Congenital cardiac disease in dogs

Thoracic conformation, age, amount of body fat, and stage of respiration and cardiac contraction affect the cardiac silhouette. Deep-chested dogs have an upright, narrow cardiac silhouette about 2 1/2 intercostal spaces wide, while barrel-chested dogs have a round, wide silhouette about 3 1/2 intercostal spaces wide. On LAT films the vessels to a lung lobe should be of equal size and 0.25-1.2 times the diameter of the upper third of the 4th rib at the 4th intercostal space. On DV projections, vessels to the caudal lung lobe should be no larger than the diameter of the 9th rib. Signs of right ventricular enlargement include loss of the cranial waist, increased width of the cardiac silhouette, increased sternal contact of the heart, and an elevated cardiac apex. Signs of left ventricular enlargement include an elevated carina, loss of the caudal waist, and a more perpendicular caudal cardiac border. Signs of left atrial enlargement include separation of mainstem bronchi, compression of the bronchus to the left caudal lung lobe, and an increased distance from the carina to the dorsal border of the caudal vena cava. Enlargement of the aorta and main pulmonary artery segment on a LAT view appears as a soft tissue density obscuring the cranial waist. Pulmonary vascular fields are usually hypervascular in patent ductus arteriosus and interventricular septal defects, normal in uncomplicated aortic or pulmonic stenosis, and hypovascular in tetralogy of Fallot.     

Splenic foreign body in a cat

An 8-year-old domestic shorthair cat was evaluated for a several day history of anorexia and vomiting. Abdominal distention was noted on physical examination and diagnostics including abdominal radiographs and abdominal ultrasound demonstrated the presence of free fluid in the peritoneal cavity. Septic peritonitis was diagnosed on cytologic evaluation of the peritoneal fluid. The cat was taken to surgery and a foreign body composed of plant material was found embedded within the spleen. A splenectomy was performed and both open and active peritoneal drainages were used to successfully treat this case.     

A practical approach to hemoperitoneum in the dog and cat.

Hemoperitoneum can occur in animals of any age and can result from many different disease processes. Neoplastic and traumatic conditions are the most common causes. Many of these patients present with hemodynamic instability but stabilize with rational intravenous fluid therapy and abdominal counterpressure. Surgical exploration of the abdomen is indicated in many situations. Surgical therapy is aimed at resection or control of the bleeding focus, removal of any devitalized tissue, and biopsy of additional sites of suspicion. Optimal treatment for all patients with hemoperitoneum frequently requires advanced critical care, anesthesia, and surgical techniques. Finally, the treatment outcome is variable and dependent on the underlying cause and its severity.     

Early central andean metalworking from mina perdida, peru

Copper and gold artifacts in contexts dated to approximately 3120 to 3020 carbon-14 years before the present ( approximately 1410 to 1090 calendar years B.C.) recovered in excavations at Mina Perdida, Lurin Valley, Peru, show that artisans hammered native metals into thin foils, in some cases with intermediate anneals. They gilded copper artifacts by attaching gold foil. The artifacts show that fundamental elements of the Andean metallurgical tradition were developed before the Chavin horizon, and that on the Peruvian coast the working of native copper preceded the production of smelted copper objects.     

Magnetic microstructure of magnetotactic bacteria by electron holography

Off-axis electron holography in the transmission electron microscope was used to correlate the physical and magnetic microstructure of magnetite nanocrystals in magnetotactic bacteria. The magnetite crystals were all single magnetic domains, and the magnetization directions of small superparamagnetic crystals were constrained by magnetic interactions with larger crystals in the chains. Shape anisotropy was found to dominate magnetocrystalline anisotropy in elongated crystals. A coercive field between 300 and 450 oersted was determined for one chain.     

Appropriate experimental ecosystem warming methods by ecosystem, objective, and practicality

The temperature of the Earth is rising, and is highly likely to continue to do so for the foreseeable future. The study of the effects of sustained heating on the ecosystems of the world is necessary so that we might predict and respond to coming changes on both large and small spatial scales. To this end, ecosystem warming studies have been performed for more than 20 years using a variety of methods. These warming methods fall into two general categories: active and passive. Active warming methods include heat-resistance cables, infrared (IR) lamps and active field chambers. Passive warming methods include nighttime warming and passive field chambers. An extensive literature review was performed and all ecosystem warming study sites were compiled into a master list. These studies were divided by latitude and precipitation, as well as the method type used and response variables investigated. The goals of this study were to identify: (1) the most generally applicable, inexpensive and effective heating methods; and (2) areas of the world that are understudied or have been studied using only limited warming methods. It was found that the most generally applicable method, and the one that is most true to climate change predictions, is IR heating lamp installation. The least expensive method is passive chambers. The extreme lower and upper latitudes have been investigated least with ecosystem warming methods, and for the upper-mid-latitudes (60–80°) there have been limited studies published using methods other than passive chambers. Ecosystem warming method limitations and recommendations are discussed.     

ENSO drove 2500-year collapse of eastern Pacific coral reefs

Cores of coral reef frameworks along an upwelling gradient in Panamá show that reef ecosystems in the tropical eastern Pacific collapsed for 2500 years, representing as much as 40% of their history, beginning about 4000 years ago. The principal cause of this millennial-scale hiatus in reef growth was increased variability of the El Ni?o-Southern Oscillation (ENSO) and its coupling with the Intertropical Convergence Zone. The hiatus was a Pacific-wide phenomenon with an underlying climatology similar to probable scenarios for the next century. Global climate change is probably driving eastern Pacific reefs toward another regional collapse.     

Vertical Flux of Biogenic Carbon in the Ocean: Is There Food Web Control?

Models of biogenic carbon (BC) flux assume that short herbivorous food chains lead to high export, whereas complex microbial or omnivorous food webs lead to recycling and low export, and that export of BC from the euphotic zone equals new production (NP). In the Gulf of St. Lawrence, particulate organic carbon fluxes were similar during the spring phytoplankton bloom, when herbivory dominated, and during nonbloom conditions, when microbial and omnivorous food webs dominated. In contrast, NP was 1.2 to 161 times greater during the bloom than after it. Thus, neither food web structure nor NP can predict the magnitude or patterns of BC export, particularly on time scales over which the ocean is in nonequilibrium conditions.