Allochronic speciation, secondary contact, and reproductive character displacement in periodical cicadas (Hemiptera: Magicicada spp.): genetic, morphological, and behavioural evidence

Periodical cicadas have proven useful in testing a variety of ecological and evolutionary hypotheses because of their unusual life history, extraordinary abundance, and wide geographical range. Periodical cicadas provide the best examples of synchronous periodicity and predator satiation in the animal kingdom, and are excellent illustrations of habitat partitioning (by the three morphologically distinct species groups), incipient species (the year classes or broods), and cryptic species (a newly discovered 13-year species, Magicicada neotredecim). They are particularly useful for exploring questions regarding speciation via temporal isolation, or allochronic speciation. Recently, data were presented that provided strong support for an instance of allochronic speciation by life-cycle switching. This speciation event resulted in the formation of a new 13-year species from a 17-year species and led to secondary contact between two formerly separated lineages, one represented by the new 13-year cicadas (and their 17-year ancestors), and the other represented by the pre-existing 13-year cicadas. Allozyme frequency data, mitochondrial DNA (mtDNA), and abdominal colour were shown to be correlated genetic markers supporting the life-cycle switching/allochronic speciation hypothesis. In addition, a striking pattern of reproductive character displacement in male call pitch and female pitch preference between the two 13-year species was discovered. In this paper we report a strong association between calling song pitch and mtDNA haplotype for 101 individuals from a single locality within the M. tredecim/M. neotredecim contact zone and a strong association between abdomen colour and mtDNA haplotype. We conclude by reviewing proposed mechanisms for allochronic speciation and reproductive character displacement.

Molecular phylogenetic analysis of the dragonfly genera Libellula, Ladona, and Plathemis (Odonata: Libellulidae) based on mitochondrial cytochrome oxidase I and 16S rRNA sequence data

Molecular phylogenetic relationships among members of the odonate genus Libellula (Odonata: Anisoptera: Libellulidae) were examined using 735 bp of mitochondrial COI and 416 bp of 16S ribosomal RNA gene sequences. Considerable debate exists over several relationships within Libellula, as well over the status of two putative genera often placed as subgenera within Libellula: Ladona and Plathemis. Parsimony and maximum-likelihood analyses of the separate and combined data sets indicate that Plathemis is basal and monophyletic and that Ladona is the sister clade to the remainder of Libellula sensu stricto (s.s.) (all species within the genus Libellula, excluding Plathemis and Ladona). Moreover, two European taxa, Libellula fulva and L. depressa, were found to occupy a sister group relationship within the Ladona clade. Relationships within Libellula s.s. are less well resolved. However, monophyletic lineages within the genus are largely consistent with morphologically based subgeneric classifications. Although tree topologies from each analysis differed in some details, the differences were in no case statistically significant. The analysis of the combined COI and 16S data yielded trees with overall stronger support than analyses of either gene alone. Several analyses failed to support the monophyly of Libellula sensu lato due to the inclusion of one or more outgroup species. However, statistical comparisons of topologies produced by unconstrained analyses and analyses in which the monophyly of Libellula was constrained indicate that any differences are nonsignificant. Based on morphological data, we therefore reject the paraphyly of Libellula and accept the outgroup status of Orthemis ferruginea and Pachydiplax longipennis.

[Vestibular neurotomy by a retrosigmoid approach: functional results. Evaluation through a triple clinical approach (otoneurologic, orthoptic and physical medicine)]

Vestibular neurotomy remains the surgical procedure of choice in the management of peripheral vertigo resistant to the usual medical treatment, for patients with preserved hearing. Menière's disease generally sums up most of the surgical indications. The authors report a personnel series of patients who underwent vestibular neurotomy during the last five years, from January to December 1998. The aim of this study was to assess with a 6 months to 3.5 years follow-up, postoperative complications and functional results, particularly the improvement of dizziness, residual unsteadiness and its impact on quality of life, and the recovery of socio-professional and physical activities. Of a total of 41 patients, 21 were evaluated by both an otoneurologic and physical medicine approach, to analyze the main sensory components of equilibrium (vestibular, proprioceptive, cervical, visual). In most of the cases, the results show disappearance of vertigo which was the main complaint. However, disabling residual instability is common in those patients who was present both a cervical pathology and binocular visual impairment or a defect in convergence, often unrecognised. The authors emphasise the necessity of a cervical examination and orthoptic investigations in addition to the vestibular assessment. This multi-disciplinary approach allows better identification of the different factors (vestibular, cervical, orthoptic) and lead to specific rehabilitation which can permit the patient with residual unsteadiness to return to work and lifestyle, the real measure of success of vestibular neurotomy.

Evaluating hypotheses on the origin and evolution of the New Zealand alpine cicadas (Maoricicada) using multiple-comparison tests of tree topology

The statistical testing of alternative phylogenetic trees is central to evaluating competing evolutionary hypotheses. Fleming proposed that the New Zealand cicada species Maoricicada iolanthe is the sister species to the major radiation of both low-altitude and montane Maoricicada species. However, using 1,520 bp of mitochondrial DNA sequence data from the cytochrome oxidase subunit I, tRNA aspartic acid, and the ATPase subunit 6 and 8 genes, we inferred that both M. iolanthe and another low-altitude species, Maoricicada campbelli, are nested within the montane Maoricicada radiation. Therefore, we examined the stability of the inferred phylogenetic placement of these two species using the newly developed Shimodaira-Hasegawa test (SH test) implemented in a maximum-likelihood framework. The SH test has two advantages over the more commonly used Kishino-Hasegawa (KH) and Templeton tests. First, the SH test simultaneously compares multiple topologies and corrects the corresponding P: values to accommodate the multiplicity of testing. Second, the SH test is correct when applied to a posteriori hypotheses, unlike the KH test, because it readjusts the expectation of the null hypothesis (that two trees are not different) accordingly. The comparison of P: values estimated under the assumptions of both the KH test and the SH test clearly demonstrate that the KH test has the potential to be misleading when the issue of comparing of a posteriori hypotheses is ignored and when multiple comparisons are not taken into account. The SH test, in combination with a variety of character-weighting schemes applied to our data, reveals a surprising amount of ambiguity in the phylogenetic placement of M. iolanthe and M. campbelli.

Exploring among-site rate variation models in a maximum likelihood framework using empirical data: effects of model assumptions on estimates of topology, branch lengths, and bootstrap support

We have investigated the effects of different among-site rate variation models on the estimation of substitution model parameters, branch lengths, topology, and bootstrap proportions under minimum evolution (ME) and maximum likelihood (ML). Specifically, we examined equal rates, invariable sites, gamma-distributed rates, and site-specific rates (SSR) models, using mitochondrial DNA sequence data from three protein-coding genes and one tRNA gene from species of the New Zealand cicada genus Maoricicada. Estimates of topology were relatively insensitive to the substitution model used; however, estimates of bootstrap support, branch lengths, and R-matrices (underlying relative substitution rate matrix) were strongly influenced by the assumptions of the substitution model. We identified one situation where ME and ML tree building became inaccurate when implemented with an inappropriate among-site rate variation model. Despite the fact the SSR models often have a better fit to the data than do invariable sites and gamma rates models, SSR models have some serious weaknesses. First, SSR rate parameters are not comparable across data sets, unlike the proportion of invariable sites or the alpha shape parameter of the gamma distribution. Second, the extreme among-site rate variation within codon positions is problematic for SSR models, which explicitly assume rate homogeneity within each rate class. Third, the SSR models appear to give severe underestimates of R-matrices and branch lengths relative to invariable sites and gamma rates models in this example. We recommend performing phylogenetic analyses under a range of substitution models to test the effects of model assumptions not only on estimates of topology but also on estimates of branch length and nodal support.

Leptin and leptin receptor are expressed in the human endometrium and endometrial leptin secretion is regulated by the human blastocyst

Embryonic implantation is a crucial event for the human reproductive function. Cytokines and paracrine molecules have been proposed as putative local regulators of this process. The leptin or the OB protein has been linked to the reproductive function and inflammatory response. In the present study, we describe for the first time the expression of leptin and leptin receptor (long form) in the secretory endometrium and that endometrial leptin secretion is regulated in vitro by the human blastocyst. Leptin and leptin receptor messenger RNA and protein were identified in secretory endometrium and in cultured endometrial epithelial cells (EECs) by RT-PCR, Western blot, and immunohistochemistry. The concentrations of immunoreactive leptin secreted by human embryos alone or cocultured with EECs were also assessed. We found that human blastocysts secrete significantly higher levels of leptin than arrested embryos. In contrast, leptin concentrations secreted by arrested embryos cocultured with EECs were significantly higher than blastocysts cocultured with EECs. These findings suggest that the human endometrium is a site for local production and a target tissue for circulating leptin. Expression of leptin and its functional receptor in the endometrium and regulation of endometrial leptin secretion by the human embryo suggests that the leptin system may be implicated in the human implantation process.

Secondary structure and conserved motifs of the frequently sequenced domains IV and V of the insect mitochondrial large subunit rRNA gene

We have analysed over 400 partial insect mitochondrial large subunit (mit LSU) sequences in order to identify conserved motifs and secondary structures for domains IV and V of this gene. Most of the secondary structure elements described by R. R. Gutell et al. (unpublished) for the LSU were identified. However, we present structures for helices 84 and 91 that are not recognized in previous universal models. The portion of the 16S gene containing domains IV and V is frequently sequenced in insect molecular systematic studies so we have many more sequences than previous studies which focused on the complete mitochondrial LSU molecule. In addition, we have the advantage of investigating several sets of closely related taxa. Aligned sequences from thirteen insect orders and nine secondary structure diagrams are presented. These conserved sequence motifs and their associated secondary structure elements can now be used to facilitate the alignment of other insect mit LSU sequences.

1997 Graduates Speak: initial employment experiences of residency and fellowship graduates

OBJECTIVE

The American College of Radiology sought to detail the initial employment experience of 1997 diagnostic radiology graduates and recent trends.

MATERIALS AND METHODS

In early 1998, questionnaires were mailed to all graduates; 65% responded. Results were compared with similar surveys of 1995 and 1996 graduates.

RESULTS

Much as in past years, immediately after graduation 4% of residency graduates and 9% of fellowship graduates spent some time working as a locum tenens, working outside radiology, or unemployed, but by 6-12 months after graduation, 2% or fewer were not employed. The median fellowship graduate's salary was 5% greater than in 1996. Twelve percent of fellowship graduates were in non-ownership-track jobs, much the same as in earlier years. Thirty-two percent had one or more of 12 possibly undesirable job characteristics, down from 39% in 1996; 14% not only had, but actually disliked, one or more of these characteristics, much the same as in 1996, but down from 23% in 1995. Multivariate analysis showed that women graduates were more likely than men to have had serious employment difficulties in the immediate postgraduation months; and that graduates having a spouse who also had to find a job in the same area were more likely than others to be in a putatively "seriously undesirable" location or in "holding pattern" employment while looking for something better or more permanent.

CONCLUSION

Unemployment remained very low. Some other indicators of the employment market showed improvement. Factors expected to affect employment outcomes-for example, training program quality or having major non-spouse-related restrictions on job location-had surprisingly little effect.

Pilot study of hydroxyurea in human immunodeficiency virus-infected children receiving didanosine and/or stavudine

OBJECTIVE

To evaluate the safety and antiviral and immunologic effects of hydroxyurea given with didanosine (ddI) and/or stavudine (d4T) to symptomatic HIV-infected children.

METHODS

HIV-infected children with a history of long term nucleoside antiretroviral therapy were treated orally with hydroxyurea (initial dose, 10 to 20 mg/kg once daily; final dose, 30 mg/kg once daily), added to existing therapy that included ddI and/or d4T.

RESULTS

Sixteen children were enrolled (mean age, 6.7 years; range, 1.8 to 13.4 years). Antiretroviral therapy used with hydroxyurea included d4T/ddI (12), ddI (2), d4T (1) and d4T/lamivudine (1). Children received between 24 and 48 weeks of therapy, which was well-tolerated. Hydroxyurea was held temporarily during the first month of therapy in 4 cases because of neutropenia; all patients resumed hydroxyurea at full dosage without recurrence of neutropenia. No patient discontinued therapy permanently because of intolerance or toxicity. For the 13 children who completed 48 weeks of study treatment, the mean plasma HIV RNA concentration decreased from 4.6 log10 copies/ml at baseline to 4.2 log10 copies/ml at study Week 48 (P = 0.035, paired t test). Eight of these 13 children experienced a 0.5-log10 copies/ml or greater drop in HIV RNA concentration in the 48 weeks of study treatment. Appreciable changes in CD4+ lymphocyte percentage were not noted.

CONCLUSIONS

Hydroxyurea, added to existing therapy with ddI and/or d4T, was well-tolerated and safe in HIV-infected children. Evidence of antiviral activity was observed in some cases.

Effect of sleep deprivation on overall 24 h growth-hormone secretion

After sleep deprivation, the blunting of the normal sleep-related growth-hormone (GH) pulse is compensated during the day. Consequently, the amount of GH secreted during a 24 h period is similar whether or not a person has slept during the night. These results argue against the belief that sleep disorders in children can inhibit growth through a daily GH deficit.

Measurement of vortex motion in a type-II superconductor: A novel use of the neutron spin-echo technique

We have used the neutron spin-echo technique to measure the small energy change of neutrons which are diffracted by a moving vortex lattice in a low-pinning Nb-Ta superconducting sample. A transport current was passed in the mixed state to cause flux line movement. In the case of uniform motion, the flux velocity v(L) was given as expected by the values of electric and magnetic fields, via E = -v(L)wedgeB. We show that with a nonuniformly moving vortex lattice, one can measure the dispersion of the velocities, opening up new possibilities for investigating moving vortex lines.

Ultradian pulsatility of plasma glucose and insulin secretion rate: circadian and sleep modulation

Insulin release is a complex oscillatory process with rapid pulses (10 min) superimposed on slower circhoral oscillations (50-100 min). The exact mechanism of the circhoral oscillations, which are probably in part the consequence of a negative feedback loop linking glucose and insulin secretion rate, remains unclear. Stimulatory effects of sleep on insulin secretion are achieved by an enhancement of the oscillation amplitude which could be partly mediated by GH. The different patterns observed after acute or chronic shift of sleep suggest however an interaction between sleep influence and circadian rhythmicity, as described for numerous pituitary hormones. The intra-sleep awakenings have a modulatory effect on glucose levels but no systematic relationship exists between glucose or insulin secretion rate oscillations and the REM-NREM sleep cycles. Irrespective of the mechanisms involved, sleep or GH stimulatory effects result from a modulation of the oscillation amplitude rather than of their frequency which is probably an important feature of insulin efficacy.

Pluripotential mesenchymal cells repopulate bone marrow and retain osteogenic properties

Precursor cells, isolated from bone marrow, can develop into various cell types and may contribute to skeletal growth, remodeling, and repair. The D1 cell line was cloned from a multipotent mouse bone marrow stromal precursor and has osteogenic, chondrogenic, and adipogenic properties. The osteogenic phenotype of these precursor cells is relevant to the process of fracture healing and osteointegration of prosthetic implants. The D1 cells were labeled genetically using a replication incompetent retroviral vector encoding beta-galactosidase, an enzyme which is used as a marker. Labeled cells are readily identifiable by staining with 5-bromo-4-chloro-3-indoyl-beta-D-galactoside and by flow cytometry, and retain the desired osteogenic characteristics in vivo as shown by von Kossa staining, alkaline phosphatase assay, an increase in cyclic adenosine monophosphate in response to parathyroid hormone, osteocalcin messenger ribonucleic acid production, and bone formation in diffusion chambers. In addition, the cells cloned from marrow stroma repopulate the marrow of host mice, persist for several weeks, and retain their osteogenic potential ex vivo. The data suggest that such cells may be used to replenish the number of osteoprogenitors in marrow, which appear to decrease with age, thereby leading to recovery from bone loss and improved bone growth and repair. Labeling these cells creates a model in which to study the potential of such cells to participate in fracture repair, ingrowth around prosthetic implants, treatment of osteoporosis, and to explore the possibility of gene delivery to correct mutations or defects in metabolism that are responsible for certain skeletal abnormalities.

Feasible "Kochen-Specker" experiment with single particles

We present a simple experimental scheme which can be used to demonstrate an all-or-nothing-type contradiction between noncontextual hidden variables and quantum mechanics. The scheme, which is inspired by recent ideas by Cabello and Garcia-Alcaine, shows that even for a single particle, path and spin information cannot be predetermined in a noncontextual way.

Electrostatic forces on the surface of metals as measured by atomic force microscopy

Electrostatic forces play an important role in modulating the interaction of plasma proteins and blood cellular components with the surface of the vascular endothelium. Based on the concept that electrostatic forces residing on the surface of metal intravascular prostheses, such as the stent, also are critical in influencing blood interactions with those surfaces and the vascular wall, these studies were designed to measure these forces on 4 metals using atomic force microscopy (AFM). AFM measurements performed in a low saline aqueous medium at physiological pH indicate a similar net electronegative surface charge level for gold and 316l stainless steel that is significantly higher than the level measured on an electropolished Nitinol surface. Heat oxidation of the Nitinol surface increased the overall electronegativity and created a more homogeneous surface charge distribution. This study demonstrates that AFM force measurements can be a valuable approach to understanding the electrostatic surface of metallic as well as other biomaterials that may be important in understanding how these surfaces influence vascular healing at intravascular interventional sites.

Protein interactions with endovascular prosthetic surfaces

Blood protein interaction with prosthetic surfaces seems to be the initial step in the chain of events leading to tissue incorporation of endovascular devices. This paper focuses on the relationship between surface free energy and protein adsorption on metals and polymers commonly used for fabricating vascular prosthetic devices. Our results support a relationship between surface energy and protein adsorption. Albumin was more easily eluted than fibrinogen and fibronectin from most metals and all polymeric surfaces considered. Following elution, metals retained a larger fraction of protein as compared to polymers.

Influence of topography on endothelialization of stents: clues for new designs

To evaluate the influence of stent design on endothelialization of the stented surface, we placed trapezoidal objects of variable thickness on a confluent culture of endothelial cells and subjected the assembly to flow and shear conditions similar to those found in arteries. After 24 h, we measured and analyzed the area on top of the objects covered by cells and the maximum migration distance from the borders. In addition, we evaluated areas devoid of cells surrounding the objects, which developed after exposure of the assembly to flow. The cell-covered area and migration distance significantly decreased on objects 75 microns thick, and it was nonexistent on objects 250 microns thick. Areas devoid of cells or gaps were largest adjacent to the downflow side of the object, disposed transversely to flow. Cell gaps were smallest along the side aligned with flow. In conclusion, endothelial cell coverage may be impaired by stent wall thickness larger than 75 microns. It is likely that this impairment is related to flow disturbances impairing cell attachment.

Genetic evidence for assortative mating between 13-year cicadas and sympatric "17-year cicadas with 13-year life cycles" provides support for allochronic speciation

Thirteen-year cicadas of brood XIX from northern Arkansas, Missouri, and southern Illinois (lineage A) are known to be genetically different at two marker loci (mitochondrial DNA and abdominal color) from 13-year cicadas to the south (lineage B) that emerge in the same year. Because 17-year cicadas from all broods (year classes) are indistinguishable from lineage A at these two marker loci, previous workers suggested that the lineage A cicadas of 13-year brood XIX were derived from 17-year cicadas by life-cycle switching (allochrony). Data presented here show that, over the same northern geographic range, lineage A is also present in 13-year cicadas belonging to brood XXIII (which always emerges four years later than brood XIX). Detailed sampling along the putative life-cycle-switching boundary in 13-year brood XXIII revealed a previously unsuspected broad zone of overlap where populations contained individuals of both lineages A and B. Despite this sympatry, and previous reports of a lack of behavioral barriers to interbreeding, a strong correlation between mitochondrial haplotype and abdominal color suggests that assortative mating has taken place. Lineage A 13-year cicadas from both broods XIX and XXIII are only found within a gap in the spatial distribution of 17-year cicadas. This, in combination with the lack of differentiation between lineage A 13- and 17-year cicadas at the marker loci and new behavioral data for 13-year brood XIX, suggests a recent derivation of all northern 13-year cicadas from the 17-year cicadas via life-cycle switching. We discuss the implications of these allochronic shifts for speciation.

High intensity focused ultrasound effect on cardiac tissues: potential for clinical application

High intensity focused ultrasound (HIFU) is an evolving technology with potential therapeutic applications. Utilizing frequencies of 500 kHz to 10 MHz, HIFU causes localized hyperthermia at predictable depths without injuring intervening tissue. Applications in neurosurgery, urology, oncology and, more recently, cardiology for selective cardiac conduction tissue ablation have been promising. A 'noninvasive' technique for causing localized tissue damage to relieve hemodynamic and life-threatening obstruction in patients with congenital cardiac anomalies could replace more invasive procedures. We, therefore, investigated the ability of HIFU to create lesions in mammalian cardiac tissues ex vivo. Porcine valve leaflet, canine pericardium, human newborn atrial septum, and right atrial appendage were studied. Specimens were mounted and immersed in a water bath at room temperature. Using a 1-MHz phased array transducer, ultrasound energy was applied with an acoustic intensity of 1630 W/cm(2) or 2547 W/cm(2) until a visible defect was created (duration 3 to 25 sec). Macroscopic and microscopic examination demonstrated precise defects ranging from 3 to 4 mm in diameter. No damage was identified to the surrounding tissues. Our study concluded that HIFU can create precise defects in different cardiac tissue without damage to the surrounding tissue. Further investigation is needed to assess potential clinical uses of this technology.

Postoperative brachytherapy alone for T1-2 N0 squamous cell carcinomas of the oral tongue and floor of mouth with close or positive margins

PURPOSE

To evaluate the efficacy of postoperative brachytherapy alone (brachy) for Stage T1-2 squamous cell carcinomas (SCC) of the floor of mouth (FM) and the oral tongue (OT) with close or positive margins.

METHODS AND MATERIALS

Between 1979 and 1993, 36 patients with T1-2 N0 (24 T1, 12 T2) OT (19), and FOM (17) SCC with close or positive margins following surgery underwent postoperative brachy. Mean patient age was 56 years (range 37-81) and sex ratio was 3.5:1 male:female. Mean surgery to brachy interval was 36 days (range 16-68). The technique used was interstitial Iridium-192 ((192)Ir) brachytherapy with plastic tubes and manual afterloading. Mean total dose was 60 Gy (range 50-67.4) at a mean dose rate of 0.64 Gy/h (range 0.32-0.94). Mean patient follow-up was 80 months.

RESULTS

The 5-year actuarial overall and cause-specific survivals of the entire group were 75% and 85%, respectively. The local control was 88.5% at 2 years, with a plateau apparent after 23 months. Of the 4 local relapses, 2 were salvaged with surgery and external beam radiotherapy (EBR). No tumor or treatment factors, including tumor size, margin status, disease site, or radiation dose, were correlated with local control. The 2 head and neck second primaries underwent curative treatment on nonirradiated tissue. One patient developed a grade 3 sequelae (bone and soft tissue necrosis). Grade 2-3 chronic sequelae were seen in 7 of 17 and 3 of 19 FOM and OT tumors, respectively (p = 0.09).

CONCLUSION

Postoperative brachy is a promising approach in T1-2 N0 OT and FOM SCC with close or positive margins. This approach is associated with high rate of locoregional control and low risk of chronic sequelae, obviates major surgery, avoids potential sequelae of EBR (xerostomia, dysgueusia, fibrosis), and avoids treatment of second head and neck primary on nonirradiated tissues.

Modelling and simulation of light-activated membrane proteins: dynamical transitions in bacteriorhodopsin

Many of the functions of membranes are carried out by proteins associated with them. A knowledge of atomic-detail membrane protein structures and dynamics is required for a full understanding of these functions. We briefly discuss recent progress in this field using modelling and simulation. One of the best characterised membrane proteins, bacteriorhodopsin, undergoes dynamical transitions with temperature. Here we present preliminary results of molecular dynamics simulation of this protein as a function of temperature, indicating the presence of dynamical transitions at approximately the temperatures seen experimentally.

[Role of bariatric surgery in the obese diabetic]

Bariatric surgery can be proposed to address severe obesity associated with comorbid conditions, when medical treatment has failed. Three surgical techniques are currently available, including 2 using coelioscopy. Short term results are encouraging regarding weight loss, which is linked with a reduction in comorbid conditions such as glucose intolerance. The number of studies is too low to assess long term results. Surgery in obese diabetic patients rapidly improves insulin resistance, thus allowing to reduce antidiabetic treatment. However these positive effects should be balanced with surgery-linked complications, therefore gastroplasty indications should be thoroughly examined.

[Juvenile goiter in a goat herd in northwest Germany]

A continuous increase in the circumference of the thyroid gland was observed in four goat kids (44.4%) of the breed of White German Goat between the third and fourth month in a herd comprising White German Goats and Coloured German Goats. Clinical, laboratory diagnostic and chemically analytical results have been obtained, illustrated and compared with the equivalent parameters from healthy control herds without pathological findings. The thyroidal secretion rate and the milk iodine content were highly significant reduced in the affected flock in comparison with the control group. The feed which was given to the affected group did not cover the nutritional requirement of pregnant, lactating and growing goats. At 40-50 mg/l, the nitrate content of the water was close to the tolerance of 50 mg/l. It can be deduced from the findings available that the case described above is a synergetic combination of a primary iodine deficiency, based on an inefficient iodine supply and of a secondary iodine deficiency resulting from a super elevated nitrate content of the drinking water.

Quantum cryptography with entangled photons

By realizing a quantum cryptography system based on polarization entangled photon pairs we establish highly secure keys, because a single photon source is approximated and the inherent randomness of quantum measurements is exploited. We implement a novel key distribution scheme using Wigner's inequality to test the security of the quantum channel, and, alternatively, realize a variant of the BB84 protocol. Our system has two completely independent users separated by 360 m, and generates raw keys at rates of 400-800 bits/s with bit error rates around 3%.