bluuebunny/crossref_metadata_2025 huggingface dataset:
Does farm-scale habitat composition predict pest-bird numbers and distribution?
Authors: MacLeod Catriona J. , Tompkins Daniel M. , Drew Keven W. , Pyke Nick
Published: November 2011

Context Bird damage to horticultural crops causes significant economic losses for growers around the globe. However, bird damage is unpredictable and pest-bird movements and abundance patterns are poorly understood. Aims To assess whether habitat management is likely to be an effective approach for controlling two pest-bird species (house sparrow, Passer domesticus, and greenfinch, Carduelis chloris) in New Zealand’s arable landscape. Methods Breeding- and winter-bird and habitat surveys were carried out over a 3-year period (2003–05) on 19 1-km × 1-km squares with arable crops on the Canterbury Plains, New Zealand. Bird abundance and/or distribution were analysed with respect to both temporal and spatial (crop- and boundary-habitat composition) variables. Results Estimated breeding-season densities for house sparrow were higher but more stable than those for greenfinch (which increased by 70% over a 3-year period), and for individual farms were more predictable across years than were winter densities. Boundary habitat was the best predictor of bird densities and distribution in the breeding season; features associated with enhanced seed abundance or access were important in the winter. However, habitat composition alone could not account for temporal and spatial variation in bird densities on farms. Conclusions Either habitat management or the reduction of key seed resources could potentially control pest-bird numbers. However, habitat management is likely to have adverse consequences for other important functions (such as the shelter and biodiversity benefits of shelterbelts), and any form of bird control applied at the farm scale is unlikely to be effective. Implications To make control actions both effective and economically viable, a coordinated program involving multiple farms is likely to be needed. We recommend investigating the effectiveness of an experimental manipulation of key food resources at the landscape scale.
Distance does matter: close approaches by boats impede feeding and resting behaviour of Indo-Pacific bottlenose dolphins
Authors: Steckenreuter Andre , Harcourt Robert , Möller Luciana
Published: November 2011

Context
Potential impacts of human disturbance on animal populations can be measured as behavioural responses and may affect the survival and fecundity of animals. In areas where human–wildlife interactions occur, conservation management needs to be in place to secure both a viable tourism industry and the sustainability of the targeted species.

Aims
We sought to evaluate whether different approach distances by boat have effects on the behaviour and group cohesion of dolphins that are targeted by Australia’s largest dolphin-watching industry.

Methods
The effects of different approach distances of boats on the behavioural states of dolphins, group dispersal and direction of movement were investigated in this area by controlled boat experiments conducted between August 2008 and December 2009.

Key results
Results showed that there was significantly less feeding when boats approached dolphin groups to a distance of 50 m than when they did to a distance of 150 m, or with controlled approaches. Resting was also observed significantly less when boats approached to a distance of 50 m than when they approached to a distance of 150 m. The dispersal of dolphin groups was significantly tighter (less dispersed) when boats approached to 50 m than that with 150-m-distance or controlled approaches. Furthermore, the dolphins’ direction of movement was less neutral when the experimental boat approaches were carried out at a distance of 50 m than when they were carried out at a distance of 150 m, or with controlled approaches. Similar results were also obtained for dolphin groups including calves.

Conclusions
On the basis of the results from this study, we recommend that the existing New South Wales regulations, which stipulate that dolphin-watching boats keep a distance of 50 m to groups with adults only and 150 m to groups with calves, are maintained within the Port Stephens–Great Lakes Marine Park (PSGLMP).

Implications
Management plans whose stated goals include both sustainability of a dolphin-watching industry and longer-term viability of a dolphin population may reconcile conflicting objectives and improve their decision making by using these empirical measures rather than best guesses.
Validation of Administrative Population-Based Data Sets for the Detection of Cesarean Delivery Surgical Site Infection
Authors: Daneman Nick , Ma Xiaomu , Eng-Chong Melanie , Callery Sandra , Guttmann Astrid
Published: November 2011

We validated population-based hospital, emergency room, and physician claim databases for the detection of surgical site infections against the reference standard of clinical surveillance. Although these data sets are highly specific and could be used to define research cohorts, their low sensitivity and positive predictive value make them inadequate for use as quality indicators.
A Real-Life Snapshot of the Use and Abuse of Urinary Catheters on General Medical Wards
Authors: Harley Geoffrey , Yeo Ai Li , Stuart Rhonda L. , Dendle Claire
Published: November 2011

An observational study was performed on 2 wards in a tertiary hospital to determine staff awareness, knowledge, and documentation of catheter use and the effects these have on duration of catheterization. Overall, there was poor knowledge of the indications and date of catheterization. Doctor awareness decreases duration of catheterization.
Frequency chirping during a fishbone burst
Authors: Marchenko V.S. , Reznik S.N.
Published: November 2011

It is shown that frequency chirping during fishbone activity can be attributed to the reactive torque exerted on the plasma during the instability burst, which slows down plasma rotation inside the q = 1 surface and reduces the mode frequency in the lab frame. Estimates show that the peak value of this torque can exceed the neutral beam torque in modern tokamaks. The simple line-broadened quasilinear burst model (Berk et al
1995 Nucl. Fusion
35 1661), properly adapted for the fishbone case, is capable of reproducing the key features of the bursting mode.
Biogeographic patterns in scaled chrysophytes from the east coast of North America
Authors: SIVER PETER A. , LOTT ANNE M.
Published: November 2011

1. We assessed the distribution of scaled chrysophytes in fresh waters along 3200 km of the east coast of North America (29° to 48°N) to determine any biogeographic patterns in relation to chemical, physical, climatic and spatial variables.

2. Scaled chrysophytes were identified using scanning electron microscopy and counted from 264 waterbodies in nine regions (20 subregions). Eighteen chemical, physical and climate variables were determined for each waterbody. We used Sorensen’s similarity index and analysis of similarity (ANOSIM) to evaluate whether the floras differed between regions, subregions, glaciated and non‐glaciated areas, as well as within sets of waterbodies with similar chemical and physical characteristics but situated in different regions. Distance‐based linear modelling (DISTLM) was used to evaluate the relative importance of the chemical, physical and climate factors in explaining the variability in the assemblages of scaled chrysophytes, and the resulting models were visualised using redundancy analysis (RDA).

3. Significant differences in the flora were found between all regions and most subregions, and between glaciated and non‐glaciated areas. Significant differences were also recorded between waterbodies with similar chemical and physical characteristics but situated in different regions. Many species were abundant along specific sections of the latitudinal gradient, but lacking from others. A set of environmental variables explained significant and independent portions of the variation in scaled chrysophytes, with pH and mean minimum July temperature accounting for 20% of the total.

4. The distribution of scaled chrysophytes along the east coast of North America is not homogeneous and there are biogeographic patterns, despite apparent dispersal mechanisms (migratory birds and wind events) that might act to reduce differences between regions. Rather, differences exist even between neighbouring subregions containing sites with statistically similar chemical and physical attributes. Environmental variables clearly play a significant role in determining whether species will inhabit a given site. However, species were not always found in waterbodies likely to support growth, implicating inadequate dispersal, poor transportability or both.
Voltage dependence of the tunnelling current: An exact expression
Authors: Noguera Claudine
Published: November 2011

An exact expression for the tunnelling current measured with a scanning tunnelling microscope (STM) is obtained. It clarifies the information deducible from the ‘spectroscopic mode’ of the STM and raises the question of the observability of surface states. The connection with the Transfer Hamiltonian approach is made, and the conditions of validity of the latter are analysed.
Single‐electron effects observed with a low‐temperature STM
Authors: van Bentum P. J. M. , van de Leemput L. E. C. , Smokers R. T. M. , van Kempen H.
Published: November 2011

We have used a low‐temperature scanning tunnelling microscope to study the effect of the Coulomb charging energy on the tunnelling behaviour of low capacitance point‐contact junctions. The tunnelling I‐V characteristics between a tungsten tip and various materials, such as stainless steel, aluminium, carbon and YBa2Cu3O7‐δ, show a quadratic behaviour at low voltages and a displaced asymptotic behaviour at high voltages. The I‐V characteristics can be quantitatively understood using the model of single‐electron tunnelling induced by the Coulomb blockade. The capacitances of this type of point‐contact tunnel junctions are in the 10−18 F range, and are adjustable by varying the distance between tip and surface. These capacitances are at least two orders of magnitude lower than can presently be achieved by electron lithography.

In a series configuration of two low‐capacitance tunnel junctions, with an isolated small particle as a common electrode, we have observed the so‐called Coulomb staircase, due to the quantization of the charge on a single small particle.

The experimental results are in good agreement with semi‐classical Monte‐Carlo simulations.

The low capacitance of an STM assembly can cause a serious complication in the interpretation of low temperature spectroscopic data. We will discuss the implications for the measurements on superconductors, and for the case of inelastic tunnelling spectroscopy.
An exact calculation of the voltage‐dependent tunnelling current in simple one‐dimensional models: Comparison with the Bardeen perturbation approach
Authors: Sacks W. S. , Noguera C.
Published: November 2011

In this paper we present an exact calculation of the tunnelling current for two different one‐dimensional barrier potentials. The purpose is twofold: First, we demonstrate the feasibility of applying the new method of C. Noguera as a direct analytical tool for solving tunnelling problems in the case of independent electrons. In this approach, the tunnelling current is expressed in terms of the logarithmic derivative of the Green's function which must be evaluated at the cutting surface. This can be done analytically in the one‐dimensional case. Secondly, we compare these results with the corresponding tunnelling current obtained using the Bardeen perturbation method, valid only in the large barrier limit. In particular, we investigate the use of the Bardeen approach in describing tunnelling spectroscopy. The dynamic conductance dI/dV, as a function of bias and barrier width, is compared in both cases.
A small scanning tunnelling microscope with large scan range for biological studies
Authors: Emch R. , Descouts P. , Niedermann Ph.
Published: November 2011

We have developed a scanning tunnelling microscope specially designed for biological applications presenting some new features: the scanner tube is mounted parallel to the surface of the sample which enables a high resolution optical microscope to be brought close to the sample when working in air or liquids. The maximum scan range is 5×20 μm with a vertical range of 20 μm and the total size of the system does not exceed 10×40 mm. The piezo‐sensitivity of the scanner tube versus applied voltage was analysed by interferometry measurements and by using scanning tunnelling microscopes. We found a value for the piezoelectric constant d13 of −1·71 Å/V at low voltages (under a few volts) going up to −2 Å/V for higher voltages. Large‐scale images of a carbon grid showed a surprisingly good linearity of the scanner tube.
Imaging of granular high‐Tc thin films using a scanning tunnelling microscope with large scan range
Authors: Niedermann Ph. , Fischer Ø.
Published: November 2011

STM images are presented in the micron scale, taken in UHV with a single‐tube scanner STM with SEM control of the tip position. For calibration, a carbon grid was used from which the coupling of x and y scan axes has been determined as well as the piezo‐sensitivity factors. Images taken of a YBa2Cu3O7‐δ, film display the granular structure of the crystallites formed during the post‐evaporation annealing. A direct comparison of STM scans with SEM micrographs was made which demonstrates the complementary information obtained by the two methods. The obtained resolution is compared to the tip shape which becomes crucial for the imaging of corrugated surfaces on the micron scale. With a simple geometric model, an attempt has been made to reconstruct the surface topography from STM scans based on the knowledge of the tip shape.
Correspondence
Authors: Smith H. L. , Tatem J. G. , Davis H. , Butterworth John
Published: November 2011

The French Erecting Prism a Camera Lucida

Linear Projection and Rotifers

Coal Plants
IX—A short Statement upon the Theory, and the Phenomena of Purpose and Intelligence exhibited by the Protozoa, as illustrated by Selection and Behaviour in the Forminnifera.*
Authors: Heron‐Allen Edward
Published: November 2011

“Unless we set out with the preconception that mind is the prerogative of man, the question whether mind is co‐extensive with living protoplasm, or is the possession of only the more highly organized animals must at some time suggest itself. But whatever prejudices we may hold, it is incumbent upon us before definitely accepting either view, to ascertain if possible the level at which the first manifestations of mind occur.”
Xiv.—An Improved Method Of Orientating Minute Specimens For Section Cutting
Authors: Wilson Douglas P.
Published: November 2011

Various methods have been described for the cutting of sections of minute objects in definite planes, and of those tried Newth's second method (1919, p. 548) most nearly approaches perfection. It forms the substantial basis of the technique here described. The latter is, indeed, really a modification in detail of this method of Newth's, but these modified details so increase the efficiency of the process that it is felt they should be placed on record. Workers nearly always experience difficulty the first time they attempt a technique involving double embedding in collodion and paraffin wax, and it is hoped that the full instructions here given will be of help to them. At the best of times the method is admittedly uncertain and tricky, but by paying throughout scrupulous attention to what at first sight may appear to be unimportant details, the number of wasted slides will not be very large.
I.—IMPROVED IMAGE ILLUMINATION AND CONTRAST WITH THE METALLURGICAL MICROSCOPE
Authors: Taylor E. Wilfred
Published: November 2011

The practice of coating glass surfaces in order to reduce the reflected and increase the transmitted light is now well known, but little attention has so far been given to the particular problems presented by the microscope objective. It will be shown that much can be done to improve observing conditions when a cover‐glass illuminator is used, and in this connection the requirements of the metallurgist will receive special consideration. It will be shown that the coating of glass surfaces may result in a marked diminution of fogging light and to enhanced contrast in the image, and also in the more efficient operation of tbe cover‐glass illuminator.
“OPTICAL MEMBRANES”: A COMMON ARTEFACT
Authors: Oettlé A. G.
Published: November 2011

SYNOPSIS.

A common group of optical artefacts is described in which regions of phase or amplitude change in the object appear in sharp outline in the image, where they may be misinterpreted and regarded as evidence of the presence of actual membranes. It is shown that these appearances are always encountered with dark‐ground illumination, of both types, oblique and central, provided the object is large enough to be resolved. Similar effects can also be obtained with bright‐ground illumination and various phase‐contrast methods.

With phase‐retarding objects in positive phase‐contrast, the appearance of a black outline to image detail is seen when reversal of contrast occurs. This is seen when the object produces higher phase change than the optimum for the particular system. This optimum depends on the ratio of direct to diffracted light: the less direct light is transmitted, the lower is the optimum range of phase change in the object.
VARIABLE DARK‐GROUND ILLUMINATION
Authors: Hartley W. G.
Published: November 2011

SYNOPSIS.

By exploiting the property of polarization, the intensity of the light directly entering an objective can be controlled, so that the illumination of the specimen may be adjusted between critical bright and dark field conditions.

The use of a suitable Polaroid substage stop in conjunction with an analyser is described, discussed, and also the conversion of an immersion paraboloid to this use. Bn &‐focal illuminating system of 0.86 N.A., suitable for this and a variety of other uses, is also described
THE DEVELOPMENT OF THE RAT SPERMATID
Authors: Austin C. R. , Sapsford C. S.
Published: November 2011

SYNOPSIS.

The stages of development of the rat spermatid as seen with the phase‐contrast microscope are described and illustrated. The process as thus discerned is generally consistent with previous accounts, but differs in certain particulars.

The short dark rods in the Golgi apparatus of the early spermatids form a U‐shaped structure at later stages.

The bead deposited by the Golgi apparatus upon the surface of the nucleus is developed by the coalescence of three or four small beads or granules which make their appearance in the Golgi apparatus.

The axial filaments of the early spermatids are generally seen entirely confined within the cytoplasm and often exhibit vigorous motility in this situation.

Three centrioles are seen for a limited period of spermatid development.

The transformation of the spermatid nucleus into the sperm head occurs by a process of lateral development and not by anterior extension.

The meaning of the terms “acrosome” and “perforatorium” is discussed. It is considered that the rod (“acrosome”) is a thickened part of the head‐cap, and that the bead probably does not contribute directly to the formation of the rod.

The mature sperm head is composed of four major parts—nucleus, rod, vesicle, and head‐cap. It is suggested that the vesicle lying near the tip of the head may carry an active agent for the penetration of the zona pellucida.
A FURTHER CONTRIBUTION TO THE KNOWLEDGE OF THE DIATOM GENUS MASTOGLOIA
Authors: Voigt Manfred
Published: November 2011

SYNOPSIS

A number of new species and varieties of Mastogloia are described from material from the Indonesian Archipelago and the South China sea. In addition, extensions to the range of previously described species are given.
III.—OBSERVATIONS ON MICROSCOPE CONDENSERS, OBJECTIVES, AND EYEPIECES.: III. Microscope Eyepieces
Authors: Payne B. O.
Published: November 2011

SYNOPSIS.

The requirements for microscope eyepieces for visual use are considered and the possibilities of achieving them are discussed in relation to the conditions under which the system is required to work. Eyepieces of various types for both visual and photomicrographic purposes are described and illustrated.
VII.—GALVANOTROPIC FRACTIONATION OP RUMEN CILIATES
Authors: Masson M. J. , Iggo A. , Reid E. S. , Mann G. P.
Published: November 2011

A technique for the galvanotropic separation of indigenous ciliate protozoa from the rumen contents of sheep is presented. A fractionation of these isolated protozoa into three populations—isotrichs, large oligotrichs, small oligotrichs—is described and illustrated. Some applications of these findings in rumen microbiology are enumerated.
VI.—RHABDOMYOSARCOMAS IN THE ALBINO RAT
Authors: Haddow A. , Timmis G. M. , Horning E. S.
Published: November 2011

SYNOPSIS

1. Out of a total of twenty Albino rats one male and one female developed rhabdomyosarcoma during treatment with 5‐β‐naphthyl‐2: 4: 6‐triaminoazopyrimidine.

2. The primary striated muscle tumour which arose in either the spermatic cord or the epididymis of the male rodent formed metastases in most organs of the body. Dissemination appears to have taken place via the lymphatic pathway.

3. The histology of these tumours has been described in detail and problems relating to the ætiology and behaviour of these rare growths have been discussed.
VII.—PHOTOMICROGRAPHY WITH THE BURCH REFLECTING MICROSCOPE
Authors: King R. J. , Roe E. M. F.
Published: November 2011

SYNOPSIS

A brief survey of the characteristics of reflecting microscopes is given, with particular reference to the Burch microscope. Accessory optical equipment for photomicrography with this microscope in the visible and ultra‐violet is described, and the adjustment of the objective and condenser mirror pairs is discussed. Some typical photomicrographs are shown.
IX.—AN IMPROVED PHASE‐CONTRAST MICROSCOPE WITH VARIABLE AMPLITUDE AND PHASE DIFFERENCE
Authors: Payne B. O.
Published: November 2011

SYNOPSIS

An instrument is described in which the back focal plane of the objective is re‐imaged into a more accessible position by the aid of a concave mirror without the introduction of any additional air‐glass interfaces. As a result, interchange of phase plates is greatly facilitated and amplitude and phase variation can be achieved efficiently at all powers.
THE MANUFACTURE AND TOLERANCING OF SCREW THREADS ON OPTICAL COMPONENTS, WITH SPECIAL REFERENCE TO THE R.M.S. MICROSCOPE OBJECTIVE AND NOSEPIECE THREADS
Authors: Nickols L. W.
Published: November 2011

SYNOPSIS

A review is made of the current practice and problems of manufacturing and gauging screw threads of fine pitch on optical components. Comments are made on a recent United States draft Standard for microscope objective and nosepiece threads. Finally, recommendations are made for the revision of the R.M.S. Standard for microscope objective and nosepiece threads.
A TECHNIQUE FOR TRANSFERRING CELLS PREPARED ON FORMVAR COATED SLIDES TO ELECTRON MICROSCOPE SPECIMEN GRIDS
Authors: Epstein M. A.
Published: November 2011

SYNOPSIS

A technique is described for transferring cells prepared on slides coated with Formvar to specimen supporting grids of the electron microscope.
RECENT OBSERVATIONS BY LIGHT AND ELECTRON MICROSCOPY ON THE CYTOPLASMIC INCLUSIONS OF THE NEURONES OF PATELLA VULGATA
Authors: Lacy D. , Rogers G. E.
Published: November 2011

SYNOPSIS

A preliminary report is given of observations made on the neurones of the pedal ganglia of Patella vulgata. Three types of cytoplasmic inclusions have been seen in these cells—mitochondria, lipochondria, and Golgi apparatus. The dictyosomes described by other workers probably correspond to pairs of Golgi membranes together with the dense (osmiophilic) substance they enclose. The archoplasm probably corresponds to numerous small Golgi vesicles.
CARBON SURFACE REPLICAS FOR ELECTRON MICROSCOPY AND ELECTRON DIFFRACTION
Authors: Scott D. B. , Wyckoff R. W. G.
Published: November 2011

SYNOPSIS

A technique is described for using evaporated carbon films in the preparation of pseudo‐replicas that can be employed for both electron microscopy and electron diffraction. The areas selected microscopically for diffraction can be as small as one square micron. Fluorescent X‐ray analyses can frequently be carried out on the same preparations.

The procedure is illustrated from current investigations of tooth enamel and with pseudo‐replicas from a variety of other solids.
NOTES ON MULTIPLE IMAGE FORMATION BY AEROSOL PARTICLES AT SUBMERGED BUBBLE SURFACES, AND ITS RELEVANCE TO A SURFACE FILM
Authors: Gardiner M. W.
Published: November 2011

SYNOPSIS

Radial striations are shown to be present as fixed appearances in the refraction rings of submerged bubbles in diverse media, and to be due to aerosol particles at the surface. They are shown to be of multiple origin, being composed of brighter parts of concentric rings of light which may be produced in this usually dark zone. Possible causes of these phenomena are discussed in relation to the bubble surface. It is concluded that the bubbles are surrounded by thin layers of static material of different refractive index from the bulk of the liquid, and that the “radial striations” are due to multiple image formation by the two interfaces produced.
ELECTRON MICROSCOPE STUDIES ON DIATOMS
Authors: Desikachary T. V.
Published: November 2011

SYNOPSIS

A review of the electron microscopy of diatom wall structure is given. The structure of the areolæ and its variations are described. The diatoms are divided into nine groups based on their wall structure. The structures of the mucilage pores, spines and the raphe are described from the electron microscopic studies.

As many as 80 genera and nearly 300 species have been investigated by different workers. A full list of these is given and the facts known about them analysed.

The writer supports the view that structural details revealed by electron microscopy have a definite place in taxonomy.
AN EXAMINATION OF THE SCALES AND BRISTLES OF MALLOMONAS IN THE ELECTRON MICROSCOPE USING CARBON REPLICAS
Authors: Harris Katharine , Bradley D. E.
Published: November 2011

SYNOPSIS

The species of the genus Mallomonas, classed amongst the algæ, are small cells covered with characteristic silica scales and bristles. These are of considerable importance in the classification of the species, but only the coarser details are visible under the optical microscope. A direct electron microscope study yields much information about the fine markings on the scales, but the use of carbon replicas produces clearer, more easily interpreted micrographs, and permits the examination of the exterior of a complete organism.

The scales and bristles of nine species, three of which are new, are described, and some variations in the markings within a single species are illustrated.
THE MORPHOLOGY OF BOAR SPERMATOZOA
Authors: Hancock J. L.
Published: November 2011

SYNOPSIS

The morphological features of boar spermatozoa in freshly ejaculated semen and in semen exposed to various experimental treatments have been studied in stained smears and with the phase‐contrast microscope and the electron‐microscope.

The spermatozoon of the boar closely resembles that of other domestic ungulates. The head is approximately 8.5μ long; it is twice as long as it is wide. The mid‐piece is approximately 10μ long and the main tail‐piece is 30μ long.

The head is covered anteriorly by a cap‐like structure—the acrosome. Evidence is presented to show that the acrosome has two components: the outer acrosome is the larger, the smaller inner acrosome is a crescentic structure. The segment‐shaped area of overlap between the two parts of the acrosome forms the equatorial segment which is a feature of living boar spermatozoa.

The surface of the head behind the acrosome impregnates with silver; this argentophil area is the post‐nuclear cap.

Three neck granules can be distinguished at the posterior border of the head and these are apparently connected to three bundles of neck fibres which the head receives from the mid‐piece.

The structure of the spermatozoon is altered by post‐mortem changes; the most prominent changes occur in the acrosome. Evidence is presented that the post‐nuclear cap is absent from dead spermatozoa.

The development of the boar acrosome has been studied in sections stained by the PAS method and in unfixed tissues with the phase‐contrast microscope. The development of the post‐nuclear cap has been studied in sections impregnated with silver. The morphological features of epididymal spermatozoa have been studied in spermatozoa from different levels of the epididymis.

The development of the acrosome is shown to resemble its development in the bull. Two separate components of the acrosome of the spermatid are distinguished. It is suggested that these develop into the two components of the acrosome of the mature spermatozoon.

Migration of the cytoplasmic droplet from the neck to the mid‐piece occurs at varying levels in the epididymis, but it is shown that it may occur in the head of the epididymis.

The findings are discussed in relation to current ideas about the structure of mammalian spermatozoa.
APPLICATIONS OF AN EPOXIDE EMBEDDING MEDIUM TO ELECTRON MICROSCOPY
Authors: Birbeck M. S. C. , Mercer E. H.
Published: November 2011

SYNOPSIS

The Araldite embedding resin, described by Glauert et al., for preparing thin sections for electron microscopy has been tried on a wide range of materials and found to prevent completely the “explosion damage” so common with methacrylate polymers.
A STUDY OF FRESH MOUSE ASCITES TUMOUR CELLS BY ULTRA‐VIOLET, PHASE‐CONTRAST AND INTERFERENCE MICROSCOPY
Authors: King R. J. , Roe E. M. F.
Published: November 2011

SYNOPSIS

Various microscopical techniques have been used to study the morphology of ascites tumour cells. These methods have the advantage that they are applicable to fresh material, thus avoiding the artefacts usually caused by fixation and associated procedures. Certain observations concerning the distribution of nucleic acids and proteins within these cells are discussed.
IV.— THE OPTICAL CORRECTION OF OBJECTIVES USED FOR MICROSPECTROSCOPY
Authors: KING R. J.
Published: November 2011

SYNOPSIS

The optical densities of small absorbing particles have been measured, initially with the microscope system well corrected optically and then after the introduction of spherical aberration by variation of the immersion fluid refractive index. It was found that several times the Rayleigh limit of spherical aberration could be tolerated without affecting the accuracy of the results, provided the condenser aperture was kept considerably smaller than the objective numerical aperture, this being a necessary condition from other considerations. There was, moreover, a surprisingly small deterioration of image quality. The effects on absorption measurements caused by the presence of coma and central obscuration in the microscope objective are also discussed.
VIII.—THE IMPREGNATION OF CANALICULI IN BONE
Authors: Weight D. E. , Waggott E.
Published: November 2011

SYNOPSIS

A method is described by which bone canaliculi can be demonstrated by deposition within them of mercuric sulphide. The technique permits the preparation either of serial sections or of large numbers of specimens for teaching purposes.
IX.—A NOTE ON LEUCOCYTES IN SALIVA
Authors: Weight Donald E.
Published: November 2011

SYNOPSIS

A method is described for the preservation and staining of leucocytes present in saliva. Some brief notes on the appearance of these cells are provided.
XI.—THE USE OF THE ABBE SUBSTAGE IN PHASE‐CONTRAST MICROSCOPY
Authors: Baker John R.
Published: November 2011

SYNOPSIS

The Abbe substage includes a tray (filter‐holder) in which illuminating annuli for phase‐contrast microscopy may conveniently be placed. Exact centration is easy.
ELECTRON MICROSCOPE STUDIES OF NEW ZEALAND MARINE PLANKTON DIATOMS*
Authors: Cassie Vivienne , Bertaud W. S.
Published: November 2011

SYNOPSIS

A description is given of the fine structure of two marine plankton diatoms from New Zealand: Stepkanopyxis orbicularis Wood and Biddulphia mobiliensis (Bailey) Grunow. Three‐dimensional structure has been elucidated by photogrammetric means from stereoscopic pairs of electron micrographs.

A hypothesis regarding the mechanism of growth in the girdle of Stephanopyxis is suggested.
THE MITOCHONDRIA DURING THE DIFFERENTIATION AND GROWTH OF THE NERVE CELLS OF SCHISTOCERCA GREGARIA
Authors: Moussa Tohamy A. , Banhawy M.
Published: November 2011

SYNOPSIS

The mitochondria occur as granules and short rods throughout the various developmental stages of the locust. No filamentous mitochondria could be detected. In early germ‐band cells the mitochondria exist as small granules and very short rods scattered in the cytoplasm. They are shared out between the dividing neuroblasts, and remain as such in the early ganglion cells and in the first four nymphal instars.

The nerve cells of the fifth instar nymph (as well as the large neurones of the fourth instar nymph) and adult locust contain, besides the normal mitochondria, a number of swollen bodies which we consider as metamorphosed mitochondria. The latter type, in old neurones, decreases in number and moves towards the cell periphery.

In the senile condition the metamorphosed mitochondria are no longer visible.

The pictures of mitochondria in living unstained or vitally stained preparations do not differ from those of fixed and stained materials.

The mitochondria are not responsible for the production of the Golgi dictyosomes as an effect of fixation and metallic impregnation, as is shown from the following:

In the early germ‐band cells, a single osmiophilic globule (Golgi body) is found, whereas the mitochondria appear in the form of many small granules and very short rods scattered in the cytoplasm.

In the early developmental stages, the mitochondria are evenly scattered in the cytoplasm, whereas the Golgi dictyosomes are polarized.

The mitochondria and dictyosomes can be demonstrated side by side in the same cell.
NOTES ON THE HISTOLOGY AND ANATOMY OF THE LARVA OF BOLITOPHILA LUMINOSA OF NEW ZEALAND
Authors: Ganguly Gouri
Published: November 2011

SYNOPSIS

The histology and fine anatomy of the larva of Bolitophila luminosa have been considered. There are two separate glands, silk (salivary) and mucus, producing the web and mucus droplets of the snare. Chordotonal (scolophore) organs have been described from the anal papillæ.
THE VISCERAL HISTOLOGY OF THE PRIMITIVE CETACEAN CAPEREA (NEOBALAENA)
Authors: Cave A. J. E. , Aumonier F. J.
Published: November 2011

SYNOPSIS

The histology is described, for the first time, of the liver, kidney, and heart muscle of the rare and primitive cetacean Caperea (Neobalœna) marginata Gray, 1844. Observations are also submitted on the hepatic histology of Physeter catodon, Megaptera novœangliœ and Lagenorhynchus cruciger, and a tentative hypothesis is advanced concerning the mode of venous drainage of the cetacean liver lobule. Attention is drawn to a hitherto undescribed histological feature of the kidney of Caperea, Physeter, Phocœna and Lagenorhynchus, and its interpretation is attempted in terms of renal structure and function.
A FURTHER CONTRIBUTION TO OUR KNOWLEDGE OF PHLYCTOCHYTRIUM UNISPINUM PATERSON
Authors: Willoughby L. G. , Townley Patricia J.
Published: November 2011

SYNOPSIS

The fungus Phlyctochytrium unispinum Paterson (Phycomycetes, Chytridiales) previously known only from the U.S.A., is described from Great Britain for the first time. Using British material, a further contribution has been made to knowledge of this chytrid.
COCCOLITHS AND DISCOASTERS FROM THE FLOOR OF THE SOUTH ATLANTIC OCEAN
Authors: Black Maurice , Barnes Barbara
Published: November 2011

SYNOPSIS

The minute structure of the coccoliths borne by several species of Chrysophyceæ is described and illustrated by electron‐micrographs of carbon replicas. The use of replicas enables anatomical details which are obscure or invisible in micrographs of the object itself to be seen clearly, and they provide a means of distinguishing with certainty between species which have very small coccoliths of similar gross appearance but different in their plan of construction.
QUANTITATIVE STUDIES ON LIVING CELL INCLUSIONS
Authors: Ross K. F. A.
Published: November 2011

SYNOPSIS

The purpose of this paper is to show that refractive‐index measurements made by interference microscopes can provide much varied and interesting information about many of the visible constituents of living cells, and consequently about the cells as a whole.

There are two main methods of measuring the refractive indices of cytoplasmic inclusions in living cells; by immersing the cells in non‐toxic isotonic mounting media with the same refractive index as their cytoplasm, and by compressing the cells to a determined thickness. Both these methods, which can under certain circumstances also be applied to measuring the refractive indices of nuclear inclusions, are described in detail.

Usually, refractive‐index measurements made on an inclusion in a living cell are used to indicate the percentage of total solid and water present in that region, but, in addition, they can sometimes provide information about its submicroscopic molecular arrangement, its histochemical nature, and its permeability properties; and examples of all these interpretations are described.
FLUORESCENCE MICROSCOPY OF MOUSE BONE‐MARROW CELLS
Authors: Ashwood‐Smith M. J. , Young M. R.
Published: November 2011

SYNOPSIS

Mouse bone‐marrow cells have been treated with a 1:20,000 concentration of acridine‐orange and mounted on slides coated with nutrient agar. Under these conditions cells spread themselves rapidly, and active movements can be observed within a few minutes. When viewed with blue‐violet light a variety of marrow cells can be distinguished. The nuclei fluoresce green and the cytoplasmic granules fluoresce red; this cytoplasmic granulation is similar to that observed with phase‐contrast microscopy. Photographs were obtained using Ektachrome high‐speed colour film which permitted greatly reduced exposure times. Black and white bromide prints made from colour transparencies could be made without difficulty. These have the advantage of being free from grain.
THE CELLULAR UPTAKE OF PROTEINS LABELLED WITH FLUORESCENT DYES
Authors: Cormack D. H. , Ambrose E. J.
Published: November 2011

SYNOPSIS

The use of the direct fluorescent‐labelling technique as a method for demonstrating the uptake of proteins by living cells is evaluated. This technique has been applied to the uptake of wheat‐germ “lipase” and insulin by a selection of normal and malignant cell types. Some enzymatic activity of the “lipase”, which shows aliesterase activity, has been shown to remain after the labelling procedure. It was taken up in relatively large amounts by pinocytosis, and accumulated on the cell membrane of normal cells. Insulin did not appear to be taken up by pinocytosis.
ULTRASONIC IRRADIATION AS AN ADJUNCT TO REPLICATION METHODS IN ELECTRON MICROSCOPY
Authors: Reed R.
Published: November 2011

SYNOPSIS

Metal replica films for microscopical examination may be rapidly detached from surfaces by briefly exposing the preparations to the action of ultrasonic radiation.
ELECTRON MICROSCOPE OBSERVATIONS ON THE PHALLIC (CONGLOBATE) GLAND OF THE COCKROACH, PERIPLANETA AMERICANA
Authors: Beams H. W. , Anderson Everett , Kessel Richard
Published: November 2011

SYNOPSIS

The lumen of the phallic gland is lined by a layer of cuticle derived from an invagination of the integument. The same layers as found in the integument are represented in the cuticular lining; namely, epicuticle, exocuticle, and endocuticle with an underlying epidermal layer. In sections through the cuticle and the underlying gland cells, small ductules are seen to penetrate the cuticular layer and extend to the surface of the gland cells where they enter them and become continuous with small intra‐cellular ductules. Upon entering the gland cell a marked change in the structure of the ductule occurs. This consists in the termination of the relatively dense, continuous epicuticle as such and the appearance of a highly reticulated layer which extends throughout the remainder of the ductule. Abutting upon the reticulated layer are the microvilli. Small vesicles are often observed in the outer border of the cell. These may serve as a transport system.

Mitochondria and relative large secretion bodies are frequently concentrated below and near the base of the microvilli. The Gogli material is present in the form of dictyosomes and the ergastoplasm as numerous rosettes, groups of small ribosomes or as vesicular elements.
A SURVEY OF EMBEDDING MEDIA FOR ELECTRON MICROSCOPY
Authors: Glauert Audrey M.
Published: November 2011

SYNOPSIS

The survey describes the various embedding media that are now available for thin sectioning and electron microscopy, with the aim of aiding a correct choice of medium in any particular investigation. The properties of the methacrylates, the epoxy resins and the polyester resins are compared and, in particular, the basic similarities between the different mixtures containing epoxy resins are emphasized. A description of water‐soluble embedding media is included.
A FIBRE MICROTOME OF SIMPLE CONSTRUCTION
Authors: Mannering M. H.
Published: November 2011

SYNOPSIS

A fibre microtome is described which combines the simplicity of the plate method of sectioning with the accuracy and efficiency of the Hardy fibre microtome. The instrument is cheap to make, uses only standard materials and may be constructed by anyone having access to a small lathe and simple hand tools.
THE SIZE OF BACTERIA, AS MEASURED WITH THE DYSON IMAGE‐SPLITTING EYEPIECE
Authors: Powell E. O. , Errington F. P.
Published: November 2011

SYNOPSIS

Using the Dyson image‐splitting eyepiece, a careful unfatigued observer can measure the dimensions of a bacterium with a standard deviation of about 0.03 μ. Systematic as well as random errors are discussed. The application of the eyepiece is illustrated by a number of specialized examples, including the growth of individual bacteria.
DIRECT EHRLICH ASCITES TUMOUR CELL DIAMETER MEASUREMENTS BY PROJECTION OF A MICROSCOPE IMAGE
Authors: Barker N. , Needham George H. , Furst Arthur
Published: November 2011

SYNOPSIS

The carcinostatic action of phenazine‐di‐N‐oxide against the Ehrlich tumour was subjected to closer study on individual cells. A method was devised whereby the increase in cell diameter could be followed by direct measurement on the projected microscope image. After standardization of the optics so that 1 μ on the slide equalled 1 mm on the ruler, 50 cells per 20 minutes could be measured randomly.

Observations 24 hours after drug administration into a mouse bearing a 7‐day tumour showed that treated cell diameters increased from a median diameter of 14 μ to a median of 21 μ (many had doubled in size) as compared to an increase of 1.9 μ in the controls. After 72 hours the treated cells reached a maximum diameter and disintegrated. By this time there was an absence of ascitic fluid. The drug acted by accelerating the growth and exaggerating the disordered mitoses of the tumour cells which were unable to cleave daughter cells, leaving a cluster of partially divided protuberances.
THE USE OF WATER‐SOLUBLE GLYCOL METHACRYLATE IN ULTRASTRUCTURAL CYTOCHEMISTRY
Authors: Leduc Elizabeth , Marinozzi V. , Bernhard W.
Published: November 2011

SYNOPSIS

A procedure for the application of cytochemical techniques directly on ultrathin sections for electron microscopy has been developed with the use of water‐soluble plastics, which act both as dehydrating agents and embedding media. Our approach has been to selectively extract proteins and nucleic acids from ultrathin sections of cells and viruses by specific enzyme hydrolysis. Glycol methacrylate is particularly useful as a component of the embedding medium because it enhances the penetrability of the enzyme into the section and preserves the biological materials in such a way that they remain susceptible to enzymic digestion. Various degrees of morphological preservation of ultrastructure are obtained with the aldehyde fixatives, formalin, acrplein, and glutaraldehyde, followed by. embedding in glycol methacrylate and the choice of fixative, at present, depends on the system which is to be studied. It is believed that the proposed method can be developed further and be used for other approaches to ultrastructural cytochemistry.
INTERFERENCE TESTING OF REFLECTING OBJECTIVES
Authors: Burch C. R. , Tubbs M. R.
Published: November 2011

SYNOPSIS

A wide‐source interferometer, capable of testing glass reflecting objectives during manufacture is described. The factors influencing the sensitivity of two‐beam interference testing are discussed.
AN ADHESION TECHNIQUE FOR SMALL AQUATIC ORGANISMS
Authors: Hawes R. S. J.
Published: November 2011

It is a recognized difficulty in making permanent preparations of small aquatic organisms, or of those cultivated in aqueous solutions, that they must either be stained in bulk, when the control of differentiation is uncertain, or they must be attached to slides or cover‐slips, when they may be stained and differentiated as precisely as sections. The latter method is plainly preferable, especially for cytological work, but its application is commonly unreliable, in that specimens are lost or distorted at one stage or another, or it is successful only in experienced hands on a limited range of material. The following technique has the advantages that slides holding many thousands of specimens may be prepared without loss or, provided that fixation has been good in the first place, distortion. It has been applied in this laboratory almost exclusively to Protozoa, including such notoriously difficult subjects as flagellates from fresh water or aqueous culture solutions, but it is equally successful with small metazoan animals such as rotifers and gastrotrichs.

The principle is to concentrate the material after fixation, washing, and dehydration, soak it in a thin solution of celloidin and allow drops of this to spread on slides. The film of celloidin containing the organisms adheres to the slide, which is thereafter treated as if it carried a section, except that precautions must be taken against the tendency of celloidin to dissolve in the higher alcohols.
Ultrastructure of mercerized cotton fibres*
Authors: ROLLINS MARY L. , MOORE ANNA T. , DEGRUY INES V. , GOYNES WILTON R.
Published: November 2011

SYNOPSIS

Some changes in the structure of cotton fibre which accompany mercerization are illustrated. The familiar swelling, rounding out, and partial untwisting of the collapsed fibre into a more nearly rod‐like shape have been investigated with both the light and the electron microscope. Shrinkage and compacting of the primary‐wall network to provide a constricting casing about the fibre, crimping of the microfibrils of the secondary‐wall cellulose, and ultimate smoothing out of the wrinkled primary wall have been observed. A technique for expansion of the fibre wall into layers further demonstrates the altered structure of the cotton fibre after tension‐mercerization.