser altimetry and MODIS visible imagery. The recent ice-shelf velocity, measured by tracking surface features between flights in 2010 and 2011, is ~1.25 km a−1, ~15–30% faster than estimates made before 2010. The steady- state along-flow ice divergence represents 6.3 Gta−1mass loss through basal melting (~5Gta−1) and surface melting and sublimation (~1.0Gta−1). Airborne laser altimeter data reveal thinning, both along a thin central channel and on the thicker ambient ice shelf. From 2007 to 2010 the ice shelf thinned by ~5 m a−1, which represents a non-steady mass loss of ~4.1 Gta−1. We suggest that thinning in the basal channels structurally weakened the ice shelf and may have played a role in the recent calving events.
Ice volume estimation inferred from ice thickness and surface measurements for Continental Glacier, Wind River Range, Wyoming, USA
Authors: Vanlooy Jeffrey A. , Miège Clément , Vandeberg Gregory S. , Forster Richard R.
Published: April 2014

The Wind River Range in Wyoming, USA, contains the largest concentration of glacial mass in the Rocky Mountains of the contiguous USA. Despite this distinction, only a few field or remotely sensed studies providing glacier volume changes have been published. The current study focuses on Continental Glacier located on the northern end of the range and uses two field datasets (high-accuracy GPS surface elevation points and ice-penetrating radar transects of the glacier bed) to create a three-dimensional model of glacier volume. Current surface elevations are compared with historical elevation data to calculate surface elevation change over time. An average thinning rate of 13.8 ± 7.8 m (0.30 ± 0.17 m a–1) between 1966 and 2012 was found. Surface elevation change rates varied across the glacier, ranging from +0.30 to –0.98 m a–1. Taking into account variable melt rates across the glacier, along with a glacial volume of 72.1 × 106± 10.8 × 106m3, we estimate that Continental Glacier will be reduced in volume by 43% over the next 100 years and will disappear completely over the next 300–400 years, if current climatic conditions persist.
Tidal modulation of ice-shelf flow: a viscous model of the Ross Ice Shelf
Authors: Brunt Kelly M. , MacAyeal Douglas R.
Published: April 2014

Three stations near the calving front of the Ross Ice Shelf, Antarctica, recorded GPS data through a full spring–neap tidal cycle in November 2005. The data revealed a diurnal horizontal motion that varied both along and transverse to the long-term average velocity direction, similar to tidal signals observed in other ice shelves and ice streams. Based on its periodicity, it was hypothesized that the signal represents a flow response of the Ross Ice Shelf to the diurnal tides of the Ross Sea. To assess the influence of the tide on the ice-shelf motion, two hypotheses were developed. The first addressed the direct response of the ice shelf to tidal forcing, such as forces due to sea-surface slopes or forces due to sub-ice-shelf currents. The second involved the indirect response of ice-shelf flow to the tidal signals observed in the ice streams that source the ice shelf. A finite-element model, based on viscous creep flow, was developed to test these hypotheses, but succeeded only in falsifying both hypotheses, i.e. showing that direct tidal effects produce too small a response, and indirect tidal effects produce a response that is not smooth in time. This nullification suggests that a combination of viscous and elastic deformation is required to explain the observations.
Les conditions climatiques de la torrentialité au cours du Petit Age Glaciaire en Provence
Authors: Prosper-Laget Valérie , Pichard Georges , Miramont Cécile , Sivan Olivier
Published: April 2014

The aim of this article is to characterize the climatic conditions of torrentiality in Provence during the Little Ice Age. The study is based on chronicles of floods and overflowings of the sub-alpine torrents (the Ubaye valley in particular) and on instrumental measures of rainfalls in Marseilles. Several periods marked by frequent floods in the Durancian hydrosystem follow periods of relative tranquillity. This study shows that streams, according to their rank, do not have the same regimes of floods, so testifying of different meteorological forcing, that the frequent occurrence of floods during the Little Ice Age is not linked to a global increase of pluviometrical but to an increased variability of interannual rains, periods of more frequent floods corresponding to series of rainy years (1750-1800, 1830-1860) and periods of rarefaction of floods corresponding to series of dry years (1800-1830). The crossing of these data with other paleoclimatic indicators such as the series of growth rings of mountain larches offers perspectives to characterize the regional nuances of the Provençal climate on the historical time scale.
Les prémices du Petit Age Glaciaire en Roussillon à travers le prisme des sources écrites
Authors: Puig Carole
Published: April 2014

Cet article a pour objectif de détecter les indices marquant le début du Petit Age Glaciaire en Roussillon et de caractériser le phénomène à partir des seules sources écrites. Le recensement des événements climatiques à partir de cette documentation est une démarche complexe, mais qui permet malgré tout de souligner que les accidents se multiplient à partir des années 1310 et surtout 1330. En parallèle, des campagnes d’endiguement des fleuves roussillonnais sont entreprises dans la plaine dans les années 1330 -1340. Enfin, l’impact de cette péjoration climatique sur les modes d’occupation du sol est également très difficile à définir. Notons toutefois, que, malgré des inondations récurrentes, causant l’ensablement de certains sites, les populations ont tenté de résister. Les abandons de villages s’étalant sur l’extrême fin du Moyen Age, le fait climatique devient alors difficilement dissociable des autres crises.
Crues historiques et vendanges en Languedoc méditerranéen oriental : la source, le signal et l’interprétation
Authors: Blanchemanche Philippe
Published: April 2014

La constitution de séries temporelles pour les cinq derniers siècles d’événements météorologiques ou de faits et actes de nature sociétale à partir de sources historiques textuelles nécessite quelques précautions avant de subir des analyses statistiques ou mathématiques de nature plus ou moins sophistiquée. Après l’examen des critères de représentativité, d’homogénéité et de continuité des séries obtenues pour les crues historiques et les dates de vendanges, leur interprétation en termes de variabilité météorologique et/ ou climatique est discutée à la lumière des fluctuations, oscillations ou ruptures observées, en particulier au cours des XVIIe et XVIIIe siècles.
Une déclinaison régionale du Petit Âge Glaciaire. Apport des archives historiques en Provence
Authors: Pichard Georges , Roucaute Emeline
Published: April 2014

This contribution is an attempt, to be continued and completed, to get a panoramic view of the Little Ice Age (LIA), declined in a southern and Mediterranean region. The objective is to try and identify its temporal limits and its various aspects from climatic indices available on the long term (up to seven centuries). The long history of fluvial ices, together with that of snows, perceived in their frequency and for the latter in their early or late character. These tests are designed to check the legitimacy of the transfer of the LIA notion from its Alpine origins to the region of lowlands. Another examined test is the frequency of floods in the Lower Rhone region, the curve of which fits the general swelling of those of ice and snow, even if shifted critical phases could be specified. The problem of the link between fall of temperature and hydric and hydrologic indices is still to be solved. It will have to be the object of future multidisciplinary investigations.