Arrangement Of Cones Research Articles

The human dermal white adipose tissue (dWAT) morphology: A multimodal imaging approach

BackgroundDermal white adipose tissue (dWAT) in humans can be characterized as a relaxed dermal skin compartment consisting of functionally interlinked adipocytes. dWAT is typically discerned both in terms of morphology and function from subcutaneous white adipose tissue (sWAT). In particular in human thigh, the dWAT appears as thin extensions from the adipose panniculus to the dermis, and it is primarily associated with pilosebaceous units, hair follicles, sebaceous glands, and erector pili muscles. In this work, human fat tissue samples obtained post-mortem from the gluteo-femoral region were analyzed focusing on the thin extensions of dWAT named dermal cones. This anatomical region was chosen to deepen the dWAT morphological features of this site which is interesting both for clinical applications and genetical studies. The purpose of this exploratory methodological study was to gain deeper insights into the morphological features of human dWAT through a multimodal imaging approach. MethodsOptical microscopy, Magnetic Resonance Imaging (MRI) and Scanning Electron Microscopy (SEM), have been employed in this study. The cones’ length and their distances were measured on the acquired images for optical microscopy and SEM. The cone’s apparent regular distribution in MRI images was evaluated using a mathematical criterion, the conformity ratio, which is the ratio of the mean nearest-neighbor distance to its standard deviation. ResultsThe imaging techniques revealed white adipocytes forming a layer, referred to as sWAT, with cones measuring nearly 2 mm in size measured on SEM and Optical images (2.1 ± 0.4 mm), with the lower part embedded in the sWAT and the upper part extending into the dermis. The distance between the cones results about 1 mm measured on MRI images and they show an overall semiregular distribution. ConclusionsMRI images demonstrated an orderly arrangement of cones, and their 3D reconstruction allowed to elucidate the dermal cones’ disposition in the tissue sample and a more general comprehensive visualization of the entire fat structure within the dermis.

Performance of tri-tubular conical energy absorber under axial compression

Quasi static axial compression loading on tri-tubular cone (TC) has been carried out using LS-DYNA finite element analysis method. Tri-tubular cones of three arrangements; the first arrangement (model TC-1) consists of cone heights of 50 mm, 75 mm and 100 mm where the inner cone is the maximum height. The second arrangement (model TC-2) consists of cone heights of 100 mm, 75 mm, and 50 mm where the outer cone is the maximum height. The third arrangement (model TC-3) consists of three cones of the same height of 100 mm. Cone semi vertex angle of 20o was maintained for all tri-tubular cones tested. Materials used for this research are glass, jute and jute-glass/epoxy. Crashworthiness analyses were performed to investigate the effect of material used, and tri-tubular cone arrangement on peak load. Crush efficiency, and absorbed energy were drawn and discussed. Failure mechanism of the fractured specimens was also discussed. Effect of number of layers and fiber stacking sequence were also investigated. Results show that the cone arrangement TC-3 gives better performance than the cone arrangement TC-2 followed by the cone arrangement TC-1. Maximum load obtained by tri-tubular cone type TC-3 was found higher 7.09% and 14.96% than TC-2 and TC-1 respectively for glass/epoxy. Material saving was achieved by using tri-tubular cones of different heights under compression. Material used has significant influence on the absorbed energy. Failure mode of tri-tubular conical energy absorber was presented and discussed.

Recognition of Ephedra yangthangensis as a new synonym of E. intermedia (Ephedraceae)

Critical study of the protologue, herbarium and live specimens of Ephedra yangthangensis Prabha Sharma & Rita Singh revealed that this species actually corresponds to E. intermedia. The description of E. yangthangensis as a new species is based on phenotypically plastic characters such as nature of microsporagiophore, size of male strobili and colour of stem, fruit and leaf, which actually fall within the circumscription of E. intermedia. Therefore, here we report E. yangthangensis as a new synonym of E. intermedia. We identify the taxonomic discrepancies in the diagnosis of E. yangthangensis and provide taxonomic keys, description with photographic illustrations of vegetative (habit, stems and leaves), reproductive (cone arrangement and nature) and anatomical characters and enlist the representative herbarium specimens.

Defect patterns on the curved surface of fish retinae suggest a mechanism of cone mosaic formation.

The outer epithelial layer of zebrafish retinae contains a crystalline array of cone photoreceptors, called the cone mosaic. As this mosaic grows by mitotic addition of new photoreceptors at the rim of the hemispheric retina, topological defects, called “Y-Junctions”, form to maintain approximately constant cell spacing. The generation of topological defects due to growth on a curved surface is a distinct feature of the cone mosaic not seen in other well-studied biological patterns like the R8 photoreceptor array in the Drosophila compound eye. Since defects can provide insight into cell-cell interactions responsible for pattern formation, here we characterize the arrangement of cones in individual Y-Junction cores as well as the spatial distribution of Y-junctions across entire retinae. We find that for individual Y-junctions, the distribution of cones near the core corresponds closely to structures observed in physical crystals. In addition, Y-Junctions are organized into lines, called grain boundaries, from the retinal center to the periphery. In physical crystals, regardless of the initial distribution of defects, defects can coalesce into grain boundaries via the mobility of individual particles. By imaging in live fish, we demonstrate that grain boundaries in the cone mosaic instead appear during initial mosaic formation, without requiring defect motion. Motivated by this observation, we show that a computational model of repulsive cell-cell interactions generates a mosaic with grain boundaries. In contrast to paradigmatic models of fate specification in mostly motionless cell packings, this finding emphasizes the role of cell motion, guided by cell-cell interactions during differentiation, in forming biological crystals. Such a route to the formation of regular patterns may be especially valuable in situations, like growth on a curved surface, where the resulting long-ranged, elastic, effective interactions between defects can help to group them into grain boundaries.

Influence of the Duration of Microwave Irradiation of Scots Pine (Pinus sylvestris L.) Cones on the Quality of Harvested Seeds

To improve the process of seed extraction, new solutions have been investigated in an attempt to develop guidelines for the construction of small seed extraction equipment. One of the solutions proposed in this field is the use of electromagnetic radiation in the first stage of hulling cones, reducing their initial moisture content, which will result in quicker scale opening. It is proposed that cones should be irradiated for a relatively short period in the first stage. This operation will allow a quicker loss of moisture from the cones that are still closed, which will result in a more intensive opening of cone scales and will also positively affect the exposure of seeds for the next phase of hulling. The aim of the study was to evaluate the effect of microwave irradiation of pine cones on the quality of the seeds obtained. Cones were exposed to microwaves produced by an 800 W generator. The research was performed in several modes, in which the variable parameters were the duration of microwave irradiation, arrangement of cones with the apex pointed towards either the inner or outer part of the turntable, and the number of cones. The temperature distribution on the surface of and inside the cones was determined using the THERM v2 (Vigo System SA, Ożarów Mazowiecki, Poland) thermal image processing software. We also assessed the energy (vitality) and germinability (quality class) of seeds that were not exposed and those after microwave treatment. The results of the research allowed us to state that, with the assumed parameters of the process, it is possible to obtain second quality class seeds after exposure to microwaves for 5 s. This result was comparable to the quality of seeds obtained without the use of microwaves. When the irradiation time was increased above 5 s, the vitality of seeds decreased and their quality was not satisfactory.

Are the male reproductive units of Juniperus drupacea Labill. (Cupressaceae s.str.) a compound, polyaxial inflorescence or a dense cluster of simple, uniaxial pollen cones?

The Juniperus Section Caryocedrus (Cupressaceae) is one of the three putatively monophyletic sections of the genus. It is monotypic, presented only by J. drupacea. Male reproductive units of this species show several distinct features distinguishing it distinctly from all other Juniperus species, including an inflorescence‐like arrangement of pollen cones, an increased number of microsporangia per microsporangiophore, and microsporangia attached to the stalk in up to three subsequent rows. The male reproductive units in J. drupacea have been investigated with paraffin technique and SEM. They are hypothesized to represent a distal cluster of densely arranged, simple pollen cones, which are interpreted as being derived from an ancestral condition that is still presented in species of the Section Juniperus. This is assumed to have occurred by a profound reduction of internodes of the fertile shoot axis carrying the pollen cone and a distal shift. The increased number of microsporangia per microsporangiophore may be a response to the decreasing number of pollen cones per tree compensating for the loss of pollen, that occurred during the evolution of inflorescence‐like male reproductive units.

Effect of vertex angle and vertex tip radius on the performance of V-cone flow meter using CFD

The aim of the present systematic study is to establish the effect of vertex angle and vertex tip radius on the performance of the V-cone flowmeter. Three different cone arrangements namely without support, front and rear supported cone element have been undertaken for a fixed beta value (β) of 0.6 with different vertex angles (φ). Shear Stress Transport k-ω (SST k-ω) turbulence model has been adopted for the closure solution. The performance evaluation is done on the basis of coefficient of discharge (Cd) and the extent of uncertainty (UCd) present in predictions within the range of Reynolds number (Re) investigated (Re = 103 to 106). This study is in the back drop of ISO 5167-5(2016) which has identified the vertex angle in the range of 52°±10°. From the study, it is revealed that in all the three mode of the cone arrangements, the cone element with vertex angle of 75° results in a discharge coefficient which is nearly constant for Reynolds number greater than 1000 with minimum uncertainty. An additional investigation has also been carried out for three vertex angles (φ) namely 60°,75° and 90° to analyze the effect of cone tip radius at Re = 5 × 105 on the performance of the V-cone flowmeter. It is seen that vertex tip radius has no effect on the performance.

Cone Photoreceptor Irregularity on Adaptive Optics Scanning Laser Ophthalmoscopy Correlates With Severity of Diabetic Retinopathy and Macular Edema.

PurposeTo determine whether cone density, spacing, or regularity in eyes with and without diabetes (DM) as assessed by high-resolution adaptive optics scanning laser ophthalmoscopy (AOSLO) correlates with presence of diabetes, diabetic retinopathy (DR) severity, or presence of diabetic macular edema (DME).MethodsParticipants with type 1 or 2 DM and healthy controls underwent AOSLO imaging of four macular regions. Cone assessment was performed by independent graders for cone density, packing factor (PF), nearest neighbor distance (NND), and Voronoi tile area (VTA). Regularity indices (mean/SD) of NND (RI-NND) and VTA (RI-VTA) were calculated.ResultsFifty-three eyes (53 subjects) were assessed. Mean ± SD age was 44 ± 12 years; 81% had DM (duration: 22 ± 13 years; glycated hemoglobin [HbA1c]: 8.0 ± 1.7%; DM type 1: 72%). No significant relationship was found between DM, HbA1c, or DR severity and cone density or spacing parameters. However, decreased regularity of cone arrangement in the macular quadrants was correlated with presence of DM (RI-NND: P = 0.04; RI-VTA: P = 0.04), increasing DR severity (RI-NND: P = 0.04), and presence of DME (RI-VTA: P = 0.04). Eyes with DME were associated with decreased density (P = 0.04), PF (P = 0.03), and RI-VTA (0.04).ConclusionsAlthough absolute cone density and spacing don't appear to change substantially in DM, decreased regularity of the cone arrangement is consistently associated with the presence of DM, increasing DR severity, and DME. Future AOSLO evaluation of cone regularity is warranted to determine whether these changes are correlated with, or predict, anatomic or functional deficits in patients with DM.

Intraretinal variability and specialization of cones in Japanese anchovy (Engraulis japonicus, Engraulidae)

The retina of anchovies is characterized by an unusual arrangement and ultrastructure of cones. In the retina of Japanese anchovies, Engraulis japonicus, three types of cones are distributed into rows. The nasal, central, temporal, and ventro-temporal regions of the retina were occupied exclusively by the long and short cones. Triple cones, made up of two lateral components and one smaller central component, were found only in the dorsal and ventro-nasal retinal regions. In the outer segments of all short and long cones from the ventro-temporal region, the lamellae were oriented along the cell axis and were perpendicular to the lamellae in the long cones, providing a morphological basis for the detection of polarization. This lamellar orientation is unique to all vertebrates. The cones were examined with respect to regional differentiation in their size and spectral properties via light microscopy, transmission electron microscopy, and microspectrophotometry. Various dimensions of cones were measured in preparations of isolated cells. The cones from the ventro-temporal region had different dimensions than cones of the same type located in other retinal regions. Triple cones from the dorsal region were significantly larger than triple cones from the ventro-nasal region. The spectral absorbance of the lateral components of triple cones in the ventro-nasal retina was identical to the absorbance of all long and short cones from the ventro-temporal region. These are shifted to shorter wavelengths relative to the absorbance of the lateral components of the triple cones located in the dorsal retina. Thus, the retina of the Japanese anchovy shows some features of regional specialization common in other fishes that improves spatial resolution for the upwards and forwards visual axis and provides spectral tuning in downwelling light environment. That results from the differentiation of cone types by size and by different spectral sensitivity of various retinal areas.

Variations in the cone packing density with eccentricity in emmetropes

To describe the parafoveal cone arrangement in emmetropic subjects and its variations with eccentricity, meridians and change in axial length in Indian eyes. We imaged 25 subjects using compact adaptive optics (AO) retinal camera prototype, the rtx1. Imaging was done at 1, 2, and 3° eccentricity from the fovea in four meridians: nasal, temporal, superior, and inferior. A statistically significant drop in the cone packing density was observed from 2 to 3° (2° eccentricity=25 350/mm(2) (5300/mm(2), 8400-34 800/mm(2)) 3° eccentricity=20 750/mm(2) (6000 mm(2), 9000-33 670/mm(2))) P<0.05. The spacing correspondingly increased with increase in distance from the fovea (2° eccentricity=6.9 μm (0.70 μm, 5.95-11.6 μm)) and 3°eccentricity=7.80 μm (1.00 μm, 6.5-13.5 μm) P<0.05. As the axial length increases, the cone density significantly decreases. Interocular variations were noted. With the advent of AO, visualization at the cellular level is now possible. Understanding the photoreceptor mosaic in the parafoveal space in terms of its density, spacing, and arrangement is crucial so as to detect early pathology and intervene appropriately. Newer therapeutic modalitites that are targeted at the cellular level like yellow micropulse laser, stem cells, gene therapy and so on may be better monitored in terms of safety and efficacy.

Mapping the Perceptual Grain of the Human Retina

In humans, experimental access to single sensory receptors is difficult to achieve, yet it is crucial for learning how the signals arising from each receptor are transformed into perception. By combining adaptive optics microstimulation with high-speed eye tracking, we show that retinal function can be probed at the level of the individual cone photoreceptor in living eyes. Classical psychometric functions were obtained from cone-sized microstimuli targeted to single photoreceptors. Revealed psychophysically, the cone mosaic also manifests a variable sensitivity to light across its surface that accords with a simple model of cone light capture. Because this microscopic grain of vision could be detected on the perceptual level, it suggests that photoreceptors can act individually to shape perception, if the normally suboptimal relay of light by the eye's optics is corrected. Thus the precise arrangement of cones and the exact placement of stimuli onto those cones create the initial retinal limits on signals mediating spatial vision.

Hydrogen Adsorption of Carbon Nanocone Arrays: Influences of Cone Arrangements

This paper used molecular dynamics (MD) simulations to investigate influences of cone arrangements (including the cone orientation, arrangement pattern and cone spacing) on hydrogen adsorption of open-tip carbon nanocone (CNC) arrays at temperatures of 100 and 300 K. To consider curvature effects for the cone structure of the CNCs, the curvature-modified Lennard-Jones potential parameters were adopted to describe the interactions between the hydrogen and carbon atoms. It was found that the cone orientation (aligned, opposite, and alternate) does not have obvious influences on hydrogen adsorption of the CNC arrays. The arrangement pattern (square and triangular), however, had significant influences on the hydrogen adsorption. The square-patterned CNC array was noticed to have higher storage weight percentage than the triangular-patterned one. Regarding to the influences of cone spacing, the storage weight percentage grew with the increase of the cone spacing and arrived at a stable value as the cone spacing reached a certain critical value. The influences cone arrangements could be ascribed to repulsive effects, which are evident as cone spacing become narrow.

Influence of sampling window size and orientation on parafoveal cone packing density

We assessed the agreement between sampling windows of different size and orientation on packing density estimates in images of the parafoveal cone mosaic acquired using a flood-illumination adaptive optics retinal camera. Horizontal and vertical oriented sampling windows of different size (320x160 µm, 160x80 µm and 80x40 µm) were selected in two retinal locations along the horizontal meridian in one eye of ten subjects. At each location, cone density tended to decline with decreasing sampling area. Although the differences in cone density estimates were not statistically significant, Bland-Altman plots showed that the agreement between cone density estimated within the different sampling window conditions was moderate. The percentage of the preferred packing arrangements of cones by Voronoi tiles was slightly affected by window size and orientation. The results illustrated the high importance of specifying the size and orientation of the sampling window used to derive cone metric estimates to facilitate comparison of different studies.

Eccentricity dependent changes of density, spacing and packing arrangement of parafoveal cones

To investigate the distribution of cone density and spacing as well as the preferred packing arrangement of the cone mosaic as a function of retinal eccentricity. An adaptive optics retinal camera (rtx1, www.imagine-eyes.com) was used to obtain images of the parafoveal cone mosaic in nineteen healthy volunteers. Cone density and spacing were estimated for each subject (both eyes) using a sampling window of 80×80 pixels, at 250-, 450-, 650- and 1100-μm eccentricities from the fovea along the nasal and temporal retina of both eyes. The inter-subject and intra-subject variation of cone density and spacing were calculated via Coefficient of Variation (CoV). Cone packing arrangement was assessed using Voronoi analysis; calculations were done over 1024×128 pixels image sections of the cone mosaic across the horizontal meridian from 200- to 1050-μm eccentricities. The inter-subject variation of parafoveal cone density ranged between 10% and 15% (p<0.001) and the intra-subject variation of cone density was lower than 8% in all subjects, except for two. The cone spacing values showed a moderate inter-subject (CoV<7%; p<0.001) and a low intra-subject variation (CoV<4% in all subjects, except for two cases). In the parafoveal region, 40-50% of cones were hexagonally arranged; the percentage of non-hexagonal Voronoi tiles increased at greater eccentricities. The use of multiple and complementary metric descriptors allows for a more detailed description of packing distribution and preferred arrangement of cone photoreceptors across the parafoveal retina.

Temporal and spatial characteristics of male cone development in Metasequoia glyptostroboides Hu et Cheng

Metasequoia glyptostroboides, a famous relic species of conifer that survived in China, has been successfully planted in large numbers across the world. However, limited information on male cone development in the species is available. In this study, we observed the morphological and anatomical changes that occur during male cone development in M. glyptostroboides using semi-thin sections and scanning electron microscopy. The male cones were borne oppositely on one-year-old twigs that were mainly located around the outer and sunlit parts of crown. Male cones were initiated from early September and shed pollen in the following February. Each cone consisted of spirally arranged microsporophylls subtended by decussate sterile scales, and each microsporophyll commonly consisted of three microsporangia and a phylloclade. The microsporangial wall was composed of an epidermis, endothecium, and tapetum. In mid-February, the endothecium and tapetum layers disintegrated, and in the epidermal layer the cell walls were thickened with inner protrusions. Subsequently, dehiscence of the microsporangia occurred through rupturing of the microsporangial wall along the dehiscence line. These results suggest that the structure, morphology, architecture and arrangement of male cones of M. glyptostroboides are mainly associated with the production, protection and dispersal of pollen for optimization of wind pollination.

Longitudinal In Vivo Imaging of Cones in the Alert Chicken

To demonstrate the feasibility of in vivo measurements of cones and their distributions as a function of normal growth without adaptive optics (AO) and also discuss the potential advantages and disadvantages of AO imaging in the chick, an animal model of myopia. Chicks were obtained on the day of hatching. Axial length and retinoscopy measurements were performed on days 0 and 14. Chicks were imaged on the day of hatching and 14 days later in a custom-built confocal scanning laser ophthalmoscope. Angular densities, linear cone spacings, and cone packing arrangements were determined. Four subarrays of hexagonally packed cones were identified on both days and, from their angular spacings, appear to correspond to different cone types. There were no significant changes in angular cone density with growth and linear spacings of cones increased with growth. This is true for both overall densities and those of the cone subtypes. There was no change in the percent of hexagonally packed cones with growth. Cones can be imaged longitudinally in vivo in the awake chick. The packing arrangement of cones is 40% hexagonally packed. Although AO is not necessary to visualize the cones, including the subarrays of like cones, some closely spaced cones of different types may not be resolved. Most importantly, there is a need to use a larger pupil with growth to maintain the same linear resolution in the larger eye. Novel longitudinal imaging techniques and methods in animal models are shown here to give insights into normal development and, in future, will give insights into visual disorders and diseases, including myopia.

Sperimagnetism in Fe78Er5B17 and Fe64Er19B17 metallic glasses: I. Moment values and non-collinear components

Magnetization measurements have been made on a Fe64Er19B17 glass, which exhibits ferrimagnetic compensation at Tcomp = 112 K, and polarized beam neutron scattering measurements have been made on Fe78Er5B17 and Fe64Er19B17 glasses to supplement the measurements made earlier on Fe64Er19B17. The magnetization data were analysed with a phenomenological model, to find the magnetic moments and their components needed to interpret the neutron data. Four spin-dependent scattering cross-sections were obtained in absolute units from each neutron experiment, to determine the atomic-scale magnetic structures of the two glasses. The finite spin-flip cross-sections confirmed that these (Fe,Er)83B17 glasses are non-collinear ferrimagnets. The cross-sections were calculated using a model based on random cone arrangements of the magnetic moments. The moment values and the random cone angles were refined in the calculations, which produced good agreement between the calculated curves and the experimental data. The forward limit of the spin-flip cross-sections |∂σ±∓/∂Ω|Q=0 of the Fe64Er19B17 glass which peaked at Tcomp and the temperature variation of the total scattering amplitudes (b∓p∥(Q)) suggested that the random cone angles open fully so that the collinear components p∥(Q) tend to zero at Tcomp. The ferrimagnetic compensation is therefore characterized by an equality of the magnetic sublattices; the reversal of the magnetic structure and a compensated sperimagnetic phase which appears at Tcomp.

Sperimagnetism in Fe78Er5B17 and Fe64Er19B17 metallic glasses: II. Collinear components and ferrimagnetic compensation

Magnetization measurements on an Fe64Er19B17 glass and polarized-beam neutron scattering measurements on Fe78Er5B17 and Fe64Er19B17 were described in part I. The finite spin-flip neutron scattering cross sections were calculated using a sperimagnetic structure based on random cone arrangements of the magnetic moments. The temperature variation of the cross sections of Fe64Er19B17 suggested that a compensated sperimagnetic phase existed at Tcomp. The analysis of the non-spin-flip neutron scattering cross sections is described here in part II. Two spin-dependent total structure factors S±±(Q) were defined from these cross sections and, despite the limited range of the data 0.5 Å−1 < Q < 6.5 Å−1, their Fourier transform gave reliable spin-dependent radial distribution functions RDF±±(r). These were interpreted in terms of the atomic pair correlation functions and their weighting factors . The data on Fe64Er19B17 at 1.5 K showed, for example, how the directions of the magnetic sublattices can be defined uniquely. The analysis of the RDF±±(r) for Fe64Er19B17 at 112 K confirmed that the mean collinear components of the magnetic moments , are zero on both sublattices in the compensated sperimagnetic structure at Tcomp. The pre-peak in the spin-dependent total structure factors at 112 K showed that it originated in the atomic structure and it may involve Fe–Er–Fe ‘collineations’ at a radial distance of ≈6.0 Å. Finally, the RDF±±(r) of Fe64Er19B17 at 180 K and of Fe78Er5B17 at 2 K show that both glasses have the (μFe UP:μEr DOWN) structure like the (Fe,Tb)83B17 collinear ferrimagnets.

Reducing traffic speed within roadwork sites using obtrusive perceptual countermeasures

Excessive speed is currently one of the primary contributory factors in traffic accidents within roadwork sites around the world. The present study evaluated two novel interventions designed to control traffic speed within an open road, roadwork site in New Zealand where drivers were required to decrease their speed from 100 to 50 km/h. Two different interventions were placed at the entrance to the work site and required drivers to pass between a 3.5 m wide passage of either evenly or decreasingly spaced cones. A multi-element baseline design was utilised. Both interventions were highly effective at reducing vehicle speed, with the greatest initial decrease in speed to 9.47 km/h below baseline for the uneven arrangement. Additionally, both arrangements more than halved the proportion of ‘dangerous’ speeders travelling faster than 20 km/h over the speed limit. The findings indicate that both arrangements of cones are effective, convenient, cost-effective strategies. It is concluded that, although both arrangements are highly effective, the use of unevenly-spaced cones is likely to most markedly reduce the number of speed-related accidents within open road roadwork zones. The findings are discussed in relation to the perceptual mechanisms by which transverse and peripheral stimuli influence speed perception and driver behaviour.

Symmetry, shape, and order.

Packing problems have been of great interest in many diverse contexts for many centuries. The optimal packing of identical objects has been often invoked to understand the nature of low-temperature phases of matter. In celebrated work, Kepler conjectured that the densest packing of spheres is realized by stacking variants of the face-centered-cubic lattice and has a packing fraction of pi /(3\square root2)\approximately 0.7405. Much more recently, an unusually high-density packing of approximately 0.770732 was achieved for congruent ellipsoids. Such studies are relevant for understanding the structure of crystals, glasses, the storage and jamming of granular materials, ceramics, and the assembly of viral capsid structures. Here, we carry out analytical studies of the stacking of close-packed planar layers of systems made up of truncated cones possessing uniaxial symmetry. We present examples of high-density packing whose order is characterized by a broken symmetry arising from the shape of the constituent objects. We find a biaxial arrangement of solid cones with a packing fraction of pi/4. For truncated cones, there are two distinct regimes, characterized by different packing arrangements, depending on the ratio c of the base radii of the truncated cones with a transition at c*=\square root2-1.