bluuebunny/crossref_metadata_2025 huggingface dataset:
Is the Medial Sural Artery Perforator Flap a New Workhorse Flap? A Systematic Review and Meta-Analysis
Authors: Daar David A. , Abdou Salma A. , Cohen Joshua M. , Wilson Stelios C. , Levine Jamie P.
Published: December 2018

Background:

The medial sural artery perforator flap offers thin, pliable tissue with a relatively long pedicle and low donor-site morbidity. This study explores the characteristics and uses of the medial sural artery perforator flap along with postoperative outcomes and complications.

Methods:

A systematic literature review was performed using PubMed, Embase, and Cochrane Central Register of Controlled Trials to identify all cases of medial sural artery perforator flap reconstruction. Descriptive and meta-analyses were performed on pooled outcomes. Multivariate logistic regression identified factors associated with increased complication rates.

Results:

Thirty-five studies encompassing 526 medial sural artery perforator flaps were included for analysis. The most common reasons for surgery were oncologic (47.6 percent) and traumatic injuries (31.8 percent). The oral cavity was the most common recipient location (45.5 percent). Average flap dimensions were 6.0 ± 2.3 cm × 9.8 ± 3.6 cm, with an average pedicle length of 10.1 ± 6.6 cm. Meta-analysis revealed an overall complication rate of 14.3 percent (Q value = 22.16; p = 0.877; I
2= −39.9). Use of chimeric medial sural artery perforator flaps was associated with significantly higher rates of complications (OR, 3.92; p = 0.039; 95 percent CI, 1.10 to 13.89). The majority of flap donor sites were closed primarily (68 percent) versus 32 percent that were covered with split-thickness skin grafts. A flap width greater than 5.75 cm had an odds ratio of 5.3 (95 percent CI, 1.3 to 21.8; p = 0.014) of having a donor-site complication if closed primarily.

Conclusions:

The medial sural artery perforator flap offers thin, pliable tissue with a relatively long pedicle and has minimal donor-site morbidity when the donor site is managed appropriately. As such, it should be considered a workhorse flap for both head and neck and extremity reconstruction.
The Occipital Artery–Based Fascial Flap for Ear Reconstruction
Authors: Reinisch John F. , van Hövell tot Westerflier Claire Vera Aimée , Tahiri Youssef , Yao Caroline A.
Published: December 2018

Background:

The temporoparietal fascia flap is frequently used in ear reconstruction. When the temporoparietal fascia flap is unavailable, options for primary or secondary salvage reconstruction are limited. In these patients, an inferiorly based occipital artery fascia transpositional flap is a good alternative for soft-tissue coverage over a framework. This article describes the use of the occipital artery fascia flap for ear reconstruction in conjunction with a porous polyethylene framework.

Methods:

The authors included all patients who underwent occipital artery fascia flap surgery with a porous polyethylene framework for ear reconstruction performed by the first author from 1992 to 2017.

Results:

A total of 83 patients received an occipital artery fascia flap: 24 for primary microtia reconstruction and 59 for revision or salvage of unsatisfactory results. All had contraindications for temporoparietal fascia flap use: prior use, flap injury from previous surgery, trauma, inappropriate flap location, or inadequate flap perfusion. Twelve patients (14 percent) developed occipital artery fascia flap complications (infection or necrosis) and underwent further revision to achieve satisfactory results.

Conclusions:

Given the paucity of reported techniques for large-scale auricular salvage/revision, the authors offer a versatile option that remains available when other conventional flaps are unavailable. The occipital artery fascia flap may be used with either alloplastic or autologous frameworks.

CLINICAL QUESTION/LEVEL OF EVIDENCE:

Therapeutic, IV.
Forward genetic screen forCaenorhabditis elegansmutants with a shortened locomotor healthspan
Authors: Kawamura Kazuto , Maruyama Ichiro N.
Published: December 2018

Two people with the same lifespan do not necessarily have the same healthspan. One person may retain locomotor and cognitive functions until the end of life, while another person may lose them during adulthood. Unbiased searches for genes that are required to maintain locomotor capacities during adulthood may uncover key regulators of locomotor healthspan. Here, we take advantage of the relatively short lifespan of the nematodeCaenorhabditis elegansand develop a novel screening procedure to collect mutants with locomotor deficits that become apparent in adulthood. After ethyl methanesulfonate mutagenesis, we isolated fiveC. elegansmutant strains that progressively lose adult locomotor activity. In one of the mutant strains, a nonsense mutation in Elongator Complex Protein Component 2 (elpc-2)causes a progressive decline in locomotor function. Mutants and mutations identified in the present screen may provide insights into mechanisms of age-related locomotor impairment and the maintenance of locomotor healthspan.
Hepatocyte-specific deletion of Pparα promotes NASH in the context of obesity
Authors: Régnier Marion , Polizzi Arnaud , Smati Sarra , Lukowicz Céline , Fougerat Anne , Lippi Yannick , Fouché Edwin , Lasserre Frédéric , Naylies Claire , Bétoulières Colette , Barquissau Valentin , Mouisel Etienne , Bertrand-Michel Justine , Batut Aurélie , Saati Talal Al , Canlet Cécile , Tremblay-Franco Marie , Ellero-Simatos Sandrine , Langin Dominique , Postic Catherine , Wahli Walter , Loiseau Nicolas , Guillou Hervé , Montagner Alexandra
Published: December 2018

Objectives

Peroxisome proliferator activated receptor α (PPARα) acts as a fatty acid sensor to orchestrate the transcription of genes coding for rate-limiting enzymes required for lipid oxidation in hepatocytes. Mice only lacking Pparα in hepatocytes spontaneously develop steatosis without obesity in aging. Altough steatosis is a benign condition it can develop into non alcoholic steatohepatitis (NASH), which may progress to irreversible damage, such as fibrosis and hepatocarcinoma. While NASH appears as a major public health concern worldwide, it remains an unmet medical need. Several drugs are being tested in clinical trials, including pharmacological agonists for the different PPAR isotypes. In current study, we investigated the role of hepatocyte PPARα in a preclinical model of steatosis.

Methods/Results

We have investigated the role of hepatocyte PPARα in a preclinical model of steatosis using High Fat Diet (HFD) feeding as a model of obesity in C57BL/6J male Wild-Type mice (WT), in whole-body (Pparα-/-) mice and in mice lacking Pparα in hepatocyte (Pparαhep-/-). We provide evidence that Pparα deletion in hepatocytes promotes NASH in mice fed an HFD. This enhanced NASH susceptibility occurs without development of glucose intolerance. Moreover, our data reveal that non-hepatocytic PPARα activity predominantly contributes to the metabolic response to HFD.

Conclusion

Taken together, our data support hepatocyte PPARα as being essential to the prevention of steatosis progression to NASH and that extra-hepatocyte PPARα activity contributes to whole-body lipid homeostasis.

Highlights

Pparα deletion in hepatocytes promotes steatosis and inflammation in HFD-induced obesity

Hepatocyte-specific deletion of Pparα dissociates NAFLD from glucose intolerance in HFD-induced obesity obesity

Extrahepatic PPARα activity contributes to the metabolic response to HFD-induced obesity
The Spatio-Temporal Control of Zygotic Genome Activation
Authors: Gentsch George E. , Owens Nick D. L. , Smith James C.
Published: December 2018

One of the earliest and most significant events in embryonic development is zygotic genome activation (ZGA). In several species, bulk transcription begins at the mid-blastula transition (MBT) when, after a certain number of cleavages, the embryo attains a particular nuclear-to-cytoplasmic (N/C) ratio, maternal repressors become sufficiently diluted, and the cell cycle slows down. Here we resolve the frog ZGA in time and space by profiling RNA polymerase II (RNAPII) engagement and its transcriptional readout. We detect a gradual increase in both the quantity and the length of RNAPII elongation before the MBT, revealing that >1,000 zygotic genes disregard the N/C timer for their activation, and that the sizes of newly transcribed genes are not necessarily constrained by cell cycle duration. We also find that Wnt, Nodal and BMP signaling together generate most of the spatio-temporal dynamics of regional ZGA, directing the formation of orthogonal body axes and proportionate germ layers.
Robust candidates for language development and evolution are significantly dysregulated in the blood of people with Williams syndrome
Authors: Benítez-Burraco Antonio , Kimura Ryo
Published: December 2018

Williams syndrome (WS) is a clinical condition entailing cognitive deficits and with an uneven language profile, which has been object of intense inquiry over the last decades. Although WS results from the hemideletion of around two dozens of genes in chromosome 7, no gene has been yet probed to account for, or contribute significantly to, the language problems exhibited by the affected people. In this paper we show that robust candidates for language disorder and for language evolution in the species, located outside the hemideleted region, are up– or downregulated in the blood of subjects with WS. Most of these genes play a role in the development and function of brain areas involved in language processing, which exhibit structural and functional anomalies in people with the condition. Overall, these genes emerge as robust candidates for language dysfunction in WS.
Dietary protein mediates terminal investment in egg quantity or quality following bacterial gut infection in Drosophila
Authors: Hudson Ali L. , Moatt Joshua P. , Vale Pedro F
Published: December 2018

Organisms have evolved a range of behavioural and physiological responses which minimize the impact of infection on fitness. When future reproductive potential is threatened, for example, as a result of pathogenic infection, the terminal investment hypothesis predicts that individuals will respond by investing preferentially in current reproduction. Terminal investment involves reallocating resources to current reproductive effort, so it is likely to be influenced by the quantity and quality of resources acquired through diet. Dietary protein specifically has been shown to impact both immunity and reproductive output in a range of organisms, but its impact on terminal investment during infection is unclear. We tested the effect of dietary protein on terminal investment in the fruit fly Drosophila melanogaster following oral exposure to the opportunist bacterial pathogen Pseudomonas aeruginosa. Oral exposure to bacteria triggered an increase in reproductive investment, but we find that the nature of the terminal investment strategy depended on the level of dietary protein. Flies feeding on a high protein diet increased the number of eggs laid when exposed to P. aeruginosa, while flies fed an isocaloric, lower protein diet did not increase the number of eggs laid but instead showed an increase in egg-to-adult viability following infection. We discuss the importance of considering diet and natural routes of infection when measuring non-immunological defenses.
Taking ‘a rightful place in our own country’: Indigenous self‐determination and the Australian people
Authors: Burney Linda
Published: December 2018

This is an edited transcript of a talk given to the colloquium at the Whitlam Institute held on the 21st February 2018 on the topic of the title of this address. Here Linda Burney indicates the state of play in the Labor Party's response to the ‘Uluru Statement from the Heart’ at that time including this Party's recommendation to the Government that it establish a Joint Select Committee to enable the Commonwealth Parliament's Response. Such a committee was established: ‘On 19 March 2018, the Parliament agreed that a Joint Select Committee on Constitutional Recognition relating to Aboriginal and Torres Strait Islander Peoples be appointed to inquire into and report on matters relating to constitutional change’ (Commonwealth of Australia 2018, 2). Linda Burney is a member of the Joint Select Committee that has produced an Interim Report (July 2018), and which is co‐chaired by Senator Patrick Dodson (First Nations Caucus within the Labor Party) and Julian Leeser, a Coalition Government MP.
Use of Electronic and Paper‐based Standardized Nursing Care Plans to Improve Nurses’ Documentation Quality in a Nigerian Teaching Hospital
Authors: Adereti Chinma Stella , Olaogun Adenike Ayobola
Published: December 2018

PURPOSE

To evaluate the effect of electronic and paper‐based standardized nursing care plans (SNCPs) use on quality of nurses’ documentation.

METHODS

Using quasi‐experimental design, two wards were grouped into electronic and paper‐based wards. Nurses were trained to use electronic‐ and paper‐based SNCPs for care‐planning and documentation. Data was collected before, 3, and 6 months postintervention and analyzed with SPSS version 20.

FINDINGS

There was improvement in documentation quality in the two wards after introducing SNCPs with higher quality scores in the electronic ward postintervention.

CONCLUSION

Providing SNCPs in electronic and paper formats is critical to improving nursing documentation.

IMPLICATION FOR NURSING PRACTICE

Adequate training and support for nurses are needed for successful implementation of SNCPs in electronic health records (EHRs) in developing nations.
Translating the matrix
Authors: Whiteford James R , Arokiasamy Samantha , De Rossi Giulia
Published: December 2018

Linked Articles

This article is part of a themed section on Translating the Matrix. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.1/issuetoc
Diabetic retinopathy in people with Type 2 diabetes and obesity treated by Roux‐en‐Y gastric bypass compared with non‐operated controls: with focus on the role of diabetes remission in a cross‐sectional and a 6‐year follow‐up study
Authors: Madsen L. R. , Bek T. , Richelsen B.
Published: December 2018

Aim

Whether or not Roux‐en‐Y gastric bypass (RYGB) and the derived metabolic improvements are beneficial to diabetic retinopathy is controversial. We aimed to determine the presence and development of retinopathy in individuals with obesity and Type 2 diabetes treated by RYGB compared with non‐operated controls, and to determine the role of diabetes remission.

Methods

We graded fundus photography using the Wisconsin Epidemiologic Study of Diabetic Retinopathy in 96 individuals with obesity and Type 2 diabetes treated by RYGB 6 years after surgery compared with 48 non‐operated controls. In a subsample, we investigated the development of retinopathy over time. In the secondary analysis, we divided the RYGB group according to diabetes remission.

Results

RYGB surgery was not statistically associated with less retinopathy [relative risk (RR) 0.82, 95% CI 0.59 to 1.14], when adjusted for diabetes duration, sex, age and BMI. During 5.9 years of follow‐up, retinopathy grading in the RYGB group was unchanged, whereas the control group displayed worse grading by 0.69 steps (95% CI 0.18 to 1.19). The RYGB group with diabetes remission (52%) showed a trend towards less retinopathy [adjusted RR (aRR) 0.45; 95% CI 0.19 to 1.06] than controls, and less retinopathy (aRR 0.33; 95% CI 0.11 to 0.94) than the RYGB group without remission in the cross‐sectional data.

Conclusions

In a cross‐sectional setting, individuals with Type 2 diabetes treated by RYGB showed a tendency towards less retinopathy than non‐operated controls, in particular diabetes remission following RYGB was associated with less retinopathy. Moreover after 5.9 years, retinopathy in the RYGB group had progressed less than in the control group. (Clinical Trial Registry No: NCT02625649)
Mouthguard sheet temperature after heating under pressure former
Authors: Mizuhashi Fumi , Koide Kaoru , Mizuhashi Ryo
Published: December 2018

Background/Aim

Ethylene vinyl acetate and polyolefin sheets have been used commonly for fabricating mouthguards. However, the change of the sheet temperature during heating of the polyolefin has not been clarified. The aim of this study was to examine the effects of changing the sheet temperature during heating, and to examine whether there were any differences between the sheet materials.

Materials and methods

The mouthguard materials used were 4.0 mm sheets of ethylene vinyl acetate and polyolefin. The sheet temperature of the two materials was measured when the center of the sheet was displaced by 10, 15, and 20 mm from the baseline after heating. The sheets were pressure‐formed when the heating temperatures reached 100°C. Mouthguard thickness and fit were measured at the central incisor and the first molar. Differences in the sheet temperature and the thickness between the sheet materials were analyzed by two‐way analysis of variance.

Results

The sheet temperature of ethylene vinyl acetate and polyolefin sheets became higher as the hanging distance became larger (P < 0.01), and there were statistically significant differences between ethylene vinyl acetate and polyolefin sheets at the hanging distance of 10 and 15 mm (P < 0.01). The thicknesses of the pressure‐formed mouthguard at the central incisor and the first molar were greater in the mouthguards formed by ethylene vinyl acetate sheets than those with polyolefin sheets (P < 0.01 and P < 0.05, respectively). The fit of the mouthguard was not different between mouthguards formed by ethylene vinyl acetate sheets and those formed by polyolefin sheets.

Conclusions

The change of mouthguard sheet temperature during heating was different between ethylene vinyl acetate and polyolefin sheets. The ethylene vinyl acetate sheets maintained the mouthguard thickness in comparison with the polyolefin sheets at the same heating temperature.
Effects of a hybrid intervention combining exergaming and physical therapy among older adults in a long‐term care facility
Authors: Wu Yu‐Zu , Lin Jia‐Yi , Wu Pei‐Ling , Kuo Ying‐Fen
Published: December 2018

Aim

Physical inactivity can cause physical frailty and sarcopenia. We investigated the effects of a hybrid intervention combining commercial exergaming with physical therapy, and clarified the reasons for physical inactivity among older adults.

Methods

This was a pilot study of older participants recruited from a long‐term care facility assigned to either an experimental or a control group. The experimental group received a 90‐min hybrid intervention twice a week for 12 weeks, whereas the control group received only assessment. The outcomes included muscle strength, walking speed, endurance, the Timed Up and Go test, the Berg Balance Scale, flow state, and safety.

Results

We enrolled 17 residents (42.5% of those eligible), with eight in the experimental group. After 12 weeks, the handgrip strength and Timed Up and Go test scores significantly improved in the experimental group. The number of participants with handgrip strength exceeding the cut‐off for sarcopenia, Timed Up and Go test scores exceeding the minimal detectable change, and walking speed exceeding the minimum clinically significant difference were greater in the experimental group than in the control group. Furthermore, no significant adverse events were reported; all participants in the experimental group entered the flow state. Overall, 32.5% of participants reported physical inactivity with common reasons, including laziness (77%), a lack of interest (69%) and the hassle of engagement (46%).

Conclusions

The hybrid intervention is safe and feasible, and could delay disability in older adults. Approximately one‐third of the participants were physically inactive. Further study is required to reduce physical inactivity. Geriatr Gerontol Int 2019; 19: 147–152.
The Estimation of Standard Error from Successive Finite Differences
Authors: Guest P. G.
Published: December 2018

Finite differences have been used to estimate random error in time series, the process being referred to as the variate-difference method (Kendall, 1948; Tintner, 1940). In this note an examination is made of the relative efficiencies of the various estimates of standard error obtained from mean differences and mean square differences (assuming a normal law), and to apply the results to the estimation of the standard error in the fitting of polynomials by means of weighted finite differences.
Subjective Judgment in Statistical Analysis: An Experimental Study
Authors: Finney D. J.
Published: December 2018

As part of an experimental study of the effect of stopping iterative maximum likelihood calculations after one cycle, twenty-one scientists were asked to judge by eye the positions for a pair of parallel probit regression lines in a biological assay. This paper reports the results obtained from each pair of lines after one cycle of various forms of probit calculation. Although all the conditions of the experiment were chosen so as to be unfavourable to the drawing of good lines, one cycle of iteration brought every estimate within 1½ per cent. of the maximum likelihood value, as compared with a range of 32 per cent. and a maximum error of 27 per cent. for the estimates read directly from the graphs. The fiducial limits as calculated after one cycle were brought within a range of about 5 per cent. around the true values.

The subjects for this study were deliberately chosen as having no experience of probit methods. The results confirm me in the opinion I have often expressed, namely that, unless a diagram showing probits plotted against log dose is exceptionally irregular, a single cycle of iteration initiated by any reasonable trial regression line will give a satisfactory approximation. Experience in drawing the trial lines undoubtedly makes the first cycle better still, but even the inexperienced can do quite well. I am in no way suggesting that the critical faculty of the statistician is unnecessary in deciding when iteration may be stopped: care is needed in order to ensure that all doubtful cases have additional cycles, but users of the probit method may find some comfort in the thought that their trial lines are seldom as bad as they fear!

When the form of calculation recently proposed by Cornfield and Mantel was used, results after one cycle were rather better, but, since those by the usual technique were so good, the practical advantage was not great. Additional calculations on some very extreme pairs of trial lines suggest that, if the data were so scanty or so irregular as to make the positions of the lines very uncertain, the Cornfield-Mantel procedure would then be markedly superior: in such circumstances, more than one cycle of iteration would certainly be needed, but this procedure might reduce the number of cycles. A further practical point in connection with data of this type is that an error of making the slopes of the trial lines too small is preferable to an error of making the slopes too large, since the latter is more likely to increase the number of cycles needed or even to make the iteration diverge.
On the Choice of a Mathematical Model to Represent Normal Bacterial Growth
Authors: Kendall David G.
Published: December 2018

The problem considered is that of constructing a stochastic process (not necessarily of the Markov type) to represent the growth of a bacterial colony in the absence of mortality and mutation. The importance of the distribution of fission-times is emphasized, and an approximate relation between the coefficient of variation of the fission-times and the asymptotic coefficient of variation of clone-size is discussed. Rahn’s model of the fission process, a rather different model put forward by the author in 1948 and a more general model (of which the other two are special cases) are examined in relation to the problem of estimating “the number of genes” in bacteria. Reasons are given for supposing that existing estimates of this number (Finney & Martin, 25; Kendall, 20) may be too low. The need for further experimental work (including an experimental determination of clone-size fluctuations) is stressed.
The Random Division of an Interval—Part III
Authors: Moran P. A. P.
Published: December 2018

The present paper is a sequel to two previous papers on this subject (Moran (1947), (1951)), and was suggested by reading Dr. A. Gardner’s recent note (1952). The distribution of the sum of the squares of the intervals into which the line is divided is further considered. The lower 5 per cent. and 1 per cent. points of the distribution can be found exactly up to n = 8 and n = 9 respectively (nine and ten intervals). Beyond about n = 20 an approximation based on the variance ratio distribution is probably adequate. In between n = 9 and n = 20 no workable formula has been reached.
Simple Graphical Techniques for Calculating Serial and Spatial Correlations, and Mean Semi-Squared Differences
Authors: Jowett G. H. , Scott J. F.
Published: December 2018

Two methods of calculating these lag statistics from the graph of a series are described. One, the slide method, uses a scale printed on a glass plate; the other, the tracing method, requires no special apparatus. Both methods give results which are accurate enough for most needs. They may be used for evenly or unevenly spaced series, and are readily adapted to the analysis of concomitant and spatial series.

For evenly spaced series, which alone are conveniently analysed on a desk calculator, the graphical methods compare favourably with it in speed. The tracing method is much quicker when the statistics are required for a large number of lags.
The Factorial Analysis of Crop Productivity
Authors: Banks Charlotte
Published: December 2018

The main purpose of this paper is to illustrate how the methods of factor analysis developed by psychologists to analyse what might be called mental productivity may be usefully applied to agricultural data, in order to deal with such problems as crop productivity.
An Improvement to Wald’s Approximation for Some Properties of Sequential Tests
Authors: Page E. S.
Published: December 2018

A simple modification of the Wald approximations to the operating characteristic and average sample number of a sequential test is given which provides estimates of their values for starting points of the test near the boundaries and an improved approximation for general starting points.
A Simple Presentation of Optimum Sampling Results
Authors: Stuart Alan
Published: December 2018

In this note, several well-known optimum sampling results in the theory of sample surveys are shown to be consequences of the Cauchy inequality. The derivations are simpler than those in the literature (which generally use the Lagrange method for constrained minima) and may be found useful in teaching.
Testing the Approximate Validity of Statistical Hypotheses
Authors: Hodges J. L. , Lehmann E. L.
Published: December 2018

The distinction between statistical significance and material significance in hypotheses testing is discussed. Modifications of the customary tests, in order to test for the absence of material significance, are derived for several parametric problems, for the chi-square test of goodness of fit, and for Student’s hypothesis. The latter permits one to test the hypothesis that the means of two normal populations of equal variance, do not differ by more than a stated amount.
A Table for Predicting the Production from a Group of Machines Under the Care of One Operative
Authors: Cox D. R.
Published: December 2018

A table is given for predicting the rate of production of a large number of machines under the care of one operative. A method is illustrated for examining the effect of random errors of estimation.
Confidence Limits for the Gradient in the Linear Functional Relationship
Authors: Creasy Monica A.
Published: December 2018

Estimates of the gradient in the linear functional relationship have been discussed by Lindley (1947). In this paper methods of obtaining confidence limits for the gradient are suggested.
Analysis of Dispersion with Incomplete Observations on One of the Characters
Authors: Rao C. Radhakrishna
Published: December 2018

In analysis of dispersion (multivariate generalization of the analysis of variance) Wilks' A criterion for testing hypotheses on all the multiple characters simultaneously cannot be applied if some observations on one or more of the characters are missing. In this article is provided a suitable criterion when data become incomplete due to missing observations in one of the characters only. This is the likelihood ratio criterion with a slight modification. The exact moments of this criterion have been found and the distribution has been exhibited in an asymptotic series with the first few terms providing a powerful approximation. Using only the first term one Chi-square and two variance ratio approximations have been suggested, and the Chi-square approximation is recommended for use as the other approximations by themselves without correction terms seem to distort the probabilities.
On Asymptotically Efficient Consistent Estimates of the Spectral Density Function of a Stationary Time Series
Authors: Parzen Emanuel
Published: December 2018

Several general classes of estimates of the spectral density function of a stationary time series are introduced, which are shown to include most estimates previously suggested by various researchers. Asymptotic expressions are given for the mean square error of these estimates. We thus determine, for each estimate, the class of time series for whose spectral density it is a consistent estimate. Further, for a given time series, the minimum integrated mean square error with which its spectral density may be estimated is determined, and evaluated for large sample sizes. Efficient estimates are defined as those which achieve, asymptotically, the minimum mean integrated square error. The asymptotic formulae derived are used to make a numerical comparison of some estimates which have been suggested. However, in this paper no conclusions are drawn or principles enunciated as to how to proceed in practice to estimate the spectral density.
A Concise Derivation of General Orthogonal Polynomials
Authors: Cox C. P.
Published: December 2018

The general form of orthogonal polynomials in regression is derived concisely by the Schweinsian expansion of a determinant.
Behaviour Sequences as Semi-Markov Chains
Authors: Cane Violet R.
Published: December 2018

Some experiments on birds, fish and insects, in which long records of steady-state behaviour are obtained, are described and the relative merits of three simple models of behaviour considered. As a first approximation, semi-Markov chains seem to offer a reasonable way of summarizing the data and provide suitable null hypotheses against which to test ethological theories.
The Estimation of Relationships with Autocorrelated Residuals by the Use of Instrumental Variables
Authors: Sargan J. D.
Published: December 2018

The instrumental variables method of estimating the coefficients of a linear relationship between time series which have measurement errors is applied to the case where the coefficients are functions of a set of parameters. The asymptotic error variance matrix of the estimates is obtained, asymptotic tests for the existence and identification of the suggested form of relationship are suggested, and asymptotic confidence regions are given. The general theory is then applied to the case of a relationship with an autoregressive residual, and practical computational methods are suggested.
Experiments with Mixtures
Authors: Quenouille M. H.
Published: December 2018

The difference is discussed between a model for experiments with mixtures proposed recently by Scheffé and an earlier model of the author's.
Some Results for the Queue with Poisson Arrivals
Authors: Prabhu N. U.
Published: December 2018

This paper is concerned with the queueing system in which (1) there is only one counter, (2) the customers arrive at random and are served in the order of arrival, and (3) the service-time distribution has a general form. The distribution of the time taken for a waiting-time x to reduce to zero for the first time is obtained, and from this are deduced the explicit expressions for the distributions of (i) the length of the busy period, (ii) the number of customers served during a busy period, and (iii) the time taken for a queue of given length to disappear.
Two Papers on Applications of Stochastic Processes to Road Traffic Problems: Delays on a Two-Lane Road
Authors: Tanner J. C.
Published: December 2018

A theoretical formula is found for the average speed achieved over a long journey by a vehicle travelling along a road according to certain rules governing overtaking, when the other traffic on the road is postulated to be of a particularly simple kind.

Except for the vehicle whose behaviour is studied, vehicles in each direction travel at the same speed, and are spaced at random, but with a certain minimum distance between vehicles. The vehicle being studied wishes to travel faster than the other vehicles; when it overtakes, it must pass the whole of a bunch of vehicles at minimum spacing in a single manoeuvre. It overtakes without delay if there is a sufficient gap in the opposing traffic. If delay occurs, then a greater gap in the opposing traffic is required, to allow for time lost in accelerating. An alternative application of the theory is to one half of a dual carriageway, in which the two traffic lanes are occupied by vehicles travelling at two different speeds.

A curious feature of the results is that when the traffic flows increase beyond a certain level, appreciably below the theoretical capacity of the road, the fast vehicle cannot maintain a higher average speed than that of the other vehicles: the whole time is spent waiting for opportunities to overtake, and the average wait per overtaking becomes infinite.

Numerical values of the average speed have been tabulated using an electronic computer. Standard values of all the constants of the model were selected for two-way and one-way roads separately, and these constants were then varied two, three or four at a time. Two general conclusions are indicated by the numerical results. Firstly, more acceleration, obtained at the expense of reduced maximum speed (and perhaps greater fuel consumption) by lowering the top gear ratio, would probably provide increased mean journey speeds for most modern cars under typical traffic conditions. Secondly, the cutting of safety margins and clearances when overtaking would not normally provide any worthwhile increase in mean journey speed.
A Note on the Renewal Function When the Mean Renewal Lifetime is Infinite
Authors: Smith Walter L.
Published: December 2018

The so-called Elementary Renewal Theorem, which is a fairly direct deduction from the strong law of large numbers, assumes that the mean renewal lifetime is finite and describes the asymptotic behaviour of H(x)/x as x → ∞, where H(x) is the expected number of renewals in the time interval (0, x). In this paper the behaviour of H(x)/x is discussed for certain cases in which the mean renewal lifetime is infinite. The arguments are elementary, and the results complement some obtained earlier by Feller using deep Tauberian methods.
On Multivariate Sign Tests
Authors: Bennett B. M.
Published: December 2018

Certain properties of the multivariate normal integral are used to develop sign tests for the equality of means in two correlated multivariate populations with p ≤ 4 characters each. A numerical example from the anthropometric data of Frets illustrates the particular case p = 2.
Interactions in Multi-Factor Contingency Tables
Authors: Darroch J. N.
Published: December 2018

Interactions in contingency tables are compared with interactions in the analysis of variance. The comparison leads to a new formulation of the hypothesis of no second-order interaction in three-way contingency tables, to an explanation of the paradoxes associated with this hypothesis and to a comparatively simple method of constructing its likelihood-ratio test statistic. The extensions to higher-order interactions are merely outlined as they are not likely to be of practical interest.
A Simple Randomization Procedure
Authors: Sandelius Martin
Published: December 2018

The paper describes a randomization procedure consisting in distributing a deck of cards into 10 decks using random decimal digits and repeating this step with each deck consisting of three or more cards. One random digit is used for randomizing a deck of two cards. This procedure, which is essentially a particular case of a general procedure described by Rao (1961), is called the multistage randomization procedure, or MRP. Some applications are described. A recursive formula is given for the expected number of random digits required by MRP for the randomization of n symbols. A measure of the efficiency of a randomization procedure is presented. The efficiency of MRP is compared with the efficiencies of two other randomization procedures, and it is proved that MRP has an asymptotic efficiency of 100 per cent.
Estimation of the Parameters in Short Markov Sequences
Authors: Edwards A. W. F.
Published: December 2018

A parametric representation of a two-state Markov process is given which enables the maximum-likelihood estimates of the two parameters to be found without iteration.
A Minimax-Regret Procedure for Choosing between Two Populations Using Sequential Sampling
Authors: Johnson N. L. , Maurice Rita J.
Published: December 2018

In this paper are considered sequential sampling procedures for two normal populations when it is required to select the one with the larger mean. The sequential probability ratio procedure is derived which minimizes the maximum regret (excess of expected loss over minimum possible expected loss) resulting from ignorance of the population means. The expected loss of the resulting sampling and selection procedure is compared with the expected loss when the procedure which minimizes the maximum expected loss is used.
Applications of Jordan’s Procedure for Matrix Inversion in Multiple Regression and Multivariate Distance Analysis
Authors: Jowett G. H.
Published: December 2018

When applied to a matrix of mean squares and products, Jordan’s procedure is rich in intermediate quantities of potentially useful application in multiple regression. It also supplies a convenient method of partitioning the multivariate distance criterion D2 into single degrees of freedom.
Some Numerical Results for the Queueing System D/EK/1
Authors: Pike M. C.
Published: December 2018

Numerical, as opposed to Monte Carlo, methods have been used to study the appointment schemes recommended by Bailey (1955) to equalize the average waiting-times of successive customers in the finite queue. Results are presented to illustrate the exact nature of Bailey's proposed scheme and a simple method is given for obtaining approximate values of mean waiting-times and total mean idle-time (of the server). The roots of the integral equation describing the equilibrium distribution of D/Ek/1 are given for k = 1(1) 5 and the traffic intensity p = ***·1(***·05) ***·8(***·01) ***·99; and the mean waiting-times are given for the same range of k and ρ.
Estimation of the Spectral Density Function in the Presence of Harmonic Components
Authors: Priestley M. B.
Published: December 2018

Consider a stationary process of the form Xt = Yt + Zt, where Yt is a linear process with a continuous spectrum, and Zt is a finite sum of harmonic components. We discuss two methods of estimating the spectral density function of Yt. In one method we first estimate the autocovariance function of Yt by “correcting” the sample autocovariance function of Xt, and then form the usual “smoothed” Fourier transform. In the other approach, we estimate the spectral density function directly from the autocovariance function of Xt by using the “double weight function” technique.
Mixture Designs for Four Factors
Authors: Draper N. R. , Lawrence W. E.
Published: December 2018

Scheffé, in two recent papers (1958, 1963), has given designs for experimenting with mixtures. The basis of these designs is the choice of symmetrical arrangements of points in the factor space and the fitting of carefully chosen models which have exactly as many coefficients as there are data points. The designs are such that some of the experiments do not contain any of one or more ingredients of the mixture. This may or may not be a disadvantage depending on the problem involved. Here an alternative form of design selection is made for the case of mixtures of four factors. It extends the method used in the three-factor case in an earlier paper (Draper and Lawrence, 1965b). This involves the premise that, in the absence of specialist knowledge about the form of the true response function, it is desired to fit a response surface equation of first or second order over the factor space of possible mixtures, and experimental runs are needed which, in a certain sense, ensure the best surface fit possible. The principles used in the choice of appropriate designs will be those originally introduced by Box and Draper (1959).
On the Waiting-Time Distribution for Queues in Series
Authors: Loynes R. M.
Published: December 2018

Suppose that customers leaving a queue M/E  2/1 immediately join another single-server queue in which the service-time is negative exponential: it will be shown that in equilibrium (if it is possible) the characteristic function of the waiting-time in the second queue is not meromorphic. This is somewhat surprising, and disagrees with a result of Ghosal (1962). If the first queue is of the type E  2/M/1 a similar though weaker result is obtained.
On Simple Rules for the Compound Decision Problem
Authors: Samuel Ester
Published: December 2018

The general non-sequential and sequential compound decision problem is considered. A rule is simple if it uses the ith observation only, in order to make the ith decision. It is shown that simple rules, the components of which are Bayes rules for the component problem, are Bayes rules also for the compound problem, and hence, under certain regularity conditions, are admissible compound rules. Nevertheless, a property (A), usually aimed at in the compound situation, cannot be achieved by any simple rule, except in trivial cases.
Sequential Compound Rules for the Finite Decision Problem
Authors: Samuel Ester
Published: December 2018

Asymptotically optimal rules are obtained for the sequential compound decision problem, where the component problem involves a finite parameter space and a finite action space. It is shown that under some regularity conditions the rule, which at each stage is a Bayes rule with respect to an estimate of the empirical distribution of the previous parameters, is asymptotically optimal. In the general situation, a randomized version of this rule is asymptotically optimal. Convergence of the compound risks and of the corresponding losses are considered.
A Generalized Least-Squares Approach to Linear Functional Relationships
Authors: Sprent P.
Published: December 2018

A linear functional relationship between mathematical variables is postulated. The problem considered is the estimation of this relationship given observed random variate values, various assumptions being made about the distribution of the departures of these from the corresponding mathematical variable values. The least-squares principle is generalized to deal with cases in which these departures are correlated. The bivariate case is considered in detail. Extension to p variates involves no new principle if only a single linear relationship is postulated. A simple application in growth studies is discussed.
Locally Unbiased Type M Test
Authors: Krishnan Marakatha
Published: December 2018

In certain tests of hypotheses concerning more than one parameter, it is found that the criterion of unbiasedness cannot be satisfied. In such situations, it is proposed to make the test locally unbiased in a modified sense, termed Type M. Here the power surface in the parametric space does not always lie above the level of significance of the test. However, the mean value of the power, in a small neighbourhood of the null point, exceeds the significance level. This paper demonstrates that the uniformly most powerful unbiased (UMPU) test (based on the sample sum of squares) for a normal variance (Neyman and Pearson, 1936; Rao, 1952; Ramachandran, 1958) is Type M unbiased against the wider class of alternatives permitting the means of the observations to differ, and similarly that the UMPU test (based on the sample variance ratio) for a population variance ratio is Type M unbiased against the same widened class of alternatives.
The Almost Full Dam with Poisson Input : Further Results
Authors: Hasofer A. M.
Published: December 2018

The dam model investigated has infinite depth, unit release per unit time, and inputs which form a compound Poisson process.

The time-dependent content distribution for arbitrary initial content is obtained explicitly by a direct method and its asymptotic properties are investigated. The distribution of the time to first overflow as well as the probability of no overflow are also obtained explicitly by a similar method.
A Modified Model for Rainfall Occurrence
Authors: Green J. R.
Published: December 2018

A class of models is considered, each including a periodicity, to generalize an earlier model used to describe rainfall occurrence at Tel Aviv and elsewhere (Green, 1964, 1965).
The Behaviour of the Variance Function of the Difference between Two Estimated Responses
Authors: Herzberg Agnes M.
Published: December 2018

In this paper the variance function of the difference between the estimated responses at any two points in the factor space is developed. In particular, the variance function is considered when the design used is rotatable. The variance function in this situation is a function of the distances of the points from the origin of the design and the angle subtending the points at the origin. Variance functions for first-order and second-order rotatable designs are discussed in detail when the two points are equidistant from the origin of the design. Examples of the variance function for a rotatable and a non-rotatable design in two dimensions are given.
Estimating the Covariance and Spectral Density Functions from a Clipped Stationary Time Series
Authors: McNeil D. R.
Published: December 2018

When estimating the covariance functions of a stationary time series from a digitalized record, adjustments to the estimates must be made to correct for the bias caused by digitalizing. In this paper we investigate a method which provides consistent estimates of the covariance and the spectral density functions, and discuss their asymptotic efficiencies.
On John's Cyclic Incomplete Block Designs
Authors: Clatworthy Willard H.
Published: December 2018

J. A. John (1966) has recently constructed a large number of cyclic incomplete block designs. A small proportion of these were incompletely identified as partially balanced incomplete block designs with two associate classes. Further identification of these particular designs is made and prior work in this area is brought to light.
A Non-Parametric Test for the Bivariate Two-Sample Location Problem
Authors: Mardia K. V.
Published: December 2018

An unconditional non-parametric test for the bivariate two-sample problem is proposed. The test is shown to possess various desirable properties. We give critical values of the distribution, some approximations and its asymptotic distribution. For the shift type of alternative hypotheses, we show here that U is distributed asymptotically as a non-central chi-square. We have derived its Pitman's asymptotic efficiency relative to Hotelling's T  2 for these alternatives and shown that in the normal case the ARE is ¼π. Suitable examples are constructed to show that the ARE can approach zero and infinity. An extension to the multivariate multi-sample problem is also indicated.