bluuebunny/crossref_metadata_2025 huggingface dataset:
Recovery of a Subtropical Dry Forest After Abandonment of Different Land Uses1
Authors: Colón Sandra Molina , Lugo Ariel E.
Published: March 2006

We studied the ecological characteristics of 45–50‐yr‐old subtropical dry forest stands in Puerto Rico that were growing on sites that had been deforested and used intensively for up to 128 yr. The study took place in the Guánica Commonwealth Forest. Our objective was to assess the long‐term effects of previous land use on this forest—i.e., its species composition, structure, and functioning. Previous land‐use types included houses, farmlands, and charcoal pits. Stands with these land uses were compared with a nearby mature forest stand. The speed and path of forest recovery after deforestation and land‐use abandonment depended on the conditions of the land. Study areas where land uses had removed the forest canopy and altered soil conditions (houses and farmlands) required a longer time to recover and had a different species composition than study areas where land uses retained a forest canopy (charcoal pits). Different forest attributes recovered at different rates. Crown area index, stem density, and litterfall rate recovered faster than stemwood and root, biomass, tree height, and basal area. Where previous land uses removed the canopy,Leucaena leucocephala,a naturalized alien pioneer species, dominated the regrowth. Native species dominated abandoned charcoal pits and mature forest. The change in species composition, including the invasion of alien species, appears to be the most significant long‐term effect of human use and modification of the landscape.
On the origin of the iron Kα line cores in active galactic nuclei
Authors: Nandra K.
Published: March 2006

X-ray observations made with Chandra and XMM–Newton have shown that there are relatively narrow cores to the iron Kα emission lines in active galactic nuclei (AGN). Plausible origins for this core emission include the outer regions of an accretion disc, a parsec-scale molecular torus, and the optical broad-line region (BLR). Using data from the literature it is shown that no correlation exists between the Fe Kα core width and the BLR (specifically Hβ) line width. This shows that in general the iron Kα core emission does not arise from the BLR. There is a similar lack of correlation between the width of the Fe Kα core and black hole mass. The average Kα width is about a factor of 2 lower than the Hβ width. It therefore seems likely that, in many cases, the narrow core arises in the torus. There is a very wide range of observed Fe Kα core widths, however, and this argues for multiple origins. The simplest explanation for the observed line profiles in AGN is that they are due to a mixing of very narrow emission from the inner edge of the torus, and broadened emission from the accretion disc, in varying proportions from object to object.
Spiral structure of the third galactic quadrant and the solution to the Canis Major debate
Authors: Moitinho A. , Vázquez R. A. , Carraro G. , Baume G. , Giorgi E. E. , Lyra W.
Published: March 2006

With the discovery of the Sagittarius dwarf spheroidal, a galaxy caught in the process of merging with the Milky Way, the hunt for other such accretion events has become a very active field of astrophysical research. The identification of a stellar ring-like structure in Monoceros, spanning more than 100°, and the detection of an overdensity of stars in the direction of the constellation of Canis Major (CMa), apparently associated to the ring, has led to the widespread belief that a second galaxy being cannibalized by the Milky Way had been found. In this scenario, the overdensity would be the remaining core of the disrupted galaxy and the ring would be the tidal debris left behind. However, unlike the Sagittarius dwarf, which is well below the Galactic plane and whose orbit, and thus tidal tail, is nearly perpendicular to the plane of the Milky Way, the putative CMa galaxy and ring are nearly co-planar with the Galactic disc. This severely complicates the interpretation of observations. In this Letter, we show that our new description of the Milky Way leads to a completely different picture. We argue that the Norma–Cygnus spiral arm defines a distant stellar ring crossing Monoceros and the overdensity is simply a projection effect of looking along the nearby local arm. Our perspective sheds new light on a very poorly known region, the third Galactic quadrant, where CMa is located.
The Tax Consequences of Long‐Run Pension Policy*
Authors: Black Fischer
Published: March 2006

A firm's pension fund is legally separate from the firm. But because pension benefits are normally independent of fund performance, pension assets impact the firm very much as if they were firm assets.

Because they are worth more when times are good and less when times are bad, common stocks in the pension fund add to the sponsoring firm's leverage. They cause contributions to a pension fund to be high just when the firm can least afford to pay them. Conversely, bonds in the pension fund will make it easier for the firm to avoid default on its own bonds when times are bad all over: The more bonds a pension fund buys, the more the firm can borrow.

The tax treatment accorded the pension fund differs notably from that accorded the firm. Some have argued that a firm can capitalize on the difference by accelerating the funding of its pension plan. The benefits of full funding are wasted, however, unless the added contributions to the fund are invested in bonds; higher pension contributions now mean lower contributions later, hence higher taxes later. The benefits come from earning, after taxes, the pretax interest rate on the bonds in the pension fund.

If the firm wants to take advantage of the differing tax treatment of bonds without altering the level of its current pension contributions, it can (1) sell stocks in the pension fund and then buy bonds with the proceeds while (2) issuing debt in the firm and buying back its own shares with the proceeds. An investment in the firm's own stock creates no more tax liability than an investment in stocks through the pension fund.
Allocating Shareholder Capital to Pension Plans
Authors: Merton Robert C.
Published: March 2006

This article discusses the corporate challenge of providing retirement income to employees while limiting the costs and risks of pension plans to the companies themselves by addressing five main questions:

What are the major issues and challenges surrounding pensions? Although the pension shortfalls have been the focus of attention, the author argues that the more serious concern is the risk stemming from the mismatch between pension assets and pension liabilities— that is, the funding of debt‐like liabilities with equity‐heavy asset portfolios.

To what extent do the equity market and equity prices reflect the shortfall in value and the mismatch in risk? While the author describes some evidence of the market's ability to capture pension risk, analysts' P/E multiples and management's assessments of cost of capital may still be distorted by failure to take full account of the risks associated with pension assets.

How should management analyze and formulate strategic solutions? Without offering specific solutions, the author presents a framework for analyzing the problem from a strategic perspective that can be used in formulating a company's pension policy. In particular, the article recommends that companies take an integrated perspective that views pension assets and liabilities as parts of the corporate balance sheet, and the pension asset allocation decision as a critical aspect of a corporate‐wide enterprise risk management program.

If a company chooses to make a major change in its pension policy, such as a partial or complete immunization accomplished by substituting bonds for stocks, how would you communicate the new policy to the rating agencies and investors?

What are the major issues to be thinking about when contemplating a change from a DB plan to a defined contribution, or DC, plan? The author argues that DC plans without some corporate oversight or responsibility for results are not a long‐term solution.
An Investment Management Methodology for Publicly Held Property/Casualty Insurers
Authors: Heyman William H. , Rowland David D.
Published: March 2006

Investment officers of publicly held property/casualty companies wrestle with the question of how best to contribute to shareholder value. Should they view themselves as managers of a closed‐end investment company that happens to be funded by insurance underwriting? Or should they instead be investing funds primarily to defease the firm's liabilities and thus support the operations of a company whose principal value derives from its insurance activities?

The authors of this article suggest that the investment policy of most insurance companies should have two primary objectives: (1) immunizing insurance reserves with a fixed‐income portfolio and (2) earning “abnormal returns” on surplus in “a responsible and disciplined” way. The latter means adhering to an asset allocation approach that takes account of the risk‐reward tradeoffs presented by a broad variety of investment types as well as the accounting treatment of investment income. Both accounting and economic considerations lead the authors to suggest that after‐tax net investment income (“NII”), as defined by U.S. GAAP, is the best benchmark of performance. While focusing mainly on the fixed income part of the portfolio, the authors suggest active management and portfolio approaches that aim to produce a growing, but relatively stable NII. Consistent with GAAP's treatment of NII (which includes interest income but excludes most capital gains) as “recurring income,” the authors argue that the market appears to assign significantly higher multiples to NII than to other sources of reported income.
How Behavioral Finance Can Inform Retirement Plan Design1
Authors: Mitchell Olivia S. , Utkus Stephen P.
Published: March 2006

Several key lessons for pension design have emerged in the last decade from behavioral economics and finance research. This article analyzes the insights from this literature on how workers decide to save, manage their retirement investments, and draw down their assets in retirement. The aim is to understand how workers and retirees deviate from the rational, well‐informed agents that underpin economic theory, public policy, and often retirement plan design.

The evidence suggests that many people save too little, others make poor investment decisions, and still others spend their accumulated assets too quickly in retirement. The “behavioral” reasons for such tendencies include overconfidence, limited self‐control, the overvaluation of the present at the expense of the future, susceptibility to “framing,” and an aversion to realizing losses.

By shedding light on why people fail to achieve an ideal outcome on their own, this literature offers practical guidance to plan sponsors and policymakers who must design, regulate, and evaluate the institutions that help provide for economic security in old age. More specifically, the literature suggests that the plan design should be made automatic for the many individuals unwilling to exercise full control over their retirement savings choices. Recommended design features include automatic enrollment, scheduled annual savings increases, and default investment options or managed account programs that represent optimal portfolio choices.
Downside Risk in Practice
Authors: Estrada Javier
Published: March 2006

Although investors associate risk with negative outcomes and downside fluctuations, modern portfolio theory does not. For investors, volatility per se is not necessarily bad; volatility below a benchmark is. A stock that magnifies the market's fluctuations is not necessarily bad; one that magnifies the market's downside swings is. Even Harry Mar‐kowitz, the father of modern portfolio theory, viewed downside risk as a better way to assess risk than the “mean‐variance” framework that he ultimately proposed and that has since become the standard.

This article highlights the shortcomings of traditional measures of risk (the standard deviation and beta), introduces the concept of downside risk, and discusses two measures of it—the “semideviation” and “downside beta.” It also discusses the use of such measures in asset pricing models to estimate required returns on equity. Data from a few well‐known companies are used to illustrate that the cost of equity based on downside risk can be substantially different from that based on the CAPM. The article concludes with a brief discussion of risk‐adjusted returns and a comparison of the traditional method of calculating such returns with both the Sharpe ratio and its counterpart in a downside risk framework, the Sortino ratio. The appendix demonstrates how to calculate these risk measures in Excel.
The influences of postdischarge management by nurse practitioners on hospital readmission for heart failure
Authors: Delgado‐Passler Patricia , McCaffrey Ruth
Published: March 2006

Purpose: The primary purpose of this literature review is to examine advanced practice nurse (APN)–directed versus registered nurse (RN)–directed telemanagement programs for heart failure patients.

Data sources: Research articles identified through CINAHL and OVID databases.

Conclusions: Implementing a telemanagement program directed by an APN after hospital discharge decreases the costs and frequent rehospitalizations associated with heart failure and improves the patient's quality of life. While APNs are more costly than RNs, it is important to understand that this level of provider has a more significant impact on the outcomes of patients who use the services provided in the comprehensive discharge programs.

Implications for practice: An APN‐directed heart failure telemanagement program can reduce the rising healthcare costs that result from frequent readmissions. These programs can improve the quality of care given to heart failure patients while reducing the cost to the institution, the patient, and the healthcare system. When considering the number of older adults hospitalized each year with heart failure, the potential patient benefits and savings to the healthcare system resulting from APN‐directed telemanagement are substantial.
Emergency contraception: Knowledge and perceptions in a university population
Authors: Corbett Patricia O. , Mitchell Cameron P. , Taylor Julie Smith , Kemppainen Jeanne
Published: March 2006

Purpose: The purpose of this study was to examine knowledge, attitudes, and behaviors regarding emergency contraception (EC) in university men and women aged 18–21.

Data sources: Data sources included responses to a 25‐item questionnaire and an 8‐item demographic survey completed anonymously at a public site on campus. Ninety‐seven university students participated in the study. Participants were asked to respond to questions relating to knowledge, attitudes, and behaviors regarding EC, perceived worthiness, objections, sources of information about EC, preferred birth‐control method and usage, and perceptions of their personal risk of unintended pregnancy.

Conclusions: Many respondents considered unintended pregnancy to be a major problem and considered EC a worthy option in the event of method failure or unprotected intercourse. While most participants were aware that there was a postcoital method of contraception, confusion existed between EC and RU‐486 (the abortion pill). Almost half (49.5%) believed that EC was the same as RU‐486. There was an association between advanced prescription for EC and its likelihood of use. Most women would be significantly more likely to use EC if they had a prescription on hand. Of the women who were less likely to choose EC, 100% indicated they would feel embarrassed or judged when asking for it. Only 34% of those women who have had a gynecological exam in the past 12 months had discussed EC with their provider.

Implications for practice: Advanced practice nurses need to incorporate EC into preventive health counseling for both men and women. Providing women with an advanced prescription increases the likelihood that women will use EC.
Therapeutic modulation of the psychoneuroimmune system by medical acupuncture creates enhanced feelings of well‐being
Authors: Walling Allan
Published: March 2006

Purpose: This article includes an explanation of how stressors disrupt physiologic regulatory mechanisms leading to disease states, how environmental challenges alter the function of the psychoneuroimmune system, and how correction of aberrant action potentials will stabilize homeostatic regulatory functions, inducing an escape response from stressors and leading to enhanced feelings of well‐being. An explanation of how medical acupuncture accomplishes this stabilization concludes the article.

Data source: Extensive review of the worldwide scientific literature from the 1970s through current literature, on acupuncture, neurophysiology, and psychoneuroimmune system, using the theoretical framework of Martha Rogers.

Conclusions:

It is estimated that 80% of all illnesses are stress induced, although the physiologic mechanisms by which stress induces detrimental changes are not well understood by the medical profession. Introducing specific rhythmic electrical impulses slightly more intense than the nervous system already generates with the intervention of medical acupuncture can therapeutically alter aberrant signals induced by stressors, which may result in the release of neuropeptides and stabilization of homeostatic regulation so that health outcomes are improved. As neurological activity is altered, the firing pattern of nerves is changed. This is a change in the electrical pattern that leads to a change in the biochemical pattern. Thus, medical acupuncture is a therapy that is in agreement with Martha Rogers’ conceptual model. Therapeutic techniques may improve the individual's level of wellness by direct actions toward homeostatic stabilization of the autonomic nervous system. These techniques will not change the amount of stressors a person is subject to but will change the physiological response to them. When the nervous system is in homeostatic balance, individuals will report enhanced feelings of well‐being, be more effective in coping with their conditions of living, and therefore be less susceptible to illness.

Implications for practice:

Nurse practitioners have an opportunity to expand into an unused dimension for nursing care through direct treatment of the central and autonomic nervous system that will influence the psychoneuroimmune system. A prescriptive theory explaining medical acupuncture provides for therapeutic interventions at the primary, secondary, and tertiary level of care. Primary preventive interventions alter the effects of stress before it leads to illness by assisting homeostatic stability of the autonomic nervous system. Secondary interventions allow treatment of many health conditions regulated by neurological activity. Tertiary care provides a method to assist autonomic regulation when the body is no longer able to maintain homeostatic stability because of chronic illness or injury.
Tobacco prevention in children and cessation in family members
Authors: Tingen Martha S. , Waller Jennifer L. , Smith T. Maria , Baker R. Randall , Reyes Juan , Treiber Frank A.
Published: March 2006

Purpose: To examine the effects of a theory‐driven tobacco prevention program in sixth‐grade children with a family tobacco cessation component implemented by school nurses in conjunction with the initiation of a statewide toll‐free Quit Line.

Data sources: Self‐report questionnaires completed by the sixth‐grade children and their parents/guardians (N= 1024) representing largely rural southern school systems from disparate areas with high prevalence rates of tobacco use and lung cancer diagnoses. Pre‐ and posttest measures that evaluated the impact of both student and parent/guardian interventions were obtained over a 10‐week period. Paired t‐tests were used to examine differences between pre‐ and posttest scores for all student and parent/guardian variables. Repeated‐measures analysis of variance was used to examine the effect of parent/guardian smoking on student pre‐ and posttest scores.

Conclusions: The student program resulted in significant improvements in drug knowledge, refusal skills, attitudes, normative expectations, assertiveness, and anxiety reduction techniques. In addition, the effectiveness of several components of the tobacco prevention program for the children was impacted by the smoking status of their parents/guardians. Drug‐use intentions and behaviors were lower at posttest for children from homes of nonsmokers versus children from homes of smokers. Parents/guardians consistently reported that smoking was detrimental to themselves, the public, and their children. Of those parents/guardians who identified themselves as smokers (26%) and received cessation materials, 46.4% indicated that the information motivated them to want to quit.

Implications for practice: Tobacco use continues to be the leading cause of preventable death in the United States, with greater than 2000 new youth becoming regular smokers each day. School nurses and nurse practitioners are in various pivotal positions to address tobacco and its related health concerns through delivery of effective family interventions that target children for tobacco prevention and parent/guardian smokers for cessation.
Primary care health issues among men who have sex with men
Authors: Gee Royal
Published: March 2006

Purpose: The purpose of the article is to examine “appropriate” health care for men who have sex with men (MSM), which is not to suggest “special” health care. As a group, MSM are at increased risk for sexually transmitted infections, anal cancer, and mental health disorders. Focus areas in this article will address health issues that the primary care nurse practitioner (NP) may encounter in clinical practice: anal carcinoma, sexually transmitted diseases (STDs), high‐risk sexual practices, depression, and substance abuse were topics chosen for inclusion in this article. These topics were among those highlighted in the Healthy People 2010 Companion Document for LGBT Health, which served to examine the healthcare disparities and lack of access to needed services related to sexual orientation.

Data source: Extensive literature review of research articles, journals, clinical practice guidelines, books, and public health department Internet Web sites.

Conclusions: There are unique health disparities that exist for MSM related to social, emotional, and mental health factors, in addition to physical issues such as STDs. There is an increasing need for primary care providers to be aware of these disparities, as well as the factors that influence these disparities, in order to provide multidimensional care and health counseling that is unique to NP practice.

Implications for practice: Both the primary care NP and the patient should be aware of the unique healthcare issues among MSM that should be incorporated into the patient's routine health maintenance program. As primary care providers, it is within the standards of practice for NPs to provide culturally competent care, along with health promotion and disease prevention for MSM.
Autosomal dominant mutation causing the dorsal ridge predisposes for dermoid sinus in Rhodesian ridgeback dogs
Authors: Hillbertz N. H. C. Salmon , Andersson G.
Published: March 2006

Objectives: To define the mode of inheritance of the dorsal ridge and investigate if the ridge predisposes to the congenital abnormality dermoid sinus in the Rhodesian ridgeback.

Methods: Segregation analysis was performed, including 87 litters (n=803) produced in Sweden between 1981 and 2002. Data were corrected to avoid bias in the segregation ratio. Chi‐squared analysis was performed including 402 litters (n=3598) for the evaluation of a possible genetic correlation between the ridge and dermoid sinus.

Results: The ridge is inherited in an autosomal dominant mode and predisposes for dermoid sinus. The frequency of ridgeless offspring in the Swedish Rhodesian ridgeback population is estimated to be 5·6 per cent.

Clinical Significance: Rhodesian ridgeback dogs that carry the ridge trait are predisposed to dermoid sinus.
Hypercalcaemia associated with granulomatous lymphadenitis and elevated 1,25 dihydroxyvitamin D concentration in a dog
Authors: Mellanby R. J. , Mellor P. , Villiers E. J. , Herrtage M. E. , Halsall D. , O'Rahilly S. , McNeil P. E. , Mee A. P. , Berry J. L.
Published: March 2006

A seven‐year‐old Labrador was presented with weight loss and mild generalised lymphadenopathy. Histopathology of an excised lymph node by the referring veterinarian demonstrated granulomatous lymphadenitis. At the time of referral, fine‐needle aspirates of the lymph nodes confirmed the presence of ongoing granulomatous inflammation. Further investigations revealed marked hypercalcaemia, a low parathyroid hormone concentration, a parathyroid hormone related protein concentration within the reference range, and an elevated serum concentration of 1,25 dihydroxyvitamin D. An underlying cause of the granulomatous lymphadenitis could not be identified. The clinical signs, hypercalcaemia and elevated serum concentrations of 1,25 dihydroxyvitamin D resolved following prednisolone treatment. In contrast to dogs, hypercalcaemia occurred secondarily to granulomatous disease and elevated 1,25 dihydroxyvitamin D concentrations is a well‐recognised condition in human beings. To the authors’ knowledge, this is the first case report to describe elevated serum calcium and 1,25 dihydroxyvitamin D concentrations in a dog with histologically confirmed granulomatous disease.
Role of carboplatin in multi‐modality treatment of canine tonsillar squamous cell carcinoma – a case series of five dogs
Authors: Murphy S. , Hayes A. , Adams V. , Maglennon G. , Neath P. , Ladlow J. , Brearley M. J.
Published: March 2006

Canine tonsillar squamous cell carcinoma is an aggressive disease with a poor prognosis. A retrospective study was undertaken of all dogs that were presented between January 1999 and January 2004 to the Animal Health Trust for the treatment of tonsillar squamous cell carcinoma. Five cases were identified, and their median survival time was 211 days (95 per cent confidence interval 80 to 352) with two of the five dogs remaining alive at the end of the study, 826 and 1628 days from diagnosis with no clinical signs of disease. The protocol was well tolerated with only one of the five dogs showing toxicity associated with carboplatin and all dogs that started radiotherapy completing it. Compared with results of previous studies, these cases suggest that surgical cytoreduction followed by coarse fractionated radiotherapy together with carboplatin may be a useful way to treat this tumour. Carboplatin alone caused partial remission in the two cases where it was used as neo‐adjunctive therapy.
Successful pregnancy following gonadotrophin‐releasing hormone analogue treatment in a previously infertile bitch
Authors: Tsumagari S. , Ishinazaka T. , Watanabe G. , Taya K. , Ishii M.
Published: March 2006

A Labrador retriever bitch was presented with repeated unsuccessful breeding during both the third and fourth oestruses, even though accurate timing for natural mating was planned based on the results obtained using a semiquantitative luteinising hormone kit and a quantitative assay of progesterone. To identify the problem, serum luteinising hormone, follicle‐stimulating hormone, progesterone, and oestradiol‐17β concentrations around the fourth oestrus stage were assayed by radioimmunoassay. Abnormal luteinising hormone fluctuations were detected during pro‐oestrus and oestrus, and lower than normal progesterone concentrations were found during the mating period. In the fifth to seventh oestrus, the bitch was successfully treated with gonadotrophin‐releasing hormone analogue at times based on the findings of the hormonal assays.
Ciclosporin treatment of suspected granulomatous meningoencephalomyelitis in three dogs
Authors: Gnirs K.
Published: March 2006

Granulomatous meningoencephalomyelitis is an idiopathic disease of the central nervous system of presumed dysimmune origin. This disorder is characterised histologically by an angiocentric inflammatory reaction involving the brain, the spinal cord, and/or the leptomeninges. To date, the standard treatment for granulomatous meningoencephalomyelitis consists of immunosuppressive dosages of glucocorticoids. Ciclosporin A, a potent immunosuppressive agent that blocks the transcription of cytokine genes in activated T cells, has been proposed as a therapeutic alternative. In the present study of three dogs with suspected granulomatous meningoencephalomyelitis, microemulsified ciclosporin, at a dose of 10 mg/kg once daily for at least six weeks, then reducing to 5 mg/kg daily, was administered after a variable period of glucocorticoid treatment, and resulted in a complete resolution of clinical signs. Satisfactory improvement of clinical signs after ciclosporin administration took more time than after glucocorticoid administration. Six weeks after the beginning of ciclosporin treatment, clinical results were similar to those obtained with prednisolone. Adverse effects were minimal with ciclosporin, with only intermittent vomiting.
Aortic foreign body (airgun pellet) embolism in a cat
Authors: Kettner F. , Kirberger R. M.
Published: March 2006

A five‐year‐old female domestic shorthair cat presented with clinical signs typical of an aortic saddle thromboembolism. An echocardiogram and thoracic radiographs excluded cardiac disease as a source of the thrombus. Two heavy metal opacity, pellet‐like objects were seen in the thoracic and abdominal radiographs. Abdominal ultrasound demonstrated occlusion of aortic blood flow by the abdominal pellet but could not indicate whether this was due to a penetrating aortic wound or pellet embolisation. A necropsy confirmed a penetrating left ventricular cardiac wound with subsequent embolisation of the pellet to the abdominal aorta.
Cohort study of COX‐1 and COX‐2 expression in canine rectal and bladder tumours
Authors: Knottenbelt C. , Mellor D. , Nixon C. , Thompson H. , Argyle D. J.
Published: March 2006

Objectives:To determine the role that cyclooxygenase‐1 (COX‐1) and cyclooxygenase‐2 (COX‐2) play in malignant transformation in canine transitional cell carcinoma and rectal tumours.

Methods:Histological sections of 21 canine rectal adenocarcinomas and 18 canine transitional cell carcinomas were stained for COX‐1 and COX‐2. Mann‐Whitney non‐parametric tests were applied to determine if there was any relationship between the percentage of cells expressing COX‐1 or COX‐2, and between COX‐1 and COX‐2 staining intensity and age, breed or sex.

Results:For rectal adenocarcinomas, 19·0 per cent of the sections were negative for COX‐1 and COX‐2. A further 38·1 per cent of the sections were negative for COX‐2 but positive for COX‐1, and 38·1 per cent of the sections had rare or occasional single cells positive for COX‐2. No significant differences were found in COX staining when compared with age, breed or sex. For transitional cell carcinomas, all of the sections were positive for COX‐1 and COX‐2. For COX‐2 staining, 16·7 per cent had more than 30 per cent positive cells. For COX‐1 staining, 38·9 per cent had more than 30 per cent positive cells. There was a significant increase in the percentage of COX‐1 positive cells in small breed dogs (P = 0·0337).

ClinicalSignificance:The variations in COX expression reported in this study may explain the differences in the clinical response of transitional cell carcinomas and rectal adenocarcinomas following treatment with non‐steroidal anti‐inflammatory drugs.
BSAVA Manual of Canine and Feline Gastroenterology (2nd edition)
Authors: Reilly Craig
Published: March 2006

BSAVA Manual of Canine and Feline Gastroenterology (2nd edition)
 Edited by Edward Hall, James Simpson and David Williams

 Published by Blackwell Publishing Ltd, 2005.

 Paperback, 320 pages. Price £75.00
Tooth Influence on Flexural and Torsional Flexibility, and Model Tooth Number Prediction for Optimum Dynamic Simulation of Wide-Faced Spur Gears
Authors: Guilbault Raynald
Published: March 2006

Refined dynamic analyses of gear pairs, including precise tooth contact description, often lead to unreasonable simulation requirements. Therefore, numerous models employ simplifications, such as two-dimensional deflection of the engaged gear set, which is inappropriate for wide-faced wheels. Other models propose three-dimensional (3D) representation of one tooth on a complete hub. This approach introduces the torsional and flexural deflection of the gear body, but underestimates the corresponding stiffness. Since forthcoming improvements of gear analysis should offer efficient 3D dynamic simulation of wide-faced gear sets, this paper primarily quantifies the flexibility error levels implied with 3D one tooth full hub spur gear models. Subsequently, a procedure is developed to determine the number of teeth required for a 3D model so that it will include the torsional and flexural flexibility of the spur gear body, within acceptable error levels. This procedure offers an efficient approach to optimize the (precision)/(simulation time) ratio. The method deals with gears of any diametral pitch, and covers the common face width and tooth number ranges.
Optimal Subassembly Partitioning of Space Frame Structures for In-Process Dimensional Adjustability and Stiffness
Authors: Lyu Naesung , Lee Byungwoo , Saitou Kazuhiro
Published: March 2006

A method for optimally synthesizing multicomponent structural assemblies of an aluminum space frame (ASF) vehicle body is presented, which simultaneously considers structural stiffness, manufacturing and assembly costs and dimensional integrity under a unified framework based on joint libraries. The optimization problem is posed as a simultaneous determination of the location and feasible types of joints in a structure selected from the predefined joint libraries, combined with the size optimization for the cross sections of the joined structural frames. The structural stiffness is evaluated by finite element analyses of a beam-spring model modeling the joints and joined frames. Manufacturing and assembly costs are estimated based on the geometries of the components and joints. Dissimilar to the enumerative approach in our previous work, dimensional integrity of a candidate assembly is evaluated as the adjustability of the given critical dimensions, using an internal optimization routine that finds the optimal subassembly partitioning of an assembly for in-process adjustability. The optimization problem is solved by a multiobjective genetic algorithm. An example on an ASF of the midsize passenger vehicle is presented, where the representative designs in the Pareto set are examined with respect to the three design objectives.
A Study of the Duality Between Planar Kinematics and Statics
Authors: Shai Offer , Pennock Gordon R.
Published: March 2006

This paper provides geometric insight into the correlation between basic concepts underlying the kinematics of planar mechanisms and the statics of simple trusses. The implication of this correlation, referred to here as duality, is that the science of kinematics can be utilized in a systematic manner to yield insight into statics, and vice versa. The paper begins by introducing a unique line, referred to as the equimomental line, which exists for two arbitrary coplanar forces. This line, where the moments caused by the two forces at each point on the line are equal, is used to define the direction of a face force which is a force variable acting in a face of a truss. The dual concept of an equimomental line in kinematics is the instantaneous center of zero velocity (or instant center) and the paper presents two theorems based on the duality between equimomental lines and instant centers. The first theorem, referred to as the equimomental line theorem, states that the three equimomental lines defined by three coplanar forces must intersect at a unique point. The second theorem states that the equimomental line for two coplanar forces acting on a truss, with two degrees of indeterminacy, must pass through a unique point. The paper then presents the dual Kennedy theorem for statics which is analogous to the well-known Aronhold-Kennedy theorem in kinematics. This theorem is believed to be an original contribution and provides a general perspective of the importance of the duality between the kinematics of mechanisms and the statics of trusses. Finally, the paper presents examples to demonstrate how this duality provides geometric insight into a simple truss and a planar linkage. The concepts are used to identify special configurations where the truss is not stable and where the linkage loses mobility (i.e., dead-center positions).
Power Loss Predictions in Geared Transmissions Using Thermal Networks-Applications to a Six-Speed Manual Gearbox
Authors: Changenet C. , Oviedo-Marlot X. , Velex P.
Published: March 2006

A model is presented which makes it possible to predict power losses in a six-speed manual gearbox. The following sources of dissipation, i.e., power inputs in the model, are considered: (i) tooth friction; (ii) rolling element bearings; (iii) oil shearing in the synchronizers and at the shaft-free pinion interfaces; and (iv) oil churning. Based upon the first principle of Thermodynamics for transient conditions, the entire gearbox is divided into lumped elements with a uniform temperature connected by thermal resistances which account for conduction, convection, and radiation. The numerical predictions compare favorably with the efficiency measurements from the actual gearbox at different speeds and torques. The results also reveal that, at lower temperatures (about 40°C), power loss estimations cannot be disassociated from the accurate prediction of temperature distributions.
Undercutting and Contact Characteristics of Cylindrical Gears With
Curvilinear Shaped Teeth Generated by Hobbing
Authors: Tseng Jui-Tang , Tsay Chung-Biau
Published: March 2006

Undercutting characteristics of the curvilinear-tooth gear, cut by a hob cutter performing motion with two independent parameters, are investigated. The tooth contact analysis (TCA) and the surface topology method are applied to study the kinematic errors (KE) and contact ellipses of the curvilinear-tooth gear under different assembly conditions. Several numerical examples are presented to demonstrate the influence of the assembly errors and design parameters of the gear on the KEs and contact ellipses of the gear pair.
Shape Optimization of Flexible Robotic Manipulators
Authors: Dixit U. S. , Kumar R. , Dwivedy S. K.
Published: March 2006

In this work, the problem of shape optimization of flexible robotic manipulators of circular cross sections is studied. Two different manipulators are considered—a manipulator with revolute joint and a roller supported Cartesian manipulator. The finite element method is used to find the natural frequency and dynamic response of a flexible manipulator by treating it as an Euler-Bernoulli beam. The cross-sectional diameter is varied along the length keeping the constraint on the mass of the manipulator and static tip deflection in order to maximize the fundamental frequency of the beam. This optimization problem is compared with other optimization problems (with different objective functions and constraints). It is observed that the proposed optimization problem is superior to other optimization problems.
Engaging Children in Engineering Design Through Popular Media
Authors: Frey Daniel D. , Wolsky Marisa
Published: March 2006

We submit that there is currently an urgent need to educate the public about engineering and attract talented people to the profession. Further, we argue that such efforts are most effective when they reach young children, and that popular media most be employed to have the desired national impact. These ideas have motivated a major new effort whose central element is a television show for public broadcasting. The television program will feature teams of high school students engaged in solving engineering challenges posed by other kids and adults. Three prototype episodes have been filmed and two of these have undergone focus group testing and analysis. These early tests indicate that the proposed format can engage an audience while reinforcing key lessons about engineering. Collaborative opportunities are currently being sought with engineers, professional societies, and K–12 educators.
Using CAD Variation Geometry and Analytic Approach for Solving Kinematics of a Novel 3-SPU/3-SPU Parallel Manipulator
Authors: Lu Yi
Published: March 2006

A novel 3-SPU/3-SPU parallel manipulator with 3-DOF is presented. The CAD variation geometric approach and analytic approach are used for solving its workspace, position, velocity, and acceleration. First, a simulation mechanism of the 3-SPU/3-SPU parallel manipulator is created by using CAD variation geometric techniques, and its kinematic characteristics are analyzed. Second, the workspace of the 3-SPU/3-SPU simulation mechanism is solved and its singularity is analyzed. Based on the kinematic characteristics of the 3-SPU/3-SPU simulation mechanism, some analytic formulas are derived for inverse and forward solving position. Third, Jacobian matrix and Hessian matrix are derived for solving velocity and acceleration. Finally, a calculation example is given. These simulation and analytic results prove that the novel 3-SPU/3-SPU parallel manipulator has a relatively large workspace and relatively large capacity of loadbearing, and are relatively easy to control. The result of computer simulation solving position is the same as that of the analytic solution. The simulation mechanism can be used to solve workspace, analyze characteristics of a moving platform, and derive a kinematic formula. The CAD variation geometric approach is straightforward, and is advantageous from the viewpoint of accuracy and repeatability without compiling any computer program.
Design of Lightweight Lead Screw Actuators for Wearable Robotic Applications
Authors: Hollander Kevin W. , Sugar Thomas G.
Published: March 2006

A wearable robot is a controlled and actuated device that is in direct contact with its user. As such, the implied requirements of this device are that it must be portable, lightweight, and most importantly safe. To achieve these goals, an actuator with a good “power to weight” ratio, good mechanical efficiency, good “strength to weight” ratio, and that is safe is desired. The design of the standard lead screw does not normally perform well in any of these categories. The typical lead screw has low pitch angles and large radii, thereby yielding low mechanical efficiencies and heavy weight. However, using the design procedure outlined in this text, both efficiency and weight are improved; thus yielding a lead screw system with performances that rival human muscle. The result of an example problem reveals a feasible lead screw design that has a power to weight ratio of 277W∕kg, approaching that of the dc motor driving it, at 312W∕kg, as well as a mechanical efficiency of 0.74, and a maximum strength to weight ratio of 11.3kN∕kg(1154kgf∕kg).
An Approach to Identify Joint Motions for Dynamically Stable Walking
Authors: Agrawal Abhishek , Agrawal Sunil K.
Published: March 2006

Biped robots are more versatile than conventional wheeled robots, but they tend to tip over easily. The dynamic stability of a biped robot needs to be maintained during walking. In this paper, a novel approach to compute dynamically stable walking motions of a planar six degree-of-freedom biped is presented. This approach is analytical and is based on the need for periodicity of the motion. The resulting gait satisfies the dynamic stability criteria. Sets of joint motions for different step sizes and speed of walking, i.e., quasi-statically and dynamically stable walking patterns, can be obtained.
A Closed-Form Solution to the Crank Position Corresponding to the Maximum Velocity of the Slider in a Centric Slider-Crank Mechanism
Authors: Zhang W. J. , Li Q.
Published: March 2006

This paper revisits a classical problem in kinematics, specifically determination of the crank position corresponding to the maximum velocity of the slider in the centric slider-crank mechanism. This position is often critical in designing products constructed using the slider-crank mechanism, e.g., industrial sewing machinery, rotary engine systems, etc. In current literature, the numerical, graphical, or approximate closed-form solution to this problem is available. In this paper, an exact closed-form solution is derived. With this new closed-form solution, it is found that there exist significant errors in an approximate closed-form solution which can be found from many machine design text books for a practica1 use.
Historical Overfishing and the Recent Collapse of Coastal Ecosystems
Authors: Jackson Jeremy B. C. , Kirby Michael X. , Berger Wolfgang H. , Bjorndal Karen A. , Botsford Louis W. , Bourque Bruce J. , Bradbury Roger H. , Cooke Richard , Erlandson Jon , Estes James A. , Hughes Terence P. , Kidwell Susan , Lange Carina B. , Lenihan Hunter S. , Pandolfi John M. , Peterson Charles H. , Steneck Robert S. , Tegner Mia J. , Warner Robert R.
Published: March 2006

Ecological extinction caused by overfishing precedes all other pervasive human disturbance to coastal ecosystems, including pollution, degradation of water quality, and anthropogenic climate change. Historical abundances of large consumer species were fantastically large in comparison with recent observations. Paleoecological, archaeological, and historical data show that time lags of decades to centuries occurred between the onset of overfishing and consequent changes in ecological communities, because unfished species of similar trophic level assumed the ecological roles of overfished species until they too were overfished or died of epidemic diseases related to overcrowding. Retrospective data not only help to clarify underlying causes and rates of ecological change, but they also demonstrate achievable goals for restoration and management of coastal ecosystems that could not even be contemplated based on the limited perspective of recent observations alone.
The Crystal Structure of Uncomplexed Actin in the ADP State
Authors: Otterbein Ludovic R. , Graceffa Philip , Dominguez Roberto
Published: March 2006

The dynamics and polarity of actin filaments are controlled by a conformational change coupled to the hydrolysis of adenosine 5′-triphosphate (ATP) by a mechanism that remains to be elucidated. Actin modified to block polymerization was crystallized in the adenosine 5′-diphosphate (ADP) state, and the structure was solved to 1.54 angstrom resolution. Compared with previous ATP-actin structures from complexes with deoxyribonuclease I, profilin, and gelsolin, monomeric ADP-actin is characterized by a marked conformational change in subdomain 2. The successful crystallization of monomeric actin opens the way to future structure determinations of actin complexes with actin-binding proteins such as myosin.
Behavioral Just-So Stories, Recast
Authors: Gowaty Patricia Adair
Published: March 2006

Animal Traditions
Behavioural Inheritance in Evolution. Eytan Avital and Eva Jablonka. Cambridge University Press, New York, 2000. 446 pp. $80, £50. ISBN 0-521-66273-7.

The authors argue for the evolutionary importance of the transfer of information between generations via culture and learning.