Search

We study the computational complexity of the N-representability problem in quantum chemistry. We show that this problem is quantum Merlin-Arthur complete, which is the quantum generalization of nondeterministic polynomial time complete. Our proof uses a simple mapping from spin systems to fermionic systems, as well as a convex optimization technique that reduces the problem of finding ground states to N representability.

We investigate quantum phase transitions (QPTs) in spin chain systems characterized by local Hamiltonians with matrix product ground states. We show how to theoretically engineer such QPT points between states with predetermined properties. While some of the characteristics of these transitions are familiar, like the appearance of singularities in the thermodynamic limit, diverging correlation length, and vanishing energy gap, others differ from the standard paradigm: In particular, the ground state energy remains analytic, and the entanglement entropy of a half-chain stays finite. Examples demonstrate that these kinds of transitions can occur at the triple point of "conventional" QPTs.

We consider multipartite states of qubits and prove that their bipartite quantum entanglement, as quantified by the concurrence, satisfies a monogamy inequality conjectured by Coffman, Kundu, and Wootters. We relate this monogamy inequality to the concept of frustration of correlations in quantum spin systems.

Skulls (n=104) of northern elephant seals from California were examined macroscopically. The animals varied in age but the numbers of each sex were roughly equal. The majority (86%) of teeth were available for examination. The mandibular first premolars were the most common teeth to be congenitally absent, with 2.3% missing. Supernumerary teeth (usually a supplemental mandibular molar) were associated with only 1.4% of normal teeth (or empty alveolar sockets). At least one persistent deciduous tooth was present in 38% of skulls, 70% of which were juvenile skulls. The majority (95.8%) of premolars had the type 2a tooth form, with only 3.8% and 0.5% of type 2b and 2c, respectively. Forty-six skulls, of which 43 were from adults, showed signs of attrition. Tooth fractures were uncommon, affecting only 33 teeth (1.2%). One skull showed an "incremental line" suggestive of enamel hypoplasia. Periodontal hard tissue lesions were seen in 44.3% of all teeth present (46.0% of skulls). Six cases of periapical disease with bone loss were observed.

Oral mucosal salivary samples were collected from 25 cats with chronic gingivostomatitis and 24 cats with periodontal disease. Viral culture and isolation of feline calicivirus and feline herpesvirus 1 were performed. Eighty-eight per cent of cats with chronic gingivostomatitis were shedding both viruses, compared to 21% of cats without chronic oral inflammatory disease. Cats with chronic gingivostomatitis are significantly more likely to concurrently shed both feline calicivirus and feline herpesvirus 1 than are cats with classical periodontal disease.

We consider a single copy of a mixed state of two qubits and derive the optimal trace-preserving local operations assisted by classical communication such as to maximize the fidelity of teleportation that can be achieved with this state. These optimal local operations turn out to be implementable by one-way communication and always yield a teleportation fidelity larger than 2/3 if the original state is entangled. This maximal achievable fidelity is an entanglement measure and turns out quantifying the minimal amount of mixing required to destroy the entanglement in a quantum state.

We discuss the relations between the violation of the Clauser-Horne-Shimony-Holt (CHSH) Bell inequality for systems of two qubits on the one side and entanglement of formation, local filtering operations, and the entropy and purity on the other. We calculate the extremal Bell violations for a given amount of entanglement of formation and characterize the respective states, which turn out to have extremal properties also with respect to the entropy, purity, and several entanglement monotones. The optimal local filtering operations leading to the maximal Bell violation for a given state are provided, and the special role of the resulting Bell diagonal states in the context of Bell inequalities is discussed.

Educational institutions should be aware of the frequency of surgical procedures in private practice, to assist both the student and the lecturer in evaluating the relative importance of procedures and to structure training programmes accordingly. The surgical caseload for 1 year at a veterinary academic hospital and 13 private companion animal hospitals registered with the South African Veterinary Council were compared. Surgical records were entered into a spreadsheet and sorted according to 96 selected surgical procedures to facilitate comparisons. Surgical procedures were in turn grouped according to date, species, degree of difficulty and frequency of occurrence. Feline procedures were more commonly performed in private hospitals. The academic hospital's caseload was dominated by major and advanced procedures while the private hospitals carried out more minor procedures. At the private hospitals more general surgery, and ear, nose and throat surgery as well as dental procedures were performed, while at the academic hospital more ophthalmic, orthopaedic, thoracic and neurosurgical procedures were carried out. The most commonly performed procedures at the academic hospital differed from those at the private hospitals. No seasonal trends were evident.

Background and Purpose: In research facilities using non-human primates, crown-height reduction with partial coronal pulpectomy ("vital pulpotomy") is routinely performed on canine teeth of adult male monkeys to reduce self-trauma and the potential for injury to staff or cage-mates. Success of pulpotomy techniques in humans is reportedly 40 to 60%. Failure leads to chronic inflammation and pulp necrosis, which introduces variability in research animals, and may affect research results. The purpose of the study reported here was to determine failure rate of this procedure by evaluating clinical and radiographic findings at 3, 9, and 24 months after crown amputation and partial coronal pulpectomy of maxillary canines in adult male rhesus monkeys., Methods: Forty-seven maxillary canine teeth from 24 adult male rhesus monkeys were treated by use of crown amputation and partial coronal pulpectomy, using standard dental technique. Follow-up clinical and radiographic examination was performed 3, 9, and 24 months after surgery., Results: At three months after surgery, there was no clinical evidence of failure at any of the teeth. On the basis of radiographic findings, 2 of 47 teeth had failed and one was suspicious for early failure. At nine months, clinical evidence of failure was not apparent; radiographically, 5 of 44 teeth appeared to have failed and 3 others were suspect. Two years post-operatively, failure was clinically evident at two teeth, with radiographic evidence of failure in five teeth, and suspicion of early failure in an additional six of 41 teeth [corrected]., Conclusions: The failure rate of crown amputation and partial coronal pulpectomy of canine teeth in adult male rhesus monkeys is high, and the chronic inflammation associated with this is cause for concern.

Objective: To determine patterns of alveolar bone loss (periodontitis) and other lesions evident on full-mouth survey radiographs of cats., Design: Retrospective study., Animals: 147 cats., Procedure: Full-mouth radiographs were evaluated for evidence and severity of alveolar bone loss, odontoclastic resorption lesions (ORL), retained roots, missing teeth, signs of endodontic disease secondary to periodontitis, and apical resorption., Results: 106 (72%) cats had some degree of periodontitis, 100 (68%) were missing teeth, 98 (67%) had ORL, 78 (53%) had expansion of the buccal alveolar bone at 1 or more canine teeth, 75 (51%) had retained roots, 48 (33%) had apical resorption, and 12 (8%) had signs of endodontic disease secondary to periodontitis. Cats < 4 years old were not significantly more likely than the general population to have normal alveolar bone height. Prevalence of ORL increased with age, but cats > or =13 years old were less likely than the general population to have moderate or severe generalized periodontitis. Purebred cats were not significantly more likely to have periodontitis or ORL than mixed-breed cats., Conclusions and Clinical Relevance: Results suggest that periodontitis is common in cats and that horizontal bone loss is the most common radiographic pattern of alveolar bone loss. Purebred cats were not more likely than mixed-breed cats to have ORL or periodontitis, but when they did have periodontitis, it was more likely to be moderate to severe. Cats with ORL were less likely than cats without ORL to have normal alveolar bone height and more likely to have severe focal vertical bone loss.

Objective: To determine whether odontoclastic resorption lesions were associated with radiographic evidence of periapical lucencies in cats., Design: Retrospective study., Animals: 265 feline dental patients., Procedure: Full-mouth radiographs were examined for evidence of odontoclastic resorption lesions, periapical lucencies, periodontitis, and fractured teeth., Results: Odontoclastic resorption lesions affecting 567 teeth were identified in 161 (60.8%) cats. Periapical lucencies were identified in 53 teeth in 35 cats. Periapical lucencies were most commonly associated with fractured teeth (25 teeth with periapical lucencies) and severe periodontitis (21 teeth). None of the periapical lucencies appeared to be specifically associated with resorption lesions. Prevalence of periapical lucencies in cats with resorption lesions was not significantly different from prevalence in cats without., Conclusions and Clinical Relevance: Results suggest that although odontoclastic resorption lesions are common in cats, pulpal involvement associated with these lesions does not appear to be associated with development of radiographically detectable periapical lucencies. Crown amputation with intentional root retention may, therefore, be a suitable alternative to extraction in selected cats with odontoclastic resorption lesions.

Oral radiography plays an important role in the diagnosis of periodontal disease. The diagnostic yield of radiographs is high, and they should be obtained in all cases presenting for periodontal treatment and to assess the long-term success of therapy. Diagnostic-quality radiographs for evaluating the periodontium are best obtained with a dental x-ray unit and with the patient under general anesthesia. The standard full-mouth radiographic survey contains a minimum of 6 views, and with practice, can be obtained with minimal effort and time. Interpretation of dental radiographs, however, requires a keen understanding of the normal radiographic anatomy of a tooth and its supporting structures. The radiographic diagnosis of periodontal disease is characterized by rounding of the alveolar crest with loss in continuity of the lamina dura, widening of the periodontal ligament space, and loss of alveolar crest height.

Objective: To determine whether intratumoral microvessel density can be used to distinguish benign from malignant mammary tumors in dogs and to predict the outcome of surgical treatment for small volume (< 3-cm diameter) tumors., Sample Population: Tissue sections from 58 mammary tumors (42 malignant and 16 benign) from dogs., Procedure: Mammary tumors were stained by immunohistochemistry for factor VIII-related antigen. Computer-assisted image analysis was used to determine intratumoral vessel density in immunostained areas. Total vascular density (TVD), calculated from 3 non-overlapping fields, was analyzed for correlation with patient or tumor histomorphologic characteristics, and results obtained by surgical treatment of small volume tumors., Results: Mean TVD of malignant tumors was significantly greater than that of benign tumors. Total vascular density was not correlated with patient age, sex, reproductive status, clinical tumor stage, or histologic type. For small volume (< 3-cm diameter) malignant tumors, mean TVD was higher in tumors that recurred after surgery than in tumors that did not recur; however, TVD was not predictive of time to recurrence., Conclusion and Clinical Implications: Immunohistochemistry and computer-assisted image analysis allowed objective quantitation of intratumoral microvessel density in formalin-fixed, paraffin-embedded tissue sections. Tumors with high TVD were more likely to recur after surgical treatment than tumors with low TVD suggesting that TVD measurements can be used by the clinician, in addition to histologic type and clinical stage, to predict prognosis after surgical treatment. These data also provide rationale for use of antiangiogenesis strategies for treatment of malignant mammary tumors in dogs.

Amelogenins are major enamel proteins within the enamel extracellular matrix. The expression of amelogenin was confirmed in neonatal tissues of the canine jaw. The sequence of a portion of canine amelogenin cDNA, within exons 5 and 6, was determined and found to be closely homologous to sequences reported in the cow, pig, mouse and human being. Two acanthomatous epulides collected from clinically affected dogs showed amelogenin expression, whereas 22 other canine oral lesions, including six additional acanthomatous epulides, did not show amelogenin expression. Examination of structural proteins may allow precise identification of the histogenesis of the odontogenic neoplasms, which are often difficult to distinguish by means of morphological criteria alone.

Objective: To determine the diagnostic value of full-mouth radiography in dogs., Sample Population: Prospective series of 226 dogs referred for dental treatment without previous full-mouth radiographic views being available., Procedure: In a prospective nested case-control analysis of multiple outcomes in a hospital cohort of dogs presented for dental treatment, full-mouth radiographic views were obtained prior to oral examination and charting. After treatment, clinical and radiographic findings were compared, with reference to presenting problems, main clinical findings, additional information obtained from the radiographs, and unexpected radiographic findings. The importance of the radiographic findings in therapeutic decision-making was assessed., Results: The main clinical findings were radiographically confirmed in all dogs. Selected presenting problems and main clinical findings yielded significantly increased odds ratios for a variety of other conditions, either expected or unexpected. Radiographs of teeth without clinical lesions yielded incidental or clinically important findings in 41.7 and 27.8% of dogs, respectively, and were considered of no clinical value in 30.5%. Radiographs of teeth with clinical lesions merely confirmed the findings in 24.3% of dogs, yielded additional or clinically essential information in 50.0 and 22.6%, respectively, and were considered of no value in 3.1%. Older dogs derived more benefit from full-mouth radiography than did younger dogs. Incidental findings were more common in larger dogs., Clinical Relevance: Diagnostic yield of full-mouth radiography in new canine patients referred for dental treatment is high, and the routine use of such radiographs is justifiable.

Objective: To determine the diagnostic value of full-mouth radiography in cats., Sample Population: 115 cats referred for dental treatment without a previous full-mouth radiographic series available., Procedure: In a prospective nested case-control analysis of multiple outcomes in a hospital cohort of cats referred for dental treatment, full-mouth radiography was done prior to oral examination and charting. After treatment, the clinical and radiographic findings were compared, with reference to presenting problems, main clinical findings, additional information obtained from radiography and unexpected radiographic findings. Importance of the radiographic findings in therapeutic decision making was assessed., Results: The main clinical findings were radiographically confirmed in all cats. Odontoclastic resorption lesions, missed on clinical examination, were diagnosed in 8.7% of cats. Analysis of selected presenting problems and main clinical findings yielded significantly increased odds ratios for a variety of other conditions, either expected or unexpected. Radiographs of teeth without clinical lesions yielded incidental or clinically important findings in 4.8 and 41.7% of cats, respectively, and were considered of no clinical value in 53.6%. Radiographs of teeth with clinical lesions merely confirmed the findings in 13.9% of cats, but yielded additional or clinically essential information in 53.9 and 32.2%, respectively., Clinical Relevance: The diagnostic yield of full-mouth radiography in new feline patients referred for dental treatment is high, and routine use of full-mouth radiography is justifiable.

Skulls (n = 155) of adult domestic cats were examined macroscopically and anatomical variations were documented. The maxillary second premolar tooth was absent in 7.9% of cases, and was found to have a single root in 27.7%, partly fused roots in 55.1% and two fully formed roots in 9.2% of cases. The maxillary first molar tooth was absent in 2.3% of cases; a single root was present in 35.0%, a partly fused root in 34.7%, and two roots in 28.0% of cases. Supernumerary roots were found on the maxillary third premolar teeth in 10.3% of cases. Other variations were found to be extremely rare.

Objective: The purpose of this study was to determine the effects of phosphate-buffered saline (PBS), sterile tap water, normal saline, and Ringer's lactate on wound healing in an in vitro model., Study Design: The effects of PBS, sterile tap water, normal saline, and Ringer's lactate on a primary line of canine embryonic fibroblasts were determined., Animals or Sample Population: A primary line of canine embryonic fibroblasts., Methods: The effects of the various lavage solutions were determined by (1) vital staining of the treated cells with a 0.5% trypan blue solution, (2) evaluation of the amount of lactate dehydrogenase released by the treated cells, and (3) cytopathologic evaluation of hematoxylin and eosin-stained monolayers of treated canine fibroblasts. The cells were exposed to the lavage treatments for the following time intervals: 0.5 minute, 1 minute, 2.5 minutes, 5 minutes, and 10 minutes. PBS was used as the control., Results: Sterile tap water significantly damaged canine fibroblasts at all time intervals (P = .05). This was attributed to the alkaline pH, hypotonicity, and presence of numerous cytotoxic trace elements in the tap water used. Cytotoxic effects were noted in fibroblasts after 10 minutes' exposure to normal saline; this may be because of the acidic pH of normal saline and lack of a buffering system. Ringer's lactate did not induce any significant fibroblast injury., Conclusions: PBS and Ringer's lactate do not induce any significant fibroblast injury, whereas normal saline and sterile tap water cause mild and severe cytotoxic effects in vitro., Clinical Relevance: Further clinical investigation is indicated to establish whether Ringer's lactate is the wound lavage solution of choice compared with normal saline. Sterile tap water may cause considerable fibroblast injury.

Skulls (n = 301) of adult feral cats from Marion Island, a sub-Antarctic island, were examined macroscopically. Congenital anomalies, which were rare, included a few supernumerary premolars, located mesially to those normally present. Supernumerary roots, mainly of the maxillary third premolar, were found in just over 10% of cases. The maxillary second premolar was absent in 16.8% of skulls; dichotomous and double-formed roots of this tooth were present in 20.1% and 1.9% of cases, respectively. Enamel hypoplasia, which is most unusual in this species, was noted in 24.6% of cases, and persistent deciduous teeth in 2.0%. Dental abrasion, which was noted in 19.3% of cats, affected only 2.3% of teeth, most commonly the lower fourth and upper third premolars. Dental fractures, mainly complicated crown fractures and root fractures, were noted in 54.8% of cats and 7.0% of teeth. Fractures were found most commonly in the canine and carnassial teeth, as also were periapical lesions, which were often severe. Mandibular fractures in various stages of healing were found in 11 cats (3.7%); such fractures most frequently affected the body of the mandible and resulted in malunion. It was concluded that the high prevalence of dental fractures and associated periapical lesions probably exerted a significant adverse effect on health and survival in this population of feral cats.

Skulls (n = 301) of adult feral cats from Marion Island were examined macroscopically. Dental calculus was found infrequently (9.0% of cats, 0.76% of teeth), unlike the hard tissue lesions of moderate and advanced periodontitis and tooth loss (presumably due to periodontitis), which were commonly seen (61.8% of cats, 14.8% of teeth). Relatively few of these abnormalities were associated with external odontoclastic resorption lesions, which affected 14.3% of cats and 1.2% of teeth-less than in most recent surveys in domestic cats. Abnormal thickening of the mandibula, found in 39.5% of specimens, was most commonly bilateral (83.3%). The lesions ranged from a focal periosteal reaction, to localized exostosis, to generalized swelling and loss of density, to grossly enlarged mandibles with increased bone density. Mandibular swelling was significantly associated with other abnormalities (periodontitis, dental fractures, external odontoclastic resorption lesions and periapical lesions), but many cases of mandibular swelling were accompanied by only minor dental defects.

Three dogs each received a three-unit fixed-fixed porcelain-veneer bridge for the replacement of traumatically-lost upper first or second incisor teeth. The bridges remained in place for a period ranging from 6-36 months, before becoming dislodged as a result of external trauma. It was concluded that this type of bridgework is technically feasible and may be justifiable.

An 8-year-old Hannoverian horse developed a swelling of the maxilla caused by a tumour of the hard palate. On histological examination the tumour was diagnosed as a primary intra-osseous carcinoma of the maxilla, a rare odontogenic tumour not previously described in the horse.

Two cases of anomalous development of the upper third premolar in a dog and a cat are described. The involved teeth have a bifid crown and 3 roots. The central root is abnormally wide and has 2 separate root canals. The anomalous tooth is the cause of malocclusion in the cat and of periodontitis in both cases. The difficulty in distinguishing gemination from fusion is discussed.

A practical method was developed to remove the different permanent teeth of the dog as atraumatically as possible and with a minimal risk of complications. Emphasis is placed on the importance of completely loosening the root from its periodontal attachment and subsequently lifting the tooth out by means of a root elevator, instead of forceful extraction with an extraction forceps. Specific considerations for each tooth are given.