Comparison of complication rates following elective arthroscopy performed as inpatient versus outpatient surgery in horses.

OBJECTIVE To report complication rates following elective arthroscopy in horses and determine whether postoperative complication rates are higher for outpatient procedures, compared with inpatient procedures. DESIGN Retrospective cohort study. ANIMALS 357 client-owned horses that had undergone 366 elective arthroscopic procedures between January 2008 and February 2015. PROCEDURES Medical records were retrospectively reviewed. Data collected included signalment, travel time to the hospital, clinical signs, joints treated, lesions diagnosed, medications administered, anesthesia and surgery times, details of the procedure (including closure method and surgeons involved), and hospitalization status (inpatient or outpatient). Inpatients were horses that remained hospitalized overnight, and outpatients were horses that were discharged in the afternoon of the day of surgery. The collected data were analyzed along with follow-up information to identify factors associated with postoperative complications and potentially associated with hospitalization status. RESULTS Data were collected on 366 elective arthroscopic procedures (outpatient, n = 168 [46%]; inpatient, 198 [54%]). Complications that occurred included bandage sores, catheter problems, colic, diarrhea, postoperative discomfort, esophageal impaction, fever, incisional drainage, postanesthetic myopathy, persistent synovitis, persistent lameness, septic arthritis, and osteochondral fragments not removed during the original surgery. None of these complications were associated with hospitalization status (outpatient vs inpatient). However, Standardbreds were overrepresented in the outpatient group, and anesthesia and surgery times were longer for the inpatient group. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that outpatient elective arthroscopy in healthy horses could be performed safely and without a higher risk of complications, com pared with similar procedures performed on an inpatient basis.

Effect of Cortical Screw Diameter on Reduction and Stabilization of Type III Distal Phalanx Fractures: An Equine Cadaveric Study.

OBJECTIVE: To compare reduction of type III distal phalangeal fractures using 4.5 and 5.5 mm cortical screws placed in lag fashion and an intact hoof capsule model. STUDY DESIGN: Cadaveric experimental study. SAMPLE POPULATION: Hooves from 12 adult horses (n=24). METHODS: Sagittal fractures were created in pairs of distal phalanges after distal interphalangeal joint disarticulation and were reduced with either 4.5 or 5.5 mm cortical screws placed in lag fashion. Contralateral phalanges served as non-reduced controls. Fracture reduction following screw placement was assessed by comparing pre-reduction and post-reduction fracture gap measurements from radiographs using paired t-tests. Effects of incremental loading (0, 135, 270, 540, 800, 1070, and 1335 kg) on fracture gaps in 6 phalanges reduced with 4.5 mm screws and 5 phalanges reduced with 5.5 mm screws were measured from fluoroscopic images and assessed by 2-way ANOVA. Significance was set at P<.05. RESULTS: Type III distal phalanx fractures were reliably created. Only 5.5 mm cortical screws, not 4.5 mm screws, significantly reduced fracture gaps and constrained fracture gap expansion 3 cm distal to the articular surface. Compressive loading closed the fracture gaps at the articular surface in both non-reduced control groups and those reduced with either 5.5 or 4.5 mm screws. CONCLUSION: The 5.5 mm cortical screws were more effective than 4.5 mm screws in reducing type III distal phalanx fractures and restricting distal fracture gap expansion under load.

Characterizing the performance of XOR games and the Shannon capacity of graphs.

In this Letter we give a set of necessary and sufficient conditions such that quantum players of a two-party XOR game cannot perform any better than classical players. With any such game, we associate a graph and examine its zero-error communication capacity. This allows us to specify a broad new class of graphs for which the Shannon capacity can be calculated. The conditions also enable the parametrization of new families of games that have no quantum advantage for arbitrary input probability distributions, up to certain symmetries. In the future, these might be used in information-theoretic studies on reproducing the set of quantum nonlocal correlations.

Using separable Bell-diagonal states to distribute entanglement.

One of the many bizarre features of entanglement is that Alice, by sending a qubit to Bob in a separable state, can generate some entanglement between herself and Bob. This protocol is stripped down to the bare essentials to better elucidate the key properties of the initial resource state that enable this entanglement distribution. The necessary and sufficient conditions under which the correlations of a Bell-diagonal state serve as a useful resource are proven, giving upper and lower bounds on the entanglement that can be distributed when those conditions are met.

Turing, ciphers and quanta.

Alan Turing has certainly contributed to a widespread belief that the quest for a perfect, unbreakable, cipher is a futile pursuit. The ancient art of concealing information has, in the past, been matched by the ingenuity of code-breakers, but no longer! With the advent of quantum cryptography, the hopes of would-be eavesdroppers have been dashed, perhaps for good. Moreover, recent research, building on schemes that were invented decades ago to perform quantum cryptography, shows that secure communication certified by a sufficient violation of a Bell inequality makes a seemingly insane scenario possible-devices of unknown or dubious provenance, even those that are manufactured by our enemies, can be safely used for secure communication, including key distribution. All that is needed to implement this bizarre and powerful form of cryptography is a loophole-free test of a Bell inequality, which is on the cusp of technological feasibility. We provide a brief overview of the intriguing connections between Bell inequalities and cryptography and describe how studies of quantum entanglement and the foundations of quantum theory influence the way we may protect information in the future.

Osteomyelitis of the patella in eight foals.

OBJECTIVE: To describe the characteristics of osteomyelitis lesions of the patella and to report short- and long-term outcome after treatment in 8 foals. STUDY DESIGN: Retrospective case series. ANIMALS: Foals (n = 8). METHODS: Medical records (2003-2007) and radiographs of foals that had osteomyelitis of the patella were reviewed. Inclusion criteria included clinical, radiographic, and surgical findings consistent with osteomyelitis of the patella, and a long-term follow-up of >15 months. Information acquired included signalment, hematologic and serum biochemical profile results, clinical and radiographic signs, surgical technique and perioperative treatment. Follow-up radiographs were evaluated and outcome was determined from veterinary examination, race records, and telephone questionnaire. RESULTS: Six foals survived long term (15 months-4 years); all had intralesional and systemic antimicrobial therapy, along with synovial lavage and antimicrobial medication. All were sound and achieved either yearling sales (n=3), show hunter or racing (2). Two foals died in the short term from renal failure and suppurative peritonitis secondary to cecal perforation, 1 remaining lame with suppurative osteonecrosis confirmed at necropsy. This foal was not administered intralesional antimicrobial therapy. CONCLUSIONS: Prompt medical and surgical therapy for osteomyelitis of the patella can result in a good prognosis for soundness and a potential athletic career. Concurrent septicemia or other systemic perinatal disease can result in prolonged therapy and delayed recovery.

Effects of reduced measurement independence on Bell-based randomness expansion.

With the advent of quantum information, the violation of a Bell inequality is used to witness the absence of an eavesdropper in cryptographic scenarios such as key distribution and randomness expansion. One of the key assumptions of Bell's theorem is the existence of experimental "free will," meaning that measurement settings can be chosen at random and independently by each party. The relaxation of this assumption potentially shifts the balance of power towards an eavesdropper. We consider a no-signaling model with reduced "free will" and bound the adversary's capabilities in the task of randomness expansion.

Perfect quantum routing in regular spin networks.

Motivated by the need for quantum computers to communicate between multiple, well separated qubits, we introduce the task of quantum routing for distributing quantum states, and generating entanglement, between these sites. We describe regular families of coupled quantum networks which perfectly route qubits between arbitrary pairs of nodes with a high transmission rate. The ability to route multiple states simultaneously and the regularity of the networks vastly improve the utility of this scheme in comparison to the task of state transfer, leading us to propose an implementation in optical lattices.

Capabilities of a perturbed toric code as a quantum memory.

We analyze the effect of typical, unknown perturbations on the 2D toric code when acting as a quantum memory, incorporating the effects of error correction on readout. By transforming the system into a 1D transverse Ising model undergoing an instantaneous quench, and making extensive use of Lieb-Robinson bounds, we prove that for a large class of perturbations, the survival time of stored information grows at least logarithmically with the system size. A uniform magnetic field saturates this scaling behavior. We show that randomizing the stabilizer strengths gives a polynomial survival time with a degree that depends on the strength of the perturbation.

Optimal cloning and singlet monogamy.

The inability to produce two perfect copies of an unknown state is inherently linked with the inability to produce maximal entanglement between multiple spins. Despite this, there is no quantitative link between how much entanglement can be generated between spins, and how well an unknown state can be cloned. This situation is remedied by giving a set of sufficient conditions such that a Completely Positive map can be optimally implemented as a teleportation operation into a standard, reference, state. The case of arbitrary 1-->N asymmetric cloning of d-dimensional spins can then be solved exactly, yielding the concept of "singlet monogamy." The utility of this relation is demonstrated by calculating properties of Heisenberg systems, and contrasting them with the results from standard monogamy arguments.

How long can a quantum memory withstand depolarizing noise?

We investigate the possibilities and limitations of passive Hamiltonian protection of a quantum memory against depolarizing noise. Without protection, the lifetime of a single qubit is independent of N, the number of qubits composing the memory. In the presence of a protecting Hamiltonian, the lifetime increases at most logarithmically with N. We construct an explicit time-independent Hamiltonian which saturates this bound, exploiting the noise itself to achieve the protection.

Nonequilibrium reliability of quantum memories.

The ability to store quantum information without recourse to constant feedback processes would yield a significant advantage for future implementations of quantum information processing. In this Letter, limitations of the prototypical model, the Toric code in two dimensions, are elucidated along with a sufficient condition for overcoming these limitations. Specifically, the interplay between Hamiltonian perturbations and dynamically occurring noise is considered as a system in its ground state is brought into contact with a thermal reservoir. This proves that when utilizing the Toric code on N2 qubits in a 2D lattice as a quantum memory, the information cannot be stored for a time O(N). In contrast, the 2D Ising model protects classical information against the described noise model for exponentially long times. The results also have implications for the robustness of braiding operations in topological quantum computation.

Anti-inflammatory and analgesic effects of intra-articular injection of triamcinolone acetonide, mepivacaine hydrochloride, or both on lipopolysaccharide-induced lameness in horses.

OBJECTIVE: To assess analgesia, inflammation, potency, and duration of action associated with intra-articular injection of triamcinolone acetonide (TA), mepivacaine hydrochloride, or both in metacarpophalangeal (MCP) joints of horses with experimentally induced acute synovitis. ANIMALS: 18 horses. PROCEDURES: Both forelimbs of each horse were injected with lipopolysaccharide (LPS) 3 times. After the first LPS injection, 1 forelimb of each horse was treated with intra-articular injection of mepivacaine (80 mg; n=6), TA (9 mg; 6), or mepivacaine with TA (same doses of each; 6) 12 hours after the initial LPS injection. Contralateral limbs served as control limbs. Joint pain was assessed via lameness score and measurements of vertical force peak and pain-free range of motion of the MCP joint. Periarticular edema was evaluated. Degree of synovial inflammation was determined via synovial fluid analysis for WBC count and total protein concentration. Samples of plasma and synovial fluid were analyzed for TA and mepivacaine concentrations. RESULTS: Each injection of LPS induced lameness and joint inflammation. Mepivacaine effectively eliminated lameness within 45 minutes after injection, regardless of whether TA was also administered, whereas TA reduced lameness, edema, and concentration of synovial fluid protein after the second LPS injection, regardless of whether mepivacaine was also injected. Treatment with TA also induced higher WBC counts and mepivacaine concentrations in synovial fluid, compared with results for mepivacaine alone. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested TA is a potent analgesic and anti-inflammatory medication for acute synovitis in horses and that simultaneous administration of mepivacaine does not alter the potency or duration of action of TA.

Surgical technique to repair grade IV rectal tears in post-parturient mares.

OBJECTIVE: To describe a surgical technique for repair of grade IV rectal tears after parturition in mares and to report outcome. STUDY DESIGN: Clinical report. ANIMALS: Horses (n=6) with grade IV rectal tears. METHODS: Mares were sedated and restrained in standing stocks. After caudal anesthesia and evacuation of feces from the rectum, the perineal region was aseptically prepared. Four stay sutures were placed through the external anal sphincter before vertical transection (12 o'clock). Caudal retraction of the tear was performed using Allis tissue forceps (5 mares) or stay sutures before accurate apposition of the tear margins with steel staples below the tissue forceps. The mucosal edges were then sharply dissected leaving approximately 5 mm edges which were apposed in a single layer (2-0 poliglecaprone 25) before stapler release. In 1 mare, the rectal tear was identified and apposed using a 2-layer hand-sutured closure. Systemic antibiotics and anti-inflammatory agents were administered postoperatively (5 mares) and standing abdominal lavage performed (3 mares). RESULTS: Four mares survived long term and subsequently became pregnant. Immediately after surgical repair, 1 mare was anesthetized for exploratory celiotomy and abdominal lavage but fractured her pelvis during recovery from anesthesia and was euthanatized. A 2nd mare was euthanatized after 72 h because of severe diffuse peritonitis; however, the repair was still intact. CONCLUSION: In standing mares, rectal tears can be exteriorized by prolapse through the anal sphincter after sphincterotomy and repaired in 2 layers with staples oversewn with a continuous suture pattern. CLINICAL RELEVANCE: Rectal tears occurring as a result of parturition can potentially be repaired efficiently using an oversewn stapled primary closure technique.

Unifying quantum state transfer and state amplification.

We present a Hamiltonian that can be used for amplifying the signal from a quantum state, enabling the measurement of a macroscopic observable to determine the state of a single spin. We prove a general mapping between this Hamiltonian and an exchange Hamiltonian for arbitrary coupling strengths and local magnetic fields. This facilitates the use of existing schemes for perfect state transfer to give perfect amplification. We further prove a link between the evolution of this fixed Hamiltonian and classical cellular automata, thereby unifying previous approaches to this amplification task. Finally, we show how to use the new Hamiltonian for perfect state transfer in the scenario where total spin is not conserved during the evolution, and demonstrate that this yields a significantly different response in the presence of decoherence.