bluuebunny/crossref_metadata_2025_split huggingface dataset:
Price Competition Under Mixed Multinomial Logit Demand Functions
Authors: Aksoy-Pierson Margaret , Allon Gad , Federgruen Awi 
Published: April 2013

In this paper, we postulate a general class of price competition models with mixed multinomial logit demand functions under affine cost functions. In these models, the market is partitioned into a finite set of market segments. We characterize the equilibrium behavior of this class of models in the case where each product in the market is sold by a separate, independent firm. We identify a simple and very broadly satisfied condition under which a pure Nash equilibrium exists and the set of Nash equilibria coincides with the solutions of the system of first-order-condition equations, a property of essential importance to empirical studies. This condition specifies that in every market segment, each firm captures less than 50% of the potential customer population when pricing at a specific level that, under the condition, is an upper bound for a rational price choice for the firm irrespective of the competitors' prices. We show that under a somewhat stronger, but still broadly satisfied, version of the above condition, a unique equilibrium exists. We complete the picture by establishing the existence of a Nash equilibrium, indeed a unique Nash equilibrium, for markets with an arbitrary degree of concentration, under sufficiently tight price bounds. We discuss how our results extend to a continuum of customer types. A discussion of the multiproduct case is included. The paper concludes with a discussion of implications for structural estimation methods. This paper was accepted by J. Miguel Villas-Boas, marketing.
On inductively free reflection arrangements
Authors: Hoge Torsten , Röhrle Gerhard 
Published: April 2013

Abstract

Suppose that W is a finite, unitary
reflection group acting on the complex
vector space V.
Let 𝒜 = 𝒜(W) be the associated
hyperplane arrangement of W.
Terao [J. Fac. Sci. Univ. Tokyo 27 (1980), 293–320] has shown that
each such reflection
arrangement 𝒜 is free.
There is the stronger notion of an inductively free arrangement.
In 1992, Orlik and Terao [Arrangements of hyperplanes, Springer-Verlag, Berlin 1992, Conjecture 6.91]
conjectured that each reflection arrangement is inductively free.
It has been known for quite some time that
the braid arrangement
as well as the
Coxeter arrangements of type B
ℓ
and type D
ℓ
are inductively free.
Barakat and Cuntz [Adv. Math. 229 (2012), 691–709]
completed this list only recently by showing
that every Coxeter arrangement is inductively free.

Nevertheless, Orlik and Terao's conjecture is false in general.
In a paper which will appear in Tôhoku Math. J., we already gave
two counterexamples to this conjecture among the exceptional
complex reflection groups.

In this paper we
classify all inductively free reflection arrangements.
In addition, we show that the notions of inductive freeness
and that of hereditary inductive freeness
coincide for reflection arrangements.

As a consequence of our classification, we get an
easy, purely combinatorial characterization of
inductively free reflection arrangements 𝒜
in terms of exponents of the restrictions
to any hyperplane of 𝒜.
Critical Behaviour of the Heat Capacity Near the α-β Phase Transition in Quartz
Authors: Yurtseven H. , Desticioğlu M. 
Published: April 2013

AbstractThe α-β transition (TQ = 578°C) is studied in quartz by analyzing the experimental heat capacity Cp data taken from the literature, using a power-law formula. Values of the critical exponent α for Cp are extracted below and above TQ, which describe the α-β transition as a second order transition in quartz. The α values obtained here are compared with the predictions of the theoretical models.
New Phenomenological Model of Hot Mean Flow Stress
Authors: Schindler Ivo , Kawulok Petr , Rusz Stanislav , Plura Jiří , Vašek Zdeňek , Pachlopník Radim 
Published: April 2013

Abstract
Based on the measurement of roll forces during the laboratory hot rolling of flat samples graded in thickness, the new phenomenological type of mean flow stress model was developed and applied on plain-carbon and HSLA steels. The obtained models describe with a very good accuracy the hot deformation resistance characteristics in the temperature range 1123 to 1463 K, large effective strain, and strain rate in the useful range of approximately 10 to 100 s−1. Difficulty in the mathematical description of the influence of temperature on mean flow stress in the wide range of temperature by a single equation was solved by introducing another constant in the temperature member of the conventional model. The newly proposed model solves by phenomenological means a frequent problem of heteroscedasticity of relative deviations between the calculated and experimental values of mean flow stress values depending on temperature. It becomes more reliable from the viewpoint of the operational application, e.g. fast prediction of mean flow stress values and power/force parameters necessary in the steering systems of hot rolling mills.
Hyperandrogenemia in male autistic children and adolescents: relation to disease severity
Authors: El-Baz Farida , Hamza Rasha T. , Ayad Mohamed S.E. , Mahmoud Nermine H. 
Published: April 2013

Abstract
Background: It has been suggested that autistic patients have elevated blood androgens, and although signs of precocious puberty have been reported in autistic patients, such a relation has not yet been clarified.
Objectives: To assess serum androgen levels in a group of Egyptian male autistic children and adolescents and their relation to disease severity. In addition, the risk for association of androgens with autism was estimated.
Methods: In comparison to 20 controls, 30 male autistic children were studied. All subjects were subjected to clinical evaluation, intelligence quotient (IQ) assessment and measurement of serum free testosterone (FT), dehydroepiandosterone (DHEA) and Δ4-androstenedione (Δ4-A).
Results: Androgens were higher in autistic patients than in controls and increased with increased autistic severity. Of the patients, 11 (36.66%) had high FT, 9 (30%) had high DHEA, 12 (40%) had high Δ4-A and 8 (26.66%) showed elevation of all androgen levels. FT (OR: 38.45, 95% CI: 2.14–688.93, p=0.013) and Δ4-A (OR: 13.6, 95%CI: 2.25–22.89, p=0.04) had a significant risk for association with autism.
Conclusions: Hyperandrogenemia is prevalent in autistic patients and increases with autistic severity. Thus, androgen levels should be assessed in autistic patients with signs of early puberty. Further studies are warranted regarding trials of anti-androgen therapy in such patients.
Robust Global Control Strategies for Improvement of Angular Stability using FACTS and HVDC Devices
Authors: Agnihotri P. , Kulkarni A.M. , Gole A.M. 
Published: April 2013

Abstract
System-wide feedback signals made available by Wide-Area Measurement Systems technology can be used in FACTS/HVDC based controllers for the improvement of angular stability. These global signals can facilitate the efficient use of controller effort to stabilize critical swing modes. This paper introduces a restricted global strategy which involves the use of specific global feedback signals which are available at the HVDC/FACTS locations. The strategy is expected to be robust to changes in the power grid as well as communication uncertainties. This paper presents a heuristic introduction to this strategy using a circuit analogy of a simplified model of a power system. Preliminary results on a small system are also presented.
Improving Power Quality in Low-Voltage Networks Containing Distributed Energy Resources
Authors: Mazumder Sumit , Ghosh Arindam , Zare Firuz 
Published: April 2013

Abstract
Severe power quality problems can arise when a large number of single-phase distributed energy resources (DERs) are connected to a low-voltage power distribution system. Due to the random location and size of DERs, it may so happen that a particular phase generates excess power than its load demand. In such an event, the excess power will be fed back to the distribution substation and will eventually find its way to the transmission network, causing undesirable voltage–current unbalance. As a solution to this problem, the article proposes the use of a distribution static compensator (DSTATCOM), which regulates voltage at the point of common coupling (PCC), thereby ensuring balanced current flow from and to the distribution substation. Additionally, this device can also support the distribution network in the absence of the utility connection, making the distribution system work as a microgrid. The proposals are validated through extensive digital computer simulation studies using PSCADTM.
Point of Connection Transmission Pricing in India
Authors: Soonee S.K. , Barpanda S.S. , Joshi Mohit , Mishra Nripen , Bhardwaj Vaishally 
Published: April 2013

Abstract
The National Electricity Policy (NEP) [1], issued by the Government of India, mandates transmission prices to be distance and direction sensitive and capture utilization of the network by each network user. In line with the mandate, the Central Electricity Regulatory Commission (CERC) [2] has issued Sharing of Interstate Transmission Charges and Losses Regulations, 2010 [3], to introduce point of connection (PoC)-based transmission pricing methodology in India. The methodology under the above regulations introduces one of the major reforms of its kind in the Indian power sector and seeks to share the total transmission charges in proportion to respective utilization of the transmission system by different entities. In this paper, the authors have enumerated their experience gained from the implementation of PoC-based transmission pricing regime in India. Authors have also discussed various issues encountered in the process of implementation and the methodology adopted.
Thyroid-stimulating hormone (TSH) level in nutritionally obese children and metabolic co-morbidity
Authors: Aypak Cenk , Türedi Özlem , Yüce Adnan , Görpelioğlu Süleyman 
Published: April 2013

Abstract

Objective: In recent years, there has been increasing focus on thyroid function in pediatric obese patients. Our aims were to investigate whether there is an association between serum thyroid-stimulating hormone (TSH) within the normal range and body mass index (BMI), and to determine if TSH levels correlate with metabolic risk factors in children.

Methods: A retrospective cross-sectional analysis was carried out on 528 euthyroid, age- and sex-matched lean, overweight, or obese children. Anthropometric indices, blood pressure, fasting blood glucose, hepatic enzymes, lipid profiles, TSH, free triiodothyronine (fT3), and free thyroxine (fT4) were assessed from medical records and compared among groups. Subjects with known presence of diabetes, using medications altering blood pressure and glucose or lipid metabolism, with TSH levels >97.5 or <2.5 percentile, or with autoimmune thyroid disease were excluded.

Results: Hypertension, dyslipidemia, and elevated levels of hepatic enzymes were found to be more common in overweight and obese children (p<0.001), and those metabolic changes were significantly correlated with the increase in BMI (p<0.05). Serum concentrations of TSH and fT3 within the normal range were higher in overweight and obese children (p<0.01), and TSH was positively correlated with total cholesterol, triglycerides, and systolic blood pressure (p<0.05).

Conclusion: Our findings suggest that obese children have higher serum TSH and fT3 levels even within the normal range, and that an increase in TSH is associated with dyslipidemia and higher systolic blood pressure. It remains to be seen whether TSH might serve as a potential marker of metabolic risk factors in obese pediatric patients.
Is there a relationship between fetal brain function and the fetal behavioral state? A fetal MEG-study
Authors: Kiefer-Schmidt Isabelle , Raufer Julia , Brändle Johanna , Münßinger Jana , Abele Harald , Wallwiener Diethelm , Eswaran Hari , Preissl Hubert 
Published: April 2013

Abstract

Aim: Fetal magnetography enables the recording of biomagnetic fetal signals, including fetal heart and fetal brain signals. These signals allow the determination of fetal behavioral states and functional brain signals with auditory evoked responses (AER). In the current study, we investigated how the behavioral state influences the AER and how stimulation affects fetal state.

Methods: One hundred and four fetuses in three age groups (28–31 weeks, 32–35 weeks and 36–41 weeks) were recorded with and without auditory stimulation. Both sessions were scored for fetal states. The AER latency was determined for each state separately. Forty-five additional subjects were recorded with two sessions of 10 min without stimulation to investigate a possible time effect on state changes.

Results: The state distribution was significantly different between stimulation and no stimulation conditions. The AER latencies were significantly shorter in active sleep (P=0.013) and active wakefulness (P=0.004) compared to quiet sleep.

Conclusion: Auditory stimulation has an effect on fetal states. The state information should be taken into account for the analysis of AER latencies.
Performance of salivary cortisol in the diagnosis of Cushing's syndrome, adrenal incidentaloma, and adrenal insufficiency
Authors: Ceccato Filippo , Barbot Mattia , Zilio Marialuisa , Ferasin Sergio , Occhi Gianluca , Daniele Andrea , Mazzocut Sara , Iacobone Maurizio , Betterle Corrado , Mantero Franco , Scaroni Carla 
Published: April 2013

ObjectiveSalivary cortisol has recently been suggested for studies on the hypothalamic–pituitary–adrenal (HPA) axis. The lack of circadian rhythm is a marker of Cushing's syndrome (CS), and some authors have reported that low salivary cortisol levels may be a marker of adrenal insufficiency. The aim of our study was to define the role of salivary cortisol in specific diagnostic settings of HPA axis disease.Subjects and methodsWe analyzed morning salivary cortisol (MSC) and late-night salivary cortisol (LNSC) levels in 406 subjects: 52 patients with Cushing's disease (CD), 13 with ectopic CS, 17 with adrenal CS, 27 with CD in remission (a mean follow-up of 66±39 months), 45 with adrenal incidentaloma, 73 assessed as having CS and then ruled out for endogenous hypercortisolism, 75 with adrenal insufficiency, and 104 healthy subjects.ResultsA LNSC value above 5.24 ng/ml differentiated CS patients from controls with high sensitivity (96.3%) and specificity (97.1%); we found higher LNSC levels in ectopic CS patients than in CD patients. We found no difference in MSC and LNSC levels between patients with CD in remission and healthy subjects. Both MSC and LNSC levels were higher in patients with adrenal incidentaloma than in healthy controls. A MSC value below 2.65 ng/ml distinguished patients with adrenal insufficiency from controls with high sensitivity (97.1%) and specificity (93.3%).ConclusionsSalivary cortisol is a useful tool to assess endogenous cortisol excess or adrenal insufficiency and to evaluate stable CD in remission.
Is Structural Equation Modeling Advantageous for the Genetic Improvement of Multiple Traits?
Authors: Valente Bruno D , Rosa Guilherme J M , Gianola Daniel , Wu Xiao-Lin , Weigel Kent 
Published: April 2013

AbstractStructural equation models (SEMs) are multivariate specifications capable of conveying causal relationships among traits. Although these models offer insights into how phenotypic traits relate to each other, it is unclear whether and how they can improve multiple-trait selection. Here, we explored concepts involved in SEMs, seeking for benefits that could be brought to breeding programs, relative to the standard multitrait model (MTM) commonly used. Genetic effects pertaining to SEMs and MTMs have distinct meanings. In SEMs, they represent genetic effects acting directly on each trait, without mediation by other traits in the model; in MTMs they express overall genetic effects on each trait, equivalent to lumping together direct and indirect genetic effects discriminated by SEMs. However, in breeding programs the goal is selecting candidates that produce offspring with best phenotypes, regardless of how traits are causally associated, so overall additive genetic effects are the matter. Thus, no information is lost in standard settings by using MTM-based predictions, even if traits are indeed causally associated. Nonetheless, causal information allows predicting effects of external interventions. One may be interested in predictions for scenarios where interventions are performed, e.g., artificially defining the value of a trait, blocking causal associations, or modifying their magnitudes. We demonstrate that with information provided by SEMs, predictions for these scenarios are possible from data recorded under no interventions. Contrariwise, MTMs do not provide information for such predictions. As livestock and crop production involves interventions such as management practices, SEMs may be advantageous in many settings.
Systematic Review of Positive Youth Development Programs for Adolescents With Chronic Illness
Authors: Maslow Gary R. , Chung Richard J. 
Published: April 2013

BACKGROUND AND OBJECTIVE:The Positive Youth Development (PYD) framework has been successfully used to support at-risk youth. However, its effectiveness in fostering positive outcomes for adolescents with chronic illness has not been established. We performed a systematic review of PYD-consistent programs for adolescents with chronic illness.METHODS:Data sources included PubMed, CINAHL, and PsychINFO. Guided by an analytic framework, we searched for studies of PYD-consistent programs serving adolescents and young adults aged 13 through 24 with chronic illness. References were screened iteratively with increasing depth until a focused cohort was obtained and reviewed in full. The authors separately reviewed the studies using structured analysis forms. Relevant study details were abstracted during the review process.RESULTS:Fifteen studies describing 14 programs were included in the analysis. Three comprehensive programs included all 3 core components of a PYD program, including opportunities for youth leadership, skill building, and sustained connections between youth and adults. Four programs were primarily mentoring programs, and 7 others focused on youth leadership. Programs served youth with a variety of chronic illnesses. The quality and type of evaluation varied considerably, with most reporting psychosocial outcomes but only a few including medical outcomes.CONCLUSIONS:The PYD-consistent programs identified in this review can serve as models for the development of youth development programs for adolescents with chronic illness. Additional study is needed to evaluate such programs rigorously with respect to both psychosocial and health-related outcomes. PYD-consistent programs have the potential to reach youth with chronic illness and promote positive adult outcomes broadly.
Survival of Patients With Spinal Muscular Atrophy Type 1
Authors: Gregoretti Cesare , Ottonello Giancarlo , Chiarini Testa Maria Beatrice , Mastella Chiara , Ravà Lucilla , Bignamini Elisabetta , Veljkovic Aleksandar , Cutrera Renato 
Published: April 2013

BACKGROUND:
Spinal muscular atrophy type 1 (SMA1) is a progressive disease and is usually fatal in the first year of life.

METHODS:
A retrospective chart review was performed of SMA1 patients and their outcomes according to the following choices: letting nature take its course (NT); tracheostomy and invasive mechanical ventilation (TV); continuous noninvasive respiratory muscle aid (NRA), including noninvasive ventilation; and mechanically assisted cough.

RESULTS:
Of 194 consecutively referred patients enrolled in this study (103 males, 91 females), NT, TV, and NRA were chosen for 121 (62.3%), 42 (21.7%), and 31 (16%) patients, respectively. Survival at ages 24 and 48 months was higher in TV than NRA users: 95% (95% confidence interval: 81.8%–98.8%) and 67.7% (95% confidence interval: 46.7%–82%) at age 24 months (P &lt; .001) and 89.43% and 45% at age 48 months in the TV and NRA groups, respectively (P &lt; .001). The choice of TV decreased from 50% (1992–1998) to 12.7% (2005–2010) (P &lt; .005) with a nonstatistically significant increase for NT from 50% to 65%. The choice of NRA increased from 8.1% (1999–2004) to 22.7% (2005–2010) (P &lt; .001).

CONCLUSIONS:
Long-term survival outcome is determined by the choice of the treatment. NRA and TV can prolong survival, with NRA showing a lower survival probability at ages 24 and 48 months.
Heated, Humidified High-Flow Nasal Cannula Versus Nasal CPAP for Respiratory Support in Neonates
Authors: Yoder Bradley A. , Stoddard Ronald A. , Li Ma , King Jerald , Dirnberger Daniel R. , Abbasi Soraya 
Published: April 2013

BACKGROUND AND OBJECTIVE:Heated, humidified high-flow nasal cannula (HHHFNC) is commonly used as a noninvasive mode of respiratory support in the NICU. The safety and efficacy of HHHFNC have not been compared with other modes of noninvasive support in large randomized trials. The objective was to assess the efficacy and safety of HHHFNC compared with nasal continuous positive airway pressure (nCPAP) for noninvasive respiratory support in the NICU.METHODS:Randomized, controlled, unblinded noncrossover trial in 432 infants ranging from 28 to 42 weeks’ gestational age with planned nCPAP support, as either primary therapy or postextubation. The primary outcome was defined as a need for intubation within 72 hours of applied noninvasive therapy.RESULTS:There was no difference in early failure for HHHFNC (23/212 [10.8%]) versus nCPAP (18/220 [8.2%]; P = .344), subsequent need for any intubation (32/212 [15.1%] vs 25/220 [11.4%]; P = .252), or in any of several adverse outcomes analyzed, including air leak. HHHFNC infants remained on the study mode significantly longer than nCPAP infants (median: 4 vs 2 days, respectively; P &lt; .01), but there were no differences between study groups for days on supplemental oxygen (median: 10 vs 8 days), bronchopulmonary dysplasia (20% vs 16%), or discharge from the hospital on oxygen (19% vs 18%).CONCLUSIONS:Among infants ≥28 weeks’ gestational age, HHHFNC appears to have similar efficacy and safety to nCPAP when applied immediately postextubation or early as initial noninvasive support for respiratory dysfunction.