bluuebunny/crossref_metadata_2025 huggingface dataset:
Headaches in Women Undergoing in Vitro Fertilization and Embryo‐Transfer Treatment
Authors: Amir Ben‐Yehuda , Yaacov Bentov , Guy Bar , Gad Potashnik , Itzhak Wirguin , Gal Ifergane
Published: March 2005

Background.—In vitro fertilization and embryo transfer has become a common therapeutic modality in modern fertility medicines. Treatment protocols are associated with exaggerated hormonal fluctuations in order to promote multiple follicular development and support of embryo survival. Estrogen is considered to be closely linked to migraine, and its extreme serum level fluctuations have been considered to trigger migrainous headaches.

Objective.—To assess the prevalence, nature, and timing of headache attacks during the course of in vitro fertilization and embryo‐transfer treatments.

Methods.—We retrospectively evaluated the prevalence and the characteristics of headache among 98 women undergoing in vitro fertilization and embryo transfer therapy using a structured telephone interview.

Results.—Out of the 98 evaluated patients 25 were migraine sufferers. Headache attacks during the in vitro fertilization and embryo transfer protocol were reported by 28.6% (n = 28) of the women and were significantly more prevalent among the migraineurs. The attacks were of debilitating severity in 82% (n = 23) of patients who reported headaches during treatment. Headache occurred most frequently following gonadotropin‐releasing hormone (GnRH) analog induced hypothalamic‐pituitary‐ovarian axis downregulation, typically associated with very low 17‐β‐estradiol (17‐β‐E2) serum level.

Conclusions.—In vitro fertilization and embryo‐transfer treatment might be associated with various degrees of headache. This is mostly observed in patients with migraine headache background and specifically during the downregulation stage of treatment, when very low levels of 17‐β‐E2 are observed.
Decreasing Incidence of Cluster Headache: A Population‐Based Study in Olmsted County, Minnesota
Authors: Black David F. , Swanson Jerry W. , Stang Paul E.
Published: March 2005

The incidence of medically recognized cluster headache within Olmsted County, Minnesota, from 1989 through 1990, was determined by using modified International Headache Society criteria. The results were compared with previously published incidence data from 1979 through 1981. The overall age‐ and sex‐adjusted incidence decreased from 9.8/100,000 person‐years in 1979–1981 to 2.07/100,000 person‐years in 1989–1990.
Headache and Combination Estrogen‐Progestin Oral Contraceptives: Integrating Evidence, Guidelines, and Clinical Practice
Authors: Loder Elizabeth W. , Buse Dawn C. , Golub Joan R.
Published: March 2005

Primary headache disorders such as migraine affect almost a third of women during their childbearing years, when decisions about contraception must be made. Headache is also a commonly reported adverse event in clinical trials of oral contraceptives (OCs). Health care practitioners will frequently be called upon to give advice about the use of OCs to women with headache. This article applies current evidence, guidelines, and recommendations about headache and OC use to treatment decisions in four clinical scenarios: initiating OC use in a woman who has migraine without aura, continuing OC use in a woman who experiences worsening of migraine and the development of aura after initiating OCs, initiating OC use in a woman with tension‐type headache (TTH) and a family history of migraine, and use of an extended duration OC regimen to minimize migraine triggered by estrogen withdrawal. The authors' recommendations regarding OC use in various primary headache disorders are summarized.
Subarachnoid Pneumocephalus From Epidural Steroid Injection
Authors: Hawley Jason S. , Ney John P. , Swanberg Margaret M.
Published: March 2005

We present a case of severe posterior headache and diplopia following an epidural steroid injection for lumbar pain.
Group I mGluR-induced Epileptogenesis: Distinct and Overlapping Roles of mGluR1 and mGluR5 and Implications for Antiepileptic Drug Design
Authors: Wong Robert K.S. , Bianchi Riccardo , Chuang Shih-Chieh , Merlin Lisa R.
Published: March 2005

The group I metabotropic glutamate receptor subtypes, mGluR1 and mGluR5, have both distinct and overlapping actions in epileptogenesis. Data are reviewed revealing how activation of these receptor subtypes participates in the induction and maintenance of the long-lasting epileptiform discharges elicited in the hippocampal circuit. Differences in the cellular actions and regional distributions of mGluR1 and mGluR5 provide hints regarding the potential usefulness and limitations of subtype-specific antagonists as antiepileptic agents.
Additive effects between platelet concentrates and desmopressin in antagonizing the platelet glycoprotein IIb/IIIa inhibitor eptifibatide
Authors: Reiter Rosemarie , Jilma‐Stohlawetz Petra , Horvath Michaela , Jilma Bernd
Published: March 2005

BACKGROUND: Platelet (PLT) glycoprotein (GP) IIb/IIIa receptor antagonists have demonstrated efficacy in decreasing ischemic complications of percutaneous coronary intervention and/or unstable angina. In case of bleeding, the drug can be stopped and PLT transfusions can be given.

STUDY DESIGN AND METHODS: This crossover study tested the additive effects of PLT concentrates (PCs) after desmopressin (DDAVP) infusion in antagonizing the anti‐PLT effects of GPIIb/IIIa inhibitors and aspirin. After eptifibatide and aspirin infusion (at standard dosages), 10 healthy volunteers received DDAVP or placebo. Thereafter, increasing amounts of PLTs from fresh single‐donor apheresis concentrates were added in vitro to blood samples of all volunteers to increase PLT counts by 30 × 109, 60 × 109, or 120 × 109 per L.

RESULTS: Adding platelets in vitro further improved PLT function after DDAVP: it shortened collagen‐adenosine diphosphate closure times (p < 0.01), to normal ranges as measured by the PLT function analyzer (PFA‐100). In contrast, normal PLT function could not be restored even when PLT counts were increased by 50 percent (120 × 109/L) in the placebo group.

CONCLUSION: Combined use of PLTs from fresh apheresis PC and DDAVP additively enhances recovery of normal PLT function after eptifibatide infusion. Such a strategy may help to avoid excessive transfusion of PC.
Monocyte enrichment of mononuclear apheresis preparations with a multistep back‐flush procedure on a cord blood filter
Authors: Wagner Stephen J. , Myrup Andrew , Xu Yanwen , Walker M. Susan , Welbon Craig , Celluzzi Christina M.
Published: March 2005

INTRODUCTION: Monocytes or mononuclear cells have been investigated for the treatment of chronic wounds and spinal cord injuries, as well as serve as a source for dendritic or endothelial cell culture. Because these cells may have clinical benefit yet no rapid and inexpensive closed system for monocyte purification is commercially available, a method was investigated to enrich monocytes from mononuclear apheresis units using a cord blood filter.

METHODS: A 4‐step method for monocyte enrichment was developed which involved 1) filtering a mononuclear apheresis unit through a cord blood filter, 2) chasing with medium to remove non‐adherent residual cells and plasma, 3) back‐flushing under low shear conditions to remove loosely adherent lymphocytes, and 4) back‐flushing under high shear conditions to collect a fraction enriched in monocytes. Apheresis units and enriched monocyte preparations were characterized by cell count and differential, filter‐isolated preparations were cryopreserved, and thawed preparations were assayed for viability, and phagocytosis. Enriched monocyte preparations were also assayed for inflammatory cytokines secretion and secretion of prostaglandin E2 during short‐term culture.

RESULTS: Monocytes were viable, capable of phagocytosis, and enriched using the multistep filter elution technique to represent 42 ± 13‐percent of white cells in the final preparation. Fifty‐three‐percent of monocytes were recovered in the final preparation, while total cell counts of red cells, platelets, neutrophils and lymphocytes were reduced to 3.0, 3.0, 4.5 and 16‐percent, respectively, from levels present in mononuclear apheresis units. Filter enriched monocyte preparations secreted IL‐8, IL‐6, MCP‐1, and MIP‐1α, during short term culture.

CONCLUSION: The use of a multi‐step back flush procedure with a cord blood filter resulted in rapid enrichment of viable and functional monocytes from mononuclear apheresis units with significant reduction of contaminating platelets and red cells.
Mononuclear cell variability and recruitment in non‐cytokine‐stimulated donors after serial 10‐liter leukapheresis procedures
Authors: Strasser Erwin F. , Zimmermann Robert , Weisbach Volker , Ringwald Jürgen , Zingsem Jürgen , Eckstein Reinhold
Published: March 2005

BACKGROUND: We introduced monitoring of mononuclear cell (MNC) counts to obtain enhanced donor control and a stable quality of MNC products, because there are limited data available about blood donors after serial leukapheresis (LP) procedures.

STUDY DESIGN AND METHODS: In a prospective paired study, 13 male healthy blood donors underwent 10‐L LP procedures performed on two apheresis devices by use of two MNC program settings (COBE Spectra, Gambro BCT, SF 250 vs. SF 500; and AS.TEC 204, Fresenius Hemocare, CP 129 vs. CP 194). Donors’ pre‐ and postdonation MNC counts were analyzed by fluorescence‐activated cell sorting.

RESULTS: After each 10‐L LP procedure, a transient decline (p < 0.05) of CD14+ monocyte and platelet counts appeared in donors. Loss of donors’ CD3+ T cells, CD19+ B cells, and CD16+56+ natural killer (NK) cells during MNC collection was partly compensated by cell recruitment. The MNC recruitment factor (RF) seems to be higher with high‐yield MNC program settings. Negative correlations (p < 0.01) were noticed between predonation counts and RFs of CD3+ T cells and CD16+56+ NK cells. Four serial 10‐L LP procedures did not result in long lasting MNC depletion for donors.

CONCLUSION: MNC recruitment seems to depend on MNC program settings and collected cell yields. Low MNC counts could result in high cell recruitment that may contribute to stable collection results to some degree. Nevertheless, there seems to be a considerable individual variation of MNC recruitment in donors that should be investigated in more detail.
NondeletionalABO*Oalleles express weak blood group A phenotypes
Authors: Seltsam Axel , Das Gupta Christa , Wagner Franz F. , Blasczyk Rainer
Published: March 2005

BACKGROUND:Owing to a single‐base deletion, the vast majority ofABO*Oalleles encode for a truncated and catalytically inactive ABO glycosyltransferase, leading to the generation of a premature stop codon. Less frequent nondeletionalABO*Oalleles such asABO*O03, in contrast, have nonsynonymous mutations that may abolish the protein's enzyme activity by altering its sugar‐binding site.

STUDY DESIGN AND METHODS:Extensive ABO phenotyping and genotyping were performed in healthy blood group O donors with weak anti‐A isoagglutinins and their relatives as well as in blood group O donors selected for the presence ofABO*O03. HeLa cells were used to transfect ABO expression plasmids.

RESULTS:Donors or relatives carryingABO*O03and/or its rare variantABO*Aw08in homozygous (n = 2) or heterozygous (n = 14) form showed weak A antigen expression detectable only by adsorption‐elution (n = 15) or by monoclonal anti‐A typing (n = 1). The serum samples of most donors (n = 13) contained weak anti‐A; in the remaining donors, anti‐A isoagglutinin reactivity was in the normal range. In the transfection studies, weak A antigen expression on HeLa cells transfected with plasmids containingABO*O03orABO*Aw08expression constructs was detectable only by adsorption‐elution.

CONCLUSION:The data provide evidence that nondeletionalABO*O03‐like alleles produce detectable amounts of A antigens.
Molecular characterization of D– Korean persons: development of a diagnostic strategy
Authors: Kim Ji Yeon , Kim Sung Yeun , Kim Chong‐Ahm , Yon Gyu Sung , Park Sung Sup
Published: March 2005

BACKGROUND: D– frequencies show wide racial differences: in particular, in Korean persons it is approximately 1/100th of that in Caucasians (0.15% vs. 15%). The molecular mechanisms of D– may be unique to races, and thus specific molecular diagnostic approaches are necessary for individual races. Such marked racial differences have been attributed to the founder effect. It was hypothesized that D– frequencies may be affected by genomic variations of Rhesus boxes, which are instruments of unequal crossing‐over.

STUDY DESIGN AND METHODS: First, the molecular basis of D– in Korean donors was characterized. A total of 264 D– persons were analyzed by performing RHD exon polymerase chain reaction (PCR), Rhesus box hybrid PCR‐PstI, RHD sequencing, and a novel RHD‐CE‐D hybrid PCR. Second, with sequencing analysis, Rhesus boxes in Korean and Caucasian persons were compared.

RESULTS: Of 264 D– Korean individuals, 74 percent completely lacked RHD, 9 percent had RHD‐CE‐D hybrid, and 17 percent had point mutations. Three genetic causes, RHD deletion, RHD‐CE(2‐9)‐D2, and 1227G>A, explained 99.4 percent of D– alleles in Korean persons. Three novel mutations were also found. The identity region of 10 Rhesus boxes in Korean persons was in complete concordance with that in Caucasian persons.

CONCLUSION: In this study, a molecular diagnostic strategy was established and the genetic causes of almost all D– Korean persons was able to be diagnosed with a simple decision tree. The study provides a good example of the molecular diagnosis of D– persons, especially in low‐frequency areas. Our hypothesis that D– frequencies are affected by genomic variations in Rhesus boxes was excluded. Rather, racial differences may be influenced by the founder effect.
Influence of prey quality on the fitness of two phenotypes of Harmonia axyridis adults
Authors: Onofre Soares António , Coderre Daniel , Schanderl Henrique
Published: March 2005

The performance of Harmonia axyridis Pallas (Coleoptera: Coccinellidae) adults of the aulica and nigra phenotypes fed on Aphis fabae Scopoli and Myzus persicae (Sulzer) was compared by measuring their voracity, daily biomass consumption, daily weight gain, efficiency of food utilisation, and reproductive capacity. Our results demonstrated differences in the suitability of A. fabae and M. persicae for the two phenotypes of the predator. This suggests that either differences occur in the nutritive requirements of the predators, or in the nutritive value of the two prey species. Both A. fabae and M. persicae supported the growth and oviposition of the aulica and nigra phenotypes. Although nigra females consumed fewer M. persicae, they achieved the same daily weight gain as aulica females. The predator phenotypes consumed the same amount of A. fabae, but the daily weight gain of aulica females was higher than that of nigra. The two predator phenotypes had the same feeding efficiency when consuming M. persicae or A. fabae. The reproductive capacity of nigra females was higher, when this phenotype consumed A. fabae rather than M. persicae.
Tongue disease in advanced AIDS
Authors: de Faria PR , Vargas PA , Saldiva PHN , Böhm GM , Mauad T , de Almeida OP
Published: March 2005

Objective:  This study describes the involvement and the histological alterations found in the tongues of 92 autopsied patients who died with AIDS.

Materials and methods:  Sex, age, CD4 cell count and clinical history were obtained from the files of 92 patients who died with AIDS. All the tongues were examined for macroscopical alterations and stained using H&E, Gomori‐Grocott, Ziehl‐Neelsen, PAS, Brow‐Hopps and Mucicarmine. Histological autopsy findings were grouped based on a protocol that was designed following the World Health Organization recommendations.

Results:  The mean age of the patients who died of AIDS and CD4 cell count were 36 years and 82 cells μL−1, respectively. Histological alterations of the tongues were found in 75% of the cadavers. The most common lesions were hairy leukoplakia (HL) (42 cases), candidosis (31 cases) and non‐specific chronic glossitis (29 cases), followed by concomitant lesions (28 cases), non‐specific chronic ulceration (17 cases), melanotic pigmentation (13 cases), herpes simplex (10 cases), lymphoepithelial cysts (two cases), cryptococcosis (two cases), mycobacteriosis (one case), histoplasmosis (one case), cytomegalovirus infection (one case) and non‐Hodgkin Lymphoma (one case). HL with oral candidosis (n = 13) were the most common concomitant lesions.

Conclusion:  These findings indicate that the tongue is a favorite site to occurrence of reactive, infectious and concurrent lesions in the end‐stage of AIDS patients.
Estimating the prevalence of urinary and faecal incontinence in Australia: systematic review
Authors: Chiarelli Pauline , Bower Wendy , Wilson Amanda , Attia John , Sibbritt David
Published: March 2005

Objectives:  To quantify the prevalence of urinary and faecal incontinence in the Australian population by deriving age and gender‐specific rates of urinary and faecal incontinence from the literature.

Methods:  Systematic review and meta‐analysis. A search of MEDLINE and EMBASE from 1995 to 2001 was performed in duplicate. The following a priori inclusion criteria were applied to studies: community based sampling frame, response rate > 65%, > 125 participants per gender group, and age and gender separation of results (stratification).

Results:  There were significant differences in the definitions used, the time frames of interest, and the populations surveyed. There was significant heterogeneity across studies. Overall prevalence of urinary incontinence for Australian adults was estimated to be 19.3% and 2.2% in Australian women and men, respectively. Overall prevalence of faecal incontinence was estimated to be 5.3% and 5.5% in Australian women and men, respectively.

Conclusions:  It is disappointing that with so many studies published in this area, there is still a lack of high quality, basic descriptive epidemiology of this important health problem. These estimates of the prevalences of urinary and faecal incontinence should assist policy making in this area.
Development of a self‐sustaining speech pathology service for residents in rural aged care facilities
Authors: Payne Rachel , Stevens John
Published: March 2005

Objective:  The literature suggests that approximately 90% of residents in aged care facilities have communication difficulties and between 40 and 60% of residents experience dysphasia. The ability of residents to attend outpatient clinics or private consultation, especially in a rural setting, is severely restricted. In an attempt to address this service gap a speech pathology service for residents in rural aged care facilities was developed and trialed over a 12‐month period.

Method:  Thirty aged care facilities in the Northern Rivers Area of New South Wales (NSW) agreed to participate in the trial.

Results and Conclusion:  An analysis of the first 9 months of data collected showed 331 resident consultations, 94 general practitioner (GP) consultations, and 111 education sessions showed that the quality of life of residents was greatly improved. As well, the skills, knowledge and the overall provision of service provided by GPs, nursing and allied health staff to residents of aged care facilities was greatly enhanced. The speech pathology service also proved to be financially self‐sustainable and was able to generate income for: (i) GPs through improved access to Enhanced Primary Care (EPC) funding; and (ii) aged care facilities through significant movements within the Resident Classification Scale.
CFTR fails to inhibit the epithelial sodium channel ENaC expressed in Xenopus laevis oocytes
Authors: Nagel G. , Barbry P. , Chabot H. , Brochiero E. , Hartung K. , Grygorczyk R.
Published: March 2005

The cystic fibrosis transmembrane conductance regulator (CFTR) plays a crucial role in regulating fluid secretion by the airways, intestines, sweat glands and other epithelial tissues. It is well established that the CFTR is a cAMP‐activated, nucleotide‐dependent anion channel, but additional functions are often attributed to it, including regulation of the epithelial sodium channel (ENaC). The absence of CFTR‐dependent ENaC inhibition and the resulting sodium hyperabsorption were postulated to be a major electrolyte transport abnormality in cystic fibrosis (CF)‐affected epithelia. Several ex vivo studies, including those that used the Xenopus oocyte expression system, have reported ENaC inhibition by activated CFTR, but contradictory results have also been obtained. Because CFTR–ENaC interactions have important implications in the pathogenesis of CF, the present investigation was undertaken by our three independent laboratories to resolve whether CFTR regulates ENaC in oocytes and to clarify potential sources of previously reported dissimilar observations. Using different experimental protocols and a wide range of channel expression levels, we found no evidence that activated CFTR regulates ENaC when oocyte membrane potential was carefully clamped. We determined that an apparent CFTR‐dependent ENaC inhibition could be observed when resistance in series with the oocyte membrane was not low enough or the feedback voltage gain was not high enough. We suggest that the inhibitory effect of CFTR on ENaC reported in some earlier oocyte studies could be attributed to problems arising from high levels of channel expression and suboptimal recording conditions, that is, large series resistance and/or insufficient feedback voltage gain.
Modulation of skeletal and cardiac voltage‐gated sodium channels by calmodulin
Authors: Young Katharine A. , Caldwell John H.
Published: March 2005

Calmodulin (CaM) has been shown to modulate different ion channels, including voltage‐gated sodium channels (NaChs). Using the yeast two‐hybrid assay, we found an interaction between CaM and the C‐terminal domains of adult skeletal (NaV1.4) and cardiac (NaV1.5) muscle NaChs. Effects of CaM were studied using sodium channels transiently expressed in CHO cells. Wild type CaM (CaMWT) caused a hyperpolarizing shift in the voltage dependence of activation and inactivation for NaV1.4 and activation for NaV1.5. Intracellular application of CaM caused hyperpolarizing shifts equivalent to those seen with CaMWT coexpression with NaV1.4. Elevated Ca2+ and CaM‐binding peptides caused depolarizing shifts in the inactivation curves seen with CaMWT coexpression with NaV1.4. KN93, a CaM‐kinase II inhibitor, had no effect on NaV1.4, suggesting that CaM acts directly on NaV1.4 and not through activation of CaM‐kinase II. Coexpression of hemi‐mutant CaMs showed that an intact N‐terminal lobe of CaM is required for effects of CaM upon NaV1.4. Mutations in the sodium channel IQ domain disrupted the effects of CaM on NaV1.4: the I1727E mutation completely blocked all calmodulin effects, while the L1736R mutation disrupted the effects of Ca2+–calmodulin on inactivation. Chimeric channels of NaV1.4 and NaV1.5 also indicated that the C‐terminal domain is largely responsible for CaM effects on inactivation. CaM had little effect on NaV1.4 expressed in HEK cells, possibly due to large differences in the endogenous expression of β‐subunits between CHO and HEK cells. These results in heterologous cells suggest that Ca2+ released during muscle contraction rapidly modulates NaCh availability via CaM.
An introductory physics and biophysics course for life science students
Authors: Buckman William G. , Parks James E. , Coohill Thomas P.
Published: March 2005

An introductory physics course entitled ’’Introduction to Physics and Biophysics’’ has been developed and implemented for life science students at Western Kentucky University. This paper describes the objectives of the course, presents a topical syllabus, and points out particular topics given special consideration. Pertinent student characteristics and comments concerning the course are also presented. As a result of the successful implementation of this course, a biophysics minor has been initiated and twelve students will graduate this year with a minor in biophysics. A laboratory is also being developed to accompany this lecture course.
On the isotropic oscillator and the hydrogenic atom in classical and quantum mechanics
Authors: Rockmore Ronald
Published: March 2005

It is shown how one may simply associate the problem of the isotropic oscillator to that of the hydrogenic atom in classical dynamics, particularly in its action−angle variable formulation, so that the solution of the one problem implies that of the other. This relationship persists in the two−dimensional quantum mechanics and provides the key to the construction of a wave pocket solution for the isotropic oscillator in the region of large principal quantum number in three dimensions.
An elementary introduction to practical holography
Authors: Porter Alan G. , George S.
Published: March 2005

Holography is not only a new branch of modern optics; it is also a new art form. The beginning holographer, whether he is an artist, an engineer, or a scientist, usually has difficulty in finding an easily understandable article describing the ’’how to do it’’ aspects of making a hologram. This article is intended to alleviate some of the difficulties by presenting both an understandable geometric model of the hologram and a step-by-step guide to the procedures involved in making a hologram.

Editor’s note: Reviewers of this article have found it technically correct but question whether a presentation that treats a subject ’’from the beginning’’ is suitable in level for the American Journal of Physics. We feel that an occasional clearly written ’’how to do it’’ article that enables the nonspecialist to set up the simplest demonstrations in a field are entirely suitable for the Journal, provided an overall balance in level and subject is maintained in the Journal as a whole.
Aerodynamics of a knuckleball
Authors: Watts Robert G. , Sawyer Eric
Published: March 2005

The nature of the forces causing the erratic motion of a knuckleball has been investigated by measuring the lateral force on a baseball in a wind tunnel. We have identified two possible sources of a lateral force imbalance that can give rise to the observed erratic changes in the direction of a knuckleball as it moves through the air. One of these results because the nonsymmetrical location of the roughness elements (strings) gives rise to a nonsymmetrical lift (lateral) force. A very slowly spinning knuckleball will have imposed upon it a lateral force that changes as the positions of the strings change. A knuckleball whose spin is identically zero has a constant lateral force unless a portion of the strings is precisely at a location where boundary layer separation occurs. If this happens, the point of boundary layer separation switches alternatively from the front to the rear of the strings, shifting the wake from one position to another, and thereby giving rise to a second possible alternating force imbalance. A two-dimensional analysis of the trajectory of the baseball indicates that the measured force can cause a deflection of the baseball’s trajectory of more than a foot. An effective knuckleball should be thrown so that it rotates substantially less than once on its path to home plate.
Solution of a simple inelastic scattering problem
Authors: Knudson Stephen K.
Published: March 2005

Simple examples of elastic scattering, typically from square wells, serve as important pedagogical tools in discussion of the concepts and processes involved in elastic scattering events. An analytic solution of a model inelastic scattering system is presented here to serve in this role for inelastic events. The model and its solution are simple enough to be of pedagogical utility, but also retain enough of the important physical features to include most of the special characteristics of inelastic systems. The specific model chosen is the collision of an atom with a harmonic oscillator, interacting via a repulsive square well potential. Pedagogically important features of inelastic scattering, including its multistate character, convergence behavior, and dependence on an ’’inelastic potential’’ are emphasized as the solution is determined. Results are presented for various energies and strengths of inelastic scattering, which show that the model is capable of providing an elementary representation of vibrationally inelastic scattering.
Efficiency of a Carnot engine at maximum power output
Authors: Curzon F. L. , Ahlborn B.
Published: March 2005

The efficiency of a Carnot engine is treated for the case where the power output is limited by the rates of heat transfer to and from the working substance. It is shown that the efficiency, η, at maximum power output is given by the expression η = 1 − (T2/T1)1/2 where T1 and T2 are the respective temperatures of the heat source and heat sink. It is also shown that the efficiency of existing engines is well described by the above result.
The quantum bouncer
Authors: Gibbs R. L.
Published: March 2005

Examples in one and two dimensions for motion in a uniform gravitational field are considered quantum mechanically. The examples of bouncing in one dimension and sliding down an incline are proposed for use as conceptual aids in an introductory course.
New analysis of the capacitance filter
Authors: Anderson J. Gerard
Published: March 2005

A new method for calculating the dc output voltage for a capacitance−input ripple filter is presented. Its predictions are much more accurate than those of the usual simple formula given in introductory textbooks. It proves possible to attain this increased accuracy with only elementary calculus and minimal arithmetic largely due to an interesting averaging property of a portion of a sine wave.
Raja Sawai Jai Singh II: An 18th century medieval astronomer
Authors: Blanpied William A.
Published: March 2005

The early 18th-century observatories constructed in five North Indian cities by the Raja Jai Singh represent the last historical attempt to carry out a major program in observational astronomy using naked eye methods alone. The major instruments are described and the precision of each is estimated. An attempt is then made to discern the motives which led Jai Singh to construct these observatories more than a century after Galileo first used the telescope for astronomical purposes. It is concluded that Jai Singh’s astronomical program can only be understood in terms of the place which science occupied in the social and political matrix of late Moghul India.
Remark on the equilibrium of moving systems
Authors: Buchdahl H. A. , Simpson M. A.
Published: March 2005

The most general motion of an isolated thermodynamic system K in equilibrium is determined by Landau and Lifshitz through an appeal to the equilibrium condition δS=0. It is argued that this work actually amounts to a demonstration of the internal consistency of the thermodynamic formalism in this case since the problem is soluble by an appeal to prior criteria. We use these to determine all motions consistent with equilibrium in the more general case of a system K which is not isolated. Although the temperature would of necessity be uniform if K were at rest, this is no longer obviously the case when it is moving. To emphasize this point, we first determine the possible relativistic motions of K, restricted to be translations in a fixed direction, and then determine explicitly the distribution of absolute temperature within it. It turns out to be nonuniform only when K is accelerated, and then it varies in a manner consistent with the principle of equivalence.
Physics and history as a bridge across the ’’two cultures’’ gap
Authors: Lerner Lawrence S. , Gosselin Edward A.
Published: March 2005

We describe a novel interdisciplinary course in which history and physics are presented as examples of humanistic and scientific disciplines. The course is offered to college seniors majoring in a wide variety of fields and has three main purposes. First, it presents a historical picture of the development of the physical sciences in the larger context of Western intellectual history. Second, by developing physical ideas in a fairly rigorous fashion, it presents this vital branch of intellectual history without falling into the trap of teaching the non−science students the history of something they do not understand. Third, it presents a historical−philosophical perspective of the development of the ’’scientific method.’’ We have devised a means of presentation which is simultaneously of value to science majors and non−science majors alike, and which encourages them to take a new and much less extreme view of the ’’two−cultures’’ gap. We describe experiments now in progress aimed at extending the technique to the high−school level, in order to eradicate the ’’two−cultures’’ gap at the crucial point in its formation.
The equivalence principle and the question of weight
Authors: Nordtvedt Kenneth
Published: March 2005

Using Einstein’s equivalence principle it is shown that both a body’s inertial weight and gravitational weight are dependent on where the accelerating or supporting force is located on the body.
Conservation of momentum in electrodynamics—an example
Authors: Scanio Joseph J. G.
Published: March 2005

We show how the law of conservation of momentum is satisfied for a charged particle moving at constant speed relative to a stationary charged particle.
Invariant relative velocity
Authors: Aurilia A. , Rohrlich F.
Published: March 2005

Different approaches are presented in a didactic way in order to lead to an understanding of the concept and equations describing relative velocity in an invariant way from the point of view of the special theory of relativity.
Mean, mean-square, and most-probable momentum for a relativistic Maxwellian ensemble
Authors: Wienke B. R.
Published: March 2005

Statistical moments of the relativistic Maxwell−Boltzmann momentum distribution are obtained from integral representations of modified Bessel functions. Approximate low temperature (m/kT≫1) behaviors for the mean and mean−square momenta are indicated via asymptotic expansions of corresponding Bessel functions and the results are briefly contrasted with the usual classical predictions. The most probable momentum is also discussed.
Student x-ray fluorescence experiments
Authors: Fetzer Homer D. , Parker Donald L. , Stuart Kenneth C.
Published: March 2005

A number of qualitative and quantitative fluorescence x−ray experiments were performed by junior and senior level physics students using a relatively inexpensive radioactive disk x−ray source and a chamber which was constructed by students. The chamber is described in detail and results of several experiments are shown. Students gained experience with sample preparation techniques, x−ray excitation and detection, analysis and interpretation of data, programming of a small calculator, machine shop techniques, and applied physics experiments.
Laboratory investigation of free and driven oscillations using a R
L
C circuit
Authors: Luke Keung L.
Published: March 2005

An experiment is described for the undergraduate electricity and magnetism or mechanics laboratory to verify results predicted by the standard mathematical theory of free and driven oscillations. All the measurements are made on a series–parallel RLC circuit which is pulsed with a pulse generator when free oscillation is being investigated and is driven with a low-impedance sinusoidal generator when driven oscillation is being studied. The agreement between experiment and theory is remarkably good.
Retardation in coupled dipole–oscillator systems
Authors: Milonni P. W. , Knight P. L.
Published: March 2005

The retarded interaction of two dipole oscillators is discussed using classical electromagnetic theory. We show how the oscillators causally exchange excitation, and how the back-and-forth signalling between the oscillators results in the familiar first-order dispersion or dipole–dipole interaction. These results are directly analogous to recently reported work on the quantum-mechanical radiative interaction of two atoms ’’sharing’’ a single excitation.
Theoretical and experimental study of the motion of the simple pendulum
Authors: Fulcher L. P. , Davis B. F.
Published: March 2005

A pedagogic experimental and theoretical study of the motion of the simple pendulum, which considers corrections to the approximation of simple harmonic motion, is presented. The period is calculated with the use of both elliptic integrals and the perturbation theory of Kryloff and Bogoliuboff. Measurements of the period of the pendulum taken with a stopwatch are compared with the calculations. The errors made in the measurements are analyzed.
Charge cloud study of atomic and molecular structure
Authors: Rioux Frank , Kroger Peter
Published: March 2005

The conceptually simple charge cloud model of atomic and molecular structure is applied to three problems: atomic hydrogen, molecular hydrogen, and crystalline lithium hydride. Because of its simplicity, the model lends itself well to calculations that are easily performed by undergraduates. While the calculations are, on the whole, only in modest agreement with experimental results, the model provides useful insights in all the areas to which it is applied.
Large-scale diffraction patterns from circular objects
Authors: Rinard Phillip M.
Published: March 2005

The diffraction of light by a U.S. penny and an aperture of the same size with the light source and viewing screen 20 m from the objects has been investigated quantitatively. It was found that the diffraction by these relatively large objects involving such unusually long light paths could be adequately described by the scalar theory of Kirchhoff in the specialized form due to Lommel. Differences noted between the theory and the measurements are discussed, with probable causes indicated.
Measurement of the longitudinal shift of radiation at total internal reflection by microwave techniques
Authors: Akylas Victor , Kaur Jasjit , Knasel T. M.
Published: March 2005

We have measured the longitudinal shift of a microwave beam at total internal reflection. Good agreement with the prediction of classical electromagnetic theory is provided. The magnitude of the effect at microwave frequencies is conveniently large and the experimental setup used is sufficiently straightforward to allow this experiment to be repeated in an undergraduate laboratory program.
Physics teaching: Does it hinder intellectual development?
Authors: Griffiths David H.
Published: March 2005

A necessary condition for effectively teaching physics is that the students have the capability of operating at the cognitive level that is matched with the logical structure that produced the discipline. Recent research indicates that a majority of students are not demonstrating this capacity. The analysis of the performance of students ’’learning’’ physics without the necessary cognitive development demonstrates behavior that hinders their intellectual growth.
Current correlation function 〈j (x,t) j (x′,t′) 〉 derived from a model based on Brownian motion
Authors: Mathews J. , Nicolet M-A.
Published: March 2005

An explicit form of the autocorrelation function of the current density j (x,t) is derived for a model in which the charge carriers independently undergo Brownian motion, as described by the Langevin equation of an individual carrier. Graphs and a table of this correlation function are given for the case of thermal equilibrium. The case where a steady-state dc current flows is discussed briefly as well.
Phosphorescence and electron paramagnetic resonance study of a photoexcited triplet state: Advanced undergraduate experiment in molecular physics
Authors: Chang Raymond , Moomaw William R.
Published: March 2005

An experiment to investigate molecular multiplet structure is described. The phosphorescence spectrum and lifetime from the lowest triplet state of naphthalene is measured by optical spectroscopy, and the zero-field splitting parameters and the lifetime of paramagnetic resonances of this photoexcited state are determined by electron paramagnetic resonance.
Laboratory course in plasma physics
Authors: Crawford F. W. , Ilić D. B.
Published: March 2005

Since 1966, a laboratory course in plasma physics has been offered at Stanford. Fourteen experiments have been developed, illustrating a wide variety of methods of producing plasmas, diagnostic techniques, and plasma properties. The evolution of the course is described, and brief descriptions of the experiments are given.
Attitudes toward physics in the high school curriculum
Authors: Redford Elmer G.
Published: March 2005

High school principals, guidance counselors, and physics teachers in the state of Wisconsin have been surveyed to determine their respective attitudes toward physics in the high school curriculum. The techniques for determining these attitudes are given. For comparison, attitudes toward biology and chemistry are also determined. The results indicate that the physics community should make a greater effort to inform principals and guidance counselors as to the value of physics in the high school curriculum.
Spin and statistics
Authors: Broyles A. A.
Published: March 2005

An exchange operator is defined in terms of rotation and displacement operators. This operator contains a rotation around the z axis that produces a factor (−1)2s in front of the wave function. By postulating that such a rotation must produce the same value for the wave function if the particles are identical, we obtain the usual connection between spin and statistics. Particle states lying in the irreducible representations of the three-dimensional rotation group are seen to allow only Fermi and Bose statistics.
Nonequilibrium thermodynamic properties of dilute Maxwellian gases
Authors: Haley S. B. , Smith Randy
Published: March 2005

The Boltzmann equation is solved analytically for a physically reasonable model of dilute neutral gas transport through a prism containing randomly located hard sphere scattering centers. The role of boundary and bulk scattering in establishing local equilibrium is clearly illustrated. Asymptotically exact expressions are given for the particle density, pressure, and temperature distributions in the limits of large and small mean free path. The particle flux and the heat flux are calculated exactly for all values of the mean free path.
Propagation and spreading of a pulse or wave packet
Authors: Bradford Henry M.
Published: March 2005

The usual textbook discussions of the velocity and spreading of a wave packet are based on special cases and approximations which have a limited range of validity. In this paper more general relations are obtained by considering the time dependence of the moments of a wave packet. Both a packet of real sinusoidal plane waves (a real pulse, e.g., sound) and a packet of complex exponential plane waves (e.g., the quantum-mechanical wave function of a free particle) are considered. The results are similar if the real wave packet contains no standing wave components. It is shown that the centroid of a wave packet moves at a constant velocity which is a weighted average of the group velocity. The spreading of the wave packet depends on the product of the variance of the group velocity and the square of the time interval before or after the time of minimum packet width. The packet moves and spreads like a collection of particles in free flight, in which the velocities of the particles are the group velocities of the wave components of the packet.
Derivation of classical and quantum statistical distributions
Authors: Barford N. C.
Published: March 2005

An elementary method is described for deriving the Boltzmann, Fermi–Dirac, and Bose–Einstein distributions that neither uses Lagrange undetermined multipliers nor requires a knowledge of Stirling’s approximation for ln(n!). Apart from giving a more direct account of the optimal properties of these distributions, which may be useful when first introducing statistical thermodynamics, the method also shows clearly how the validity of the distributions depends upon the size of the system. Extensions of the method demonstrate the statistical origin of temperature and the dominance of the most probable macrostate.
Teaching ’’team’’ research techniques and technical report writing in elementary physics laboratories
Authors: Early Douglas , Stutz Conley
Published: March 2005

One of the problems the student encounters when working with partners or in ’’teams’’ in physics laboratories is identifying the role each participant is to play in doing the experiment and writing the report. In this article we outline a very successful approach to solving this problem while, at the same time, teaching technical report writing as outlined in the AIP Style Manual.
Some recent determinations of the velocity of light. III
Authors: Mulligan Joseph F.
Published: March 2005

Recent measurements of the velocity of electromagnetic waves involving simultaneous high-precision determinations of the frequency and wavelength of highly monochromatic radiation sources are reviewed. After an account of the frequency stabilization of lasers using Lamb-dip and saturated molecular absorption techniques, the recent measurements of visible and infrared frequencies at NBS (Gaithersburg), NBS (Boulder), and NPL (Teddington) are discussed. The resulting experimental values for the velocity of light in vacuo are summarized, and the remarkable improvement in our present knowledge of c obtained from these laser measurements is indicated. The article concludes with a discussion of the suggestion that the velocity of light should be made a defined constant and of the effect such a definition would have on future light-velocity measurements.
Equilibrium properties of a mixture of reacting gases: A soluble model
Authors: Kreuzer H. J.
Published: March 2005

We calculate exactly the equilibrium properties of a large system consisting of two kinds of Bose particles, a and b, that can be transformed into each other by an external field. The enhancement in the specific heat around the threshold (internal excitation) energy of the b particles is studied as a function of the external field strength, and the mass–action law is derived. Bose–Einstein condensation can occur in our mixture of reacting gases at a transition temperature lower than that of a one-component ideal gas. Also, the condensate occupancy increases faster than T3/2 as the temperature is lowered.
Some remarks on clock rates in special relativity
Authors: Barron Robert H. , Mazur Paul
Published: March 2005

In part I a simple gedanken experiment is discussed that clearly develops a connection between the rates of accelerated clocks in special relativity theory and the rates of clocks at different points in a uniform gravitational field in any theory which incorporates the equivalence principle, such as general relativity theory. In part II it is shown that the time dilation effect observed when the rate of a moving clock is compared with that of a clock at rest can be derived by observing the Doppler shift, not only of light waves emitted by the moving clock, but of any periodic wave, e.g., sound.
Cultivating the capacity for formal reasoning: Objectives and procedures in an introductory physical science course
Authors: Arons A. B.
Published: March 2005

Experience in a physical science course for preservice elementary teachers, inservice elementary teachers, and other nonscience majors has led to the identification of certain specific factors and procedures that seem to assist the attainment of the formal operational level of intellectual development on the part of students who are initially at a concrete or transitional stage.