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1.
Nature ; 551(7678): 67-70, 2017 11 02.
Artículo en Inglés | MEDLINE | ID: mdl-29094694

RESUMEN

The merger of two neutron stars is predicted to give rise to three major detectable phenomena: a short burst of γ-rays, a gravitational-wave signal, and a transient optical-near-infrared source powered by the synthesis of large amounts of very heavy elements via rapid neutron capture (the r-process). Such transients, named 'macronovae' or 'kilonovae', are believed to be centres of production of rare elements such as gold and platinum. The most compelling evidence so far for a kilonova was a very faint near-infrared rebrightening in the afterglow of a short γ-ray burst at redshift z = 0.356, although findings indicating bluer events have been reported. Here we report the spectral identification and describe the physical properties of a bright kilonova associated with the gravitational-wave source GW170817 and γ-ray burst GRB 170817A associated with a galaxy at a distance of 40 megaparsecs from Earth. Using a series of spectra from ground-based observatories covering the wavelength range from the ultraviolet to the near-infrared, we find that the kilonova is characterized by rapidly expanding ejecta with spectral features similar to those predicted by current models. The ejecta is optically thick early on, with a velocity of about 0.2 times light speed, and reaches a radius of about 50 astronomical units in only 1.5 days. As the ejecta expands, broad absorption-like lines appear on the spectral continuum, indicating atomic species produced by nucleosynthesis that occurs in the post-merger fast-moving dynamical ejecta and in two slower (0.05 times light speed) wind regions. Comparison with spectral models suggests that the merger ejected 0.03 to 0.05 solar masses of material, including high-opacity lanthanides.

2.
Br J Surg ; 108(5): 484-498, 2021 05 27.
Artículo en Inglés | MEDLINE | ID: mdl-34043773

RESUMEN

BACKGROUND: Lynch syndrome is the most common genetic predisposition for hereditary cancer but remains underdiagnosed. Large prospective observational studies have recently increased understanding of the effectiveness of colonoscopic surveillance and the heterogeneity of cancer risk between genotypes. The need for gene- and gender-specific guidelines has been acknowledged. METHODS: The European Hereditary Tumour Group (EHTG) and European Society of Coloproctology (ESCP) developed a multidisciplinary working group consisting of surgeons, clinical and molecular geneticists, pathologists, epidemiologists, gastroenterologists, and patient representation to conduct a graded evidence review. The previous Mallorca guideline format was used to revise the clinical guidance. Consensus for the guidance statements was acquired by three Delphi voting rounds. RESULTS: Recommendations for clinical and molecular identification of Lynch syndrome, surgical and endoscopic management of Lynch syndrome-associated colorectal cancer, and preventive measures for cancer were produced. The emphasis was on surgical and gastroenterological aspects of the cancer spectrum. Manchester consensus guidelines for gynaecological management were endorsed. Executive and layperson summaries were provided. CONCLUSION: The recommendations from the EHTG and ESCP for identification of patients with Lynch syndrome, colorectal surveillance, surgical management of colorectal cancer, lifestyle and chemoprevention in Lynch syndrome that reached a consensus (at least 80 per cent) are presented.


Asunto(s)
Neoplasias Colorrectales Hereditarias sin Poliposis/genética , Neoplasias Colorrectales Hereditarias sin Poliposis/terapia , Antiinflamatorios no Esteroideos/uso terapéutico , Aspirina/uso terapéutico , Quimioprevención , Colonoscopía , Neoplasias Colorrectales Hereditarias sin Poliposis/diagnóstico , Técnica Delphi , Procedimientos Quirúrgicos del Sistema Digestivo , Detección Precoz del Cáncer , Femenino , Tamización de Portadores Genéticos , Pruebas Genéticas , Neoplasias de los Genitales Femeninos/diagnóstico , Neoplasias de los Genitales Femeninos/genética , Humanos , Estilo de Vida , Procedimientos Quirúrgicos Profilácticos
3.
HNO ; 69(3): 221-228, 2021 Mar.
Artículo en Alemán | MEDLINE | ID: mdl-33095325

RESUMEN

An 87-year-old patient reported a nodular, progressively enlarging mass of the anterior nasal septum leading to partial obstruction of the nostrils. The tumor showed no infiltration of the subcutis, bone, or paranasal sinuses in imaging or intraoperatively. Histological examination revealed a chondroid tumor with lobular growth and physaliferous cell morphology. Immunohistochemistry revealed a brachyury-positive tumor without EWSR1 rearrangement, leading to the diagnosis of a chondroid chordoma. The reported case demonstrates the differential diagnostic considerations pertaining to this rare tumor, which can also have an untypical and very rare extra-axial location. Review of the literature identified 34 primary extraosseous chordomas of the nose, nasopharynx, and paranasal sinuses, and allowed the nasal chordoma presented herein to be included in this group of extra-axial chordomas.


Asunto(s)
Cordoma , Senos Paranasales , Anciano de 80 o más Años , Cordoma/diagnóstico por imagen , Cordoma/cirugía , Humanos , Inmunohistoquímica , Cavidad Nasal/diagnóstico por imagen , Cavidad Nasal/cirugía , Tabique Nasal/diagnóstico por imagen , Tabique Nasal/cirugía
4.
Phys Rev Lett ; 125(26): 262701, 2020 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-33449748

RESUMEN

The interpretation of observations of cooling neutron star crusts in quasipersistent x-ray transients is affected by predictions of the strength of neutrino cooling via crust Urca processes. The strength of crust Urca neutrino cooling depends sensitively on the electron-capture and ß-decay ground-state-to-ground-state transition strengths of neutron-rich rare isotopes. Nuclei with a mass number of A=61 are predicted to be among the most abundant in accreted crusts, and the last remaining experimentally undetermined ground-state-to-ground-state transition strength was the ß decay of ^{61}V. This Letter reports the first experimental determination of this transition strength, a ground-state branching of 8.1_{-3.1}^{+4.0}%, corresponding to a log ft value of 5.5_{-0.2}^{+0.2}. This result was achieved through the measurement of the ß-delayed γ rays using the total absorption spectrometer SuN and the measurement of the ß-delayed neutron branch using the neutron long counter system NERO at the National Superconducting Cyclotron Laboratory at Michigan State University. This method helps to mitigate the impact of the pandemonium effect in extremely neutron-rich nuclei on experimental results. The result implies that A=61 nuclei do not provide the strongest cooling in accreted neutron star crusts as expected by some predictions, but that their cooling is still larger compared to most other mass numbers. Only nuclei with mass numbers 31, 33, and 55 are predicted to be cooling more strongly. However, the theoretical predictions for the transition strengths of these nuclei are not consistently accurate enough to draw conclusions on crust cooling. With the experimental approach developed in this work, all relevant transitions are within reach to be studied in the future.

5.
Nature ; 505(7481): 62-5, 2014 Jan 02.
Artículo en Inglés | MEDLINE | ID: mdl-24291788

RESUMEN

The temperature in the crust of an accreting neutron star, which comprises its outermost kilometre, is set by heating from nuclear reactions at large densities, neutrino cooling and heat transport from the interior. The heated crust has been thought to affect observable phenomena at shallower depths, such as thermonuclear bursts in the accreted envelope. Here we report that cycles of electron capture and its inverse, ß(-) decay, involving neutron-rich nuclei at a typical depth of about 150 metres, cool the outer neutron star crust by emitting neutrinos while also thermally decoupling the surface layers from the deeper crust. This 'Urca' mechanism has been studied in the context of white dwarfs and type Ia supernovae, but hitherto was not considered in neutron stars, because previous models computed the crust reactions using a zero-temperature approximation and assumed that only a single nuclear species was present at any given depth. The thermal decoupling means that X-ray bursts and other surface phenomena are largely independent of the strength of deep crustal heating. The unexpectedly short recurrence times, of the order of years, observed for very energetic thermonuclear superbursts are therefore not an indicator of a hot crust, but may point instead to an unknown local heating mechanism near the neutron star surface.

6.
Pathologe ; 41(3): 230-237, 2020 May.
Artículo en Alemán | MEDLINE | ID: mdl-32239324

RESUMEN

Autoimmune enteropathy (AIE) was originally believed to be a pediatric disease until there were increasing numbers of adult cases reported over the last 20 years. AIE is an autoimmune disease that manifests as severe chronic diarrhea.The histological hallmark is villous atrophy. Histology alone is not sufficiently sensitive and consistent. Four different histological patterns are known. There are many differential diagnoses to be considered relating to both histology and symptoms.We present the case of a young woman with fatal AIE and homozygous germline-mutation of the CLEC7A gene. The course of disease is documented in multiple intestinal biopsies, which show a morphological change over time.Histology and symptoms often resemble celiac disease. In order to recognize this rare disease early in its course there is a need for a special awareness among attending physicians and pathologists.


Asunto(s)
Diarrea/diagnóstico , Poliendocrinopatías Autoinmunes/diagnóstico , Adulto , Biopsia , Enfermedad Celíaca , Diagnóstico Diferencial , Diarrea/etiología , Femenino , Humanos , Mucosa Intestinal/patología , Poliendocrinopatías Autoinmunes/complicaciones
7.
Pathologe ; 40(2): 152-156, 2019 Mar.
Artículo en Alemán | MEDLINE | ID: mdl-29666909

RESUMEN

The update of the 4th edition of the WHO classification for hematopoietic neoplasms introduces changes in the field of mature aggressive B­cell lymphomas that are relevant to diagnostic pathologists. In daily practice, the question arises of which analysis should be performed when diagnosing the most common lymphoma entity, diffuse large B­cell lymphoma. We discuss the importance of the cell of origin, the analysis of MYC translocations, and the delineation of the new WHO entities of high-grade B­cell lymphomas.


Asunto(s)
Linfoma de Células B Grandes Difuso , Patólogos , Humanos , Translocación Genética , Organización Mundial de la Salud
8.
Pathologe ; 40(2): 157-168, 2019 Mar.
Artículo en Alemán | MEDLINE | ID: mdl-30019203

RESUMEN

After 8 years, the WHO has now published the updated version of the 4th edition of the classification of hematopoietic and lymphoid tumors. This update provides a conceptual rewrite of existing entities as well as some new provisional entities and categories, particularly among the aggressive B­cell lymphomas. Important new diagnostic categories include the high-grade B­cell lymphomas, the large B­cell lymphoma with IRF4 rearrangement, and the Burkitt-like lymphoma with 11q aberrations. Of particular importance, new concepts concerning the taxonomy and classification of early lymphoid lesions or precursor lesions are included, such as the in situ follicular neoplasia or the in situ mantle cell neoplasia. In addition, the concept of indolent lymphoproliferations, such as breast-implant-associated anaplastic large cell lymphoma and the indolent T­cell lymphoproliferative disorder of the gastrointestinal tract, has been strengthened. Finally, diagnostic criteria for existing lymphoma entities have been refined.


Asunto(s)
Linfoma , Linfoma de Burkitt , Humanos , Linfoma de Células B , Trastornos Linfoproliferativos , Organización Mundial de la Salud
9.
HNO ; 67(12): 948-951, 2019 Dec.
Artículo en Alemán | MEDLINE | ID: mdl-31187149

RESUMEN

This article presents an oncologic patient with oropharyngeal cancer. After surgery with bilateral neck dissection and adjuvant radiation, the patient developed foreign body granuloma in the area of neck dissection in addition to cervical and mediastinal granuloma. Possible differential diagnoses in this situation are sarcoidosis or tumor-derived sarcoid-like lesions, but also metastases. Therefore, intensified follow-up is particularly important for oncologic patients developing granulomas.


Asunto(s)
Granuloma de Cuerpo Extraño , Sarcoidosis , Diagnóstico Diferencial , Humanos , Cuello , Disección del Cuello
10.
Int J Cancer ; 142(7): 1369-1378, 2018 04 01.
Artículo en Inglés | MEDLINE | ID: mdl-29148152

RESUMEN

Chordoma is a rare bone tumor with a known intrinsic heterogeneity. Here, we address this tumor heterogeneity in a new cell culture model for tumor diversity and progression in chordoma. The three cell lines U-CH17P, U-CH17M, and U-CH17S were established from a primary sacral chordoma and its derived metastases, a soft tissue and a skin metastasis, respectively. The lesions had divergent differentiation patterns which are conserved in the derived cell lines making them a suitable in vitro model for the analysis of tumorigenesis in chordoma. A common feature of the three cell lines is the expression of typical chordoma markers, such as Brachyury, vimentin, cytokeratins, EMA and S100 protein. A comparison of the genomic aberrations by array comparative genomic hybridization of the cell lines and the corresponding parental tumor tissues revealed that the precursor cells of U-CH17P, U-CH17M and U-CH17S were already present in the primary tumor. Therefore, we show that clonal diversity of this chordoma exists in the primary tumor and that not all of these subclones tend to metastasize. All cell lines had a CDKN2A loss. A comparison of the gene expression profiles of the cell lines revealed significant differences in the expression of several genes like MAGEC2 and SEMA6A known to be associated with the tendency to metastasize or proliferation and migration. Since the underlying mechanisms of tumor progression in chordoma are still largely unclear, the three U-CH17 cell lines are a suitable in vitro model for elucidating chordoma oncobiology.


Asunto(s)
Neoplasias Óseas , Técnicas de Cultivo de Célula/métodos , Línea Celular Tumoral/citología , Cordoma , Neoplasias Óseas/genética , Neoplasias Óseas/patología , Cordoma/genética , Cordoma/patología , Progresión de la Enfermedad , Humanos
11.
Acta Anaesthesiol Scand ; 62(2): 147-158, 2018 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-29094339

RESUMEN

BACKGROUND: Complications following major abdominal surgery are common and an important cause of morbidity and mortality. The aim of this study was to describe 1-year mortality and identify factors that influence adverse outcomes after abdominal surgery. METHODS: This prospective observational cohort study was performed in Landspitali University Hospital and included all adult patients undergoing abdominal surgery requiring > 24-h hospital admission over 13 months. The follow-up period was 60 days for complications and 24 months for mortality. RESULTS: Data were available for 1113 (99.5%) of the 1119 patients who fulfilled inclusion criteria. A total of 23% of patients had at least one underlying co-morbidity. Non-elective surgeries were 48% and 13% of the patients were admitted to ICU post-operatively. A total of 20% of patients developed complications. Mortality at 30 days, 1 and 2 years was 1.8%, 5.6%, and 8.3% respectively. One-year mortality for those admitted to ICU was 18%. The long-term survival of the individuals surviving 30 days was significantly worse than for an age- and gender-matched population control group. Independent predictors for 1-year mortality were age, pre-operative acute kidney injury and intermediate- or major surgery. CONCLUSION: Post-operative complication rates and mortality following abdominal surgery in Iceland were comparable or in the lower range of previously published outcomes, validating the utility of offering a full host of abdominal surgical services in geographically isolated region with a relatively small referral base.


Asunto(s)
Abdomen/cirugía , Complicaciones Posoperatorias/epidemiología , Complicaciones Posoperatorias/mortalidad , Lesión Renal Aguda/epidemiología , Lesión Renal Aguda/etiología , Lesión Renal Aguda/mortalidad , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Estudios de Cohortes , Comorbilidad , Cuidados Críticos , Femenino , Estudios de Seguimiento , Humanos , Islandia/epidemiología , Masculino , Persona de Mediana Edad , Estudios Prospectivos , Sistema de Registros , Factores Sexuales , Análisis de Supervivencia , Resultado del Tratamiento
12.
Pathologe ; 39(2): 125-131, 2018 Mar.
Artículo en Alemán | MEDLINE | ID: mdl-29110035

RESUMEN

A giant cell tumor of bone (GCTB) is one of the giant cell-rich lesions of bone and has to be differentiated from non-ossifying fibroma, aneurysmatic bone cyst, chondroblastoma, "brown tumor" and osteosarcoma containing giant cells. A hallmark of GCTB is the presence of the distinct histone 3 (H3F3A) mutation G34W and its detection either by sequencing methods or using immunohistochemistry with a novel antibody against this mutational site. Worrisome is the fact that under denosumab therapy a histological change of the lesions can be seen and there are first reports of sarcomas arising after therapy. When diagnosing giant cell-rich lesions, pathologists should be aware of the various differential diagnoses and morphological spectrum within GCTB.


Asunto(s)
Neoplasias Óseas , Tumor Óseo de Células Gigantes , Osteosarcoma , Histonas , Humanos , Inmunohistoquímica
13.
Pathologe ; 39(2): 181-185, 2018 Mar.
Artículo en Alemán | MEDLINE | ID: mdl-29018939

RESUMEN

A 26-year-old woman presented with a painful bulge at the rima ani. The tumor was located in the presacral region. Histological examination revealed a well-circumscribed biphenotypical tumor with papillary configured myxoid areas and strongly sclerosing regions. This case of a myxopapillary ependymoma is a rare example of a myxoid neoplastic lesion in the sacral region.


Asunto(s)
Ependimoma , Adulto , Femenino , Humanos
14.
Pathologe ; 39(2): 117-124, 2018 Mar.
Artículo en Alemán | MEDLINE | ID: mdl-29236139

RESUMEN

Benign notochordal tumors (BNCT) and chordomas are primary bone tumors of the spine with a predominant localization in the sacrum and clival region followed by the vertebral bodies. Besides the most common variant (NOS [not otherwise specified] with hepatoid or renal carcinoma cell-like differentiation) chordomas with chondroid, and polymorphic to anaplastic morphology are described. An unfavorable variant are pediatric chordomas with a loss of INI-1. BNCT and chordomas are characterized by the following immunohistological profile: vimentin+, cytokeratin+/-, epithelial membrane antigen (EMA)+/-, S100 protein+/-, brachyury+. This profile helps to distinguish these tumors from other lesions such as chondrosarcoma, chordoid meningioma, and metastases of carcinoma.


Asunto(s)
Neoplasias Óseas , Condrosarcoma , Cordoma , Niño , Humanos , Queratinas , Proteínas S100
15.
Pathologe ; 39(5): 451-456, 2018 Sep.
Artículo en Alemán | MEDLINE | ID: mdl-30046846

RESUMEN

This article presents the case of a metachronic multicentric giant cell tumor of bone (GCTB). The patient obtained his first diagnosis of GCTB in the left humerus at the age of 47 years. Furthermore, he suffered from a GCTB in the head of his 4th left metacarpal bone and from a recurrence of the latter. All tumors carried the characteristic H3F3A mutation, which was proven by Sanger sequencing and a mutation specific antibody. The case is the first description of a multicentric H3F3A mutated GCTB.


Asunto(s)
Neoplasias Óseas , Tumor Óseo de Células Gigantes , Histonas/genética , Neoplasias Óseas/genética , Tumor Óseo de Células Gigantes/genética , Humanos , Masculino , Persona de Mediana Edad , Mutación , Recurrencia Local de Neoplasia
16.
Phys Rev Lett ; 118(7): 072701, 2017 Feb 17.
Artículo en Inglés | MEDLINE | ID: mdl-28256889

RESUMEN

The ß-decay half-lives of 94 neutron-rich nuclei ^{144-151}Cs, ^{146-154}Ba, ^{148-156}La, ^{150-158}Ce, ^{153-160}Pr, ^{156-162}Nd, ^{159-163}Pm, ^{160-166}Sm, ^{161-168}Eu, ^{165-170}Gd, ^{166-172}Tb, ^{169-173}Dy, ^{172-175}Ho, and two isomeric states ^{174m}Er, ^{172m}Dy were measured at the Radioactive Isotope Beam Factory, providing a new experimental basis to test theoretical models. Strikingly large drops of ß-decay half-lives are observed at neutron-number N=97 for _{58}Ce, _{59}Pr, _{60}Nd, and _{62}Sm, and N=105 for _{63}Eu, _{64}Gd, _{65}Tb, and _{66}Dy. Features in the data mirror the interplay between pairing effects and microscopic structure. r-process network calculations performed for a range of mass models and astrophysical conditions show that the 57 half-lives measured for the first time play an important role in shaping the abundance pattern of rare-earth elements in the solar system.

17.
Scand J Gastroenterol ; 52(6-7): 704-710, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28276832

RESUMEN

OBJECTIVE: Population-based studies on patients with ischemic colitis (IC) are limited. We aimed to determine the incidence, risk factors and outcome of patients with IC. METHODS: A retrospective nationwide study was conducted on adult patients with histologically confirmed IC in 2009-2013 in Iceland. IC patients were matched for age and gender with patients hospitalized with lower gastrointestinal bleeding. Data were collected on clinical presentation, comorbidities, smoking habits, management and outcome. RESULTS: Eighty-nine patients, 61 (69%) females and mean age of 65 years (±17), fulfilled the predetermined criteria. Females were older than males, 68 years (±14) vs. 59 years (±20) (p = .0170). The mean cumulative incidence was 7.3 cases per 100,000 inhabitants. A total of 57 (64%) patients presented with abdominal pain, hematochezia and diarrhea. IC was localized in the left colon in 78 (88%) patients. Overall, 62 (70%) patients had cardiovascular disease vs. 53 (60%) of control group (NS) and 55 (62%) had a history of smoking vs. 53 (60%) in control group (NS). Ten (11%) patients required surgery and/or died within 30-days from hospital admission. At the end of follow-up, 7 (9%) patients had experienced recurrence of IC with an estimated 3-year recurrence rate of 15%. CONCLUSIONS: IC is a common clinical phenomenon that affects a wide range of age groups, but is most prominent among elderly women. It typically presents with a clinical triad of abdominal pain, hematochezia and diarrhea. Most cases are mild and self-limiting with a good prognosis.


Asunto(s)
Colitis Isquémica/epidemiología , Colitis Isquémica/fisiopatología , Colon/patología , Hemorragia Gastrointestinal/etiología , Adulto , Distribución por Edad , Anciano , Anciano de 80 o más Años , Estudios de Casos y Controles , Comorbilidad , Femenino , Hospitalización , Humanos , Islandia/epidemiología , Incidencia , Modelos Logísticos , Masculino , Persona de Mediana Edad , Recurrencia , Estudios Retrospectivos , Factores de Riesgo , Índice de Severidad de la Enfermedad , Adulto Joven
18.
ORL J Otorhinolaryngol Relat Spec ; 79(1-2): 14-23, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28231577

RESUMEN

Curative treatment of head and neck squamous cell carcinoma includes surgery and/or (chemo)radiation, whereas in the palliative setting, chemotherapy and/or immunotherapy represent(s) the standard approach. With regard to quality control, methods for determining treatment response are sorely needed. For surgical therapy, histopathology is the standard quality control. Established criteria for high-risk patients include resection margins of the primary tumor and extracapsular extension of lymph node metastases. After definitive chemoradiation, treatment response is generally evaluated by tomographic imaging combined with endoscopy including re-biopsy of the tumor region. Single-cycle induction chemotherapy may be used to determine the radiosensitivity of tumors, helping to define surgical and nonsurgical treatment options. Innovative approaches with implications for prognosis include the analysis of immune infiltrates, liquid biopsy, molecular characterization (proteomics, genomics), molecular and functional imaging (PET-CT, PET-MRI), as well as advanced imaging data analysis (radio[geno]mics/texture analysis). Human papilloma virus, as a prognostically relevant parameter, is currently being investigated for de-escalation strategies. With regard to the extended personalization of oncologic therapy, markers predicting treatment response are desirable and seem to be important, also from a socioeconomic perspective.


Asunto(s)
Carcinoma de Células Escamosas/terapia , Quimioradioterapia/métodos , Neoplasias de Cabeza y Cuello/terapia , Ganglios Linfáticos/parasitología , Oncología Médica/métodos , Carcinoma de Células Escamosas/mortalidad , Carcinoma de Células Escamosas/patología , Terapia Combinada , Supervivencia sin Enfermedad , Medicina Basada en la Evidencia , Femenino , Neoplasias de Cabeza y Cuello/mortalidad , Neoplasias de Cabeza y Cuello/patología , Humanos , Masculino , Disección del Cuello/métodos , Invasividad Neoplásica/patología , Estadificación de Neoplasias , Valor Predictivo de las Pruebas , Pronóstico , Ensayos Clínicos Controlados Aleatorios como Asunto , Medición de Riesgo , Carcinoma de Células Escamosas de Cabeza y Cuello , Análisis de Supervivencia , Resultado del Tratamiento
19.
J Fish Biol ; 90(1): 147-155, 2017 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-27739056

RESUMEN

This osteological survey of 249 specimens of Brevimyrus niger ranging in size from 44 to 137 mm standard length (LS ) demonstrated that developmental changes in anal-fin morphology can serve as a predictor of sexual maturity in this species. Anal-fin ray bases begin to expand when fish reach c. 90 mm LS at which size and above there were roughly equal numbers of individuals observed with expanded and unmodified anal-fin bases, reflecting a 1:1 sex ratio.


Asunto(s)
Aletas de Animales/anatomía & histología , Pez Eléctrico/anatomía & histología , Pez Eléctrico/fisiología , Maduración Sexual/fisiología , Animales , Femenino , Masculino , Razón de Masculinidad
20.
J Fish Biol ; 91(3): 947-967, 2017 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-28776682

RESUMEN

An assessment of vertical distribution, diel migration, taxonomic and functional diversity of fishes was carried out at offshore platforms in The (Arabian-Iranian-Persian) Gulf. Video footage was recorded at the Al Shaheen oil field between 2007 and 2014 using a remotely operated vehicle (ROV). A total of 12 822 individual fishes, from 83 taxonomic groups were recorded around the platforms. All the species identified are considered native to The Gulf, although Cyclichthys orbicularis and Lutjanus indicus were recorded for the first time in Qatari waters. Several trends were uncovered in the vertical distribution of the fish community; most species were observed between 20 and 50 m depth and fish abundance decreased towards the bottom, with the highest abundances recorded in the upper layers, i.e. down to 40 m depth. Vertical variation in fish diversity, however, was generally not accompanied by differences in vertical movements. Carnivores and invertivores were the dominant trophic groups, being found at each depth range from surface to seabed. The functional indices showed no significant differences between water depths or diel cycles. The study demonstrates that oil platforms represent a hotspot of fish diversity and interesting sites for studying fish communities, abundance and behaviour.


Asunto(s)
Biodiversidad , Peces/fisiología , Yacimiento de Petróleo y Gas , Robótica , Animales , Conducta Animal , Cadena Alimentaria , Irán , Dinámica Poblacional
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