Stratigraphic framework of the late Miocene Pisco Formation at Cerro Los Quesos (Ica Desert, Peru)

The enormous concentration of marine vertebrates documented within the Pisco Formation is unique for Peru and South America and places this unit among the prime fossil Lagerstätten for Miocene to Pliocene marine mammals worldwide. In order to provide a robust stratigraphic framework for the fossil-bearing locality of Cerro Los Quesos, this study presents a 1:10,000 scale geological map covering an area of about 21 km2, a detailed measured section spanning 290 m of strata, and a refined chronostratigraphy for the studied succession well constrained by diatom biostratigraphy and high-resolution 40Ar/39Ar isotopic dating of three interbedded ash layers. Within the apparently monotonous, diatomite-dominated sedimentary section, the Pisco Formation has been subdivided into six local members, with stratigraphic control over the different outcrops facilitated by the establishment of a detailed marker bed stratigraphy based on fifteen readily distinguishable sediment layers of different nature

Evaluation of a preoperative pain score in response to pressure as a marker of postoperative pain and drugs consumption in surgical thyroidectomy.

INTRODUTION:: The success and effectiveness of a day surgery model are essentially related to a good postoperative course with a rapid recovery. Adequate management of analgesia during the hospital stay and after discharge becomes mandatory in reducing postoperative patient discomfort, and in facilitating discharge to home. BACKGROUND: The aim of this study was to identify the efficacy of preoperative visual analog scale (VAS) score in predicting postoperative pain and analgesic drugs consumption. The hypothesis of a significant relation between preoperative pain and postoperative pain tolerance thresholds was tested using Spearman rank-order correlations, applied to patients scheduled for thyroidectomy in a Day Surgery Unit. METHODS: Patients scheduled for total thyroidectomy underwent a preoperative pain test to assess the VAS value after a fixed stimulus (inflation of a sphygmomanometer with a pressure of 250 mm Hg). To estimate the power of the VAS in prediction of the postoperative analgesic requests, we divided the patients into 3 groups according to the preoperative VAS values (A group, including all patients with preoperative VAS≤3; B group including patients with preoperative VAS>3≤6; C group with preoperative VAS>6).Then we correlated preoperative results with postoperative VAS values and postoperative analgesic drug consumption, analyzing the correlation between the sensitivity and the specificity of the VAS test for a range of different cutoff values. RESULTS: Thirty-two patients were included. A group (10 patients) showed a medium postoperative VAS<4, and required less analgesics than other groups (ketorolac, 51 mg). B group (10 patients) and C group (12 patients) showed higher postoperative VAS value and required more analgesic drug (B, 80 mg; C, 90 mg+1 g acetaminophen). Using the receiver operating characteristic or relative operating characteristic examination and calculating the underlying area , we could measure the discriminating ability of the test and found that the best VAS score cutoff was 3. CONCLUSION: The use of a preoperative test to assess individual pain threshold may be predictive for postoperative pain and analgesic request. The mathematical and statistical model used in this study confirms that a difference in the value of VAS of 3 shall be mathematically eligible for analgesia treatment

Evaluation of a Preoperative Pain Score in Response to Pressure as a Marker of Postoperative Pain and Drugs Consumption in Surgical Thyroidectomy

INTRODUTION:: The success and effectiveness of a day surgery model are essentially related to a good postoperative course with a rapid recovery. Adequate management of analgesia during the hospital stay and after discharge becomes mandatory in reducing postoperative patient discomfort, and in facilitating discharge to home. BACKGROUND:: The aim of this study was to identify the efficacy of preoperative visual analog scale (VAS) score in predicting postoperative pain and analgesic drugs consumption. The hypothesis of a significant relation between preoperative pain and postoperative pain tolerance thresholds was tested using Spearman rank-order correlations, applied to patients scheduled for thyroidectomy in a Day Surgery Unit. METHODS:: Patients scheduled for total thyroidectomy underwent a preoperative pain test to assess the VAS value after a fixed stimulus (inflation of a sphygmomanometer with a pressure of 250 mm Hg). To estimate the power of the VAS in prediction of the postoperative analgesic requests, we divided the patients into 3 groups according to the preoperative VAS values (A group, including all patients with preoperative VAS≤3; B group including patients with preoperative VAS>3≤6; C group with preoperative VAS>6).Then we correlated preoperative results with postoperative VAS values and postoperative analgesic drug consumption, analyzing the correlation between the sensitivity and the specificity of the VAS test for a range of different cutoff values. RESULTS:: Thirty-two patients were included. A group (10 patients) showed a medium postoperative VAS<4, and required less analgesics than other groups (ketorolac, 51 mg). B group (10 patients) and C group (12 patients) showed higher postoperative VAS value and required more analgesic drug (B, 80 mg; C, 90 mg+1 g acetaminophen). Using the receiver operating characteristic or relative operating characteristic examination and calculating the underlying area , we could measure the discriminating ability of the test and found that the best VAS score cutoff was 3. CONCLUSION:: The use of a preoperative test to assess individual pain threshold may be predictive for postoperative pain and analgesic request. The mathematical and statistical model used in this study confirms that a difference in the value of VAS of 3 shall be mathematically eligible for analgesia treatment

Intraformational unconformities as a record of late Miocene eustatic falls of sea level in the Pisco Formation (southern Peru)

Field mapping and sedimentological study of outcrop sections exposed along the Ica River valley permitted the establishment of a regional allostratigraphic framework for the upper Miocene portion of the Pisco Formation. The stratigraphy of the studied interval is illustrated using a new 1:20,000-scale geological map which reveals that this formation is a cyclical sedimentary succession composed of three fining-upward allomembers. The bounding surfaces defining each allomember are transgressively modified subaerial unconformities. They converge and merge landward into a single composite surface representing the time-transgressive lower boundary of the Pisco Formation. Accordingly, the extent of the stratigraphic gap associated with the basal unconformity varies significantly throughout the basin and increases toward the basin margins. The timing of allomember-bounding surfaces coincides with that of major oxygen-isotope maxima in the deep-sea oxygen isotopic record and matches the ages of eustatic sequence boundaries identified elsewhere, indicating glacio-eustatic falls due to the growth of Antarctica ice sheets as a viable mechanism for their development

Geology of the Late Miocene at Cerro Los Quesos, Ica Desert, Peru Pisco Formation

This 1:10,000 scale geological map covers an area of about 21 km2 where the late Miocene portion of the Pisco Formation (Ica desert, Peru) is exposed

A heavyweight early whale pushes the boundaries of vertebrate morphology

The fossil record of cetaceans documents how terrestrial animals acquired extreme adaptations and transitioned to a fully aquatic lifestyle1,2. In whales, this is associated with a substantial increase in maximum body size. Although an elongate body was acquired early in cetacean evolution3, the maximum body mass of baleen whales reflects a recent diversification that culminated in the blue whale4. More generally, hitherto known gigantism among aquatic tetrapods evolved within pelagic, active swimmers. Here we describe Perucetus colossus—a basilosaurid whale from the middle Eocene epoch of Peru. It displays, to our knowledge, the highest degree of bone mass increase known to date, an adaptation associated with shallow diving5. The estimated skeletal mass of P. colossus exceeds that of any known mammal or aquatic vertebrate. We show that the bone structure specializations of aquatic mammals are reflected in the scaling of skeletal fraction (skeletal mass versus whole-body mass) across the entire disparity of amniotes. We use the skeletal fraction to estimate the body mass of P. colossus, which proves to be a contender for the title of heaviest animal on record. Cetacean peak body mass had already been reached around 30 million years before previously assumed, in a coastal context in which primary productivity was particularly high

Sequence stratigraphy and paleontology of the Upper Miocene Pisco Formation along the western side of the lower Ica Valley (Ica Desert, Peru)

The sequence stratigraphic framework and a summary of the fossil fauna of the upper Miocene portion of the Pisco Formation exposed along the western side of the Ica River (southern Peru) is presented through a new geological map encompassing an area of about 200 km2 and detailed chronostratigraphic analyses. Extensive field mapping and sedimentological study of outcrop sections have shown that the Pisco Formation is a cyclical sediment unit composed of at least three fining-upward, unconformity-bounded depositional sequences, designated P0, P1, and P2 from oldest to youngest. In the study area, these sequences progressively onlap a composite basal unconformity from southwest to northeast. Integration of biostratigraphic and tephrochronologic age determinations constrains the ages of the three Pisco sequences within the study area. Based on the age of surrounding sediments, a conservative estimate of the age of P0 suggests deposition of these strata between 17.99 ± 0.10 Ma and 9.00 ± 0.02 Ma, whereas diatom biostratigraphy and calculated 40Ar/39Ar ages converge to indicate that strata of the P1 sequence were deposited sometime between 9.5 Ma and 8.9 Ma and that those of the P2 sequence are younger than 8.5 Ma and older than 6.71 ± 0.02 Ma. Our survey for both vertebrate and macro-invertebrate remains in the three sequences confirms the outstanding paleontological value of the Pisco Formation and contributes to depict regional faunal shifts in the fossil assemblage