Projected Entangled Pair States: Fundamental Analytical and Numerical Limitations.

Matrix product states and projected entangled pair states (PEPS) are powerful analytical and numerical tools to assess quantum many-body systems in one and higher dimensions, respectively. While matrix product states are comprehensively understood, in PEPS fundamental questions, relevant analytically as well as numerically, remain open, such as how to encode symmetries in full generality, or how to stabilize numerical methods using canonical forms. Here, we show that these key problems, as well as a number of related questions, are algorithmically undecidable, that is, they cannot be fully resolved in a systematic way. Our work thereby exposes fundamental limitations to a full and unbiased understanding of quantum many-body systems using PEPS.

Lateral preference in Williams-Beuren syndrome is associated with cognition and language.

Williams-Beuren syndrome (WBS) is a genetically defined neurodevelopmental disorder presenting with intellectual disability associated with a specific neurocognitive profile characterized by anxiety, hypersociability, poor visuospatial skills and relatively preserved language. We have defined the lateral preference in 69 individuals (40 males and 29 females, age range 5-47 years) with WBS confirmed by molecular testing, and explored its correlation with cognition, behavior problems, the main aspects of the behavioral phenotype, and specific molecular variants (parental origin and size of the 7q11.23 deletion). Lateral preference (hand, foot, eye and ear) and neurobehavioral features [intelligence quotient (IQ), sociability, visuospatial construction, narrative skills and behavior] were assessed by a battery of tests and parental interviews. A large proportion of WBS individuals showed either left or mixed handedness (26 and 19%, respectively). Hand, foot and ear lateral preference showed significant association with IQ, with individuals with mixed lateral preference presenting lower general IQ, especially verbal IQ, with respect to subjects with well-defined laterality. Approachability, visuospatial ability, behavior problems or molecular variants were not associated with lateral preference. Our results indicate that, as in other neurodevelopmental disorders, laterality is poorly defined in a significant proportion of WBS individuals, and reinforces the idea that a correct definition of lateral preference is important for cognition and language.

Lieb-Robinson bounds for spin-boson lattice models and trapped ions.

We derive a Lieb-Robinson bound for the propagation of spin correlations in a model of spins interacting through a bosonic lattice field, which satisfies a Lieb-Robinson bound in the absence of spin-boson couplings. We apply these bounds to a system of trapped ions and find that the propagation of spin correlations, as mediated by the phonons of the ion crystal, can be faster than the regimes currently explored in experiments. We propose a scheme to test the bounds by measuring retarded correlation functions via the crystal fluorescence.

Operator space theory: a natural framework for bell inequalities.

In this Letter we show that the field of operator space theory provides a general and powerful mathematical framework for arbitrary Bell inequalities, in particular, regarding the scaling of their violation within quantum mechanics. We illustrate the power of this connection by showing that bipartite quantum states with local, Hilbert space dimension n can violate a Bell inequality by a factor of order sqrt[n]/(log{2}n) when observables with n possible outcomes are used. Applications to resistance to noise, Hilbert space dimension estimates, and communication complexity are given.

[Suburethral endometrioma]. / Endometrioma suburetral.

Endometriosis is a common disease affecting mostly women in childbearing age. It usually involves the internal pelvic organs but occasionally can present in unusual locations. We report on a 32-year-old nulliparos female presenting with a suburethral painful mass causing obstructive voiding symptoms; she had also a long history of dismenorreia, perimenstrual pelvic pain, urinary tract infections, disúria and dispareunia. The diagnostic work-up revealed a suburethral cystic lesion consistent with a complicated urethral diverticulum or a suburethral endometrioma. Complete surgical excision confirmed an endometriotic cyst. The differential diagnosis of this rare suburethral location of endometriosis with other vaginal cysts is discussed.

Retinal Sensitivity in Patients with Type I Diabetes without Retinopathy or with Minor Retinal Changes.

Objective: To evaluate the ability of short-wavelength automated perimetry (SWAP) for the detection of visual impairment in patients with type I diabetes without retinopathy or with minor retinal vascular changes. Design: Comparative cross-sectional study. Participants: 30 eyes of 30 healthy subjects and 73 eyes of 73 patients with type I diabetes mellitus were studied. Methods: Ophthalmic examination of diabetic patients showed no retinopathy or minimal changes (less than 5 microaneurisms in each eye) with no previous laser treatment. All patients were examined by means of the SWAP 24-2 strategy. Mean Deviation (MD) and Pattern Standard Deviation (PSD) were compared between both groups. Results: There were differences in the clusters of altered points between both groups (p=0.004). SWAP MD was lower in the diabetic group than in the controls (-2.89 dB vs. -0.20 dB, p<0.001). SWAP PSD also differed between both groups (2.50 dB in control group, 3.12 dB in the diabetic group, p=0.003). In the diabetic group, mean period from the onset of diabetes was 12.6±6.7 years and minimal vascular changes were observed in the retina of 18 eyes (24.7%), while 55 had no lesions (75.3%). No differences in SWAP changes were found between patients without and with minimal diabetic retinopathy. Conclusions: Retinal sensitivity assessed by SWAP is depressed in patients with type I diabetes regardless of the presence of retinal vascular changes.

Insulin potentiation therapy: a new concept in the management of chronic degenerative disease.

In insulin potentiation therapy the hormone insulin is used as an adjunct in the medical management of the chronic degenerative diseases including malignant neoplasia. In this, the recognized physiological action of insulin--that of increasing cell membrane permeability--is taken advantage of to potentiate the pharmacological actions of medications administered concurrently in the therapy. This potentiation occurs because of the heretofore unrecognized applicability of this membrane permeabilizing effect of insulin to a much wider range of tissues than is classicly accepted, and further the observed effect of this permeabilizing phenomenon as it relates to drug molecules, most importantly the antineoplastic agents. The historical context of insulin potentiation therapy is described, and scientific corroboration for its novel hypotheses is given. Insulin potentiation therapy represents a potentially revolutionary concept in the medical management of diseases and is, in the authors' opinion, deserving of intensive scientific investigation through in vitro and in vivo experimentation and properly conducted human clinical trials in a university teaching hospital setting.

Acute thrombosis of abdominal aortic aneurysm. An uncommon entity.

Acute thrombosis of an abdominal aneurysm is a catastrophic complication which is little known. It presents as a sudden event, characteristically with lower abdominal pain, signs of profound lower extremity ischemia and pronounced bilateral lower extremity neuromuscular dysfunction. While the mechanism of thrombosis is not understood and is unpredictable, it is certain that the condition is rapidly fatal if uncorrected. The mortality of acute thrombosis is very high, similar to rupture, which is the most common complication of an abdominal aortic aneurysm. Diagnosis is not difficult, and must be followed by prompt surgical restoration of circulation of the lower half of the body, if death is to be prevented. This can be accomplished by aneurysm resection and graft replacement. Retrograde transfemoral thromboembolectomy should not be done. This report describes two successfully operated cases which dramatize the symptomatology of the condition and show the gratifying results of immediate surgical intervention. Only 30 cases (15 fatal) have been reported in the literature.

[Leiomyoma of the female urethra]. / Leiomioma de uretra femenina.

Leiomyoma of the female urethra is a benign mesenchymal tumour highly infrequent in the clinical practice. There is controversy as to its degree of oestrogen hormone dependency and its diagnosis is reached only after pathohistological study of the resection specimen. This type of tumour has excellent prognosis, with few tumoral relapses and no case of malignant transformation having been reported for the time being. Contribution of one case report of leiomyoma of the female urethra with typical clinical-epidemiological features but very uncommon from a topographic insight, as it was located in the anterior side of the distal urethra.

[Metachronous tumors of the upper urinary tract following primary superficial tumors of the bladder]. / Tumores del tracto urinario superior metacrónicos subsiguientes a tumores superficiales primarios de vejiga.

OBJECTIVE: To evaluate the long term incidence of upper urinary tract tumours in patients with surface tumours of the bladder. MATERIAL AND METHODS: Analysis of 78 patients with primary tumour of the bladder pTa-pTl diagnosed between 1978 and 1988. These patients were followed for up to 10 to 21 years (mean follow-up 13.4 years) and were treated with transurethral resection and a variety of endovesical cytostatic agents. RESULTS: Of all 78 patients, 9 (11%) developed an upper urinary tract tumour over an average of 9 years (range 4-18); 2 in the first 5 years, 4 between 5 to 10 years, and 3 between 10 and 18 years. The likelihood of finding a tumour in the upper tract if all 20-year old patients were to be followed would be 25.6% (Kaplan-Meier's method). A high percentage of all upper urinary tract tumours are infiltrant, but the cause of death in 44% of these patients is progression of the tumour of the bladder. CONCLUSIONS: The percentage of tumours of the upper urinary tract that become metachronic following a tumour of the bladder, increases with the duration of the follow-up. A high percentage of these cases are already in high stages when diagnosed. It would be convenient to monitor the upper urinary tract with the same periodicity than the bladder in order to establish early diagnoses. These patients show a high mortality rate, in most cases secondary to progression of the tumour of the bladder.

[Bilateral testicular luxation]. / Luxación testicular bilateral.

Contribution of a case report of long-standing bilateral testicular luxation, the result of scrotal trauma caused by a soccer ball. Good aesthetic, endocrine and exocrine results were obtained with surgical treatment. Androgenic hormonal profile and spermiogram performed at six months showed values within the normal range.

[A massive hernia of the bladder into the scrotum. A report of a case]. / Hernia vesical masiva de vejiga en escroto. Aportación de un caso.

The hernia of the bladder in the scrotum is a highly uncommon observation. From the clinical standpoint the usual manifestation is a two-stroke voiding. The recommended urological examinations to reach a diagnosis are ultrasound, endovenous urography, retrograde urethrocystography and cystoscopy. Management includes the de-obstruction of the lower urinary tract, if present, resection of associated peritoneum, resection or reduction of the vesical hernia and repairment of inguinal path. The case contributed corresponds to a vesical hernia in a 72-year-old patient, with no obstructive cause, that was treated surgically by resection of the herniated bladder, with good morphological and functional results.

[Superficial cancer of the bladder: which controls should follow and for how long the free of tumor patients?]. / Cáncer superficial de vejiga: que controles han de seguir y durante cuándo tiempo, los pacientes libres de tumor?

OBJECTIVES: To answer the following question: what monitoring and for how long should be maintained in patients with Ta-T1 vesical neoplasia and no tumoral relapse? MATERIAL AND METHOD: Analysis of relapse probabilities in 123 patients with Ta-T1G1G2G3 primary tumours who had not relapsed for at least three years of follow up after transurethral resection. All patients were treated between January 1976 and December 1986; they all have follow-up potential of over 10 years. Mean follow-up 8.1 years, minimum 4 years, maximum 18 years. RESULTS: Probabilities of relapse at 3 to 5 years, 6 to 10 years, 11 to 18 years are 18%%, 24% and 13%, respectively. Relapses were superficial in 38 cases (90%), infiltrant in 4 (10%) G1 in 21 (50%), G2 in 12 (29%), G3 in 9 (9%), single in 33 (79%), multiple in 9 (21%), under 2 cm in 35 (83%), over 2 cm in 7 (17%). CONCLUSIONS: Epidemiologically, individuals with a background of surface vesical tumour have a much higher risk of relapse than the Spanish normal population and therefore they should be monitored for life. Relapses are usually superficial, low grade, single and small in size. Cystoscopy is the monitoring technique offering more possibilities for detection.

[Value of non-contrast helical computerized tomography in nephrotic colic assessment]. / Valor del TAC helicoidal sin contraste en la evaluación del cólico nefrítico.

OBJECTIVE: To compare non-contrast helicoid CAT to urological ultrasound in order to determine the sensitivity of both in the etiological diagnosis of nephritic colic. MATERIAL AND METHODS: Retrospective study conducted on a total of 86 patients seen in our ER service over a 12-month period with a diagnosis of nephritic colic. All patients with suspicious diagnosis of nephritic colic underwent X-ray examination, with either non-contrast helicoid CAR or urological ultrasound, or with a combination of both imaging techniques. Radiologic diagnosis of nephritic colic was made by direct visualization of the obstructive cause or by the presence of indirect radiological signs of upper urinary tract obstruction. RESULTS: Of 86 patients studied, in 84 (97.67%) a urinary stone was the cause for obstruction. Overall sensitivity of helicoid CAT to diagnose colic etiology was 94.73%, whereas ultrasound sensitivity was only 53.42%, displaying a particularly low sensitivity when the obstruction was located at the mid third level of the ureter. CONCLUSIONS: Non-contrast helicoid CAT shows superior sensitivity as a radiologic technique than ultrasound to identify the cause of a nephritic colic in any segment of the upper urinary tract.

[Indications for BCG in surface tumors of the bladder]. / Indicaciones de la BCG en los tumores superficiales de vejiga.

Overall view of Bacille de Calmette-Guerin (BCG) immunotherapy in the prophylaxis and treatment of surface cancer of the bladder. A series of issues, on some of which a consensus has been reached while controversy is still frequent in others are discussed. Intravesical instillation of BCG as the single route has been considered to best mode of administration. With regard to the BCG strain to be used, there is still no consensus after the analysis of the data provided by the studies conducted. Relative to the treatment schedule, it appears clear that maintenance therapy is superior to an exclusively induction regime. No consensus has been reached about optimal dosage or the possibility to reduce toxicity. Although some studies support the belief that intravesical immunotherapy with BCG is superior to chemotherapy, further data is required to confirm such assumption. In conclusion, although treatment with BCG has proven to be effective in patients with surface tumours of the bladder, it should not be considered a panacea to be indiscriminately used in any patient with this malignancy.

[Metastatic prostate adenocarcinoma in hernial sac. Contribution of one case]. / Metástasis de adenocarcinoma prostático en saco herniario. Aportación de un caso.

Presentation of a case of stage D2 prostatic adenocarcinoma, diagnosed through a chance finding of micrometastasis in the pathohistological study of the hernial sac of a patient undergoing inguinal herniorrhaphy. Most usual sites for prostate cancer metastasis are lymph nodes, bones, lungs, liver, and brain. During our revision of unusual anatomical sites for prostatic carcinoma metastasis, we found references of metastasis on the uvea, larynx, orbit and maxillary sinus. The peritoneal cavity was not found to be a common site for metastatic implants. It was also found that such peritoneal spread was usually diagnosed after a postmortem examination.

[Extragonadal germ cell tumor with "burned-out" phenomenon in the testis]. / Tumor extragonadal de células germinales con fenómeno "burned-out" en testículo.

The "burned-out" phenomenon in germ-cell neoplasias is defined by the presence of an extragonadal germ-cell tumour with no tumour at the testis level where a series of distinctive histological lesions can be detected indicative of the earlier presence of an already disappeared testicle tumoration. Extragonadal germ-cell tumours with "burned-out" phenomenon show better evolution than their primary counterparts and are treated similarly to primary tumours of the testis. Currently, in the presence of retroperitoneal tumoration, a scrotal ultrasound study with high frequency transducers can lead to a suspected picture of tumoral involution. This paper contributes one retroperitoneal seminoma with "burned-out" phenomenon in the homolateral testis in a 35-year old patient. Available clinical and radiological criteria were enough to reach a suspected diagnosis. Homolateral orchiectomy and biopsy of retroperitoneal tumoration were performed, rounding treatment up with polychemotherapy. Evolution was good with immediate complete response.

[Use of retinal photography in the diagnosis of diabetic macular edema]. / Utilidad de las retinografías en el diagnóstico del edema macular diabético.

OBJECTIVE: To determine the validity of retinal photography in the diagnosis of diabetic macular edema. Determine the number and size of the photographs for its correct diagnosis. METHODS: Cross-sectional observational study consisting of 420 eyes of patients with diabetic retinopathy, using a combination of retinography (simple, stereoscopic, red-free light), after expansion, to determine its validity in the diagnosis of diabetic macular edema. Sensitivity, specificity, positive and negative predictive values and the correlation with the gold standard test (optical coherence tomography) were calculated. The retinographs were evaluated by three experts and their results analyzed by the statistical program SPSS 15.0 Windows. RESULTS: Sensitivities were below 80% in simple photographs and above 80% in the stereoscopic retinography, whereas those associated with red-free filters, reaching the 30° green stereoscopic photography, showed a sensitivity of 94.3%. The specificity was 95% in color and red-free stereoscopic retinography of 45° and 30°. The positive predictive value was greater than 95% and the negative value greater than 90% with a coefficient of agreement of 80%, and a degree of consistency with the benchmark of over 80%. CONCLUSIONS: The results of the stereoscopic retinographs are sufficient to enable them to be used in screening for diabetic macular edema. The use of a green filter and its combination with visual acuity improves results in the diagnosis of this disease.

Behavioral features of Williams Beuren syndrome compared to Fragile X syndrome and subjects with intellectual disability without defined etiology.

Williams-Beuren syndrome (WBS) is a genetically determined neurodevelopmental disorder caused by a heterozygous deletion of 26-28 genes on chromosome band 7q11.23. During the past few years, researchers and clinicians have significantly contributed to define the phenotype of the syndrome, including its cognitive and behavioral aspects. However, it is not well known yet whether the psychological problems are specific to the syndrome or secondary to the intellectual disability (ID). The aim of our study was to better define the psychopathological profile of WBS and whether or not it is related with IQ or anxiety symptoms. Twenty-five subjects (12 girls, 13 boys) with a diagnosis of WBS were compared to 27 boys with Fragile X Syndrome and to 24 boys with ID of non-specific etiology using the Child Behavior Checklist. Anxiety, depression and attention problems were the main behavioral problems found in WBS with no gender differences. Significant differences between cohorts were observed in somatic complaints, delinquent behavior, aggressive behavior, and externalizing problems. Some associations between IQ and anxiety items were found. The findings are discussed in terms of behavioral phenotypes, genetic implications and ID.